.‘i . \ a 2.. mid ,_v 4 L' Lin 3355" w - Jami} ‘3' - “In-t . Wit .J-J; a.» .. if a £2 4 $31113: . 2m. 4,; - 4.2 ’ “'M-‘_. . -. '.—. _- h-'f "' _ 0.05. The LSD was used to compare differences of mean numbers among the different treatments. All data were analyzed using MSTAT [1993]. Table 1. Particle size analysis of root zones mixes and topdressing sand. Description Gravel Very Coarse Coarse Medium Fine Very Fine Silt & Clay Diameter (nun) >2.0 2.0-1.0 1.0-0.5 0.5—0.25 0.25-0.1 0.1-0.05 <0.05 Mixture Percentage of each diameter size retained on each sieve (by weight) 80:20 0.2 4.8 34.6 46.7 12.2 0.9 0.6 80:10:10 1.9 6.8 31.1 40.4 16.6 1.9 1.3 Topdress 0.0 2.8 30.6 48.4 17.3 0.6 0.3 Table 2. Annual rates of nutrients applied to the destructive sampling area for the analysis of soil physical properties. kg ha" Nitrogen P205 K20 1996 170 49 98 1997 170 0 98 1998 170 98 0 1999 146 98 0 2000 146 0 122 50 1:] Cumulative 45 IAnnual amount 40 35 30 25 20 1 5 10 1995 1996 1997 1998 1999 2000 Year Figure 1. Accumulation of sand topdressing layer on Agrostis palustris Huds. greens annually measured in October, East Lansing, MI. 10 RESULTS AND DISCUSSION Organic Matter Content The organic matter content (OMC) in the three different root zones is reported in Tables 3-5. Data fi'om 1999 was discarded due to apparent erroneous results. In Table 3 the OMC in the sand topdressing layer (STL) is given. Since the STL is the same soil texture in all root zones no differences were anticipated and no significant differences occurred. The 0-7.6cm depth below the STL soil interface is reported in Table 4. Within that depth the native root zone had significantly more OMC than the other two root zones in 1998. The other two years the data was not statistically significant. The OMC in the 7.6-15.2 cm depth (Table 5) had similar results to that of the 0- 7.6cm depth with 1998 the only year resulting in significantly more OMC in the native root zone. Since the native soil root zone was undisturbed (located where it had vegetative cover previous to green construction) and the other two root zones were transported in, it is reasonable the native soil root zone would have a higher OMC below the STL. OMC was fiirther analyzed split for time. Data analyzed in this manner are presented in Table 6. Again, no significant differences were observed in OMC in the STL among the root zones and the native root zone had more OMC in the 0-7.6cm depth than the 80:20 root zone. There were no significant differences between the 80:20 and 80: 10: 10 root zones. Furthermore, the OMC increased with time in the STL with no significant data or trends resulting in the other two depths. Foth [1990] states soil organic matter can decompose in mineral soils at a rate of up to 4% per year. However, over time plant residues are expected to maintain OMC at a ll new equilibrium. Below the STL none of the root zones significantly changed over the four-year period. Other research monitoring OMC over time in predominantly sand based greens report mixed results with increases, decreases, and no significant change several years after establishment [Baker et al., 1999, Werner, 1995, Landry et. al., 2001, Gibbs et al., 2001]. Table 3. Main effects and mean squares for treatment effects of root zone on percentage organic matter in the topdress layer 1997, 1998, and 2000. Percentage organic matter Root zone Oct. 1997 Oct. 1998 Oct. 2000 80:20 2.70 2.98 3.28 80:10:10 2.94 2.95 3.61 Native 3.24 3.32 3.91 Significance NS NS NS Source df Mean square Replication 2 0340* 0.088 0.020 Soils 2 0.217 0.125 0.295 Error 4 0.035 0.061 0.166 * Significant at the 0.05 probability level. 1' NS, nonsignificant at the 0.05 level. Table 4. Main effects and mean squares for treatment effects of root zone on percentage organic matter 0-7.6cm below the topdressing soil interface 1997, 1998, and 2000. Percentage organic matter Root zone Oct. 1997 Oct. 1998 Oct. 2000 80:20 1.59 1.56b 1.61 80:10:10 1.91 1.78b 2.20 Native 2.45 2.4% 2.60 Significance NS ** NS Source df Mean square Replication 2 0.120 0.122 0.375 Soils 2 0.858 0.703" 0.744 Error 4 0.174 0.026 0.163 ** Significant at the 0.01 probability level. 1' NS, nonsignificant at the 0.05 level. 12 Table 5. Main efl‘ects and mean squares for treatment effects of root zone on percentage organic matter 7.6-15.2 cm below the topdressing soil interface 1997, 1998, and 2000. Percentage organic matter Root zone Oct. 1997 Oct. 1998 Oct. 2000 80:20 1.09 1.15b 1.18 80:10:10 1.34 1.50b 1.55 Native 2.12 2.31a 2.22 Significance NS * NS Source df Mean square Replication 2 0.024 0.065 0.35 l Soils 2 0.559 1062* 0.830 Error 4 0.144 0.107 0.160 *, ** Significant at the 0.05 and 0.001 probability levels, respectively. 1‘ NS, nonsignificant at the 0.05 level. Table 6. Main effects and mean squares for treatment effects of root zone split for time on percentage organic matter at three depths 1997, 1998, and 2000. Percentage organic matter by depth Root zone Sand topdressing 0-7 .6 cm 7 .6-15.2cm 80:20 2.99 1.59b 1.14 80:10:10 3.17 1.96ab 1.46 Native 3.49 2.51a 2.22 _§gnificance NS * NS Year 1997 2.96b 2.05 1.55 1998 3.08b 1.88 1.62 2000 3.60a 2.14 1.65 Si ' cance ** NS NS Source df Replication 0.047 0.298 0.401 Soils 0.579 1920* 2.713 Error 0.172 0.296 0.451 Year 1.033" 0.085 0.031 Soils x Year 0.029 0.040 0.005 Error 0.097 0.078 0.026 *, ** Significant at the 0.05 and 0.001 probability levels, respectively. '1‘ NS, nonsignificant at the 0.05 level. Nitrogen Total soil nitrogen is mainly comprised of organic compounds that occur as consolidated amino acids or proteins, free amino acids, amino sugars, and other complex, generally unidentified compounds [Tisdale et al, 1985]. Total-N in the three different root zones is reported in Tables 7-9. Total-N in the STL layer is significantly different 13 for the root zones in 1998 (Table 7). The native soil had significantly greater total-N than the other two root zones in this surface layer. In Table 8 total-N in the 0-7.6cm depth below the STL layer is reported. Within that depth the native soil had significantly more total-N three of the four years compared to the 80:20 root zone and also had significantly greater total-N than the 80: 10:10 mix two of the years. Total N in the 7.6-15.2 cm below the topdressing soil interface was always significantly greater in the native soil than the other two root zones (Table 8). No statistical differences resulted between either of the predominantly sandy root zones at any depth. Total nitrogen concentrations in the top 0.3m of cultivated soils in the United States normally vary between 0.03 and 0.4% [Tisdale et al, 198 5]. The native root zone was consistently within this range. The 80:20 fell slightly below it in 1998 and 2000 at depths below the STL and the 80: 10: 10 fell below it in 1998 in the 0-7.6cm depth. Table 7. Main effects and mean squares for treatment effects of root zone on percentage total nitrogen in the topdress layer 1997-2000. Percentage total nitrogen Root zone Oct. 1997 Oct. 1998 Oct. 1999 Oct. 2000 80:20 0.12 0.05b 0.08 0.11 80:10:10 0.11 0.05b 0.09 0.11 Native 0.12 0.10a 0.12 0.13 Significance NS * NS NS Source df Mean square Replication 2 0.001 0.000 0.000 0.001 Soils 2 0.000 0002* 0.001 0.000 Error 4 0.001 0.0003 0.0003 0.001 * Significant at the 0.05 probability level. ’r NS, nonsignificant at the 0.05 level. 14 Table 8. Main effects and mean squares for treatment effects of root zone on percentage total nitrogen 0-7.6cm below the tgpdressing soil interface 1997-2000. Percentage total nitrogen Root zone Oct. 1997 Oct. 1998 Oct. 1999 Oct. 2000 80:20 0.04b 0.02b 0.04 0.01b 80: 10: 10 0.06b 0.02b 0.05 0.04ab Native 0.11a 0.11a 0.07 0.09a Significance * * NS " Source df Mean square Replication 2 0.000 0.001 0.004 0.001 Soils 2 0.004" 0009* 0.001 0.006 Error 4 0.0003 0.001 0.001 0.001 ** Significant at the 0.01 probability level. 1' NS, nonsignificant at the 0.05 level. Table 9. Main effects and mean squares for treatment effects of root zone on percentage total nitrogen 7.6-15.2 cm below the topdressing soil interface 1997-2000. Percentage total nitrogen Root zone Oct. 1997 Oct. 1998 Oct. 1999 Oct. 2000 80:20 0.03b 0.01b 0.05b 0.001b 80:10:10 0.04b 0.03b 0.05b 0.00% Native 0.09a 0.1 1a 0.11a 0.088a Significance at: u an: at Source df Mean square Replication 2 0.000 0.000 0.001 0.001 Soils 2 0003* 0.007" 0.003“ 0.007"I Error 4 0.0005 0.0003 0.0001 0.001 *, ** Significant at the 0.05 and 0.01 probability levels, respectively. 1 NS, nonsignificant at the 0.05 level. About 90% of soil N is unavailable in organic matter with most of the remainder fixed as ammonium in clays and at any one instant about 1% or less of the total-N in soils is available to plants as nitrate or exchangeable ammonium [F oth and Ellis, 1997]. In 1999 and 2000 inorganic forms of nitrogen in the root zones were analyzed and are reported in Tables 10 and 11, respectively. No significant differences occurred in the STL. In 1999 significantly more N03-N was in the 0-7.6 cm depth in the native soil than in the 80: 10:10 root zone with no difference between the 80: 10: 10 and the 80:20. In 2000 there was more NH4-N at this depth in the native soil than in the sandy root zones. 15 In the 7.6-15.2 cm depth there was significantly more NH4-N in the native soil than the other two root zones during both years. The only significant difference between the 80:20 and 80: 10: 10 regarding inorganic nitrogen pools was that 80: 10: 10 held significantly more NH4-N than the 80:20 root zone in the 7.6-15.2 cm depth in 2000. Nitrate-N and NH4-N decreased with depth in the 80:20 root zone and increased with depth in the native soil, for both years of data collection. Certainly soil nitrogen is dynamic in a relatively short period of time and data reported here only reflects a snapshot in time. Therefore, it would be erroneous to make strong conclusions regarding NO3-N in the 80:20 root zone, but similarly it would be shortsighted to ignore that nitrates did not increase with depth in the 80:20 root zone. Rieke and Ellis [1973] researched N leaching in a sand texture and concluded when judicious nitrogen rates are applied the potential for appreciable leaching of NO3-N would be limited under most turfgrass conditions. Additionally, Brown et al [1982] reported methylene urea resulted in less NO3-N leaching than four other nitrogen fertilizers in their study on USGA-type profiles and that ammonium losses contributed very little to N losses from golf greens. Though not always significant, a trend is evident that ammonium nitrogen in the 80:20 < 80:10: 10 < native root zone below the STL. This would be expected due to the cationic nature of NH4-N allowing it to be adsorbed and retained by soil colloids [Tisdale et al., 1985]. 16 Table 10. Main effects and mean squares for treatment efl‘ects of root zone on inorganic forms of nitrogen at various depths (October 1999). Inorganic N forms at three depths in ppm Topdress layer 0-7.6cm depth 7.6-15.2cm depth Root zone N03 NH4 N03 NH4 N03 NH4 80:20 0.47 8.35 0.25ab 5.81 0.14 3.82b 80: 10: 10 0.72 10.42 0.04b 6.25 0.40 6.96b Native 0.72 15.04 0.74a 14.01 0.79 16.70a Significance NS NS * NS NS ** Source df Mean squares Replication 2 0.698 14.22 0.147 8.12 0.010 5.94 Soils 2 0.063 35.25 0382* 63.78 0.32 135.36" Error 4 0.091 8.64 0.051 11.76 0.21 4.41 *, ** Significant at the 0.05 and 0.01 probability levels, respectively. 1‘ NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). Table 11. Main effects and mean squares for treatment effects of root zone on inorganic forms of nitrogen at various depths (October 2000). Inorganic N forms at three depths in ppm Topdress layer 0-7.6 cm depth 7.6-15.2 cm depth Root zone N03 NH4 N03 NH4 N03 NIL 80:20 0.59 11.42 0.39 4.87b 0.32b 3.23c 80:10: 10 0.45 9.28 0.44 10.28b 0.48ab 8.21b Native 0.52 9.94 0.56 21.86a 0.74a 16.18a Significance NS NS NS "' * *** Source df Mean squares Replication 2 0.03 9.73 0.03 26.64 0.03 3.05 Soils 2 0.01 3.63 0.02 22599“ 0.13“ 127.89*** Error 4 0.02 8.74 0.02 22.21 0.02 0.82 *, *** Significant at the 0.05 and 0.001 probability levels, respectively. 1 NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). Saturated Hydraulic Conductivity Saturated hydraulic conductivity, bulk density, and soil porosities were collected from non-rolled and rolled plots and were analyzed as a two-factor study (root zone split by rolling). In Table 12 the saturated hydraulic conductivity (Km) of the root zones is reported. As is often the case with field samples taken to the lab for hydraulic conductivity, there was a high degree of variability in the data. For all seven dates the 17 80:20 mix had significantly faster conductivity rates than the native root zone and was significantly faster than the 80: 10:10 root zone on six of those seven dates. The last five of the seven dates there were no significant differences between the 80:10: 10 and the native root zones. Plots rolled three times per week always resulted in averaged conductivity rates lower than non-rolled plots however; none of the data was statistically significant. Bulk Density Soil bulk density measurements revealed relatively small differences among the three different root zones (Table 13). Coarse-textured surface soils are expected to have higher bulk densities than finer-textured soils due to the greater development of structure in the fine-textured soils [Foth, 1990]. Possibly due to the destruction of structure and compaction by machinery during construction the predominantly sandy 80:20 root zone had a significantly lower bulk density than the native root zone on 5 of the 7 sampling dates. Lightweight rolling resulted in no significant differences regarding soil bulk density in any of the root zones. Nikolai et a1. [2001] reported similar results on greens rolled three times per week but that data was fi'om one year. 18 Table 12. Main effects and mean squares for treatment effects of root zone and rolling on saturated conductivity 1997-2000. Saturated conductivity, cm hr‘l Root zone Oct. 97 June 98 Oct. 98 June 99 Oct. 99 June 00 Oct. 00 80:20 15.5a 29.9a 21.3a 17.2a 12.3a 15.1a 29.7a 80: 10:10 8.6b 13.4b 8.3b 7.2b 4.2b 5.2b 8.2ab Native 3.4c 5.3c 0.6b 0.6b 1.6b 1.6b 1.4b Significance *** *9! IN! I! it 1|! * Rolling Rolled 6.7 14.4 5.8 7.1 4.7 4.0 9.5 Not Rolled 11.7 17.9 14.3 9.6 7.4 10.6 16.7 Significance NS1 NS Ns NS NS NS NS Source df Mean square Replication 2 86.3 18.7 92.8 100.3 32.9 53.9 457.4 Soils 2 223.5*** 948.5" 663.4" 417.3* 1900* 294.1* 1310.6* Error 4 3.7 24.4 34.5 31.9 22.7 29.6 185.9 Rolling 1 114.0 56.9 329.4 28.6 32.3 194.0 229.0 Soil X Rolling 2 4.3 2.2 141.9 8.5 17.1 50.0 122.2 Error 6 88.2 23.6 86.6 49.6 17.7 34.8 91.2 *, **, *** Significant at the 0.05 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. Table 13. Main effects and mean squares for treatment effects of root zone and rolling on soil bulk density 1997-2000. Soil bulk density, g cc" Root zone Oct. 97 June 98 Oct. 98 June 99 Oct. 99 June 00 Oct. 00 80:20 1.5b 1.5b 1.55b 1.5b 1.5 1.5 1.42b 80:10:10 1.5b 1.5b 1.58ab 1.5b 1.5 1.5 1.47ab Native 1.63 1.63 1.67a 1.6a 1.6 1.5 1.553 Significance * * * * NS NS * Rolling Rolled 1.6 1.5 1.60 1.5 1.5 1.5 1.48 Not Rolled 1.5 1.5 1.60 1.5 1.5 1.5 1.48 Significance NST NS NS Ns NS NS NS Source df Mean square Replication 2 0.007 0.002 0.007 0.004 0.004 0.002 0.017 Soils 2 0041* 0020* 0022* 0.017* 0.024 0.011 0.027 * Error 4 0.005 0.002 0.003 0.001 0.006 0.008 0.003 Rolling 1 0.002 0.000 0.000 0.001 0.005 0.009 0.000 Soil X Rolling 2 0.001 0.000 0.002 0.004 0.002 0.001 0.002 Error 6 0.001 0.002 0.001 0.001 0.001 0.002 0.001 *Significant at the 0.05 probability level. 1 NS, nonsignificant at the 0.05 level. Porosity Capillary, air-filled and total porosities are reported in Tables 14-16, respectively. On 6 of the 7 sampling dates capillary porosity was significantly lower for the 80:20 root l9 zone than the other two root zones with no significant differences between the 80: 10: 10 and the native root zones (Table 14). Lightweight rolling had no statistically significant effect on capillary porosity though on all dates capillary porosity was higher on plots rolled three times per week. The 80:20 root zone had significantly higher air-filled porosities than the other two root zones on all sampling dates (Table 15). The 80: 10: 10 root zone was significantly higher than the native root zone on the first three dates but no significant differences resulted between the two root zones for the last four dates. Lightweight rolling resulted in significant reduction in air-filled porosity on the final three of seven sampling dates. No soils by rolling interactions were significant. Total porosity is reported in Table 16. Only three of the dates resulted in significant differences with the native root zone always resulting in less total porosity than the 80:20 mix. On three of the seven sampling dates total porosity was significantly lower on rolled plots Table 14. Main effects and mean squares for treatment effects of root zone and rolling on capillary porosity at 40 cm 1997-2000. Capillary porosity at 40 cm tension Root zone Oct. 97 June 98 Oct. 98 June 99 Oct. 99 June 00 Oct. 00 80:20 25.2 27 .9b 24.5b 26.4b 24.0b 24.5b 25.4b 80: 10: 10 30.0 33.4a 30.53 33.1a 31.1a 31.3a 33. la Native 33.0 33% 32.3a 34.1a 33.6a 33.8a 32.7a Si ' cance NS “I I”! it INK *4! *4! Rolling Rolled 30.0 32.3 30.1 31.8 30.4 30.6 31.4 Not Rolled 28.7 31.3 28.2 30.6 28.7 29.1 29.3 Sifl'ficance NS NS NS NS NS NS NS Source df Mean square Replication 2 40.42 21.43 24.20 3844* 4001* 35.28 3556* Soils 2 93.13 67.05** 99.99" 106.92" 149.69“ 139.91” 113.43" Error 4 19.29 4.55 4.60 5.39 5.87 5.72 5.18 Rolling 1 7.48 4.70 16.06 7.60 12.67 9.68 19.84 Soil X Rolling 2 14.58 14.36 13.58 7.80 22.46 16.95 19.42 Error 6 6.60 9.95 7.45 10.23 6.61 5.12 6.45 *Significant at the 0.05 probability level. 1 NS, nonsignificant at the 0.05 level. 20 Table 15. Main effects and mean squares for treatment effects of root zone and rolling on air-filled porosity at 40 cm tension 1997-2000. Air-filled porosity at 40 cm tension Root zone Oct. 97 June 98 Oct. 98 June 99 Oct. 99 June 00 Oct. 00 80:20 22.43 17.53 17.43 18.3a 20.33 19.03 19.2a 80: 10: 10 15.7b 10.6b 10.8b 11.3b 12. lb 12.3b 11.2b Native 10.0c 7.1c 7.0c 8.5b 9.9b 9.6b 12.7b Si ’ canoe flit Illtlll ** *It fit #11! *III Rolling Rolled 14.5 9.4 10.4 11.6 12.3 12.1 13.1 Not Rolled 17.6 11.3 13.1 13.9 15.9 15.2 15.6 Significance NS NS NS NS ** * * Source df Mean square Replication 2 36.97 11.32 14.47 20.74 25.01 2953* 16.86 Soils 2 234.20 183.52*** 164.28" 153.30“ 180.88“ 138.94" 107.55“ Error 4 12.39 2.91 5.40 5.27 11.41 3.31 6.34 Rolling 1 43.24 16.82 32.00 24.73 58.68" 44. 18* 2812* Soil X Rolling 2 9.31 10.62 10.63 5.25 11.68 10.94 4.08 Error 6 9.47 7.86 7.57 9.78 2.83 4.62 4.66 *Significant at the 0.05 probability level. T NS, nonsignificant at the 0.05 level. Table 16. Main effects and mean squares for treatment effects of root zone and rolling on total porosity 1997-2000. Total porosity Root zone Oct. 97 June 98 Oct. 98 June 99 Oct. 99 June 00 Oct. 00 80:20 47.73 45.43 41.9 44.73 44.3 43.4 44.5 80: 10: 10 45.8b 44.lab 41.3 44.33 43.3 43.5 44.3 Native 42.9c 41. lb 39.3 42.6b 43.5 43.4 45.4 Si ' canoe ** * NS * NS NS NS Rolling Rolled 44.6 42.9 40.5 43.4 42.7 42.6 44.5 Not Rolled 46.3 44.2 41.2 44.5 44.7 44.3 45.0 Significance NS NS * NS * * NS Source df Mean square Replication 2 1.24 5.17 6.20 3.84 4.79 3.63 9.62 Soils 2 35.42" 2969* 10.56 7.53* 1.74 0.03 1.97 Error 4 1.14 4.28 1.69 1.14 6.11 5.59 6.95 Rolling 1 12.84 7.35 2.42* 4.91 17.01* 1267* 0.89 Soil X Rolling 2 2.35 1.38 0.76 0.66 6.33 1.03 607* Error 6 2.84 3.71 0.33 1.64 1.60 1.32 0.80 *Significant at the 0.05 probability level. 1 NS, nonsignificant at the 0.05 level. 21 CONCLUSIONS A problem associated with sand based greens is difficulty in managing the accumulation of organic matter in the surface layer [Gibbs et al., 2001]. There were no significant differences among the root zones in accumulation of organic matter in the STL and data pooled among root zones resulted in OMC significantly increasing in the STL over time. There were no root zones x time interactions. In the 0-7.6cm depth the native root zone had a significantly greater OMC than the 80:20 root zone. However, the OMC did not significantly increase in that depth over time. In all years and depths total-N was greater in the native root zone than the 80:20 root zone with no significant differences occurring between the predominantly sandy root zones. Nitrate-N decreased with depth in the 80:20 root zone. This decrease supports the notion that judicious rates of slow release nitrogen sources are not necessarily leached from sandy profiles. The 80: 10: 10 root zone did not result in greater total-N or NO3-N in the soil and on only one occasion did it have greater retention of NH4-N. The 80:20 root zone had significantly higher saturated hydraulic conductivity rates than the 80: 10: 10 root zone on all but one date and it was consistently higher than the native root zone on all dates. There were no significant differences between the 80: 10: 10 and the native root zone during the last five sampling dates. No significant differences resulted between the 80:10: 10 and the native root zones in respect to capillary porosity. The 80:20 root zone had lower capillary porosity on the final six of seven sampling dates. In regards to air-filled porosity, the first three sampling dates resulted an inverse relationship between the amount of fines and the amount pore space. The final four 22 sampling dates there were no significant difi‘erences between the 80: 10: 10 and the native root zone and the 80:20 root zone always had higher air-filled porosity. Though there is no statistically significant data it is noteworthy the practice of sand topdressing may have had an effect on diminishing significant differences of saturated hydraulic conductivity and air-filled porosity between the 80: 10: 10 and the native root zones. Lightweight green rolling three times per week resulted in no significant differences in bulk density, capillary porosity, or saturated hydraulic conductivity. Significant differences included air-filled porosity reduction on the last three sampling dates and reduced total porosity on 3 of seven sampling dates. It is noteworthy that while there were no increases in bulk density associated with rolling, all plots were on a light, frequent sand topdressing program. Had greens not been on a sand topdressing program increases in bulk density may have resulted 23 REFERENCES Anonymous. 1994. Expensive sand greens not necessary, argues proponent of new system. Turf Management. August p.3. Arthur, J. 1994. Who needs performance standards? Turf Management. May p. 11. Baker, S. W., S. J. Mooney, and A. Cook. 1999. The effects of sand type and rootzone amendments on golf green performance. 1. Soil properties. J. of Turfgrass. Science. 7522-17. Beard, J. 1994. In search of the ultimate putting green. Greenkeeper Int. December222- 25. Bremner, J. M. 1965. Total nitrogen. p.1149-1178. In C. A. Black et al. (ed.) Methods of soil analysis. Part 2. Agron. Monogr. 9. ASA, Madison, WI. Brown, K. W., J. C. Thomas, and R. L. Duble. 1982. Nitrogen source effect on nitrate and ammonium leaching and runoff losses from greens. Agronomy Journal 74(6):947-950. Bundy, L. G. and J. J. Meisinger. 1994. p. 951-984. In J. M. Bigham et al. (ed) Methods of soil analysis. Part 2. Agron. Monogr. ASA, Madison, WI. Combs, S. M. and M. V. Nathan. 1998. Soil organic matter. P.53-58. In B. Ellis et 31. Recommended chemical soil test procedures for the north central region. Missouri Agri. Expe. Sta. Columbia, MO. Foth H. D. and B. G. Ellis. 1997. Soil Fertility 2nd Ed. Lewis Publishers Boca Raton, FL. F oth H. D. 1990. Fundamentals of soil science 8th Ed. John Wiley & Sons. New York. Garman, W. L. 1952. Permeability of various grades of sand and peat and mixtures of these with soil and vermiculite. USGA J. Turf Manag. 6(1):27-28. Gibbs, R. J ., C. Liu, M.-H. Yang, and MP. Wrigley. 2001. Effect of rootzone composition and cultivation/aeration treatment on the physical and root growth performance of golf greens under New Zealand conditions. Int. Turfgrass Soc. Res. J. 92506-517. Grifiin, H. M. 1966. Recipe for good greens. USGA Green Section Record. 3(5): 1-2. Hardy, J. A. 1999. Factors affecting creeping bentgrass quality of three different putting green construction methods. MS. Thesis. Michigan State University. 24 Hartwiger, C. 1996. The ups and downs of rolling putting greens. USGA Green Section Record 34(4): 1-4. Hutchinson, H. G. 1906. Golf greens and green-keeping. Country Life Ltd. & George Newnes, Ltd. London. Hummel, N. W. 1993. Rationale for the revisions of the USGA green construction specifications. USGA Green Section Record. March/April: 7-21. Hummel, N. W. 1993. Laboratory methods for evaluation of putting green root zone mixes. USGA Green Section Record. March/April: 23-32. Kussow, W. R. 1995. Some USGA putting green management issues. The Grass Roots. 23(3):44-45. Landry, G. and M. Schlossberg. 2001. Bentgrass (Agrostis spp.) cultivar performance on a golf course putting green. Int. Turfgrass Soc. Res. J. 92886-891. Lodge, T. A., S. W. Baker, P.M. Canaway, and D.M. Lawson. 1991. The construction irrigation and fertilizer nutrition of golf greens. 1. Botanical and reflectance assessments after establishment and during the first year of differential irrigation and nutrition treatments. J. Sports Turf Res. Inst. 67 :32-43. Lodge, T. A., and D. M. Lawson. 1993. Sand topdressing: where are we going? The- construction irrigation and fertilizer nutrition of golf greens. Botanical and soil chemical measurements over three years of differential treatment. J. Sports Turf Res. Inst. 69:59-73. Lucas, L. T. 1995. Diseases of bentgrass on high-sand-content golf green. TurfFiles: NCSU web site. May; 1-3. MSTAT. 1993. Microcomputer statistical program. Michigan State Univeristy, East Lansing, MI, USA. Nelson D. W. 1983. Determination of ammonium in KC] extracts of soils by the salicylate method. Communin soil sci. plant anal. 14(11), 1051-1062. Nikolai T. A., P. E. Rieke, J. N. Rogers, 111, and I. M. Vargas Jr. 2001. Turfgrass and soil responses to lightweight rolling on putting green root zone mixes. Int. Turf. Soc. Res. J. 92604-609. Radko, A. M. 1973. Refining Green Section Specifications for putting green construction. Proc. Sec. Int. Turfgrass Research Con. 287-297. Rieke, P. E. and B. G. Ellis. 1973. Effects of nitrogen fertilization on nitrate movements under turfgrass. . Int. Turfgrass Soc. Res. J. 2: 120-130. 25 Tisdale 3. L., N. L. Werner, and 1. D. Beaten. 1985. Soil Fertility and Fertilizers 4th Ed. Macmillan Publishing Company, New York, New York. Travis, W. J. 1901. Practical Golf. Harper & Brothers. New York. USGA Green Section Staff. 1960. Specifications for a method of putting green construction. USGA Journal and Turf Management. 13(5):24-28. Werner, S. 1995. Comparison among golf-green constructions in a field trail. Rasen- Turf-Gazon. 26(4): 1 16-122. 26 CHAPTER TWO TURFGRASS RESPONSES TO LIGHTWEIGHT ROLLING ON THREE PUTTING GREEN ROOT ZONE MIXES ABSTRACT Three putting green root zones: an 80:20 (sand: peat v/v) mixture constructed to USGA recommendations; an 80: 10: 10 (sand: soil: peat v/v) mixture 0.3m deep built with subsurface tile drainage; and an undisturbed sandy clay loam native soil green were established to study the effects that rolling and fertility treatments had on the root zones. Rolling treatments consisted of rolled 3x/week and not rolled. Fertility treatments consisted of two nitrogen rates (146 and 293 kg ha'1 year") and three potassium rates (0, 195, and 390 K20 kg ha'1 year"). Rolling greens three times per week produced greater ball roll distance without detriment to turfgrass quality. Lightweight rolling consistently resulted in less dollar spot (Sclerotinia homoeocarpa), most notably in the predominantly sandy root zones. Speculations are made about why lightweight rolling three times per week reduced dollar spot severity. Lightweight rolling also resulted in fewer bird beak intrusions through the turfgrass canopy into the root zone. It is theorized that the reduction may be due to less cutwonn activity on rolled greens. Rolled plots also had significantly less broadleaf weeds during the one-year broadleaf weeds were observed on the site. Color and quality ratings revealed no meaningful differences among the three different root zones. There was an inverse relationship between the amount of fines in the root zone and dollar spot severity. Nitrogen rate consistently resulted in significant 27 differences in dollar spot counts, but the amount of time that passed after the nitrogen application appeared to be a factor. The higher rate of nitrogen resulted in fewer dollar spot infections when nitrogen fertility averaged 14 days after application. The lower rate of nitrogen resulted in fewer dollar spot infections when nitrogen fertility averaged 32 days after application. The lower rate of nitrogen had significantly greater ball roll distance than the higher rate of nitrogen. There was also a trend as the difference in ball roll distance increased between the two nitrogen rates with differences of 8cm in 1998, 10 cm in 1999, and 19 cm in 2000. Significant localized dry spot differences were observed one year. At that time the higher nitrogen rate resulted in a greater percentage of localized dry spot than the lower nitrogen rate. At the higher N-rate localized dry spot was reduced with the practice of rolling. The native soil and 80:20 root zones had more localized dry spot than the 80:10: 10 root zone. Potassium had no effect on ball roll distance, dollar spot, color, quality, or localized dry spot. 28 INTRODUCTION In 1901 green keeper Walter Travis wrote, “From May until October each green should be rolled daily with alight roller, rather than once or twice a week with a heavy one” [Travis, 1901].” For the next quarter century numerous publications addressed roller frequency, weight, compaction and soil texture [Hutchinson 1906, Harban, 1922; Piper and Oakley, 1921; Anonymous, 1926] without coming to any clear conclusions. Shortly thereafter, the practice of frequent rolling ceased as turfgrass research showed a link between high levels of soil compaction and turf root growth [DiPaola and Hartwiger, 1994] The practice of lightweight green rolling returned in the 1990’s attributed to the demand for fast ball roll distances. However, concerns that existed in the 1920’s remain in that some golf course superintendent’s view rolling as a means of improving putting quality, while others believe rolling causes additional stress that makes putting green management more dificult [Hartwiger, 1996]. Besides the near century old concerns regarding compaction, there is also the need to investigate the potential for above ground turfgrass problems associated with continual season-long turf rolling and the possibility that pathogens may invade crushed tissues, leading to diseased turf [Beard, 1994]. To address these questions a lightweight rolling study was initiated at Michigan State University in 1995 on greens constructed with different root zones [Nikolai et al., 2001]. In that study plots were rolled three times per week. Results included significant increases in ball roll distance (BRD) the day of and the day after rolling treatments were applied. Furthermore, rolled plots had significantly less dollar spot (Sclerotinia homoeocarpa) than non-rolled plots during the second year of the study and on one 29 occasion rolling resulted in more pink snow mold (Microdochium) [Nikolai et al., 2001]. To fiirther investigate the potential impact lightweight rolling had on disease severity it was determined to continue the rolling study four more years. With the continuation of the study, plots were split for nitrogen and potassium rates to address the impact rolling might have on root zones under different fertility programs. The objectives of this portion of the study were to evaluate the effects of season long lightweight green rolling and fertility on ball roll distance, turfgrass color and quality, and disease susceptibility on three putting green root zones. MATERIALS AND METHODS The research was conducted at the Hancock Turfgrass Research Center at Michigan State University, East Lansing, Michigan on a 1,3 88 m2 (36.6 x 36.6m) experimental putting green constructed in summer 1992, and seeded with ‘Penncross creeping bentgrass (Agrostis palustris Huds.) in spring, 1993. The three root zone mixes were: an 80:20 (sand: peat v/v) mixture constructed to USGA recommendations; an 80: 10: 10 (sand: soil: peat v/v) mixture built 0.3m deep with subsurface tile drainage; and an undisturbed sandy clay loam (58% sand, 20.5% silt, and 21.5% clay) native soil green. The cation exchange capacities of the root zones was 5.8, 6.7, and 9.6 me/ 100g, respectively. Michigan peat was used in both sand mixes. Both sands were within USGA specifications for putting green root zone mixes (Table 1). Each putting green was 148.8 m2 (12.2 x122 m) and was arranged in a randomized complete block design with three replications of each green. Each 12.2 x 12.2m putting green had four Rain Bird Maxi Paw irrigation heads model number 2045A 30 (Rain Bird Distribution. Co. CA) at the corners for individual plot irrigation. Irrigation was applied on a daily basis with the exception of dry down periods to permit collection of data on the development of localized dry spot. The experimental design was a split-split-plot, randomized complete block design with three replications. Main plots were root zone mixes split for rolling (rolled 3x/week and not rolled). Rolling was split for two nitrogen rates and three potassium rates. Greens were constructed with the specific purpose of comparing among different root zones managed under similar management regimes. Each green was split into two 10.4 x 5.2m greens that were mowed at 0.4cm cutting height six times per week with a walk- behind Toro GM 1000 (Bloomington, MN) greens mower. One green from each construction plot was randomly selected and rolled three times per week (Monday, Wednesday, Friday) with an Olathe (Olathe Manufacturing Inc., Industrial Airport, KS) lightweight green roller Model 396 from May through October 1997-2000. The other green in the same root zone block was not rolled and was utilized as a check. The Olathe roller had three smooth rollers that were 980 mm in length and 150 mm in diameter. The machine weighed 427 kg without an operator. Fertility treatments consisted of two nitrogen rates (146 and 293 kg ha'1 year”) and three potassium rates (0, 195, and 390 K20 kg ha'1 year"). In 1997 individual plots designated as 0 kg ha'1 potassium actually received potassium based on October, 1996 soil samples results. No further potassium was applied on the 0 potassium plots in 1998- 2000. Each fertility plot was 4.7 m2 (0.9 x 5.2 m). Fertilizer was applied with a 0.9m width drop spreader. Methylene urea applied as Nutralene 40-0-0 (The Andersons, Maumee, OH) was the nitrogen source during the warmer months with urea applications 31 being made in May and November of each year. Potassium sulfate (0-0-50) was the potassium source. All plots received the same amount of P during the study. Sand topdressing was applied on all three-root zone mixes on a light, frequent basis throughout the growing season (Figure 1). Additionally, no vertical mowing or core cultivation occurred on the research plots prior to or during the study. Fungicides were applied on a curative basis to allow for disease observations to occur. Ball roll distance (BRD) measurements were obtained on several dates in 1998- 2000 on the day of and the day following rolling treatments. Measurements were initiated approximately 3 and 27 hours after rolling. Measurements were taken with a Stimpmeter in accordance with USGA instructions (U SGA Green Section Staff, 1996). Data reported reflect the means of all six numbers across treatments. Sclerotim'a homoeocarpa (dollar spot), broadleaf weed, and bird beak intrusion counts were taken when symptoms occurred by counting the number of individual spots per plot. Localized dry spot (LDS) was determined by estimating the percentage of each plot afflicted with LDS. Color and quality ratings were taken prior to a nitrogen application (generally four weeks after the last nitrogen application). Both color and quality were rated on a scale of 1 (dead or chlorotic turf) to 9 (excellent turf). Numbers 6 and above were regarded as acceptable turf for a bentgrass putting green. Analyses of variance were performed on pooled measurements followed by Fischer’s protected Least Significant Difference (LSD) if difi‘erences were found at P_>_ 0.05. The LSD was used to compare differences of mean numbers among the different treatments. All data were analyzed using MSTAT [1993] with the exception of standard 32 error estimators for interactions in the split-split-plot design. Interactions were computed by hand with the appropriate degrees of freedom for interactions determined by the procedure introduced by Satterthwaite [Kuehl, 1994 RESULTS & DISCUSSION Ball Roll Distance In 1998 and 2000 Stimpmeter measurements were completed three times on the day rolling was applied (Table 17) with six measurements taken in 1999 (Table 18). Root zone had minimal effect on ball roll distance (BRD) during the period as only three of the eleven dates resulted in significant differences. On all three of those dates the native soil green was slower than the other two root zones. However, differences were small and surveys indicate the average golfer cannot detect differences in BRD of 15cm or less [Karcher et al., 2000]. Similar results have been reported by Lodge and Baker [1991] Rolling resulted in statistically significant BRD on all 11 dates the rolling treatment was applied. Rolled plot BRD ranged from 29-43 cm (11 to 17 %) faster than the non-rolled plots over the three-year period averaging approximately 35 cm (13%) faster overall. These results are similar to previously reported data [Nikolai er al, 2001]. Stimpmeter measurements taken the day after a rolling event are reported in Table 19. Four measurements were obtained in 1999 and two in 2000. Once again, root zone had a minimal effect on BRD during the period as only one of the six dates showed significant differences. On that date (3 Aug. 00) the native soil plot was once again significantly slower than the sandier root zones. On all six dates rolling resulted in an 33 average increase of approximately 6% greater than the non-rolled plots the day after the rolling treatment was applied. Nikolai et al. [2001] reported similar results. Three soil x rolling interactions occurred over the seventeen dates that BRD measurements were taken with no obvious trends (data not shown). Nitrogen rate also had a significant effect on BRD on all seventeen dates that Stimpmeter measurements were taken. The 146 kg ha'1 plots averaged 12cm greater distance than the 293 kg ha'1 plots over the three years. The inverse relationship between increasing nitrogen rate and BRD is well documented and has been attributed to the increased growth with the higher N rate [Rieke and McElroy, 1985, Throssell and Duich, 1981]. There was also a trend as the difference in BRD between the two nitrogen rates increased with time with differences of 8cm in 1998, 10cm in 1999, and 19cm in 2000. Numerous golf course superintendents believe that higher K rates increase BRD due to their understanding that K makes the plant more rigid and upright (verbal communications). Potassium rates in this study resulted in a significant difference on only one occasion (3 Aug, 00) and the difference was minimal (6cm). Some believe the Stimpmeter is not a very accurate tool. Scientists, as well as golf course superintendents, that have utilized the Stimpmeter often rationalize hard to explain measurements as the natural variability that exists with the instrument [Hamilton, 1994]. Data from potassium plots in this study refiite the notion the Stimpmeter is not an accurate device as the range of BRD measurements from potassium treatments were 1-6cm with the average magnitude only 3cm. These data suggest the Stimpmeter is a more precise tool than some believe and support the conclusions of Duich [1983] that with a limited amount of experience the Stimpmeter can be used with a high degree of precision. 34 Table 17. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on Stimpmeter measurements the day rolling treatment were applied, 1998 and 2000. Stimpmeter measurements in meters Root zone 4 June 98 20 June 98 11 JmL98 7 June 00 19 June 00 17 July 00 80:20 2.893 2.70 3.31 2.84 2.60 2.77 80: 10: 10 2.873 2.73 3.28 2.95 2.73 2.85 Native 27% 2.69 3.23 2.93 2.67 2.80 Significance * NS NS NS NS NS Rolling Rolled 3.06 2.92 3.46 3.10 2.86 2.98 Not Rolled 2.64 2.49 3.08 2.71 2.47 2.64 Mficance an *1“! *4”! inn: *1": *1“: Annual N rate 293 kg ha" 2.81 2.81 3.25 2.81 2.57 2.72 146 kg ha" 2.89 2.93 3.29 3.01 2.76 2.90 Significance *IHI NS NS *1“! "It IIHHI Annual K rate 0 kg ha“ 2.84 2.73 3.28 2.91 2.68 2.81 195 kg ha" 2.87 2.68 3.26 2.91 2.67 2.81 390 kg ha" 2.83 2.71 3.28 2.90 2.64 2.80 Significance NS NS NS NS NS NS Source df Mean square Replication 2 0.007 0.195 0087* 0645* 0.028 0.051 Root zone (S) 2 0100* 0.020 0.057 0.117 0.167 0.065 Error 4 0.014 0.034 0.012 0.091 0.083 0.014 Rolling (R) 1 4703*M 5.004*** 3.882 4.123*** 4.183*** 3.219*** SR 2 0.046 0.013 0.200 0.004 0.050 0055* Error 6 0.021 0.118 0.123 0.042 0.012 0.008 Nitrogen (N) 1 0.204*** 0.037 0.046 1.086*** 0.969*** 0835*" SN 2 0.006 0.040 0.035 0.034 0.011 0021* RN 1 0.005 0.013 0.005 0.095** 0.036 0.007 SRN 2 0.012 0.007 0.006 0.000 0.005 0.005 Potassium (K) 2 0.017 0.023 0.006 0.002 0.017 0.001 SK 4 0.023 0.001 0.017 0.017 0.030 0.015 RK 2 0.001 0.032 0.026 0.006 0.009 0.010 SRK 4 0.003 0.048 0.004 0.005 0.015 0.007 NK 2 0.018 0.045 0.004 0.012 0.004 0.008 SNK 4 0.033 0.018 0.027 0.003 0.023 0.002 RNK 2 0.001 0.016 0.024 0.012 0.019 0.002 SNRK 4 0.012 0.003 0.019 0.006 0.014 0.011 Error 60 0.017 0.020 0.017 0.013 0.013 0.007 *, **, *** Significant at the 0.05 0.01, and 0.001 probability levels, respectively. 35 Table 18. Main efi'ects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on Stimpmeter measurements the day rolling treatment were applied, 1999. Stimpmeter measurements in meters Root zone 5 Aug. 9 Aug. 11 Aug. 16 Aug. 25 Aug. 80:20 2.65a 2.89 2.85 2.83 2.603 80: 10; 10 2.663 2.94 2.90 2.90 2.65a Native 25% 2.80 2.79 2.87 2.42b flgnificance * NS NS NS * Rolling Rolled 2.78 3.03 3.02 3.01 2.71 Not Rolled 2.49 2.72 2.67 2.72 2.41 Significance I"!!! Illa”! “It *4! “It Annual N rate 293 kg ha" 2.58 2.84 2.79 2.82 2.52 146 kg ha" 2.69 2.92 2.90 2.92 2.60 Significance INHI #11"! "a: It"!!! “It Annual K rate 0 kg ha" 2.62 2.86 2.86 2.90 2.55 195 kg ha" 2.64 2.88 2.84 2.84 2.55 390 kg ha" 2.64 2.89 2.85 2.86 2.58 Significance NS NS NS NS NS Source df Mean square Replication 2 0.019 0.105 0.025 0.016 0.204 Root zone (S) 2 0058* 0.171 0.097 0.039 0522* Error 4 0.006 0.027 0.027 0.051 0.063 Rolling (R) 1 2.21 l*** 2.593*** 3.371*** 2.282" 2376*" SR 2 0.013 0.060 0.030 0.017 0.158 Error 6 0.026 0.013 0.010 0.084 0.070 Nitrogen (N) 1 0320*** 0.171*** 0.324*** 0.269*** 0150*** SN 2 0.008 0.016 0.007 0.014 0.015 RN 1 0.019 0.013 0.002 0.008 0.020 SRN 2 0.004 0.017 0.007 0.003 0.015 Potassium (K) 2 0.014 0.008 0.003 0.026 0.007 SK 4 0.034 0.012 0.003 0.028 0.006 RK 2 0.023 0.000 0.000 0.037 0.007 SRK 4 0.005 0.011 0.008 0.032 0.021 NK 2 0.002 0.025 0.025 0.043 0.039 SNK 4 0.020 0.020 0.012 0.015 0.009 RNK 2 0.020 0.005 0.001 0.010 0.004 SNRK 4 0.020 0.007 0.006 0.010 0.017 Error 60 0.014 0.010 0.013 0.021 0.013 *, **, *** Significant at the 0.05 0.01, and 0.001 probability levels, respectively. 36 Table 19. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on Stimpmeter measurements the day after rolling, 1999 and 2000. Stimpmeter measurements meters Root zone 6 Aug. 99 12 Aug. 99T 17 Aug 99 26 Aug 99 6 June 00 3 Aug 00 80:20 2.75 2.61 2.98 2.74 2.81 2.523 80: 10:10 2.75 5.71 2.98 2.74 2.87 2.503 Native 2.67 2.60 2.99 2.59 2.82 2.416 _§ignificance NS NS NS NS NS * Rolling Rolled 2.83 2.71 3.05 2.93 2.96 2.52 Not Rolled 2.62 2.60 2.92 2.66 2.71 2.44 Sigiificance IHHlI at: *1”! It *** =1: Annual N rate 293 kg ha" 2.68 2.61 2.92 2.65 2.74 2.37 146 kg ha" 2.76 2.71 3.05 2.74 2.92 2.58 Significance *alull aunt: *Ilull “It taut Ill-HI Annual K rate 0 kg ha“ 2.71 2.68 2.97 2.70 2.84 2.51a 195 kg ha" 2.75 2.63 2.99 2.69 2.84 2.456 390 kg ha" 2.71 2.66 2.99 2.69 2.82 2.476 Significance NS NS NS NS NS * Source df Mean square Replication 2 0.025 0.056 0162* 0.091 0.029 0145* Root zone (S) 2 0.075 0.096 0.003 0.273 0.036 0133* Error 4 0.018 0.034 0.021 0.052 0.089 0.013 Rolling (R) 1 1.190*** 0.324 0.428*** 0138* l.658*** 0180* SR 2 0.019 0.059 0193** 0.041 0076* 0.019 Error 6 0.007 0.034 0.011 0.012 0.015 0.024 Nitrogen (N) 1 0.183*** 0285*** 0459*** 0194*** 0.902*** 1.171*** SN 2 0.020 0.009 0.001 0.003 0063* 0033* RN 1 0.001 0.022 0.011 0.001 0.010 0.000 SRN 2 0.002 0.003 0.010 0.004 0.001 0.020 Potassium (K) 2 0.017 0.025 0.003 0.001 0.005 0035* SK 4 0.011 0.004 0.020 0.009 0.014 0.015 RK 2 0.001 0.015 0.015 0.003 0.000 0.003 SRK 4 0.010 0.018 0.023 0.014 0.001 0.004 NK 2 0.017 0.016 0.004 0.006 0.000 0.004 SNK 4 0.005 0.006 0.022 0.009 0.007 0.011 RNK 2 0.009 0.010 0.002 0.009 0.021 0.003 SNRK 4 0.014 0.009 0.012 0.010 0.024 0.019 Error 60 0.011 0.009 0.014 0.010 0.016 0.008 *, **, *** Significant at the 0.05 0.01, and 0.001 probability levels, respectively. T Rained after rolling and after BRD measurements were made on one replication. 37 Disease Observations Sclerorinia homoeocarpa (dollar spot) activity data was collected on twelve dates from 1997-2000 (Tables 20 and 21). On five dates root zone resulted in significant differences with the native soil root zone consistently having less dollar spot than the 80:20 root zone and the 80: 10: 10 mix continuously resulted in an average number of dollar spots between the 80:20 and native soil root zones. On three occasions the 80: 10: 10 root zone resulted in significantly less dollar spot than the 80:20 root zone. Lightweight rolling resulted in pooled data with significantly less dollar spot than the non-rolled plots on all dates. These data strengthens earlier observations reported by Nikolai et al. [2001] since dollar spot severity was reduced on rolled plots with every dollar spot outbreak over the four-year period. A conclusive answer to why lightweight rolling three times per week reduces dollar spot severity is elusive. For conjecture, Williams and Powell [1995] noted that guttation droplets escape from wound exudates and these droplets are rich in nutrients that pathogens may use during hyphal growth. Release of these exudates may be exacerbated in the early dawn hour due to a combination of a fresh wound being produced by mowing and that turgor pressure may be high at this time. Rolling, following an early morning mowing, may remove inoculum with excess clippings that failed to be caught in the mower bucket and it may also disperse concentrated guttation water, thus reducing disease severity. However, a dew removal dollar Spot study performed by Williams and Powell [1995] suggests it is unlikely that dew and guttation removal would account for reductions of the magnitude observed on the research plots. 38 Another possible reason rolling reduced dollar spot includes the possibility that the water holding capacity of the root zone may be increased near the surface layer. This would be relevant because Couch and Bloom found low soil moisture to be important in the development of dollar spot and Howard and Smith reported more dollar Spot in seasons with less rainfall [Vargas, 1994]. Therefore, if rolling does increase the water holding capacity of the soil it may reduce dollar spot severity. A final theory for reduced severity of dollar spot is rolling may increase phytoalexin production in the plant. Resistance to disease can be increased by altering plant response to parasitic attack through the synthesis of phytoalexins [Marschner, 1995]. Phytoalexins are antimicrobial low-molecular-weight secondary metabolites that are induced to accumulate as a defense response within the plant [Hammerschmidt, 1999]. It is possible that rolling may stress the plant enough to activate phytoalexin accumulation. Nitrogen rate effect on dollar spot was significant on all dates evaluated. However, on eight dates the higher rate of nitrogen had less dollar spot and on the other four the higher rate resulted in more dollar spot. Vargas [1994] wrote, “According to one school of thought, the number of infections will be greater at high nitrogen levels but the damage will be less severe than if nitrogen levels are low, because although fewer spots appear in the latter case, they tend to be larger and the damage more severe.” Following this “school of thought” it stands to reason the number of days after a nitrogen application (as well as nitrogen source and time of year) could be of consequence on the severity of dollar spot infections. Review of dates nitrogen was applied revealed that on the four dates that the higher rate of nitrogen resulted in more dollar spot infections the average amount of days after treatment was 32. For the eight dates that resulted in the 39 higher rate of nitrogen having fewer dollar spot infections the average days after nitrogen application was 14. This supports the theory that during periods of severe dollar spot infection nitrogen levels must be maintained and that alight frequent method of application may be the best form of managing the disease [Vargas, 1994]. It has been reported that maintaining high potassium fertility during periods of dollar spot activity will help control the disease [Smiley, 1983]. However, at no time were significant dollar spot counts obtained regarding the three potassium rates in the study. A root zone x rolling x nitrogen interaction occurred on six of the twelve dates that dollar spot observations were made (Figures 2-8). Root zone apparently had the biggest impact on the amount of dollar spot infestation with an inverse relationship between the amount of fines and the occurrence of the disease symptoms. In the 80:20 and 80: 10: 10 root zones, lightweight rolling reduced the amount of dollar spot, most notably at the lower nitrogen rate. The effect of nitrogen rate on dollar spot was variable and as previously stated, apparently had to do with the amount of time that passed after nitrogen was applied. Color and Quality Ratings Color and quality ratings were taken periodically fi'om 1998-2000. Both were rated on a scale of 1-9 with 9 signifying excellent, 6 and above acceptable, and 1 equaling chlorotic or dead turf. Color ratings are reported in Tables 22-24. On the 13 dates that color ratings were taken only two were significant in regards to root zone. On those two dates the 80:20 root zone had better color than the 80:10: 10 mix with no significance 40 between the 80:20 and native soil root zones. Root zone x nitrogen interactions occurred on 5 dates over the three-year period (Table 27) but no trends resulted from color in the interactions even at the lower nitrogen rate. This indicates that the 146 kg ha'1 rate was adequate for turfgrass color even in the 80:20 root zone. 41 Table 20. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on dollar spot, 1997- Aug. 1998. No. of dollar spot in2 1997 1998 Root zone 24 June 23 July 20 Aug. 16 June 11 July 11 Aug. 80:20 11.69 20.253 2046a 2008a 44.573 23.66 80: 10: 10 9.81 13.60a 9.46ab 4.536 11.936 7.35 Native 2.16 2.15b 0.496 0.50b 1.176 0.55 Significance NS * * ** ** NS Rolling Rolled 3.28 5.24 5.70 4.75 11.95 7.34 Not Rolled 12.49 18.74 14.57 12.00 26.49 13.70 Significance 4: M 4: 4- :1: 4: Annual N rate 293 kg ha" 9.70 13.64 10.96 7.33 16.73 9.30 146 kg ha" 6.07 10.35 9.32 9.42 21.71 11.74 Significance an 4: 4: *4: 4:4: 4: Annual K rate 0 kg 6a" 7.91 12.56 9.97 8.43 20.48 11.82 195 kg ha" 6.29 10.45 9.49 8.43 18.51 9.32 390 kg ha" 9.45 12.96 10.96 8.26 18.67 10.41 Significance NS NS NS NS NS Ns Mean square Source df Replication 2 526.79 1198.36 1068.81 523.41 1637.06 536.66 Root zone (S) 2 917.85 3017.09* 3601.34* 3848.67** 18386.01" 5080.99 Error 4 250.56 235.76 476.53 176.98 980.96 1013.60 Rolling (R) 1 2291.38* 4915.87** 2122.57* 1420.01* 5709.84* 1090.45* SR 2 590.09 1032.69 655.20 422.15 1335.78 287.75 Error 6 255.88 423.63 354.90 173.74 845.12 191.14 Nitrogen (N) 1 355.93*** 292.09* 7271* 117.75** 667.99** 161.31* SN 2 71.91 55.03 4821* 30.68 444.04** 204.26** RN 1 245.24** 221.15* 6948* 4.71 0.09 1.46 SRN 2 14.05 7.24 4731* 61. 19* 24.57 2.12 Potassium (K) 2 89.94 65.42 20.14 0.35 43.11 56.81 SK 4 43.86 72.54 15.52 0.74 77.70 57.67 RK 2 116.24 52.08 36.71 1.43 74.90 21.58 SRK 4 47.70 97.81 30.33 1.46 124.49 9.88 NK 2 39.86 36.57 15.58 9.50 8.28 3.48 SNK 4 12.86 38.85 9.37 7.44 75.17 6.31 RNK 2 24.07 71.66 29.09 6.54 106.12 25.41 SNRK 4 7.82 15.94 8.95 5.93 29.29 33.44 Error 60 30.84 47.96 14.31 15.26 69.31 29.78 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. 1 NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 42 Table 21. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on dollar spot Sept. 1998, 1999, and 2000. No. of dollar spot rn‘2 1998 1999 2000 Root zone 17 Sep. 10 June 30 June 14 June 14 July 9 Aug. 80:20 25.86 9.97 6.193 6.04 3.02 10.17 80:10:10 7.92 5.01 2.40b 4.87 2.61 3.19 Native 1.04 0.47 0.43b 2.78 2.62 1.35 Significance NS NS * NS NS NS Rolling Rolled 5.95 1.45 1.07 2.66 1.19 2.63 Not Rolled 17.26 8.85 4.94 6.50 4.30 7.17 Significance “I II! it all *4: *4: Annual N rate 293 kg ha‘r 16.26 3.94 1.80 3.09 2.19 2.34 146 kg ha" 6.96 6.36 4.21 6.04 3.30 7.45 Significance IMHO! **Ill **all **It *4: **III Annual K rate 0 kg ha" 11.80 4.89 2.72 4.01 2.63 4.98 195 kg ha" 11.66 5.32 3.58 4.60 2.95 4.65 390 kg ha" 11.36 5.25 2.72 5.09 2.62 5.01 Significance NS NS NS NS NS NS Mean square Source df Replication 2 979.19 122.68 53.41 58.30 35.37 55.57 Root zone (S) 2 5909.47 813.49 307.77" 98.17 2.01 780.64 Error 4 1050.41 155.03 21.36 113.59 48.40 233.19 Rolling (R) 1 3453.78" 1482.01* 405.97* 391.20* 262.53" 555.86" SR 2 706.69 370.89 125.87 111.92 2.90 174.09 Error 6 228.34 144.03 35.70 45.92 22.50 40.22 Nitrogen (N) 1 2334.08*** 157.57*** 156.34*** 235.30*** 33.10** 709.40*** SN 2 779.47*** 92.15*** 87.61*** 116.99*** 33.77*** 357.06*** RN 1 697.63*** 98.78*** 122.61*** l47.22*** 21.73* l73.43*** SRN 2 100.75* 47.74*** 7058*” 3005* 12.65 57.17** Potassium (K) 2 1.78 2.00 8.90 10.57 1.10 1.84 SK 4 12.20 1.02 6.98 8.18 1.58 6.46 RK 2 17.89 3.31 3.63 17.07 0.55 2.63 SRK 4 4.89 1.25 5.14 4.24 1.99 1.55 NK 2 10.38 2.15 0.86 10.92 1.15 7.19 SNK 4 5.60 2.22 1.56 10.70 1.50 3.21 RNK 2 13.32 1.38 2.96 0.55 0.05 0.29 SNRK 4 16.43 4.97 3.90 1.13 2.91 1.11 Error 60 30.12 5.12 5.60 8.60 4.60 9.78 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. 1' NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 43 Enact... was 95.2 Co 266. $222“. .0 02mm 65 an 9.3 .02 .6 «.06. 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E9053 3.0 u :89 om: 65:9 0:0 0:94. :09 :0 _0>0_ 090m 0:: :0 509:: :0 m_0>0_ ::90::_3 mod n :89 am: .:::0E:09: c0005: 0 99:0 0:00 N: ooou .:m:m:< m :090 30:: 0.50300 9:099: 899:0: 050090 0 :0 :03 0:00 :0 0:9 509:: 0:0 65:9 .0:0~ :09 :0 8:00:95 .0 9:9”. 0:3 :03: 02:02 ore—.60 omnom z-ul JOdS amp '0" z :6. 8:9 :o: a z :9: 8:9 :o: a z :5. 8:9 a z :9: 8:9 9 50 Table 22. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on color ratings, 1998. Color rating (9 = excellent, 62 acceptable, 1 = dead) Root zone 30 May 13 June 11 July 10 Aug. 10 Oct. 80:20 6.8 7.1 7.5 7.63 7.2 80:10: 10 7.1 7.5 7.2 7.4b 6.5 Native 7.3 7.7 7.6 7.5a 6.8 Significance NS NS NS ** NS Rolling Rolled 7.3 7.4 7.3 7.5 6.6 Not Rolled 7.1 7.3 7.6 7.6 7.1 Significance NS NS NS NS ** Annual N rate 293 kg ha" 7.7 7.9 7.7 7.9 7.1 146 kg ha" 7.0 6.9 7.2 7.2 6.6 Significance *1”: in”: “I!!! **III *1”! Annual K rate 0 kg lta'I 7.2 7.4 7.5 7.6 6.8 195 kg ha“ 7.1 7.4 7.5 7.6 6.8 390 kg ha" 7.2 7.4 7.4 7.5 6.8 Significance NS NS NS NS NS Mean square Source df Replication 2 0.29 2.70 0.71 0.21* 0.08 Root zone (S) 2 6.36 3.47 1.19 0.71** 3.45 Error 4 1.29 0.83 0.53 0.02 0.81 Rolling (R) 1 0.93 0.28 1.45 0.93 6.65** SR 2 0.31 0.002 0.50 1.07 5.18** Error 6 0.45 0.31 0.43 0.33 0.43 Nitrogen (N) 1 25.04*** 29.56*** 9.19*** 15.56*** 7.89*** SN 2 0.25* 057* 0.21 0.11* 0.16 RN 1 0.75** l.95*** 0.06 0.01 0.16 SRN 2 030* 0.24 0.03 0.02 0.11 Potassium (K) 2 0.07 0.03 0.06 0.01 0.01 SK 4 0.08 0.04 0.08 0.01 0.22 RK 2 0.04 0.11 0.02 0.03 0.02 SRK 4 0.04 0.05 0.01 0.01 0.08 NK 2 0.02 0.11 0.01 0.02 0.12 SNK 4 0.05 0.05 0.06 0.02 0.03 RNK 2 0.09 0.03 0.02 0.002 0.04 SNRK 4 0.00 0.08 0.01 0.01 0.08 Error 60 0.07 0.15 0.08 0.03 0.12 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly difl'erent according to LSD (0.05). 51 Table 23. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on color ratings, 1999. Color rating (9 = excellent, 63 acceptable, 1 = dead) Root zone 13 May 10 Aug. 8 Sep. 5 Oct. 80:20 6.2 7.0 7.1 6.7 80: 10: 10 6.6 6.6 6.8 6.5 Native 6.7 6.6 7.0 6.7 Si ' canoe NS NS NS NS Rolling Rolled 6.5 6.7 7.1 6.6 Not Rolled 6.4 6.8 6.9 6.6 Significance NS NS NS NS Annual N rate 293 kg lra'I 6.8 7.2 7.4 7.1 146 kg ha" 6.1 6.3 6.5 6.1 Mficance **III **t **III *1”! Annual K rate 0 kg ha" 6.5 6.7 7.0 6.6 195 kg ha" 6.5 6.7 7.0 6.6 390 kg ha" 6.5 6.8 7.0 6.6 Significance NS NS NS NS Mean square Source df Replication 2 0.45 3.88 1.96 0.26 Root zone (S) 2 2.34 2.53 0.95 0.67 Error 4 0.59 0.97 0.37 0.22 Rolling (R) 1 0.28 0.75 0.93 0.002 SR 2 0.07 0.53 215* 0.22 Error 6 0.18 0.50 0.40 0.39 Nitrogen (N) l 13.72*** 18.75*** 22.23*** 29.56*** SN 2 1.47*** 025* 0.46** 0.11 RN 1 0.06 0.23 0.01 0.002 SRN 2 0.18 0.17 0.22 029* Potassium (K) 2 0.002 0.02 0.03 0.03 SK 4 0.02 0.01 0.06 0.06 RK 2 0.002 0.02 0.24 0.12 SRK 4 0.04 0.03 0.01 0.07 NK 2 0.002 0.05 0.04 0.45** SNK 4 0.04 0.01 0.06 0.03 RNK 2 0.002 0.06 0.03 0.04 SNRK 4 0.023 0.11 0.04 0.04 Error 60 0.102 0.07 0.09 0.08 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly difl‘erent according to LSD (0.05). 52 Table 24. Main effects and mean squares for treatment effects of root zone, rolling nitrogen and potassium fertilization on color ratings, 2000. Color rating (9 = excellent, 6_>_ acceptable, 1 = dead) Root zone 22 May 22 May 28 June 3 Aug. 80:20 6.5 6.6 7.2 7.4 80:10: 10 6.5 6.2 6.2 7.3 Native 6.5 5.9 6.6 7.4 Significance NS NS "‘ NS Rolling Rolled 6.5 6.3 6.7 7.3 Not Rolled 6.5 6.2 6.6 7.4 Significance NS NS NS NS Annual N rate 293 kg ha" 8.0 6.7 7.4 8.0 146 kg ha" 5.0 5.8 6.0 6.7 Significance NS “III! Hill! **II Annual K rate 0 kg liarI 6.5 6.2 6.6 7.3 195 kg ha" 6.5 6.2 6.7 7.3 390 kg ha“ 6.5 6.3 6.7 7.4 Significance NS NS NS NS Mean square Source df Replication 2 0.00 2.02 5.44 0.29 Root zone (S) 2 0.00 4.78 811* 0.04 Error 4 0.00 1.30 0.76 0.15 Rolling (R) 1 0.00 0.06 0.23 0.08 SR 2 0.00 0.50 0.04 0.11 Error 6 0.00 1.11 1.38 0.05 Nitrogen (N) l 0.00 20.89*** 52.08*** 4156*" SN 2 0.00 0.29 0.33 0.15 RN 1 0.00 0.02 0.45 0.08 SRN 2 0.00 0.34 0.15 0.11 Potassium (K) 2 0.00 0.27 0.11 0.06 SK 4 0.00 0.10 0.22 0.05 RK 2 0.00 0.09 0.04 0.58** SRK 4 0.00 0.09 0.26 0.07 NK 2 0.00 0.22 0.11 0.01 SNK 4 0.00 0.11 0.28 0.13 RNK 2 0.00 0.02 0.34 0.19 SNRK 4 0.00 0.05 0.15 0.10 Error 60 0.00 0.13 0.24 0.12 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. 1’ NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 53 Table 25. Main effects and mean squares for treatment efl‘ects of root zone, rolling, nitrcgen and potassium fertilization on quality ratings, 1998. Qualiy rating (9 = excellent, 6_>_ acceptable, 1 = dead) Root zone 13 June 11 July 10 Aug. 10 Oct. 80:20 6.5 7.3 7.41: 6.7 80: 10: 10 7.1 7.1 7.0c 6.1 Native 7.1 7.4 7.6a 6.3 Significance NS NS ** NS Rolling Rolled 7.0 7.2 7.3 6.1 Not Rolled 6.8 7.3 7.4 6.7 Significance NS NS NS NS Annual N rate 293 kg ha'1 7.7 7.6 7.8 6.8 146 kg ha" 6.2 6.9 6.9 6.0 Significance in”! INN! **Ik *1“: Annual K rate 0 kg ha" 6.8 7.2 7.3 6.4 195 kg ha" 6.9 7.3 7.3 6.3 390 kg ha“ 7.0 7.2 7.3 6.4 Significance NS NS NS NS Mean square Source df Replication 2 7.56 2.96 0.32 0.78 Root zone (S) 2 5.65 0.81 3.54** 3.82 Error 4 4.74 0.50 0.15 1.77 Rolling (R) 1 1.84 0.93 0.28 9.49** SR 2 0.01 238* 1.13 12.45*** Error 6 0.37 0.32 0.56 0.53 Nitrogen (N) 1 59.41*** 13.37*** 20.02*** 16.33*** SN 2 1.31** 050* 021* 0.05 RN 1 3.38*** 0.08 0.02 0.04 SRN 2 0.23 0.05 0.15 0.07 Potassium (K) 2 0.35 0.01 0.002 0.02 SK 4 0.07 0.07 0.06 0.16 RK 2 0.37 0.002 0.15 0.03 SRK 4 0.08 0.04 0.05 0.05 NK 2 0.36 0.04 0.06 0.27 SNK 4 0.22 0.11 0.07 0.10 RNK 2 0.15 0.05 0.05 0.02 SNRK 4 0.26 0.08 0.03 0.12 Error 60 0.19 0.13 0.07 0.14 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. 1’ NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 54 Table 26. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on quality ratings, 1999. Quality rating (9 = excellent, 63 acceptable, 1 = dead) Root zone 13 May 10 Aug. 8 Sep. 5 Oct 80:20 5.8 5.5 6.4 6.4 80:10:10 6.4 5.7 6.2 6.3 Native 6.4 6.5 7.0 6.5 Significance NS NS NS NS Rolling Rolled 6.3 6.4 6.7 6.5 Not Rolled 6.1 5.4 6.1 6.5 Significance NS ** * NS Annual N rate 293 kg ha" 6.7 6.2 6.9 7.1 146 kg ha" 5.7 5.6 5.9 5.9 Mfimce **t "It HUI! **Ik Annual K rate 0 kg 1a1 6.1 5.9 6.4 6.6 195 kg ha" 6.1 5.9 6.4 6.5 390 kg ha" 6.2 6.0 6.4 6.4 Significance NS NS NS NS Mean square Source df Replication 2 0.42 1.18 5.09 0.21 Root zone (S) 2 3.88 11.25 2.42 0.96 Error 4 1.22 7.10 0.97 0.17 Rolling (R) 1 0.84 29.04** 12.00 0.15 SR 2 0.46 2.02 046* 0.21 Error 6 0.28 2.23 1.26 0.59 Nitrogen (N) l 26.50*** 1070*** 26.01*** 41.56*** SN 2 1.47*** 0.17 046* 0.11 RN 1 0.11 093* 0.00 0.01 SRN 2 063* ‘ 0.18 046* 0.10 Potassium (K) 2 0.13 0.23 0.01 0.11 SK 4 0.10 0.10 0.07 0.06 RK 2 0.11 0.12 0.09 029* SRK 4 0.11 0.06 0.11 0.10 NK 2 0.02 0.01 0.21 0.45** SNK 4 0.20 0.04 0.11 0.002 RNK 2 0.18 0.01 0.01 0.01 SNRK 4 0.18 0.12 0.09 0.04 Error 60 0.15 0.15 0.13 0.08 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. I Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 55 Table 27. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on quality ratings, 2000. Quality rating (9 = excellent, 62 acceptable, 1 = dead) Root zone 14 April 22 May 28 June 3 Aug. 80:20 6.5 6.5 7.2a 7.4 80:10:10 6.5 6.0 6.2b 7.3 Native 6.5 5.7 6.6ab 7.4 Si ‘ canoe NS NS * NS Rolling Rolled 6.5 6.1 6.7 7.3 Not Rolled 6.5 6.0 6.6 7.4 Significance NS NS NS NS Annual N rate 293 kg ha'I 8.0 6.6 7.4 8.0 146 kg ha" 5.0 5.5 6.0 6.7 Significance NS "a: *1”: "at: Annual K rate 0 kg ha“ 6.5 6.0 6.6 7.3 195 kg ha" 6.5 6.0 6.7 7.3 390 kg ha" 6.5 6.1 6.7 7.4 Significance NS NS NS NS Mean square Source df Replication 2 0.00 3.40 5.44 0.29 Root zone (S) 2 0.00 6.79 8.11* 0.04 Error 4 0.00 1.06 0.76 0.15 Rolling (R) 1 0.00 0.45 0.23 0.08 SR 2 0.00 1.23 0.04 0.11 Error 6 0.00 0.92 1.38 0.05 Nitrogen (N) 1 0.00 35.59*** 52.08*** 41.56*** SN 2 0.00 2.26*** 0.33 0.15 RN 1 0.00 0.59 0.45 0.08 SRN 2 0.00 0.73 0.15 0.11 Potassium (K) 2 0.00 0.06 0.11 0.06 SK 4 0.00 0.15 0.22 0.05 RK 2 0.00 0.03 0.04 0.58** SRK 4 0.00 0.09 0.26 0.07 NK 2 0.00 0.18 0.11 0.01 SNK 4 0.00 0.07 0.28 0.13 RNK 2 0.00 0.02 0.34 0.19 SNRK 4 0.00 0.06 0.15 0.10 Error 60 0.00 0.25 0.24 0.12 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. I Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 56 .00w090: :0 :96: 50:08:00 :0 080m 9:: :0 0000 :00: 0003:0m m .0000 :00: 9:00 :0 00008 5ng 0003:0m H 00090.62 09:09:: 002 80:: 9008905 :0000 9:0 0: 000000 0:03 000:: 00:0: 3050 0:0 03000 090: :0w0:::z :. -.0 :00 00.: .000 00.: 0: .0 e~0 0~.0 :80 000 0: 0.0 :.: 0.: 0.0 :.: 9002 n0 0.: 0.0 0.: 0.0 0.: 0:0: 00 0.0 0.: 0.0 0.: on 0.: 0000 00: we: 0: 0-0: 00: m0~ em: 00: 0: ea: 00: m0~ ea: 00: 0: H.0: 00: m0~ 2:00 :80 000: .3 0: 000: :3: : 000: 000: 2 .8000 u : 03900000 M0 45:88 .1. 0: :90: 5ng 0:0 9:00 :00: .3 00:00::0 00 0950: 9:000 .mm 030:. .00w090: :0 :96: 2:90:90 :0 0900 9:: :0 0:00 :00: 0003:0m m .0000 :00: 00:00 :0 00000: comp—:8 0003:0m w 00:80:62 095:5 >02 90:: 9009905 00:00 x06. 0: 002000 0:03 00.23 090: :00000 0:0 039:0 090: 00392 : ~00 9.0 00.0 :.0 00.0 00009004: 0~.0 :: .0 -.0 ~: .0 20 use 00: 0.0 0.: ~.0 0.0 0.0 0.0 0.: 0.0 m.: :0 9,002 ~.:: 0.: :.0 :.: ~.: 0.0 0.: 0.: 0.0 0.0 0: ”0:00 :.0 0.: 0.0 0.: 0.0 0.0 ~.: 0.0 0.0 :.: 0~00 ea: 00. 0: ea: 00: ~0~ ea: 0: 0: .2 0: m0~ .0: we: 03 ea: 00: m0~ .0: m: 0: .0: 0: m0~ .0: we. 0: .0: 0: 8~ 0:00 :80 000: .000 0 000: .03: 0: 000: :02 2 000: .03: 0: 000: 000: 2 _- :00» 00:: we: 0: 0:0: :0w0:::z .8000 u : 03900000 No .::0=00x0 n 0: :90: Smog: 000 9:00 :00: .3 090000 0.0 09:00: 8:00 .3 030:. 57 Rolling had little impact on turfgrass color with only one date resulting in a significant difference (Table 22). On that date non-rolled plots had better color. On two occasions a soil x rolling x nitrogen interaction occurred in regard to color. On both dates the rolled plots, at both nitrogen rates, received higher color ratings (data not shown). Not surprisingly, the higher nitrogen rate resulted in a better color rating on all dates. Potassium had no significant effect on color. There was a nitrogen x potassium interaction on 5 October 1999. On that date the highest nitrogen rate at the highest potassium rate had significantly lower color (data not shown). Quality ratings take into account turfgrass color and density and are presented in Tables 25-27. Only two of the twelve dates resulted in significant differences with the 80:20 having significantly better quality than the 80: 10: 10 on both dates. Rolling also resulted in significant differences on two dates and on both of those dates the rolled plots had better quality than the non-rolled plots. On all twelve dates the higher rate of nitrogen had significantly better quality while potassium rates had no impact on turfgrass quality. Quality rating interactions affected by root zone and nitrogen rate are in Table 29. Quality ratings were afi‘ected by dollar spot severity and therefore the native soil green tended to have better quality. Miscellaneous Data During 1998 broadleaf weeds, T araxacum oflicinale and Plantago major, infested the plots. On 2 October counts on these broadleaf weeds were made (Table 30). The higher nitrogen rate resulted in significantly less weeds than the lower nitrogen rate. This 58 would be expected since increased turf density, attributed to higher N rates, is known to reduce weed encroachment. Rolled plots also resulted in significantly fewer broadleaf weeds. Root zone and potassium treatments had no effect on broadleaf weed counts. Following a rain event in August 2000, irrigation was turned-off to allow the plots to dry for the development of localized dry spot (LDS). Similar attempts were made in previous years to collect LDS data but no significant data resulted. In Table 30 significant LDS data is presented. On 29 August both the rolled plots and lower N fertility plots resulted in less LDS. In September no significant data resulted due to rolling, however, the lower nitrogen rate maintained less LDS than the higher rate. The rolling x nitrogen interaction regarding LDS is presented in Table 31. Plots with the higher nitrogen rate that were not rolled averaged the greatest amount of LDS. However, there were no significant differences between nitrogen rates on rolled plots. Potassium rate had no effect on LDS. A root zone x nitrogen rate interaction occurred in September (Table 32). On that date the native soil green at the high rate of N had the most localized dry spot. The 80: 10: 10 mix had significantly less localized dry spot than the other two- root zones at both nitrogen rates. The practice of sand topdressing most likely had an effect on the LDS among the root zones. Since the majority of roots are in the STL, (Table 54 Chapter IIlI ) and the native root zone would be expected to have more micropores, it is possible the fine-textured soil below the coarse-textured STL would draw water away fro the STL into the native root zone. The STL would have less of an impact on the other two root zones, thus the sandy root zone with more fines (80: 10: 10) would conceivably have less LDS than the 80:20 root zone. 59 Table 30. Main efl‘ects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on broadleaf wwds and localized dry spot. Broadleaf weeds m'T % localized dry spot m'2 2 October 1998 29 August 2000 7 September 2000 Root zone 80:20 0.925 1.17 1.42 80: 10: 10 0.769 0.42 0.30 Native 0.890 1.95 2.05 Significance NS NS NS Rolling Rolled 0.664 0.69 0.99 Not Rolled 1.058 1.67 1.52 Significance *** * NS Annual N rate 293 kg ha" 0.465 1.44 1.62 146 kg ha" 1.258 0.92 0.89 Significance no u INN! Annual K rate 0 kg ha" 0.755 1.06 1.20 195 kg ha" 0.925 1.20 1.19 390 kg ha" 0.904 1.28 1.38 Significance NS NS NS Mean square Source df Replication 2 1.502 19.07 47.09 Root zone (S) 2 0.243 21.09 28.31 Error 4 0.357 5.10 17.13 Rolling (R) 1 4190*" 2556* 7.77 SR 2 0.497 5.07 4.36 Error 6 0.120 2.61 8.06 Nitrogen (N) 1 16.962*** 7.49" l4.6l*** SN 2 0.121 2.61 3.88* RN 1 0.584 9.81" 1.12 SRN 2 0.132 1.82 0.16 Potassium (K) 2 0.312 0.45 0.43 SK 4 0.010 1.42 0.24 RK 2 0.059 0.36 1.09 SRK 4 0.217 0.67 2.09 NK 2 0.001 0.91 0.24 SNK 4 0.043 0.92 0.56 RNK 2 0.329 0.18 0.87 SNRK 4 0.251 0.24 0.62 Error 60 0.182 1.01 0.90 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly difierent according to LSD (0.05). 60 Table 31. Percentage of localized dry spot 111'2 as affected by rollingT and nitrogen ratex. 29 August 2000 Root zone 293 kg ha“ 146 kg ha“ Rolled 0.66 0.73 Not Rolled 2.23 1.10 LSD (005,“ 0.55 LSD @031 0.73 1' Rolling was applied three times per week from May till September with an Olathe lightweight green roller. 1 Nitrogen rates shown are annual rates which were applied in six equal increments from May through November . § Between nitrogen treatments at same rolling treatment. 1] Between rolling treatments at the same or different level of nitrogen. Table 32. Percentage of localized dry spot m'2 as affected by root zone and nitrogen rateT. 7 September 2000 Root zone 293 kg ha” 146 kg ha" 80:20 1.81 1.02 80:10:10 0.34 0.27 Native 2.73 1.35 LSD (005,1 0.63 LSD (005,“ 1.41 T Nitrogen rates shown are annual rates which were applied in six equal increments from May through November. 1 Between nitrogen means at same root zone. § Between root zone at the same or different level of nitrogen 61 Table 33. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on bird beak holes, 1999-2000. No. of bird beak holes m7 19 July 1999 14 August 2000 Root zone 80:20 14.075 1.146 80:10: 10 10.508 0.961 Native 7.404 0.748 Significance NS NS Rolling Rolled 6.236 0.576 Not Rolled 15.088 1.324 Simficance * NS Annual N rate 293 kg 10‘1 12.492 1.087 146 kg ha" 8.833 0.816 Si ’ cance *** II Annual K rate 0 kg ha" 9.874 0.961 195 kg lia‘l 11.590 0.990 390 kg ha" 10.522 0.904 Significance NS NS Mean square Source df Replication 2 685.054 7.777 Root zone (S) 2 401.128 1.433 Error 4 176.160 2.123 Rolling (R) 1 2115.456* 14.992 SR 2 149.848 4.250 Error 6 219.865 2.755 Nitrogen (N) 1 361.539*** 1976* SN 2 80.806*** 0.380 RN 1 110.892“ 0.015 SRN 2 16.032 0.440 Potassium (K) 2 27.023 0.068 SK 4 17.635 0.210 RK 2 17.426 0.119 SRK 4 9.182 0.183 NK 2 4.009 0.285 SNK 4 3.129 0.319 RNK 2 15.630 0.236 SNRK 4 21.679 0.196 Error 60 11.029 0.485 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, rapectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 62 Bird activity was high on the site coinciding with numerous Agrotis ipsilon (black cutworm) observed on the plots in July of 1999 and August of 2000. There were significantly less bird beak intrusions on greens that were rolled three times per week in July 1999 (Table 33). Reductions of 56% have previously been reported on rolled plots [Nikolai et al., 2001]. In 1999 there were 59% less bird beak intrusions on the rolled greens and in 2000, 56% fewer. Potter [1998] reported that black cutworm moths lay nearly all their eggs on the tips of leaf blades and that many eggs survive passage through the mower blades and will hatch later. Considering debris (excess clippings that miss the bucket) adhered to the rollers and was transported off-site, it is conceivable that rolling could have decreased the amount of cutworms per green by removing the eggs with the excess debris. The higher rate of nitrogen had significantly more bird beak instructions in both years. The rolling by nitrogen interaction is presented in Table 34. Rolling significantly decreased the amount of bird beak intrusions at both rates of nitrogen (60% less at 293 kg ha'1 and 56% less at 146 kg ha'l) and there was no significant effect of nitrogen on rolled plots. The interaction of root zone by nitrogen rate is presented in Table 35. On the sandier soil nitrogen had more of an impact on the bird beak holes with no significant difference on the native soil plots. Furthermore, the 80:20 had the most bird beak intrusions. This data is consistent with previous findings [Nikolai et al. 2001]. 63 Table 34. Number of bird beak holes in2 as afiected by rollingT and nitrogen rate}. 19 July 1999 Root zone 293 kg ha" 146 kg ha'I Rolled 7.05 5.42 Not Rolled 17.93 12.24 LSD (0.05,’ 1.81 LSD (005,1 5.85 T Rolling was applied three times per week from May till September with an Olathe lightweight green roller. 1 Nitrogen rates shown are annual rates which were applied in six equal increments from May through November . § Between nitrogen treatments at same rolling treatment. 1| Between rolling treatments at the same or difl‘erent level of nitrogen. Table 35. Number of bird beak holes m'2 as afl‘ected by root zone and nitrogen rateT. 19 July 1999 Root zone 293 kg liarI 146 kg 11ar 80:20 17.31 10.83 80:10:10 12.50 8.51 Native 7.66 7.15 LSD (005,1 2.21 LSD (0.05)“ 6-45 T Nitrogen rates shown are annual rates which were applied in six equal increments from May through November. 1 Between nitrogen means at same root zone. § Between root zone at the same or different level of nitrogen. 64 CONCLUSIONS The frequency of green rolling three times per week produced increased ball roll distance (BRD) without detriment to turfgrass quality. It is important to note that greens were on a fi'equent sand topdressing program. It is conceivable that if sand topdressing was not applied rolling may have negatively impacted soil physical properties and reduced turfgrass quality. Therefore, prior to initiating or suggesting a green rolling program of three times per week, consideration should be taken as to whether or not greens are on a frequent sand topdressing program. More money is spent trying to manage dollar spot than any other turfgrass disease [Vargas, 1994] and lightweight rolling consistently resulted in less dollar spot, most notably in the predominantly sandy root zones. Though some would argue that no amount of disease activity is tolerable, reductions in disease pressure could decrease the rate or frequency of fungicide applications required for adequate disease control [Williams and Powell, 1995]. While there are numerous theories as to why rolling reduced dollar spot no valid conclusion can be made from data collected in this study. Lightweight rolling also resulted in fewer broadleaf weeds and bird beak intrusions. Prior to the study it was hypothesized the lower rate of nitrogen (146 kg ha'1 year' 1) would result in increased color ratings in native root zones compared to the other two root zones due to greater nutrient retention. However, color and quality ratings resulted in no meaningful differences regarding the three different root zones. Greens with less soil generally had greater dollar spot symptoms. This supports observations by Couch and Bloom that higher soil moisture may reduce dollar spot development [Vargas, 1994]. 65 The lower rate of nitrogen had significantly greater BRD than the higher rate of nitrogen. There was also a trend as the difference in ball roll distance increased between the two nitrogen rates with differences of 8cm in 1998, 10cm in 1999, and 19cm in 2000. This may indicate the turf was becoming thinner with time at the lower N rate. Nitrogen rate consistently resulted in significant differences in dollar spot counts, but the amount of time that passed after the nitrogen application appeared to be a factor. The higher rate of nitrogen resulted in fewer dollar spot infections when nitrogen fertility averaged 14 days after application. The lower rate of nitrogen resulted in fewer dollar spot infections when nitrogen fertility averaged 32 days after application. This data supports the notion that light frequent applications of nitrogen are best for controlling the disease especially during periods of warm weather [Vargas, 1994]. Higher nitrogen rates also resulted in more bird beak intrusions as compared to the lower nitrogen rate. Ifthe bird beak intrusions were due to cutworm activity it makes sense the black cutworm moth would lay eggs in a succulent site for the best camouflage and nutrition of its young (verbal communication with Terry Davis). Significant localized dry spot (LDS) differences were observed in 2000. The higher nitrogen rate resulted in a larger % LDS than the lower nitrogen rate. At the higher rate LDS was reduced with the practice of rolling. The native soil and 80:20 root zones had more LDS than the 80: 10: 10 root zone. Potassium had no affect on color, quality, dollar spot, bird peak intrusions, LDS, or BRD. Additionally, BRD differences between the three rates of K averaged 3cm indicating the Stimpmeter can be utilized with a high degree of precision. 66 REFERENCES Anonymous, 1926. Rolling the fairways and putting greens. Bulletin of the Green Section of the US Golf Association. 6(3): 59. Beard, J. B., 1994. Turf rolling. Grounds Maintenance. 29(1) 44,46,48,52. DiPaola, J. M. and C. R. Hartwiger, 1994. Ball roll distance, rolling and soil compaction. Golf Course Management. 62(9): 49-51,78. Duich, J. M. 1983. Management factors affecting putting ball roll distance. In Proc. 53rd Michigan Turfgrass Conf., Vol 12, East Lansing, MI, 18-19 Jan. 1983 p. 76-77. Hamilton, G. W. Jr.; D. W. LivinBRDton, and A. E. Grover. 1994. The effects of light- weight rolling on putting greens. Science and Golf II, p. 425-430. Harbin, W. S., 1922. The effect of trampling and rolling on turf. Bulletin of the Green Section of the US. Golf Association. 2(5): 148-150. Hamilton, G. W., D. W. LivinBRDton, and A. E. Gover. 1994. The effect of light- weight rolling on putting greens. Science and Golf II, p.425-430. Hammerschmidt, R. 1999. Phytoalexins: what have we learned after 60 years? Annu. Rev. Phytopathol. 37:285-306. Hartwiger, C., 1996. The ups and downs of rolling putting greens. USGA Green Section Record. 34(4): 1-4. Hummel, N. W. 1993. Rationale for the revisions of the USGA green construction specifications. USGA Green Section Record. March/April: 7-21. Karcher, D., T. A. Nikolai, and R. N. Calhoun. 2001. Golfers’ perceptions of greens speeds vary. Golf Course Management 69(3):57-60. Kuehl, R. O. 1994. Statistical principles of research design and analysis. Duxbury Press. Belmont, CA. Lodge, T. A. and S. W. Baker. 1991. The construction, irrigation, and fertiliser nutrition of golf greens. II. Playing quality during the first year of differential irrigation and nutrition treatments. J. Sports Turf Res. Inst. 67: 44-52. Marschner, H. 1995. Mineral nutrition of higher plants 2“d Ed. Academic Press Inc, San Diego, CA. 67 Nikolai T. A., P. E. Rieke, J. N. Rogers, III, and J. M. Vargas Jr. 2001. Turfgrass and soil responses to lightweight rolling on putting green root zone mixes. Int. Turf. Soc. Res. J. 9:604-609. Piper, C. V. and R. A. Oakley. 1921. Rolling the turf. Bulletin of the Green Section of the US. Golf Association. 1(3): 36. Potter, D. A. 1998. Destructive turfgrass insects: Biology, diagnosis, and control. Ann Arbor Press, Chelsea, MI. Rieke, P. E. and M. T. McElroy. 1986. Turfgrass soil management research report-1985: [IV. Effect of topdressing program and nitrogen fertility on Penneagle creeping bentgrass green]. In Proc. 56th Michigan Turfgrass Conf., Vol 15, East Lansing, MI, 13-15 Jan. 1986 p. 7,9-10. Smiley, R. W. 1983. Compendium of turfgrass diseases. The American Phytopathological Society, St. Paul, MN. Throssell, C. S. and J. M. Duich. 1981. Management factors affect golf course ball roll distances. Science in Agriculture 28(4):9. USGA Greens Section Staff. 1996. Stimpmeter instruction booklet. USGA Golf House, Far Hills NJ. Vargas, J. M. Jr. 1994. Management of turgrass diseases. 2“cl ed. Lewis publishers, Boca Raton, FL. Williams, D. W. and A. J. Powell Jr. 1995. Dew removal and dollar spot on creeping bentgrass. Golf Course Management 63(8):49-52. 68 CHAPTER THREE RESPONSE OF PUTTING GREEN GRASS AND ROOT ZONE TO FERTILTIY AND ROLLING ABSTRACT A four-factor study (root zones split for rolling and split for nitrogen and potassium fertility) was utilized to study turfgrass growth and plant tissue and soil chemical analysis of three common putting green construction methods. Research greens were constructed with three different root zones: an 80:20 (sand: peat v/v) mixture constructed to USGA recommendations; an 80: 10: 10 (sand: soil: peat v/v) mixture 0.3m deep built with subsurface tile drainage; and a undisturbed sandy clay loam native soil green. Lightweight rolling consisted of plots rolled 3x/week and not rolled. Nitrogen rates were 146 and 293 kg ha'1 year'1 and potassium treatments were 0, 195, and 390 K20 kg ha'1 year'l. The study took place 3-7 years after the greens were seeded with ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.). All root zones were on a frequent sand topdressing program that accumulated in depth from 21-43mm over the length of the study. All four years soil chemical analysis data were collected the native soil root zone had higher levels of P, K, Ca, Mg, than the soil-less 80:20 root zone. However, few significant differences resulted between the 80:20 root zone and the 80:10:10 root zone. The reason the 80: 10:10 root zone did not result in consistently greater nutrient retention compared to the 80:20 root zone was most likely because differences in the cation exchange capacities were minimal and soil test samples included the sand topdressing layer (STL). 69 Approximately 7 5% of the roots were located in the STL regardless of the original root zone. Additionally, the native root zone had fewer roots in the 7.6-15.20m depth than the sandy root zones. The native root zone resulted in significantly more plant tissue K than the 80:20 root zone from 1997-1999. In 2000 no significant differences resulted from any of the root zones for any of the plant tissue nutrients. This could possibly be due to the fact that the STL was 43mm deep in 2000. Pooled root zone data resulted in few significant and no meaningful differences in clipping weights. However, rolling resulted in significantly less clippings the majority of the time and root zone by rolling interactions indicated the majority of the decrease was attributed to reduced clippings on the rolled 80: 10: 10 root zone. Rolling resulted in no consistent trends on soil tests and plant nutrient analyses. However, rolling significantly increased the amount of roots in the STL both years data was taken. The higher N rate decreased soil test K and P from 1998-2000. Clipping yields and plant tissue analyses indicate the decrease in soil K may be the result of increased growth and nutrient uptake related to the higher N rate. Results of plant tissue P were not consistent. Soil test K increased with increasing K20 fertility rates but fertility did not have a significant effect on any of the other cations reported in the soil test results. Though not always significant, the lowest K20 rate resulted in higher % Ca and %Mg in the plant tissue. Potassium had no effect on clipping weights but did result in increased root growth one year in the STL. 70 INTRODUCTION After World War II the game of golf became increasingly popular [Beard, 1994]. With this increase in play many native soil greens did not perform well because they did not posses adequate permeability [Garman, 1952]. The 1950’s were a decade of research that led to the development of the United States Golf Association (USGA) Green Section Specifications [Hummel, 1993]. The underlying principles associated with the USGA greens include the necessity of a drainage system to move excess water quickly fiom the site and a layered profile to create a perched water table for the conservation of moisture and nutrients in the root zone [Snow, 1993]. The majority of greens built since 1960 have been under the guidelines of the USGA recommendations and industry concerns have led to three revisions [Snow, 1993]. The latest revision included soils suitable for the mixing into the predominantly sand- based mix [Humme1, 1993]. Undoubtedly, the primary reason for adding soil to the mix is nutrient and moisture retention. Sands are free draining but the presence of nutrients naturally occurring in sand is limited and leaching potential is great which means greater care and management is required in the nutrition of sand greens [Isacc and Canaway, 1987]. Zontek [1990] wrote that green mixes should be prepared with soil to provide some silt and clay to improve nutrient availability. Certainly, fertilizer recommendations have changed over the years. In 1912 Hall wrote that no fertilizer containing potash should ever be used on golf course putting greens [Isaac and Canaway,, 1987]. Oakley [1925] suggested the possibility for the use of potassium but stated where a sufficiency of K existed none should be supplied. Work 71 performed by Christians et al. [1979] led them to conclude the role of potassium may play a more important role in turfgrass fertilization than previously realized. They noticed that as the level of K increased less N was required to attain maximum quality and concluded that additional work under field conditions was required to evaluate the importance of the interaction [Christians, et al., 1979]. Although the effects of K on turfgrasses have been studied for decades there is no consensus among turfgrass managers as to the proper K fertilization rates [Sartain, 2002]. Furthermore, no one has yet determined with any precision what soil levels of P or K are optimum for turfgrass growth [Turgeon,l996]. Many turfgrass managers believe increasing K rates relative to N will lead to improved disease resistance, heat, drought, and wear tolerance, and will enhance root growth. The analyses of turfgrass commercial fertilizers reflect the change in philosophy regarding K fertilization. Twenty years ago a common analysis was 23-3-3, but today analysis such as 20-3-15 and 30-0-30 are common as turf managers are being extreme by applying high levels of K and very low levels of N [Christians, 1998]. So while it is true that the relationship of nutrients in sand greens has received considerable attention [Christians et al., 1981, Isaac and Canaway, 1987, Dahlsson 1993, and Mitchel et al., 1978] there is filrther need for detailed nutrient management studies and the issue of potassium management in sand putting greens is urgently needed [Kussow, 1995]. Standard values for turfgrasses need to be established based on density, color, and other components of turf quality as well as grth and how a nutrient level could affect stress tolerance as very little research has been conducted on these relationships. [Carrow et al. , 2001] 72 Soil mixtures with grasses suitable for British Isles putting green conditions have been evaluated under different fertility regimes [Lodge et al. 1991, Lodge and Dawson 1993]. However, little data are available regarding the response of creeping bentgrass (Agrsotis palustris Huds.) maintained at putting green height to varying fertility levels growing on different soils. The objectives of this research were to compare the growth and soil and plant nutrient content of putting green turf under Michigan climatic conditions on differing soil types receiving different rates of nitrogen and potassium fertilizer. MATERIALS AND METHODS The research was conducted at the Hancock Turfgrass Research Center on the campus of Michigan State University, East Lansing, Michigan on a 1,3 88 m2 (36.6 x 36.6m) experimental putting green constructed in 1992 and seeded with ‘Penncross creeping bentgrass (Agrostis palustris Huds.) in spring, 1993. The three root zone mixes were: an 80:20 (sand: peat v/v) mixture constructed to USGA green recommendations; an 80: 10: 10 (sand: soil: peat v/v) mixture 0.3m deep built with subsurface tile drainage; and an undisturbed sandy clay loam (58% sand, 20.5% silt, and 21.5% clay) native soil green. The cation exchange capacity of the root zones was 5.8, 6.7, and 9.6 me/100g, respectively. Michigan peat was used in both sand mixes. Both sands were within USGA specifications for putting green root zone mixes (Table 1). Each putting green was 148.8 m2 (12.2 x12.2 m). They were arranged in a randomized complete block design with three replications of each green. Each 12.2 x 12.2m green had four Rain Bird Maxi Paw irrigation heads model number 2045A (Rain 73 Bird Distribution. Co. CA) at the corners for individual plot irrigation. Irrigation was applied on a daily basis with the exception of dry down periods to permit collection of data on the development of localized dry spot. The experimental design was a split-split-plot, randomized complete block design. Main plots were root zone mixes split for rolling (rolled 3x/week and not rolled). Rolling was split for two nitrogen rates and three potassium rates. Greens were constructed with the specific purpose of comparing among different root zones managed under similar management regimes. Each green was split into two 10.4 x 5.2m greens that were mowed at 0.4cm cutting height six times per week with a walk-behind Toro GM 1000 (Bloomington, MN) greens mower. One green from each construction plot was randomly selected and rolled three times per week (Monday, Wednesday, Friday) with an Olathe (Olathe Manufacturing Inc, Industrial Airport KS) lightweight green roller Model 396 from May through October 1997-2000. The other green in the same root zone block was not rolled and was utilized as a check. The Olathe roller had three smooth rollers that were 980 mm in length and 150 mm in diameter. The machine weighed 427 kg without an operator. The fertility program design was a 2 x 3 factorial with two nitrogen levels (146 and 293 kg ha’1 year") and three potassium levels (0, 195, and 390 kg ha'1 year"). The fiequency and rates of application are reported in Table 36. The fertility programs were evaluated over 18 subplots (3 reps x 3 soils x 2 rolling regimes). In 1997 individual plots designated as 0 kg ha'1 potassium received potassium based on October 1996 soil test results. No filrther potassium was applied on the 0 potassium plots in 1998-2000. Each fertility plot was 4.7 m2 (0.9 x 5.2 m). Fertilizer was applied with a LESCO (LESCO, 74 Inc. Rocky River, OH) drop spreader model 012587 with a 0.9 m drop width. Methylene urea applied as Nutralene 40-0-0 (The Andersons, Maumee, OH) was the nitrogen source during the warmer months with urea applications being made in May and November of each year. Potassium sulfate (0—0-50) was the potassium source. Phosphorous (P) was not a factor in the study however; P data fi'om soil tests and plant tissue analysis are reported. Triple superphosphate (0-46-0) was applied to the entire area when the common visual P deficiency (purpling of the leaf tissue) was observed on some plots. Applications of P took place in 1996 (49 kg ha’1 year'l) 1998 (98 kg ha'1 year—l) and 1999 (98 kg ha'1 year'l). Turfgrass clippings were collected in the bucket of the walk behind mower prior to fertility application from May through September. A single pass was made down the middle of each plot. Clippings were placed in a paper bag and oven dried at 60° C for 48 hours before recording the weights. Samples obtained in this manner in spring of each year were analyzed for plant tissue nutrient concentration prior to initiation of the annual fertility program. Total nitrogen of the clippings was determined using the micro- Kjeldahl procedure using Lachat flow injection analyzer [Homeck and Miller, 1998] and total spectrographic analysis was determined by dry ashing procedure samples analyzed using DCP [Miller, 1998]. In the fall of 1996, 1998, 1999, and 2000 soil samples were collected from each plot for soil chemical analysis with a 1.9cm diameter soil probe. After removal from the soil the verdure was removed and the succeeding 0-7.6 cm depth was used for chemical analysis. All plots were on a sand topdressing program and therefore each year more sand was in each sample. Six samples were taken form each plot. Extractable K, 75 calcium (Ca), and magnesium (Mg) were determined with neutral (pH 7.0) 1M NHaOAc (ammonium acetate) [Warncke and Brown, 1998]. Phosphorus was determined by the Bray and Kurtz P-l extractant (0.03M NH4F + 0.025 M HCl) to assess plant-available P[Frank er al., 1998]. Soil pH was determined using a 1 soil: 1 water mixture with 1 drop of 1.0 M Ca C12. [Watson and Brown, 1998]. August 1999 and 2000 root samples were collected from three depths (STL, 0- 7.6cm, and 7.6-15.2cm) with a 3.20m diameter soil probe. Three samples were taken from each depth on each fertility plot for root grth estimates. Roots were washed free of soil, oven dried at 65°C for 24 hours and weighed. Analyses of variance for clipping and root weights and soil and plant chemical analysis were performed on pooled measurements followed by Fischer’s protected Least Significant Difference (LSD) if differences were found at P2 0.05. The LSD was used to compare differences of mean numbers among the different treatments. All data were analyzed using MSTAT [1993] with the exception of standard error estimators for interactions in the split-split-plot design. Interactions were computed by hand with the appropriate degrees of freedom for interactions determined by the procedure introduced by Satterthwaite [Kuehl, 1994]. Numerous interactions occurred and only meaningful interactions that occurred on more than one date will be presented and discussed. Table 36. Fertility frequency and rates in kg ha ‘1, 1997 -20007. Treatment May June July Aug. Sept. Nov. Nitrogen 48.8 48.8 48.8 48.8 48.8 48.8 Nitrogen 24.4 24.4 24.4 24.4 24.4 24.4 K20* K20 48.7 48.7 48.7 48.7 K20 98.0 48.7 48.7 48.7 48.7 98.0 T Fertility study initiated in August 1996. I In 1997 individual plots received soil test recommendations with 0 K20 applied from 1998- 2000. 76 RESULTS AND DISCUSSION Soil Chemical Analyses Soil samples for chemical analysis were taken in October 1996, 1998, 1999, and 2000. The pH levels of the 80:20, 80: 10: 10, and native root zones were 7 .8, 7.8, and 7.7, respectively at the initiation and conclusion of the study (data not shown). The fertility study was initiated August 1996. The short duration between initiation of the study and the first sampling is most likely the reason no significant differences were observed regarding nitrogen (N) and potassium (K) rates in 1996 (Table 37). The native soil green had higher levels of phosphorous (P), K, Ca, and Mg, than the 80:20 root zone all four years (Tables 37-40). With the exception of Ca being lower in the 80:20 root zone in 2000 no significant differences were observed in soil tests between the 80:20 and the 80: 10: 10 root zones. Higher N rates resulted in significantly less P and K in the root zones fi'om 1998- 2000. Increases in N rates have been shown to decrease P and K in root zones attributed to higher uptake of P and K associated with more vigorous growth and greater demand for nutrients [Colclough and Lawson, 1990]. Furthermore, since clippings are removed fi'om the site there is no recycling of nutrients. In 1999 and 2000 higher N rates resulted in significant increases in the amount of Mg in the soil and in 1999 Ca also significantly increased with the higher N rate. Since less K was in the soil at the higher N rate, and Mg and Ca compete for exchange sites with K, it is intuitive that more Mg and Ca in soil tests would be the result. Consistent with increasing K fertility, higher soil test K were in the soil. 77 A two-way interaction between root zones and N rates on soil test K occurred in 1998 and 2000 (Table 41). In both years, N rate had no effect on the amount of K in the 80:20 root zone while the native soil had significantly less K at the higher N fertility rate. The 80: 10: 10 root zone had significantly less soil K with increasing N in 1998 but the difference was not significant in 2000. Furthermore, native soil had greater soil K at both N rates than the other two root zones both years. In 1998 the 80:20 had significantly less soil K than the 80: 10: 10, but there were no significant differences between the two in 2000. Potassium rate x soil interactions from 1998 and 2000 are in Table 42. The native soil and 80: 10: 10 root zones had significantly more soil test K with increasing K rates. However, the 80:20 root zone resulted in no significant differences between the zero and 195 kg ha 4 rates both years interactions occurred. Regardless of the K fertility rate the native root zone had more soil K than the other two-root zones. In 1998 the zero K rate resulted in no significant difference between the 80:20 and 80: 10:10 mixes but the 80: 10: 10 did have significantly more K than the 80:20 at the other two K fertility rates. In 2000, there were no significant difference between 80:20 and the 80: 10: 10 root zones at any K rate. Research conducted by Dest and Guillard [2001] suggests that release of K from primary minerals in some root zones with high sand content proceeds at rates to satisfy bentgrass requirement for K. 78 Table 37. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on soil chemical tests, October 1996. Soil chemical tests, kg ha’1 Root zone P K Ca Mg 80:20 26b 63b 2675b 288b 80: 10:10 57ab 73b 2895b 276b Native 98a 199a 3602a 619a Significance 4t cal-a1: u an Rolling Rolled 60 105 3077 369 Not Rolled 61 117 3038 420 Significance NS NS NS * Annual N rate“ 293 kg ha" 61 112 3095 404 146 kg ha" 60 111 3020 384 Significance NS NS NS NS Annual K rate’ 0 kg ha’“ 63 112 3119 408 195 kg ha" 58 107 2990 381 390 kg ha" 60 116 3062 394 Significance NS NS NS NS Mean squares Source df Replication 2 2855 1153 359956 49259 Root zone (S) 2 47160* 206848*** 8437006" 1367587" Error 4 5281 1925 575018 41843 Rolling (R) 1 86 4008 40200 71948“ SR 2 960 2304 55631 7385 Error 6 357 718 241915 6860 Nitrogen (N) 1 22 65 149669 9996 SN 2 249 605 13412 2554 RN 1 394 1449 37899 340 SRN 2 626 690 151224 2582 Potassium (K) 2 263 642 149089 6425 SK 4 69 356 19090 980 RK 2 160 803 61511 534 SRK 4 275 488 20159 835 NK 2 266 977 96918 602 SNK 4 112 453 69067 2059 RNK 2 20 1194 200330 3594 SNRK 4 342 533 73400 1886 Error 60 213 602 74466 3186 *, *"‘, **"‘ Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). § Fertility portion of research initiated August 1996. 1] Soil test results from individual plots received soil test recommended rates of K in 1997. 79 Table 38. Main effects and mean squares for treatment efl‘ects of root zone, rolling, nitrogen and potassium fertilization on soil chemical tests, October 1998. Soil chemical tests, kg ha'1 Root zone P K Ca Mg 80:20 29b 45b 2915b 284b 80:10: 10 63ab 676 3178ab 2656 Native 97a 215a 3507a 582a Si ' canoe It INN! It I"! Rolling Rolled 63 108 3173 353 Not Rolled 63 110 3227 401 Significance NS NS NS ** Annual N rate 293 kg ha" 60 100 3193 380 146 kg ha“ 66 118 3207 374 Significance "' *** NS NS Annual K rate 0 kg ha" 66 80c 3166 379 195 kg ha" 61 996 3218 379 390 kg ha" 61 148a 3216 372 Significance NS *** NS NS Mean squares Source df Replication 2 5023 1274 384367 25788 Root zone (S) 2 42072* 305815m 3161336“ 1139051" Error 4 4488 1158 417209 19772 Rolling (R) 1 1 148 81073 63803" SR 2 71 1886 131378 10121 Error 6 681 504 98950 3249 Nitrogen (N) 1 817* 8503*“ 5635 1019 SN 2 251 2837*" 5566 425 RN 1 5 340 23720 1994 SRN 2 198 231 22719 414 Potassium (K) 2 207 43370*** 31167 627 SK 4 148 6312*" 19449 3087 RK 2 68 77 67420 4024 SRK 4 15 220 54794 238 NK 2 296 146 2627 2347 SNK 4 151 365 28958 1923 RNK 2 85 20 4130 881 SNRK 4 73 421 73281 1784 Error 60 209 254 32533 1664 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 80 Table.39. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on soil chemical tests, October 1999. Soil chemical tests, kg ha’1 Root zone P K Ca Mg 80:20 456 696 22236 2816 80:10:10 80ab 856 24496 2656 Native 113a 201a 3112a 484a Si ' canoe * In"! III I"! Rolling Rolled 78 121 2647 334 Not Rolled 81 116 2542 352 Significance NS NS * NS Annual N rate 293 kg ha" 75 107 2641 353 146 kg ha" 84 130 2548 334 Significance It!!! *4“! t I": Annual K rate 0 kg ha'I 83 77c 2582 346 195 kg ha" 77 1206 2633 348 390 kg ha" 78 158a 2570 335 Significance NS *** NS NS Mean squares Source df Replication 2 4561 9254* 651809 27641 Root zone (S) 2 41622* 185788*** 7682524* 540469** Error 4 3433 1191 489424 19894 Rolling (R) l 294 558 297360* 8523 SR 2 336 972 221578* 668 Error 6 663 871 33070 4983 Nitrogen (N) 1 2366** 13694*** 233258* 9888** SN 2 233 2091** 88310 1467 RN 1 841 128 6897 810 SRN 2 32 488 6756 325 Potassium (K) 2 327 59467*** 39913 1697 SK 4 223 6710*** 15591 904 RK 2 274 416 21006 541 SRK 4 412 412 11980 1660 NK 2 115 1974** 95231 981 SNK 4 161 881* 28187 698 RNK 2 67 240 12152 514 SNRK 4 337 481 65655 1284 Error 60 258 286 36115 922 **, **, "* Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly difi‘erent according to LSD (0.05). 81 Table 40. Main efl‘ects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on soil chemical tests, October 2000. Soil chemical tests, kg ha" Root zone P K Ca Mg 80:20 276 666 2642c 2156 80: 10: 10 56ab 716 29936 2056 Native 81a 2173 3623a 404a Significance III in“: 1H! “I Rolling Rolled 55 117 3110 267 Not Rolled 54 119 3061 283 Significance NS NS NS NS Annual N rate 293 kg ha'I 48 108 3119 282 146 kg ha" 61 128 3053 268 Significance **Il: INN! NS II Annual K rate 0 kg ha" 57 80c 3137 283 195 kg ha" 53 1116 3041 270 390 kg ha1 55 163a 3080 272 Significance NS *** NS NS Mean squares Source df Replication 2 4032 615 1089423 29254 Root zone (S) 2 26721* 263342*** 8908812** 454309** Error 4 3233 1131 268396 12538 Rolling (R) 1 28 173 65393 6772 SR 2 106 3162** 366430 7558 Error 6 233 241 298716 6617 Nitrogen (N) 1 4371*** 10278*** 119041 4632* SN 2 836** 44l6*** 25985 983 RN 1 143 13 5782 119 SRN 2 323 304 54287 599 Potassium (K) 2 116 62359*** 83379 1721 SK 4 28 10912*** 44079 1062 RK 2 194 31 84099 1225 SRK 4 100 1270* 88011 1386 NK 2 30 1838* 41992 711 SNK 4 58 701 26183 727 RNK 2 43 52 92030 1861 SNRK 4 46 67 138129* 634 Error 60 125 422 54673 712 *, "**, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. T Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 82 Table 41. Soil potassium tests in kg ha’1 as affected by root zone and nitrogen rate’. October, 1998 October, 2000 Root zone 293 kg ha" N 146 kg ha" N 293 kg ha" N 146 kg ha“ N 80:20 44 46 64 68 80: 10: 10 60 74 66 76 Native 196 233 194 239 LSD (003* 10.6 13.7 LSD (005,5 13.6 14.8 T Nitrogen rates shown are annual rates which were applied in six equal increments from May through November. 1 Between nitrogen means at same root zone. § Between root zone at the same or different level of nitrogen. Table 42. Soil potassium tests in kg ha" as affected by root zone and potassium ratel. October, 1998 October, 2000 Root zone 0 kg ha" 195 kg ha" 390 kg ha" 0 kg ha:1 195 kg ha" 390 kg ha“ 80:20 30.4 42.0 63.4 48.6 60.7 88.7 80: 10; 10 45.2 59.5 97.0 44.8 67.2 100.9 Native 165.2 196.9 282.3 147.6 203.9 298.2 LSD (0.5,: 13.0 16.8 LSD (0.05)5 15.5 17.7 T Potassium rates shown are annual rates that were applied from May through November. 1 Between potassium means at same root zone. § Between root zone at the same or different level of potassium. Plant Tissue Nutrient Analyses Plant tissue macronutrient analysis data from 1997-2000 are presented in Tables 4346, respectively. Sufficiency ranges for nutrient concentrations in turfgrass are only general as specific ranges have not been developed for most turfgrass species and cultivars, yet all four years tissue nutrient analyses were taken every primary macronutrient fell within the common sufficiency range [Carrow et al., 2001]. However, using creeping bentgrass sufiiciency standards [Mills and Jones, 1996] the %N and %K were always below sufficiency standards while %P was within standard the first two years but decreasing to below sufficiency standards by the final year In 1997-1999 the native root zone resulted in significantly higher tissue %K than the 80:20 root zone, which was only significantly different than the 80: 10: 10 root zone in 83 1998. That year the 80: 10: 10 root zone resulted in a higher %K in the plant tissue. In 2000 no significant differences resulted from pooled root zone data for %K in the plant tissue. The only other nutrients that were found at significantly difi‘erent percentages in plant tissue regarding root zone were the P and sulfur (S) in 1999. Both nutrients were found in higher concentrations growing in turf in the native soil than in the 80:20 root zone with no difference between the predominantly sandy root zones. Rolling resulted in minimal significant differences in tissue nutrient content. In 1998 rolling resulted in a significant increase in the amount of K in the tissue and in 1999 rolling resulted in a decrease in the amount of P. Higher N fertility rates resulted in increased plant tissue N and K all four years. Since higher N rates also resulted in decreases in soil test K (Tables 38-40) the data is consistent with the theory that higher N rates may decrease root zone K because there is higher K uptake due to more vigorous grth and greater demand for nutrients [Colclough and Lawson, 1990]. Higher N rates also resulted in significantly less %Mg and %P in 1997 and %Ca in 2000. In 2000 the % P in the plant tissue increased with higher N rate, as did the % S. As K fertility rates increased tissue K increased in 1997 and 1999 with decreases in the percentages of Ca and Mg in the plant tissue both of those years. No differences resulted in plant tissue nutrients as affected by K fertility in 1998. In 1999 zero-K fertility plots had significantly less in %K in leaf tissue than the 195 and 390 kg ha'1 K fertility rates with an inverse relationship resulting in an increase in the % Ca in the plant tissue. 84 The majority of interactions were not duplicated over years and no obvious trends from percentage of nutrients in leaf tissue were evident in interactions that occurred more than one year (data not shown). Table 43. Main efl‘ects and mean squares for treatment efi‘ects of root zone, rolling, nitrogen and potassium fertilization on macronutrient content of Agrostis palustris cv. Penncross clippings, May, 1997. Percentage of nutrients in the leaf tissue Root zone N P K Ca Mg S 80:20 3.58 0.35 1.77 6 0.676 0.273 0.457 80:10:10 3.73 0.36 1.90 ab 0.660 0.257 0.431 Native 3.71 0.38 2.02 a 0.594 0.241 0.439 Significance NS NS ** NS NS NS Rolling Rolled 3.68 0.36 1.88 0.655 0.255 0.437 Not Rolled 3.67 0.36 1.91 0.632 0.260 0.447 Significance NS NS NS NS NS NS Annual N rate 293 kg ha“ 3.81 0.36 1.94 0.637 0.253 0.443 146 kg ha" 3.54 0.37 1.85 0.650 0.261 0.442 Significance "it: :1: “HI! NS 41* NS Annual K rate 0 kg ha" 3.66 0.36 1.83 c 0.673a 0.262 a 0.442 195 kg ha" 3.70 0.37 1.90 6 0.6436 0.259 a 0.443 390 kg ha" 3.67 0.36 1.95 a 0.615c 0.251 6 0.442 Significance NS NS *** *** *** NS Mean Squares Source df Replication 2 0.141 0.002 0.112 0.057 0.001 0.010 Root zone (S) 2 0.243 0.007 0.577" 0.068 0.009 0.007 Error 4 0.189 0.014 0.027 0.053 0.008 0.006 Rolling (R) 1 0.007 0.000 0.034 0.014 0.001 0.003 SR 2 0174* 0.012 0.137 0.011 0.000 0.005 Error 6 0.028 0.006 0.090 0.011 0.001 0.005 Nitrogen (N) 1 1920*" 0002* 0259*“ 0.004 0.002“ 0.000 SN 2 0.043 0002* 0.011 0015* 0001* 0.002 RN 1 0.065 0.000 0.007 0.000 0.000 0.000 SRN 2 0.003 0.000 0.009 0.001 0.000 0.001 Potassium (K) 2 0.012 0.001 0141"" 0031*" 0001*" 0.000 SK 4 0.008 0.000 0.004 0.000 0.000 0.001 RK 2 0.003 0.000 0.002 0.005 0.000 0.000 SRK 4 0.024 0.000 0.005 0.002 0.000 0.000 NK 2 0.004 0.000 0.000 0.002 0.000 0.000 SNK 4 0.017 0.000 0.013 0.003 0.000 0.000 RNK 2 0.001 0.000 0.002 0.000 0.000 0.000 SNRK 4 0.021 0.000 0.003 0.003 0.000 0.000 Error 60 0.017 0.0005 0.008 0.003 0.00015 0.001 ‘, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). § Soil test results from individual plots received soil test recommended rates of K in 1997. 85 Table 44. Main efi‘ects and mean squares for treatment efi'ects of root zone, rolling, nitrogen and potassium fertilization on macronutrient content of A grostis palustris cv. Penncross clipgings, May, 1998. Percentage of nutrients in the leaf tissue Root zone N P K Ca Mg 80:20 3.81 0.31 1.75c 0.96 0.28 80:10:10 4.01 0.31 1.926 0.83 0.24 Native 3.96 0.37 2.05a 0.67 0.23 Significance NS NS ** NS NS Rolling Rolled 3.85 0.32 1.88 0.84 0.25 Not Rolled 4.00 0.34 1.94 0.79 0.25 Significance NS NS * NS NS Annual N rate 293 kg ha" 4.26 0.33 1.94 0.79 0.25 146 kg ha" 3.59 0.33 1.88 0.84 0.25 Significance *** NS *** NS NS Annual K rate 0 kg ha" 3.90 0.34 1.92 0.80 0.25 195 kg ha" 3.95 0.33 1.89 0.83 0.25 390 kg ha" 3.92 0.32 1.92 0.82 0.25 Significance NS NS NS NS NS Mean Squares Source df Replication 2 0.216 0.004 0.013 0.029 0.004 Root zone (S) 2 0.380 0.037 0.821** 0.857 0.023 Error 4 0.152 0.016 0.033 0.171 0.017 Rolling (R) 1 0.573 0.017 0112* 0.066 0.000 SR 2 0.046 0018* 0.019 0194* 0.016 Error 6 0.106 0.004 0.017 0.040 0.004 Nitrogen (N) 1 12.369*** 0.000 0.110*** 0.076 0.001 SN 2 0.005 0.002 0.001 0.004 0.000 RN 1 0.026 0003* 0.032 0.005 0.002 SRN 2 0.134 0.002 0028* 0.029 0.000 Potassium (K) 2 0.024 0.002 0.009 0.006 0.000 SK 4 0.057 0.000 0.005 0.015 0.002 RK 2 0.189 0.002 0.026 0.051 0.002 SRK 4 0.026 0.000 0.004 0.012 0.001 NK 2 0.098 0.000 0.001 0.070 0.005 SNK 4 0.177 0.003** 0.043** 0107* 0007* RNK 2 0.410** 0.000 0.008 0119* 0008* SNRK 4 0.049 0.002** 0.015 0084* 0005* Error 60 0.071 0.001 0.009 0.033 0.002 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 86 Table 45. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on macronutrient content of A grostis palustris cv. Penncross clippingg, May, 1999. Percentage of nutrients in the leaf tissue Root zone N P K Ca Mg S 80:20 3.20 0.28 6 1.50 6 0.995 0.304 0.328 6 80:10:10 3.43 0.29 6 1.49 6 1.002 0.289 0.355 ab Native 3.56 0.33 a 1.73 a 0.972 0.301 0.362 a Significance NS ** * NS NS * Rollifl Rolled 3.37 0.29 1.56 0.976 0.292 0.339 Not Rolled 3.36 0.30 1.59 1.003 0.304 0.358 Significance NS * NS NS NS NS Annual N rate 293 kg ha" 3.50 0.30 1.61 0.976 0.300 0.354 146 kg ha" 3.23 0.30 1.53 1.003 0.295 0.343 Significance *** NS *** NS NS NS Annual K rate 0 kg lia'I 3.39 0.30 a 1.49 c 1.036 a 0.310 a 0.353 195 kg ha" 3.36 0.30 a 1.58 6 0.986 6 0.298 ab 0.344 390 kg ha" 3.52 0.29 6 1.66 a 0.947 6 0.286 6 0.348 Significance NS It It" "It *** NS Mean Squares Source df Replication 2 0.17 0.01 0.17 0.056 0.003 0.002 Root zone (S) 2 0.71 0.02** 070* 0.009 0.002 0012* Error 4 0.11 0.001 0.09 0.083 0.003 0.002 Rolling (R) 1 0.01 001* 0.03 0.019 0.004 0.010 SR 2 004* 000* 0.07 0.005 0.001 0.003 Error 6 0.01 0.001 0.06 0.012 0.002 0.002 Nitrogen (N) 1 1.90*** 0.00 0.17*** 0.020 0.001 0.003 SN 2 0.01 0.00 0.02 0.004 0.001 0.001 RN 1 0.00 000* 004* 0.023 0.002 0.001 SRN 2 0.01 0.00 0.02 0.067*** 0.004** 0.001 Potassium (K) 2 0.01 0.00 0.26*** 0.072*** 0.005*** 0.001 SK 4 0.00 0.00 0.14 0.008 0.000 0.001 RK 2 0.00 0.00 0.00 0.001 0.000 0.001 SRK 4 0.00 0.00 0.01 0.005 0.000 0.001 NK 2 0.00 0.00 0.02 0.004 0.000 0.001 SNK 4 0.01 0.00 0.00 0.001 0.000 0.001 RNK 2 0.00 0.00 0.01 0.004 0.000 0.000 SNRK 4 0.00 0.00 0.01 0.002 0.000 0.002 Error 60 0.01 0.0002 0.01 0.007 0.001 0.001 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 87 Table 46. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on macronutrient content of Agrostis palustris cv. Penncross clippings, May, 2000. Percentage of nutrients in the leaf tissue. Root zone N P K Ca Mg S 80:20 2.88 0.27 1.71 2.107 0.603 0.342 80:10: 10 2.99 0.28 1.75 2.074 0.607 0.336 Native 2.92 0.29 1.83 1.998 0.605 0.316 Si ' cance NS NS NS NS NS Ns Rolling Rolled 2.95 0.29 1.78 2.075 0.604 0.332 Not Rolled 2.91 0.27 1.75 2.044 0.607 0.330 Significance NS NS NS NS NS Ns Annual N rate 293 kg ha“ 3.16 0.29 1.82 1.962 0.586 0.348 146 kg ha" 2.71 0.27 1.71 2.158 0.625 0.315 Significance *** tn: *** II NS “It Annual K rate 0 kg ha" 2.90 0.28 1.61 6 2.230 a 0.639 0.331 195 kg ha" 2.94 0.28 1.82 a 1.966 6 0.585 0.334 390 kg ha" 2.96 0.28 1.87 a 1.984 6 0.592 0.329 Significance NS NS *** * NS NS Mean square Source df Replication 2 0.001 0.001 0.042 0.238 0.043 0.001 Root zone (S) 2 0.098 0.004 0.135 0.112 0.000 0.007 Error 4 0.241 0.001 0.024 2.129 0.165 0.003 Rolling (R) 1 0.041 0.000 0.026 0.026 0.000 0.000 SR 2 0279* 0.002 0.110 0.056 0.002 0.002 Error 6 0.031 0.002 0.061 0.137 0.010 0.002 Nitrogen (N) 1 5.567*** 0.005** 0.341*** 1040* 0.041 0.030*** SN 2 0.003 0.00 0.013 0.060 0.002 0.001 RN 1 0.009 0.002 0.043 0.002 0.000 0.001 SRN 2 0.046 0.000 0.003 0.108 0.008 0.000 Potassium (K) 2 0.033 0.000 0.731*** 0783* 0.030 0.000 SK 4 0.016 0.000 0.011 0.137 0.013 0.000 RK 2 0.017 0.000 0.011 0.127 0.010 0.000 SRK 4 0.017 0.000 0.022 0.275 0.022 0.000 NK 2 0.030 0.000 0.040 0.115 0.005 0.001 SNK 4 0.037 0.001 0.031 0.185 0.011 0.001 RNK 2 0.018 0.002 0.055 0.249 0.011 0.002 SNRK 4 0.016 0.000 0.018 0.209 0.014 0.000 Error 60 0.036 0.001 0.028 0.235 0.015 0.001 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 88 Clipping Weights Turfgrass clippings were collected on 15 dates from 1997-2000 (Tables 47-49). Of the 15 collection dates root zone resulted in significant data on only three occasions with no obvious trend resulting. On eight of the 15 dates rolling three times per week resulted in lower yields. Higher N fertility consistently produced more yields. Potassium had no effect on the amount of clippings. Interactions repeated over the years included six soils x nitrogen rate interactions (Tables 50-51). In all six interactions the higher nitrogen rate resulted in more yield than the lower nitrogen rate for all three-root zones. Beyond that, no general trend applies though in most cases the native soil produced more clippings than the 80:20 with little difference between the 80:20 and 80: 10: 10. High yields are not necessarily the goal with turfgrasses [Carrow et al., 2001], in fact lower yields are preferable as long as acceptable color, quality, and stress tolerances are maintained. Seven soil x rolling interactions occurred in the data (Table 52-53). On all seven dates rolling resulted in no significant differences in yield in the native root zone and on only one date (17 June 1997) rolling resulted in fewer clippings in the 80:20 root zone. However, rolling consistently reduced the amount of clippings in the 80: 10: 10 root zone. 89 Table 47. Main efi’ects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on clipping weights, 1997 and 1998. Clipping weight in grams 1997 1998 Root zone 17 June 6 Oct. 5 May 13 June 22 July 27 Aug. 80:20 7.52 6.78 18.54 28.95 7.02 11.89 80:10:10 9.26 7.21 19.68 33.16 8.21 12.17 Native 8.28 7.72 20.85 33.39 8.76 13.33 Significance NS NS NS NS NS NS Rolling Rolled 7.51 6.61 18.73 28.74 8.03 9.22 Not Rolled 9.20 7.86 20.65 34.93 7.97 15.70 Significance an: an: :1- 4: NS *** Annual N rate 293 kg lta'r 9.63 7.93 23.07 35.14 9.54 16.13 146 kg 1a1 7.07 6.54 16.31 28.53 6.46 8.80 Significance *** *** *** *** *** *** Annual K rate 0 kg lta'T 8.37 7.24 19.75 32.31 8.11 13.19 195 kg ha" 8.52 7.12 19.57 32.06 7.89 11.64 390 kg 1a1 8.17 7.34 19.76 31.12 7.99 12.56 Significance NS Ns NS NS NS NS Mean square Source df Replication 2 0.35 3.05 73.16 215.04 18.96 122.23 Root zone (S) 2 27.30 8.05 47.96 225.40 28.37 21.15 Error 4 21.26 17.39 81.15 739.41 12.28 69.81 Rolling (R) 1 76.57** 41.81** 9938* 1032.93* 0.08 1134.26*** SR 2 21. 15* 38.19** 219.71** 322.55 2.59 51.37 Error 6 4.05 3.62 14.80 120.69 1.68 27.36 Nitrogen (N) 1 176.74*** 52.36*** 1234.92*** 1180.08*** 256.38*** 1452.00*** SN 2 511* 1.99 2144* 42.68 2.36 0.78 RN 1 0.19 0.65 16.18 117.40 0.72 17.93 SRN 2 3.02 0.54 3.76 72.72 0.80 32.26 Potassium (K) 2 1.11 0.45 0.40 14.12 0.42 22.01 SK 4 1.00 1.80 0.19 57.69 0.37 7.84 RK 2 1.55 2.17 4.33 3.45 1.21 21.18 SRK 4 1.99 1.22 3.85 77.66 0.40 9.20 NK 2 0.44 0.85 8.62 24.17 0.38 36.69 SNK 4 1.33 2.88 3.95 18.79 0.38 4.72 RNK 2 1.31 0.64 2.98 23.09 0.23 15.68 SNRK 4 1.00 1.82 9.12 44.50 2.26 16.34 Error 60 1.19 1.76 5.30 33.47 1.27 22.53 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 90 Table 48. Main efi'ects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on clipping weights, 1999. Clipping weight in grams Root zone 12 May 18 June 26 July 9 Sep. 7 Oct. 80:20 14.44 13.99 13.85 3.64 3.85 80: 10: 10 17.11 14.49 14.03 3.33 4.28 Native 22.60 15.25 17.59 3.64 5.03 Significance * NS * NS NS Rolling Rolled 17.85 14.42 14.72 3.17 3.97 Not Rolled 18.25 14.74 15.60 3.91 4.81 Significance NS NS NS * ** Annual N rate 293 kg ha‘I 20.44 17.01 17.07 3.83 5.71 146 kg ha'1 15.66 12.14 13.54 3.24 3.07 Significance ttt ttt ttt ttt ttt Annual K rate 0 kg ha" 18.21 14.45 15.44 3.67 4.66 195 kg ha'1 17.89 14.77 15.01 3.47 4.37 390 kg ha‘1 18.05 14.51 15.02 3.47 4.14 Significance NS NS NS NS NS Mean square Source df Replication 2 52.61 20.57 23.56 9.45 2.93 Root zone (S) 2 623.48“ 14.48 160.50“ 1.12 12.97 Error 4 45.46 9.96 18.85 1.59 3.97 Rolling (R) l 4.32 2.83 20.93 1481* 19.34“ SR 2 67.65 18.15“ 11.81 2.56 18.58" Error 6 15.06 1.38 7.63 2.34 1.21 Nitrogen (N) 1 618.29*** 639.43*** 369.37*** 948*" 188.55*** SN 2 18.54 5.01* 1017* 0.40 4.48 RN 1 18.53 1.38 1.81 0.33 1.36 SRN 2 3.91 4.17 5.67 0.58 1.15 Potassium (K) 2 0.93 1.04 2.19 0.45 2.44 SK 4 8.62 0.49 3.89 1.93* 0.64 RK 2 8.77 0.52 2.26 0.45 0.87 SRK 4 2.92 0.69 3.48 1.87* 0.26 NK 2 16.68 2.43 6.15 212* 0.45 SNK 4 2796* 2.87 5.86 1.12 0.37 RNK 2 3.20 1.08 1.03 0.19 0.98 SNRK 4 9.00 1.70 4.39 1.69* 2.03 Error 60 8.88 1.48 3.25 0.61 1.64 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 91 Table 49. Main effects and mean squares for treatment efiects of root zone, rolling, nitrogen and potassium fertilization on clipping weights, 2000. Clipping weight in grams Root zone 15 May 20 June 24 July 6 Sep. 80:20 12.49 9.14 7.17 32.86 80: 10:10 12.55 10.37 4.86 24.78 Native 14.58 11.62 4.16 30.42 Significance NS NS ** NS Rolling Rolled 12.99 8.43 5.42 25.65 Not Rolled 13.43 12.33 4.38 33.06 Significance NS *** NS NS Annual N rate 293 kg ha“ 16.03 13.02 7.25 39.04 146 kg ha1 10.39 7.74 3.55 19.67 Sigificance ttt ttt ttt ttt Annual K rate 0 kg ha" 13.56 10.31 5.37 28.86 195 kg ha" 13.32 9.92 5.53 29.64 390 kg ha“ 12.75 10.91 5.29 29.56 Significance NS NS NS NS Mean square Source df Replication 2 22.23 38.95 4253* 767.59 Root zone (S) 2 51.00 55.63 89.16" 618.68 Error 4 19.23 138.82 3.18 1873.11 Rolling (R) 1 5.33 412.23*** 0.04 1481.48 SR 2 41.98 108.83** 11.79** 666.23 Error 6 8.81 9.94 0.72 338.51 Nitrogen (N) 1 857.90*** 751.03*** 370.37*** 10130.70*** SN 2 1438* 1.16 30.06*** 150.73 RN 1 3.63 13.65 1.97 151.70 SRN 2 1.15 14.60 0.97 360.73 Potassium (K) 2 6.21 8.83 0.52 6.56 SK 4 5.44 8.21 2.07 137.49 RK 2 5.70 3.94 0.65 121.56 SRK 4 5.66 4.14 1.54 115.61 NK 2 0.78 23.28 0.19 43.73 SNK 4 3.61 2.25 0.72 99.22 RNK 2 1.83 2.36 0.56 129.84 SNRK 4 1059* 4.97 0.33 53.83 Error 60 3.48 8.49 1.70 138.02 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 92 Table 50. Clipping weight (g) as affected by root zone and nitrogen ratei, June, 1997-June, 1999. 17 June 1997 5 May 1998 18 June 99 Root zone 293 kg ha" 146 kg ha" 293 kg ha‘T 146 kg ha" 293 kg ha'1 146 kg ha" 80:20 8.48 6.57 22.76 14.32 16.85 11.13 80:10:10 10.96 7.57 22.91 16.46 16.75 12.23 Native 9.46 7.09 23.55 18.15 17.43 13.07 LSD (005,1 0.73 1.53 0.78 LSD (005,“ 2.24 3.19 1.59 T Nitrogen rates shown are annual rates that were applied in six equal increments from May through November. 1 Between nitrogen means at same root zone. § Between root zone at the same or difl‘erent level of nitrogen. Table 51. Clipping weight (g) as afi'ected by root zone and nitrogen rateT, July, 1999-July, 2000. 26 July 1999 15 May 2000 24 July 2000 Root zone 293 1g ha" 146 kg lia'I 293 kg haT 146 kg ha" 293 kg ha" 293 kg ha" 80:20 16.08 11.62 15.98 9.01 10.04 4.29 80: 10: 10 15.33 12.72 15.28 9.82 6.43 3.30 Native 19.81 15.38 16.82 12.35 5.28 3.04 LSD (005,1 1.20 1.24 0.89 LSD (0059 2.22 2.25 1.04 T Nitrogen rates shown are annual rates that were applied in six equal increments from May through November. 1 Between nitrogen means at same root zone. § Between root zone at the same or different level of nitrogen. 93 wan—8 mo 3%: 626% .8 2:3 65 «a 28m 88 5053 a 6:8 62 688 “a 888 95.8 5283 w 5:8 :85 530.5%: 6520 5 5E nonaoaom .3 LEE 89a x83 Ba 8:5 625 com—nan my: waged .P ”we 2 .n m: use amt. $5 ”2 8d Lace om.— 2a m? em: and 8.4 Re 2,82 :.m 24 8.2 fie Sn 8a 2 ”2 new 36 a: Rs 8a :.4 men 33 8:9: 62 8.3 33 62 33 8:2 82 8.3 88 sex 88 be. a 82 ca: cm 82 .3680 e 6ch 5:733 @3360 mamas—8 28 Son 88 3 360% mm 88% E 9:303 meaqao .3 Bean. wen—8 mo .96— EBoE—c no 2:8 65 an neon 88 5953 a 6:8 32 2:8 3 888 wen—8 .8283 H 3:2 52» 2385:»: 6520 SW 55 conEoEom a. 132 Bob :83 con 8:5 8:: conga was ”mica ._. 2; 34 8d :.N saga am.— ee... :2 Sc 43 use 9mg 3.2 2.2 3.8 3.: m: 8.” e3 e3 382 3.2 2.2 3.2 5.2 3.» Se 99 8s 25:8 2.2 2.: c2: 3.”: S.» Re 8.» 3e one» 8.3 .62 8:3. 8.2 .62 Bee Base .62 B=cm 38¢ 62 Base 88 .8..— eez one. 2 :2 as: m 32 c.8660 e 33 one. 5 .82 65782 as; unease as seen .68 S 88% a use» a sense 9.530 .9. 63¢ 94 Root Weights Root weights collected 31 August 1999 and 28 August 2000 are presented in Table 54. Interestingly, regardless of parent root zone nearly 3/4 of the root system was located in the STL. Ranges inclusive of years resulted in 68-72% of the roots in the STL, 20-25% at 0-7.6cm depth, and 6-9% located in the 7.6-15.2cm depth. The only significant effect of root zone occurred in the 7.6-15.2cm depth in 1999 as the native root zone had significantly less roots than the other root zones. The data in 2000 was similar but not significant. Regarding the other three factors: 1) rolling resulted in an increase in the amount of roots in the topdress layer for both years; 2) the lower N rate resulted in more roots located in the 7.6-15.2 cm depth in 2000 and; 3) zero K plots had significantly fewer roots in the STL layer in 1999 with no differences between plots receiving annual K rates of 195 kg ha'1 and 390 kg ha]. In 1999 a soil x K interaction resulted in the 80:20 root zone having significantly more roots than the native root zone at all K rates and more roots than the 80: 10: 10 at the highest and lowest K rates (Table 55). Furthermore, the 80: 10: 10 had significantly more roots at all K rates than the native soil. Potassium rate had no impact on root weights in the 80: 10: 10 and native root zone with the 195 kg ha'1 rate in the 80:20 root zone having significantly less roots than the zero and 390 kg ha’1 rates. Overall, the 80:20 at zero K was the only treatment to have significantly more roots than any other treatment. In 2000 two three-way interactions occurred at the 7.6-15.2cm depth. Generally speaking, 80:20 root zone had more roots than the other two root zones (Figures 9-10.) with low N rolled plots receiving intermediate K resulting in the most roots in the 80:20. 95 Of the four factors, the most consistent data for both years was that rolling significantly increased the root mass in the STL layer and inclusive of interactions the 80:20 root zone had more roots at the 7 .6-15.2cm depth than the native soil root zone. Table 54. Main effects and mean squares for treatment effects of root zone, rolling, nitrogen and potassium fertilization on root weights. Root weight in grams 31 Awst 1999 28 August 2000 Root zone Topdress 0-7.6cm 7 .6-15.2cm Tgpdress 0-7.6cm 7 .6-15.2cm 80:20 1.329 0.410 0.146a 1.192 0.345 0.146 80: 10: 10 1.573 0.465 0.126a 1.022 0.361 0.120 Native 1.430 0.484 0.085b 1.229 0.448 0.098 Significance NS NS ** NS NS NS Rolling Rolled 1.584 0.462 0.118 1.296 0.366 0.123 Not Rolled 1.303 0.444 0.120 1.000 0.403 0.120 Significance * NS NS ** NS NS Annual N rate 293 kg ha“T 1.381 0.433 0.120 1.138 0.382 0.113 146 kg ha‘1 1.506 0.473 0.118 1.158 0.388 0.130 Significance NS NS NS NS NS * Annual K rate 0 kg ha‘1 1.177b 0.494 0.118 1.173 0.407 0.128 195 kg ha'1 162% 0.442 0.114 1.100 0.372 0.116 390 kg ha'1 1.525a 0.423 0.125 1.170 0.375 0.121 Significance ** NS NS NS NS NS Mean square Source df Replication 2 4.373 0921* 0.003 0.118 0.064 0.013 Root zone (S) 2 0.542 0.054 0.035" 0.439 0.110 0.021 Error 4 4.123 0.132 0.001 0.785 0.035 0.013 Rolling (R) 1 2.128* 0.009 0.000 2.364** 0.037 0.000 SR 2 1.363 0.291 0.002 0.184 0.177 0.001 Error 6 0.359 0.103 0.005 0.162 0.034 0.004 Nitrogen (N) 1 0.423 0.043 0.000 0.011 0.001 0008* SN 2 0.081 0.096 0.000 0.064 0.060 0.002 RN 1 0.093 0.004 0.006 0.020 0.069 0.005 SRN 2 0.525 0.076 0.001 0.117 0.015 0006* Potassium (K) 2 2.020** 0.049 0.001 0.062 0.013 0.001 SK 4 0.602 0.022 0004* 0.074 0.044 0.004 RK 2 0.310 0.016 0.000 0.189 0.023 0.000 SRK 4 0.870 0.044 0.001 0.249 0.015 0.001 NK 2 1.010 0.029 0.000 0.038 0.017 0.002 SNK 4 0.511 0.032 0.002 0.019 0.029 0005* RNK 2 0.252 0.094 0.001 0.101 0.042 0.004 SNRK 4 0.182 0152* 0.003 0.128 0.008 0.003 Error 60 0.436 0.060 0.001 0.143 0.022 0.002 *, **, *** Significant at the 0.05, 0.01, and 0.001 probability levels, respectively. T NS, nonsignificant at the 0.05 level. 1 Within columns, means followed by the same letter are not significantly different according to LSD (0.05). 96 Table 55. Root weights in grams from 7.6 to 15.2 cm depth as affected by root zone and annual potassium rateT. 31 August 1999 Root zone 0 kg ha'I 195 kg ha" 390 kg ha" 80:20 0.166 0.120 0.151 80:10:10 0.112 0.130 0.137 Native 0.075 0.093 0.087 LSD (005,1 0.021 LSD [005,9 0.021 T Potassium rates shown are annual rates that were applied from May through November. 1 Between potassium means at same root zone. § Between root zone at the same or different level of potassium. 97 2 32 8:2 .2 a z .52 8:2 .2 m z :2 8:2 u z :9; 8:2 a 9an :32:: new 9.52 .0 .65. E2§€ co 6E9. 65 Hogan 82 ,8 m_o>u_ «c2823 mod n 80.8 09 Adouofic ucu 2.3 82 “.o _o>o_ 2:8 65 8 05:2 Co 336. E225; mod n 60.8 am; 695.2 2:... BEN 62 .0 _o>o_ 62$ 65 «a 562:: .o m_o>o_ 222:3 vod n 80.8 ow.‘ doom 4253‘ mm 520 43:: @628 $6203 829:3 05320 a E2. Egon 26 .6136.» So: mE2u E 35925 .02 :o :32? can 05:2 .o:o~ 82 .o 5:022... .o 2:90 2.3 «com ofiotow 0N5» :.0 Nwd 9.0 3.0 9.0 9.0 5.0 9.0 2.0 N0 sulufi u! mfigaM 98 v. a... 2 32m. v. v.5 2 32s v. 2 2 so. a v. .5... 2 =25 x 6.6 2 gain. v. c: z 3.5:. .22322. ecu :32:: Lo _o>o. E222: .o 6E8 65 2.: 0:3 82 co m_o>u_ E2653 8.0 n 698 00.. 623.822. ecu wcow 82 co _m>o. oEmm 05 E :32:: he m_o>o_ E2653 mod u $98 00.. Emmet... ucm econ 82 he _m>o_ 626m 05 «a 23.320: 00 m_m>e_ £2653 mod n 60.8 004 .88 .6392 mm $20 $2.... $528 383$ 329:8 0:388 w :o 5an .5 «9.0.5 E2. mEEu :. 9:925 82 :0 E2828 9.: :32:: 6:3 82 ac 22822:. .9 2.6.". «:3 “com 0232 0 to F50 owuow sums 11! 5111691111 soon 99 CONCLUSIONS Each year of this study soil chemical analysis data were collected the native soil root zone had higher levels of P, K, Ca, Mg, than the soil-less 80:20 root zone. However, few significant differences resulted between the 80:20 root zone and the 80: 10: 10 root zone. The reason the 80: 10:10 root zone did not result in consistently greater nutrient retention compared to the 80:20 root zone was most likely because soil test samples included the sand topdressing layer (STL). Carrow, et al. [2001] noted (especially for cool-season grasses) most roots will be in the STL layer and therefore soil test should be inclusive of the STL layer. Data from this study supports their premise, as approximately 75% of the roots were located in the sand topdressing layer regardless of the original root zone. Considering the majority of roots were in the STL it is not surprising that few significant differences resulted in plant tissue nutrient analysis from turf growing in the three different root zones. Additionally, the native root zone had fewer roots in the deepest profile than the sand root zones. The most consistent plant tissue analysis data was the native root zone resulted in significantly more tissue K than the 80:20 root zone from 1997-1999. In 2000 no significant differences resulted from any of the root zones for any of the plant tissue nutrients. At that time the mean STL was 4.3cm deep and soil samples for soil chemical test were taken fi'om the O-7.6cm depth. Pooled root zone data for clipping weights resulted in few significant and no meaningful differences. However, rolling resulted in significantly less clippings the majority of the time and root zone by rolling interactions indicated that the majority of the decrease was attributed to the rolling effect on clippings from the 80: 10: 10 root zone. 100 Rolling resulted in no consistent trends on soil tests and plant nutrient analyses. However, rolling significantly increased the amount of roots in the STL both years data was taken. The higher N rate decreased soil test K and P fiom 1998-2000. Clipping yields and plant tissue analysis indicates that the decrease in soil K may be the result of increased growth and nutrient uptake related to the higher N rate since clippings are removed. Results of plant tissue P were not consistent. Soil test K increased with increasing K20 fertility rates but fertility did not have a significant effect on any of the other cations reported in the soil test results. Though not always significant, the lowest K20 rate resulted in higher % Ca and %Mg in the plant tissue. Potassium had no effect on clipping weights but did result in increased root growth one year in the STL. 101 REFERENCES Beard, J. 1994. In search of the ultimate putting green. Greenkeeper Int. December222- 25. Colclough, T., and D. M. Lawson. 1990. Fertiliser nutrition of sand golf greens. VII. Rootzone chemical analysis. J. of the Sports Turf Res. Inst. 66: 100-108. Carrow, R. N., D. V. Waddington, and P. E. Rieke. 2001. Turfgrass soil fertility and chemical problems: assessment and management. Sleeping Bear Press, Chelsea, Ml. Christians, N. E. 1998. Fundamentals of Turfgrass Management. Sleeping bear press, Chelsea, MI. Christians, N.E., D.P. Martin, and K]. Karnok. 1981. The interrelationship among nutrient elements applied to calcareous sand greens. Agron J. 73 2929-933. Christians, NE, D. P Martin, and J. F. Wilkinson. 1979. Nitrogen, phosphorous, and potassium effects on quality and grth of Kentucky Bluegrass and creeping bentgrass. Agron. J. 71:564-567. Dahlsson, SO. 1993. Effects of four potassium sources at N:K ratios on putting greens. Int’l Turfgrass Soc. Res. J. 7:528-532. Dest, W. M., and K. Guillard. 2001. Bentgrass response to K fertilization and K release rates from eight sand rootzone sources used in putting green construction. Int. Turf. Soc. Res. J. 92375-381. Frank, K., D. Beegle, and J. Denning. 1998. Phosphorus. p. 21-30. In B. Ellis et al. Recommended chemical soil test procedures for the North Central Region. - Missouri Agri. Expe. Sta. Columbia, MO. Garman, W. L. 1952. Permeability of various grades of sand and peat and mixtures of these with soil and vermiculite. USGA J. Turf Manag. 6(1):27-28. Homeck, D. A., and R. 0. Miller. 1998. Determination of total nitrogen in plant tissue. P In Y. P. Kalra Handbook of reference methods for plant analysis. Soil and plant analysis council. CRC Press, Boca Raton, FL. Hummel, N. W. 1993. Rationale for the revisions of the USGA green construction specifications. USGA Green Section Record. March/April: 7-21. Issac, SP, and PM. Canaway. 1987. The mineral nutrition of F estuca-Agrostis golf greens2A review. J. Sports Turf Res. Inst. 63 :9-27. 102 Kuehl, R. O. 1994. Statistical principles of research design and analysis. Duxbury Press. Belmont, CA. Kussow, W. R. 1995. Some USGA putting green management issues. The Grass Roots. 23(3):44-445. Lodge, T. A., S. W. Baker, P.M. Canaway, and D.M. Lawson. 1991. The construction irrigation and fertilizer nutrition of golf greens. 1. Botanical and reflectance assessments after establishment and during the first year of differential irrigation and nutrition treatments. J. Sports Turf Res. Inst. 67:32-43. Lodge, T. A., and D. M. Lawson. 1993. The construction irrigation and fertilizer nutrition of golf greens. Botanical and soil chemical measurements over three years of differential treatment. J. Sports Turf Res. Inst. 69:59-73. Miller, R. O. 1998. High-temperature oxidation: dry ashing. p. 53-56. In Y. P. Kalra Handbook of reference methods for plant analysis. Soil and plant analysis council. CRC Press, Boca Raton, FL. Mills, H. A., and J. B. Jones, Jr. 1996. Plant analysis handbook 11. Athens, GA: Micro- Macro Publ., Inc. Mitchell, W.H., A.L. Morehart, L.J. Cotnoir, BB. Hesseltine, and D.N. LanBRDton, III. 1978.Effect of soil mixtures and irrigation methods on leaching of N in golf greens. Agron. J. 70:29-35. Oakley, R. A. 1925. Fertilizers in relation to quality of turf and to weed control. Bulletin of the Green Section of the US. Golf Association. 5(3):50-56. Sartain, J. B. 2002. Tifway berrnudagrass response to potassium fertilization. Crop Sci. 42:507-512. Snow, J. T. 1993. The whys and hows of revising the USGA green construction recommendations. USGA Green Section Record. March/April: 4-6. Turgeon, A. J. 1996. Turfgrass management. 4th ed. Prentice-Hall, Inc. Upper Saddle River, NJ. Wamke, D., and J. R. Brown, 1998. Potassium and other cations. P.31-34. In B. Ellis et al. Recommended chemical soil test procedures for the North Central Region. Missouri Agri. Expe. Sta. Columbia, MO. Watson, M. E. and J. R. Brown. 1998. pH and lime requirement. P. 13-16. In B. Ellis et al. Recommended chemical soil test procedures for the north central region. Missouri Agricultural Experiment Station. Columbia, MO. 103 Zontek, S. J. 1990. Managing fertility in high-sand-content greens. USGA Green Section Record 28(4): 1-5. 104 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII lull!llljjllljljljlmljlWI