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THE FATE OF NITROGEN APPLIED TO A MATURE, lO-YEAR OLD,
KENTUCKY BLUEGRASS TURFSTAND
presented by

Kevin Matthew 0 'Reilly

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6/01 cJCIRC/DatoDuopBS—sz

THE FATE OF NITROGEN APPLIED TO A MATURE, lO-YEAR OLD,
KENTUCKY BLUEGRASS TURFSTAND

By

Kevin Matthew O'Reilly

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Crop and Soil Science

2003

ABSTRACT

THE FATE OF NITROGEN APPLIED TO A MATURE, 10-YEAR OLD,
KENTUCKY BLUEGRASS TURFSTAND

By

Kevin Matthew O’Reilly

Extensive research on nitrate-nitrogen (N 03-N) leaching in turfgrass systems
indicates that in most cases leaching poses little risk to the environment. Most of the
research, however, was conducted on research sites that. were either recently disturbed or
established, and the potential exists for NO3-N concentrations in leachate to increase on
mature turf sites. The fate of nitrogen (N) was examined for a lO-year old Kentucky
bluegrass (Poa pratensis L.) turfstand using intact monolith lysimeters and microplots.
From October 2000 through 2002, half of the lysimeters and microplots were treated
annually with urea at a high N rate of 245 kg N ha'1 (49 kg N ha'1 application"). The
remaining lysimeters and microplots were treated annually with urea at a low N rate of 98
kg N ha’1 (24.5 kg N ha'1 application'l). The October 2000 urea application was made
with ”N double-labeled urea to facilitate fertilizer identification among clippings,
verdure, thatch, soil, roots, and leachate. The average total N recovery for the low and
high N rates was 78 and 74%, respectively. NO3-N concentrations in leachate for the low
N rate were typically below 5 mg L". For the high N rate, N03-N concentrations in
leachate were typically greater than 20 mg L". Over approximately two years, 1.3 and
10.9% of labeled fertilizer-N was recovered in leachate for the low and high N rates,
respectively. These results indicate that total yearly applications of 245 kg N ha'1 in the
form of urea to a lO-year old Kentucky bluegrass stand with monolith lysimeters in place,

resulted in elevated levels of NO3-N in leachate.

To my parents for their many sacrifices, love, and support

iii

ACKNOWLEDGMENTS

I would like to thank my advisor, Dr. Kevin Frank, for his time, support, and
guidance throughout my graduate program. I thank my committee members, Dr. James
Crum and Dr. James Flore, for their insight and guidance throughout both my graduate
and undergraduate studies. I would like to thank Dr. Sasha Kravachenko for her
invaluable assistance with the statistical portion of this research. I thank Jon Bristol and
Chad Cates for their attention to detail and hard work preparing samples for analysis in
the laboratory. I would like to thank Mark Collins, Frank Roggenbuck, and the rest of
the staff at the Hancock Turfgrass Research Center for all their assistance. I thank Dr.
Paul Rieke and The Friends of Dr. Paul Rieke Committee for honoring me as the first
recipient of the Dr. Paul Rieke graduate fellowship. I would like to thank the United
States Golf Association, The Michigan Agricultural Experiment Station, and The
Michigan Turfgrass Foundation for their support of this research. And a special thank
you to Debi Wamock and Brian Leach for your friendship and assistance with so many of
the “smaller” details in life and graduate school.

I would like to thank my parents, Daniel and Eleanor O’Reilly, for their many
sacrifices, love, and unending support throughout my studies and life. I thank my

brothers Darren and Brian for their friendship, encouragement, and stress relief.

iv

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES
INTRODUCTION
LITERATURE REVIEW
MATERIALS AND METHODS

RESULTS AND DISCUSSION

Clippings

Verdure

Thatch

Roots

Soil

Leachate
Nitrogen Derived From Fertilizer
NH4—N Concentration
N03-N Concentration

Total Nitrogen Recovery

CONCLUSIONS
APPENDIX

BIBLIOGRAPHY

vi

13

20
20
24
27
29
38

53
53
58
63
65

88

Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

Table 6.

Table 7.

Table 8.

Table 9.

Table 10.

LIST OF TABLES

Background atom % 15 N values for Kentucky bluegrass
plant, soil, and leachate components.

Analysis of variance table for nitrogen derived from
fertilizer (NDF F) and percent N recovered from
fertilizer (%NRFF) in Kentucky bluegrass clippings.

Total amount of nitrogen derived from fertilizer
(NDFF) in the clippings of Kentucky bluegrass for the
N rate X days after treatment (DAT) interaction.

Total percent of nitrogen recovered from fertilizer
(%NRFF) in the clippings of Kentucky bluegrass for
the N rate X days after treatment (DAT) interaction.

Analysis of variance table for nitrogen derived fiom
fertilizer (NDFF) and percent N recovered from
fertilizer (%NRFF) in the verdure and thatch layers of
Kentucky bluegrass.

Nitrogen derived from fertilizer (NDF F) in Kentucky
bluegrass verdure for the N rate X days after treatment
(DAT) interaction.

Percent nitrogen recovered from fertilizer (%NRFF) in
Kentucky bluegrass verdure for the N rate X days after
treatment (DAT) interaction.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass thatch for the N rate X days after treatment
(DAT) interaction.

Percent nitrogen recovered from fertilizer (%NRFF) in
Kentucky bluegrass thatch for the N rate X days after
treatment (DAT) interaction.

Analysis of variance table for nitrogen derived from

fertilizer (NDFF) and percent N recovered from
fertilizer (%NRFF) for Kentucky bluegrass roots.

vi

21

21

22

25

25

26

28

28

30

Table 11.

Table 12.

Table 13.

Table 14.

Table 15.

Table 16.

Table 17.

Table 18.

Table 19.

Table 20.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass roots for the N rate X days after treatment
(DAT) X depth interaction separated by N rate.

Analysis of variance table for the total amount of
nitrogen derived from fertilizer (NDFF) and percent N
recovered from fertilizer (%NRFF) in Kentucky
bluegrass roots.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass roots when all depths were totaled for the N
rate X days after treatment (DAT) interaction.

Percent nitrogen recovered from fertilizer (N DFF) in
Kentucky bluegrass roots when all depths were totaled
for the N rate X days after treatment (DAT)
interaction.

Analysis of variance table for nitrogen derived from
fertilizer (NDFF) and percent N recovered from
fertilizer (%NRFF) for Kentucky bluegrass soil.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass soil for the N rate X days after treatment
(DAT) X depth interaction separated by N rate.

Analysis of variance table for nitrogen derived from
fertilizer (NDF F) and percent N recovered from
fertilizer (%NRFF) in Kentucky bluegrass soil.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass soil when all depths were totaled for the N
rate X days after treatment (DAT) interaction.

Percent nitrogen recovered from fertilizer (NDFF) in
Kentucky bluegrass soil when all depths were totaled
for the N rate X days after treatment (DAT)
interaction.

Analysis of variance table for nitrate-nitrogen
(N 03-N) concentration, ammonium-nitrogen
(NH4-N) concentration, nitrogen derived from
fertilizer (NDFF), and percent N recovered from
fertilizer (%NRFF) in leachate collected from
lysimeters.

vii

33

35

35

36

39

40

43

45

45

46

Table 21.

Table 22.

Table 23.

Table 24.

Table 25.

Table 26.

Table 27.

Table 28.

Table 29.

Table 30.

Table 31.

Nitrogen derived from fertilizer (NDFF) in leachate
fi'om lysimeters for the N rate X days after treatment
(DAT) interaction.

Nitrogen derived from fertilizer (NDFF) in leachate
fiom lysimeters for the N rate X days after treatment
(DAT) interaction.

Analysis of variance table for nitrogen derived from
fertilizer (NDFF) and percent N recovered from
fertilizer (%NRFF) in leachate from lysimeters.

Nitrogen derived fiom fertilizer (NDFF) in leachate
fiom lysimeters for the N rate X days after treatment
(DAT) interaction.

Percent nitrogen recovered from fertilizer (%NRFF)
in leachate from lysimeters for the N rate X days after
treatment (DAT) interaction.

Ammonium-nitrogen (N H4-N) concentration (mg L'l)
in leachate from lysimeters for the N rate X sampling
date interaction.

Flow-weighted means of nitrate-nitrogen (N 03-N) and l

ammonium-nitrogen (N H4-N) concentrations in
leachate from lysimeters.

Nitrate-nitrogen (N O3-N) concentration (mg L'l) in
leachate from lysimeters for the N rate X sampling
date interaction.

Analysis of variance table nitrogen derived fiom
fertilizer (NDFF) and percent nitrogen recovered from
fertilizer (%NRFF) in all components of Kentucky
bluegrass.

Nitrogen derived from fertilizer (NDFF) in all
components of Kentucky bluegrass for the N rate X
days after treatment (DAT) interaction.

Nitrogen derived from fertilizer (NDFF) and percent
nitrogen recovered from fertilizer (%NRFF) in
Kentucky bluegrass components treated at the low and
high N rates at all sampling dates.

viii

47

48

50

50

51

54

55

56

59

59

60

Table 32.

Table 1A.

Table 2A.

Table 3A.

Percent nitrogen recovered from fertilizer (%NRFF)
in all components of Kentucky bluegrass for the N
rate X days after treatment (DAT) interaction.

Mean organic matter concentration (%) of
experimental soil.

Chemical and physical characteristics of experimental
soil.

Weather and irrigation data for the lysimeter plot area,

Hancock Turfgrass Research Center, East Lansing, MI
(October 17, 2000 — 2002) Continued on pages 67-87.

ix

61

66

66

67

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

LIST OF FIGURES

Total amount of nitrogen derived from fertilizer
(NDFF) in clippings for the N rate X days after
treatment (DAT) interaction and regression of NDF F
on DAT for each N rate.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass roots for the N rate X days afier treatment
(DAT) X depth interaction for the low N rate (98 kg N
ha' ).

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass roots for the N rate X days after treatment
(DAT) X depth interaction for the high N rate (245 kg
N ha' ).

Nitrogen derived fiom fertilizer (NDF F) in Kentucky
bluegrass roots when all depths were totaled for the N
rate X days afier treatment (DAT) interaction.

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass soil for the N rate X days after treatment
(DAT) X depth interaction for the low N rate (98 kg N
ha-l).

Nitrogen derived from fertilizer (NDFF) in Kentucky
bluegrass soil for the N rate X days after treatment
(DAT) X depth interaction for the high N rate (245 kg
N ha-l)

Nitrogen derived from fertilizer (NDF F) in leachate
from lysimeters by days after treatment (DAT) for the
N rate X DAT interaction and regression of NDFF on
DAT for each N rate.

23

31

32

37

41

42

52

INTRODUCTION

Nitrogen (N) is the nutrient most commonly applied to a turfgrass system (Beard,
1973). The potential for N to leach is increased by high N rates, type of N carrier, over
watering, and sandy soils. Turf managers reduce the potential for N leaching by using
slow release fertilizers, applying N at low rates over multiple applications, reducing N
rates on sandy soils, promoting deep root systems, and adjusting irrigation practices so
that excessive water is not applied.

Extensive research on nitrate-nitrogen (NO3-N) leaching in turfgrass systems
indicates that in most cases leaching poses little risk to the environment. Previous
research (Starr and DeRoo, 1981; Miltner et al., 1996; Frank, 2000; and Horgan et al.
2002) using 15N labeled fertilizers applied to cool season turf stands lead to the following
estimates: 26% of applied fertilizer N is recovered in clippings; 3-13% is recovered in the
verdure; 21-40% is recovered in the thatch; 14-41% is recovered in the soil; 2% is
recovered in roots; 5% is lost through denitrification; and trace amounts are leached.
Total recovery of applied fertilizer N ranged fiom 64 to 90%. These studies, however,
were conducted on younger sites that ranged in age from 1 to 7 years old.

The potential exists for NO3-N concentrations in leachate to increase on mature
turf sites. Porter et al. (1980) examined total N content in soil to a depth of 40 cm within
105 turf systems ranging in age from 1 to 125 years old. The data suggests that soil
organic N accumulation is rapid in the first 10 years after establishment, and slowly
builds to an equilibrium at 25 years where no further net N immobilization occurs. Porter
et al. (1980) concluded that there is a rather limited capacity of the soil to store organic N

and that after 10 years the potential for overfertilization is “greatly enhanced.” Valiela et

al. (1997), based on the data of Porter et al. (1980), modeled the flux of N through a
coastal watershed, and predicted that 61% of N applied to a 10 year or older turf stand
leaches to groundwater. Conclusions such as these show the need to examine the fate of
N applied to a mature turf stand. The objectives of this research were to quantify NO3-N
and ammonium-nitrogen (N H4-N) concentrations in leachate, and the fate of 15N double-
labeled urea fertilizer among clippings, verdure, thatch, soil, roots, and leachate for a

Kentucky bluegrass turfstand 10 years after establishment.

LITERATURE REVIEW

Groundwater quality is likely to decline as a result of human activities altering the
global N cycle (Vitousek et al., 1997). The United States Environmental Protection
Agency (EPA) has set a safe drinking water standard of 10 mg NO3-N L". Violation of
the EPA nitrate standard for drinking water has closed more public water supplies in the
United States than any other contaminant (Bhumbla, 2002). Drinking water in excess of
the nitrate standard may cause: acute health effects including blue-baby syndrome
(methemoglobinemia) and sometimes death; chronic health effects including diuresis,
increased starchy deposits and hemorrhaging of the spleen (EPA, 2002). The misuse of
fertilizers applied to home lawns may potentially have a significant impact on water
quality. These concerns have prompted several studies examining the fate of N applied
to turf systems. Four of the major fates of N in a turf system are leaching, gaseous loss,

plant uptake, and soil storage.

Leaching

A nutrient is considered leached once it has moved past the turfgrass root zone
(Carrow et al., 2001). Factors that influence N leaching losses from a turfgrass system
are N rate and carrier, amount of water that moves through the root zone, soil texture, and
N uptake by the grass (Carrow et al., 2001). Cultural practices that reduce N leaching
include: using slow release fertilizers; applying N at low rates over multiple applications
(spoon feeding); enhancing the cation exchange capacity of sands; promoting deep root
development and root viability; and adjusting irrigation practices so that excessive water

is not applied (Carrow et al., 2001).

Morton et al. (1988) studied three N fertilization rates (0, 97, and 244 kg N ha" as
urea and methylene urea) and two irrigation practices (scheduled by a tensiometer to
prevent drainage from the root zone and overwatering consisting of 3.75 cm wk"
regardless of rainfall) on a 90% Kentucky bluegrass and 10% red fescue (F estuca rubra
L.) turfstand established 4 years earlier. Suction plate lysimeters, to a depth of 70 cm,
were used to sample leachate from the turf system. When irrigation was scheduled using
a tensiometer, the average NO3-N concentration in leachate for the 0, 97, and 244 kg N
ha" rates was 0.51, 0.87, and 1.24 mg L", respectively. In the overwatering treatments
NO3-N concentrations in leachate averaged 0.36, 1.77, and 4.02 mg L", for the 0, 97, and
244 kg N ha" rates, respectively. The authors concluded that leaching losses from home
lawns did not pose a threat to drinking water aquifers.

Gold and Groffrnan (1993) compared the leaching of NO3-N from four different
land uses over a 2 year period. The four land uses consisted of a home lawn turf
(established 6 years earlier), corn grown for silage (plowed each spring), a mature mixed
oak-pine forest (80-120 years old), and a septic system. Nitrogen was applied to the turf
system in the form of urea and UREAFORM at an annual rate of 344 kg N ha" divided
into five applications. Nitrogen applied to the corn was in the form of urea at an annual
rate of 202 kg N ha" (34 kg N ha" in June and 168 kg N ha" in July). Nitrogen entered
the septic system through household wastewater, and the forest system through natural
deposition. NO3-N leaching was highest for the septic system, with an average
concentration of 59 mg L". Concentrations in the silage corn leachate ranged from 3-50
mg NO3-N L", and home lawns contained concentrations in the range of 0.2-5.0 mg N03-

N L". NO3-N concentration from the mature forest was consistently near 0.2 mg L".

The authors concluded that septic systems are major contributors of N leaching to
groundwater, while the extended growing period and small, frequent applications of
fertilizer maximized the ability of the home lawn turf to absorb the fertilizer, reducing the

potential of NO3-N leaching.

l5N Research

To gain a greater understanding of N applied to a turf system, the naturally
occurring isotope 15N can be applied as fertilizer. Fertilizers enriched with 15N enable a
researcher to distinguish fertilizer N from N that is already in the system. 15N is a
powerful tool to study the fate of applied N because it can be followed in the plant-soil
system as it enters, is transported within, or leaves the system (Hauck and Bremmer,
1976).

Starr and DeRoo (1981) applied lsN labeled ammonium nitrate at a rate of 180 kg
N ha", divided into two applications, to a mixture of Kentucky bluegrass and creeping
red fescue established the previous spring. They measured the concentration of labeled
fertilizer N in clippings, thatch, soil (to a depth of 30 cm), and leachate. One year after
15N application, 64 and 73% of the labeled fertilizer N was recovered within the system
when clippings were either removed or returned, respectively. Suction lysimeters used to
sample soil water to depths ranging from 180 to 240 cm showed NO3-N concentrations in
leachate averaging 1.9 and 2.0 mg L" when clippings were either removed or returned,
respectively. The authors concluded that little, if any, leaching losses of N from the turf

plots occurred.

Frank (2000) applied 15’N labeled ammonium nitrate to 7 year old stands of
Kentucky bluegrass (cv. ‘Adelphi,’ ‘Baron,’ ‘Merit,’ and ‘Touchdown’) and tall fescue
(Festuca arundinacea Schreb., cv. ‘Arid,’ ‘Mustang,’ and ‘Olympic’) at two rates, 24.4
and 48.8 kg N ha". Mass N balance was determined for each N treatment among top
growth, thatch, roots, and soil to a depth of 64 cm. The average percent N recovered
from fertilizer (%NRFF) for the thatch and soil was 37 and 42%, respectively. The total
%NRFF at the 24.4 and 48.8 kg N ha" rates was 95 and 73%, respectively. Based on
these data, Frank (2000) concluded that the majority of applied N is either retained in the
soil or taken up by the turf.

Over a period of 3 years, Miltner et al. (1996) studied the fate of 15N labeled urea
applied to a 1 year old polystand of Kentucky bluegrass (cv. ‘Adelphi,’ ‘Nassau,’ and
‘Nugget’). Nitrogen was applied at an annual rate of 196 kg N ha" divided into five
applications of urea over 38 day intervals, defined by either a spring or fall application
schedule. The first application of the spring schedule was in April and the last was in
September, while the fall application schedule began in June and ended in November.
Using intact monolith lysimeters (1.2 m deep), NO3-N concentrations in leachate were
generally below 1 mg L'1 throughout the study. Only 0.23% of the labeled 15N was
collected in leachate. The majority of the labeled 15N was collected in clippings, thatch,
and soil. Total recovery of the labeled 15N was 64 and 81% for the spring and fall
application schedules, respectively. Miltner et al. (1996) concluded that NO3-N leaching

for both the spring and fall application schedules was negligible.

Gaseous Losses

In many studies using 15’N labeled fertilizers, the authors have suggested that
denitrification and NH3 volatilization losses were responsible for incomplete recovery of
applied l5N (Starr and DeRoo, 1981; Miltner et al., 1996). Similar to leaching losses,

denitrification and volatilization losses have received increased attention in recent years.

Denitrification

Denitrification results in the gaseous loss of N in the form of nitric oxide (N O),
nitrous oxide (N 20'), or N2 gas. The reaction for denitrification involves the following
sequence:

NO;;' —+ NO;' —* NO ——>N20 —>N2
Factors that influence denitrification include: the presence of a thatch layer and/or readily
decomposable organic matter; soil moisture and oxygen content; soil temperature; soil
pH; plant growth and root activity; and NO3’ level (Carrow et al., 2001).

Mancino et al. (1988) studied the effects of soil texture, percent soil saturation,
and ambient temperature on denitrification losses from 'Baron' Kentucky bluegrass
fertilized with potassium nitrate (KNO3) at a rate of 45 kg N ha". Over a 10 day period,
maximum denitrification losses occurred when soils were saturated and accounted for 2.2
and 5.4% of applied N for the silt loam and silt soils, respectively. Below 80%
saturation, little to no denitrification losses were observed when soil temperature was
maintained at 22° C. When high soil temperatures (30 and 35° C) were combined with
saturated soil conditions, denitrification losses were 44.6 and 92.6% of applied N for the

silt loam and silt soils, respectively. The authors concluded that saturated soil conditions

in combination with high soil temperatures could result in large denitrification losses in a
fertilized turfstand.

Horgan et al. (2002) examined denitrification rates from Kentucky bluegrass after
a 49 kg N ha" application of 15N labeled KNO3' in solution. Over a 6 week period in the
spring, recovery of N2 and N20 averaged 4.3 and 0.6% of applied N, respectively. Over
a 4 week period in the summer, N2 and N20 concentrations averaged 15 and 5.6% of
applied N, respectively. The authors concluded that the higher N20 and N2 levels
observed in the summer were due to ideal conditions for denitrification, including
elevated soil temperatures and anaerobic conditions caused by 8.9 cm of rainfall 4 days

after fertilization.

Volatilization
Volatilization is the gaseous loss of N in the form of ammonia~(NH3).
Volatilization losses are common to fertilizers that contain urea (Carrow et al., 2001).
The enzyme urease is responsible for the following hydrolysis reaction:
urease
CO(NH2) + H2O ———> 2NH3 + CO2
(urea)
Factors that influence NH3 volatilization include: level of urea and ammonium (NHX)
present; temperature; soil pH; soil moisture; cation exchange capacity; N carrier, form
(liquid versus dry), and rate; and the presence of a thatch layer (Carrow et al., 2001;
Petrovic, 1990).

Nelson et al. (1980) compared the influence of a thatch layer and N carrier on

volatilization rates fi'om Kentucky bluegrass. When a 5 cm thatch layer was present, 39

and 4% of applied N volatilized after 8 days from urea and isobutyldine diurea (IBDU)
applications, respectively. When no thatch layer was present, 5 and 2% of applied N
volatilized from urea and IBDU applications, respectively. Although the N application
rate was extremely high (253 kg N ha" in a single application), the authors concluded
that in turf stands with high thatch accumulations, the use of slow release N carriers and
reduction of the thatch layer would decrease NH3 volatilization losses.

Bowman et al. (1987) studied the influence of supplemental irrigation on NH3
volatilization rates after urea application (50 kg N ha") to Kentucky bluegrass.
Immediately after urea application, irrigation at the rate of 0, 0.5, 1, 2, or 4 cm was
applied. Without supplemental irrigation, losses of up to 36% were observed. With 1 cm
of supplemental irrigation, losses were reduced to 3 to 8%; with 4 cm of irrigation, 1% of
applied N was lost. In a second experiment the authors determined that in the irrigated
plots NH3 losses returned to control levels 11 hours following urea application. In the
uninigated plots, NH; losses continued for up to 24 hours after urea application. The
authors concluded that irrigation should be applied as soon as possible after fertilizer
application to reduce volatilization losses.

Urease inhibitors have been suggested as a means to reduce volatilization losses.
Urease inhibitors slow the conversion of urea-N to NH3-N. The thatch layer contains
large quantities of urease, increasing volatilization losses. Joo et al. (1991) investigated
the effectiveness of using a urease inhibitor to reduce volatile N losses. ‘5 N labeled urea
was applied at 49 kg N ha" to a 6 year old blend of cv. ‘Adelphi,’ ‘Glade,’ ‘Parade,’ and
‘Rugby’ Kentucky bluegrass. After 5 weeks, 28.8% of applied N was retained in

clippings, shoots, thatch, and the top 15 cm of soil. When 0.25 and 0.5 % of the urease

inhibitor N—(n-butyl) thiophosphoric triamide (NBP’I) was added, 45.0 and 36.1% of
applied 15N was recovered, respectively. Although leachate was not collected, the
authors speculated that a large portion of the 15N leached through the soil profile due to
13 cm of rainfall on the fifih day after treatment. The authors concluded that NBPT, in
combination with proper water management to move the urea into the soil profile, would

reduce NH4 volatilization losses.

Mature sites

The majority of N fate research has been conducted on relatively young turf
stands, ranging in age from 1 to 7 years; however, the age of a turf stand has been
proposed as an important factor in determining the fate of N. Bouldin and Lathwell
(1968) suggested that the ability of a soil to store organic N under relatively constant
management and climatic conditions, which are typical of turf systems, would decrease
with time and eventually an equilibrium level of soil organic N would be obtained.
Porter et al. (1980) examined total N content in soil to a depth of 40 cm in 105 turf
systems ranging in age fi'om l to 125 years old. The data suggest that soil organic matter
accumulation is rapid in the first 10 years after establishment, and slowly builds to an
equilibrium at 25 years, when no further net N immobilization occurs. Porter et al.
(1980) concluded that there is a rather limited capacity of the soil to store organic N, and
that after 10 years the potential for overfertilization is greatly increased.

In a 1990 review article entitled ‘The Fate of Nitrogenous Fertilizers Applied to
Turfgrass,’ Petrovic hypothesized, based on the data of Porter et al. (1980), that older turf

sites, or sites with high organic matter contents, should be fertilized at a reduced N rate to

10

minimize the potential for NO3-N leaching. Petrovic theorized that the rate of N applied
to younger turf stands (less than 10 years of age) should equal the rate at which N is used
by the plants, lost to the atmosphere, and stored in the soil. Older turf sites (greater than
25 years of age) lose the ability to store additional N in the soil, and therefore should be
fertilized at a rate equal to the rate N is used by the turf and lost to the atmosphere
(Petrovic, 1990).

Valiela et al. (1997) modeled the flux of N through a coastal watershed. The
model assumed, based on the data of Porter et al. (1980), that “...net N storage in plants
and soil does not increase after the first decade following establishment.” The model also
assumed that on average all turf parcels within the watershed were greater than 10 years
old. Based on these assumptions and combined data from numerous studies, the authors
estimated that 39% of applied fertilizer N is lost through gaseous means (volatilization
and denitrification), and the remaining 61% leaches to the subsoil below the turf parcel.

One study has examined leaching losses of N applied to a mature Kentucky
bluegrass stand. Duff et al. (1997) applied four N fertilization rates, (0, 104, 180, and
257 kg N ha") in the form of urea divided into five equal applications, on a mature
Kentucky bluegrass turf stand. Prior to this study, the soil had been in turf for at least 25
years and although soil organic matter contents were not measured, the soil was assumed
to have a high organic N content. It is unclear, however, what the age of the turfstand
was at the initiation of this study. Suction plate lysimeters, to a depth of 60 cm, were
installed in the seventh year of the study to sample leachate from the turf system. Over a
19-month period (June 1992 through December 1993), NO3—N concentrations in leachate

were below 10 mg L" for all N fertilization rates, except for two sampling dates in the

11

autumn of the second year for the 257 kg N ha" rate. After 8 years of intensive
management, NO3-N concentrations in leachate were not appreciably greater than those

reported for younger sites.

12

MATERIALS AND METHODS

Between 1989 and 1991, four monolith lysimeters were constructed according to
the specifications of Miltner et al. (1996) at the Hancock Turfgrass Research Center,
Michigan State University. The lysimeters, 1.14 m in diameter and 1.20 m deep, were
constructed with grade 304 stainless steel (0.05 cm thick). The bottom of each lysimeter
was constructed with a 3% slope to facilitate collection into a 19 L jug.

In September 1990 the lysimeters and surrounding area were treated with
glyphosate and then sodded with a polystand of Kentucky bluegrass (cv. ‘Adelphi’,
‘Nassau’, and ‘Nugget’). Prior to the glyphosate application, the area had been a
turfgrass stand for six years. Between 1991 and 1993, the lysimeters were used for a
mass N balance study conducted by Eric D. Miltner and associates. The soil type was a
Marlette fine sandy loam (F inc-loamy, mixed mesic Glossoboric Hapludalfs) with a pH
of 7.2. For complete soil physical and chemical characteristics see Appendix Table 2A.
The lysimeters and surrounding plot area received fertilizer applications, mowing, and
irrigation to maintain optimum growing conditions. The turfgrass was mowed twice a
week at 7.6 cm with the clippings returned. Irrigation replaced 80% of potential
evapotranspiration, estimated by a WS-200 Rainbird Maxi weather station (Rainbird,
Glendora, CA). For complete weather and irrigation data see Appendix Table 3A.

In the fall of 2000, 90 microplots were installed in the area adjacent to the
lysimeters. Of the 90 microplots, 56 were for this study and 34 were reserved for future
research. The microplots were constructed of 20 cm diameter polyvinyl chloride (PVC)

piping 45 cm in length. To preserve the soil structure within the microplots, the leading

13

edge of the PVC piping was beveled and driven into the ground using a hydraulic press
until it was flush with the soil surface.

On October 17, 2000, 15 N double-labeled urea with 10% enrichment was applied
in solution to the microplots and lysimeters, followed by 0.50 cm of irrigation. Two of
the lysimeters and half of the microplots were treated at a low N rate of 24.5 kg N ha",
and the remaining lysimeters and microplots were treated at a high N rate of 49 kg N ha".

In 2001 and 2002, the lysimeters and microplots received unlabeled N in the form
of urea in solution, followed by 0.50 cm of irrigation. The low N treatment lysimeters
and microplots were treated annually with 98 kg N ha", divided into four applications of
24.5 kg N ha". The high N treatment lysimeters and microplots were treated annually
with 245 kg N ha", divided into five applications of 49 kg N ha". The application dates
were May 7, June 4, July 3, and October 8, 2001, and May 8, June 6, July 3, and October
15, 2002. The high N treatment lysimeters and microplots received additional
applications on September 13, 2001 and September 13, 2002.

Clipping samples were collected weekly from each microplot throughout the
growing season. Eight microplots, four from each N treatment, were excavated and
collected intact on seven sampling dates: November 1, 2000 (15 I_)_ays After lsN
Treatment); December 1, 2000 (45 DAT); April 19, 2001 (184 DAT); July 18, 2001 (274
DAT); October 9, 2001 (357 DAT); April 20, 2002 (549 DAT); and July 17, 2002 (637
DAT). The PVC pipe containing the microplot was cut away, and the remaining core
was partitioned into verdure, thatch, and soil samples, all of which were dried in a 60°C

convection oven for 72 hr.

14

Verdure samples included the crown and leaf portions of the plants. Thatch
samples consisted of all plant material above the soil surface afier verdure was removed.
Soil within the thatch samples was removed by hand massaging, and then ground to a
fine powder using a mortar and pestle. Clipping, verdure, and thatch samples were
weighed and then ground to pass a 0.5 mm screen using a UdyMill Cyclone Sample Mill
(Udy Corporation, Fort Collins, CO).

The soil portion was partitioned into depths of 0-5, 5-10, 10-20, and 20-40 cm.
At each soil depth two subsamples were taken. The first subsample (250 g oven dry
weight) was placed in a 500 ml F1eaker(Coming Glass Works, Corning, NY) with
approximately 10 m1 of a 5% sodium hexametaphosphate dispersion agent and filled with
water to reach a 450 ml volume. The Fleaker was capped and placed on a horizontal
shaker for 24 hr to displace the soil from the roots. The F leaker cap was removed and the
Fleaker was placed on a US Standard Sieve (0.05 mm) under running water, to float the
roots and fine soil particles out of the Fleaker with the water, leaving the heavier soil
particles in the Fleaker. The smaller soil particles passed through the sieve, while the
roots were retained. Root samples were collected and dried in a 60°C convection oven
for 72 hr, weighed, and then ground to pass a 0.5 mm screen using a UdyMill Cyclone
Sample Mill. The second subsample, 320 cm3 in volume, was ground to a fine powder
using a mortar and pestle after all visible root material was removed. The ground
samples of clippings, verdure, thatch, roots, and soil were dried for an additional 24 hr in
a 60°C convection oven.

Leachate collected from the monolith lysimeters was collected continuously

throughout the experiment. The final leachate sampling date occurred on December 23,

15

2002, 796 DAT. The volume of leachate was measured when the jugs were
approximately 75% full, and two subsamples were taken. One subsample was sent to the
Soil and Plant Nutrient Testing Lab, Michigan State University, to determine NO3-N and
NH4-N concentrations by flow injection analysis (QuikChem 10-107-04-1-A) using a
LaChat rapid flow injection unit (LaChat Instruments, Milwaukee, WI). The second
subsample was used to determine l5N enrichment by the N diffusion technique of Moran
et al. (2002). Due to the low ”N concentration in the leachate an analysis was performed
for N03-N and NH4-N species combined.

Total N concentration and '5 N enrichment in clipping, verdure, thatch, root, soil,
and leachate samples were determined using a Europa 20-20 mass spectrometer (Europa
Scientific, Crewe UK). Mass of N and percent of ”N recovered calculations were from
Kessavalou (1994), the calculations are listed below. Soil bulk densities were as follows:
0-10 cm, 1.14 g cm"; 10-20 cm, 1.54 g cm”; 20-40 cm, 1.58 g cm”. Background atom
% ” N values are presented in Table 1. The background atom % l5N value for leachate
was taken from Miltner et al. (1996). It was assumed that after nine years l5N enrichment

in the leachate samples returned to background levels.

1. Percent nitrogen derived from fertilizer (%NDFF)

%NDFF -—- (A-B)
(C-D)

A = Atom % ”N of the plant, soil, or leachate sample
B = Background atom % ”N of the unfertilized plant, soil, or leachate sample
C = Atom % ”N of the nitrogen fertilizer

D = Background % 15N of the atmosphere

l6

2. Nitrogen derived from fertilizer (NDFF, kg N ha")
NDFF = %NDFF * TN
%NDF F = Percent N derived from fertilizer

TN = Total nitrogen in the plant or soil, kg N ha"

3. Percent nitrogen recovered from fertilizer (%NRFF)

%NRFF = (NDFF, kg N ha";
(Total fertilizer nitrogen applied, kg N ha")

The experimental design was a completely randomized design. NH4-N
concentration, NO3-N concentration, NDFF, and the %NRFF were determined for each
sampling date for the leachate from lysimeters. Leachate data were analyzed as a two-
factor experiment, with N rate and sampling date as the two factors. Soil and root NDFF
and %NRFF data were analyzed as a three-factor experiment with N rate, DAT, and
depth as the three factors. Potential correlation between the measurements taken on the
same core at different depths was accounted for by analyzing the measurements taken at
different depths as repeated measures. All depths for the soil and root samples were then
totaled to determine the cumulative amount of NDFF and the %NRFF at each sampling
date. Weekly clipping data was summed to determine the cumulative amount of NDFF
and %NRFF from all weekly sampling dates prior to the corresponding microplot
sampling date. Leachate data was summed to determine the cumulative amount of NDFF
and %NRFF from all sampling dates prior to the corresponding microplot sampling date.

Kentucky bluegrass clipping, verdure, thatch, soil, root, and leachate components were

17

combined to determine the total amount of NDF F and the %NRFF at each sampling date.
The clipping, verdure, thatch, soil, root, leachate, and total recovery data were analyzed
as a two-factor experiment with N rate and DAT as the two factors. Treatment
differences were analyzed using the Proc Mixed procedure of SAS (SAS Institute Inc.,
2001). Means were separated using Fischer’s LSD procedure at the 0.05 level of

probability.

18

Table 1. Background atom % 15N values for Kentucky bluegrass plant, soil, and

leachate components.

 

 

 

Component Atom % l5N
Clippings 0.3680
Verdure 0.3676
Thatch 0.3706
Root (cm)
0-5 0.3705
5-10 0.3699
10-20 0.3695
20-40 0.3697
Soil (cm)
Thatch Soil 0.3675
0-5 0.3681
5-10 0.3672
1020 0.3677
20-40 0.3680
Leachate 0.3712

 

l9

RESULTS AND DISCUSSION

Clippings

There was a significant N rate X DAT interaction for the total amount of NDFF in
clippings (Table 2). The high N rate had a greater total amount of NDF F in clippings
than the low N rate on all sampling dates (Table 3). For the low N rate the total amount
of NDFF in clippings increased from 0.29 kg N ha" at 45 DAT to 1.73 kg N ha" at 637
DAT. For the high N rate, the total amount of NDFF in clippings increased from 0.77 kg
N ha" at 45 DAT to 4.76 kg N ha" at 637 DAT. Kentucky bluegrass treated at the high
N rate had a greater %NRFF than the low N rate on all sampling dates (Table 4). The
amount of NDF F and %NRFF in Kentucky bluegrass clippings were the summed amount
of all weekly sampling dates prior to microplot sampling date. The increase in the amount
of NDFF and %NRFF in Kentucky bluegrass clippings from 45 to 637 DAT, regardless
of N rate, would be expected due the accumulation of weekly sampling dates. Only one
weekly sampling date occurred prior to the 45 DAT sampling date, thus resulting in a low
amount of NDF F and %NRFF in the clippings, regardless of N rate. By 637 DAT, 35
weekly sampling dates had occurred resulting in a greater amount of NDFF and %NRFF
in clippings than at 45 DAT, regardless of N rate.

There was a significant linear effect for the N rate X DAT interaction (Figure 1).
The high N rate had a steeper positive slope, indicating a more rapid increase of NDFF in

clippings over time than at the low N rate.

20

Table 2. Analysis of variance table for nitrogen derived fi'om fertilizer (NDFF)
and percent N recovered fi'om fertilizer (%NRFF) in Kentucky bluegrass clippings.

 

 

 

 

Clippings
Source df NDFF %NRFF
Pr > F
N rate 1 <.0001 <.0001
DATT 5 <.0001 <.0001
N rate X DAT 5 <.0001 0.002

 

T Days after treatment

 

Table 3. Total amount of nitrogen derived from fertilizer (NDFF) in the
clippings of Kentucky bluegrass for the N rate X days after treatment (DAT)
interaction.

 

 

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
---------- kg N ha"
45 0.29Bldi 0.77Ad
184 0.29Bd 0.77Ad
274 1.23Bc 3.35Ac
357 1.4513b 4.34Ab
549 1.47Bb 4.14Abc
637 1.73Ba 4.76Aa

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.03

 

21

Table 4. Total percent of nitrogen recovered from fertilizer (%NRFF) in the
clippings of Kentucky bluegrass for the N rate X days after treatment (DAT)

interaction.

 

DAT

45

184
274
3 57
549
637

N Rate

98 kg N ha" 245 kg N ha"

%

 

1.17Bld*
1.17Bd

5.02Bc

5.93Bb

5.98Bb

7 .04Ba

1.57Ac
1.57Ac
6.84Ab
8.86Aa
8.45Aab
9.71Aa

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)
IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

22

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Verdure

There was a significant N rate X DAT interaction for the amount of NDFF in
verdure (Table 5). The high N rate had a greater amount of N DFF in verdure than the
low N rate at the 15, 45, and 184 DAT sampling dates (Table 6). Following 184 DAT,
the amount of NDF F in verdure, regardless of N rate, declined significantly and was not
statistically different between the two N rates. The largest amount of NDFF in verdure
was 10.22 kg N ha" (20.85 %NRFF) at 184 DAT at the high N rate. At 274 DAT at the
high N rate, the amount of NDFF in verdure declined to 1.66 kg N ha" (3.39 %NRFF), a
decline of 17% from 184 DAT. The amount of NDFF in verdure, for the 15, 45, and 184
DAT sampling dates at the low N rate were not statistically different, averaging 3.7 kg N
ha" (15.11 %NRFF). At 274 DAT at the low N rate, the amount of NDFF declined to
1.02 kg N ha’1 (4.15 %NRFF), a decline of 11% from the mean of the 15, 45, and 184
DAT sampling dates. With respect to %NRFF, the two N rates were not statistically
different on 6 of 7 sampling dates (Table 7).

The amount of NDFF reported was similar to the values reported by Miltner et al.
(1996) and greater than the values reported by Frank (2000), for similar N rates applied to
Kentucky bluegrass turf. Miltner et a1. (1996) reported %NRFF in verdure declining
from 22.7% at 199 DAT to 0.69 % at 752 DAT for a fall application of 39.2 kg N ha".
These values were similar to the decline from 20.85% at 184 DAT to 1.06% at 637 DAT
for the current research. Frank (2000) reported %NRFF in verdure declining from 7.1 to
2.1 % for a 24.4 kg N ha" rate. The difference in the %NRFF in verdure between the
current research and the Frank (2000) study is most likely related to mowing height.

Plots for the current research were maintained at 7.6 cm, whereas the plots in the Frank

24

Table 5. Analysis of variance table for nitrogen derived from fertilizer (NDFF)
and percent N recovered from fertilizer (%NRFF) in the verdure and thatch layers

 

 

 

 

of Kentucky bluegrass.
Verdure Thatch
Source df NDFF %NRFF NDFF %NRFF
Pr > F
N rate 1 <.0001 0.0336 <.0001 0.3338
DATT 6 <.0001 <.0001 <.0001 <.0001
N rate X DAT 6 <.0001 0.0236 <.0001 <.0001

 

I Days after treatment

Table 6. Nitrogen derived from fertilizer (NDFF) in Kentucky bluegrass
verdure for the N rate X days after treatment (DAT) interaction.

 

 

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
---------- kg N ha'1 -----------
15 3.65B'a‘ 7.95Ab
45 3.79Ba 8.34Ab
184 3.66Ba 10.22Aa
274 1.02Ab 1.66Ac
357 0.91Ab 1.70Ac
549 0.47Ab 1.19Ac
637 0.30Ab 0.52Ac

 

' Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

25

Table 7. Percent nitrogen recovered from fertilizer (%NRFF) in Kentucky
bluegrass verdure for the N rate X days after treatment (DAT) interaction.

 

N Rate
DAT 98 kg N ha" 245 kg N ha"

.............. % --------------
15 14.91AlaI 16.22Ab

45 15.49Aa 17.02Ab
184 14.93Ba 20.85Aa

 

 

274 4.15Ab 3.39Ac
357 3.71Ab 3.48Ac
549 1.93Ab 2.43Ac
637 1.21Ab 1.06Ac

 

' Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

26

study were maintained at 5 cm. Since mass is used to determine the amount of NDFF in
a particular component, an increased mowing height would have a greater mass of
verdure and therefore a greater amount of NDF F in verdure. Similar to the current
research, Miltner et al. (1996) and Frank (2000) reported a decline over time in the

amount of NDF F recovered in verdure.

Thatch

There was a significant N rate X DAT interaction for the amount of NDFF in
thatch (Table 5). The high N rate had a greater amount of NDFF in thatch than the low N
rate for all sampling dates, except at 637 DAT where they were not statistically different
(Table 8). Similar to verdure, the amount of NDFF in thatch, regardless of N rate,
declined significantly after the 184 DAT sampling date. Within each N rate the largest
amount of NDFF in thatch was observed at 184 DAT. At 184 DAT for the low and high
N rates, the amount of NDFF in thatch was 4.55 and 6.81 kg N ha", respectively. At 274
DAT for the low and high N rates, the amount of NDF F in thatch declined to 1.07 and
1.93 kg N ha", respectively. From 184 DAT to 274 DAT, a decline of 14 and 10% was
observed for the low and high N rates, respectively. With respect to %NRFF the high N
rate had a greater %NRFF at the 15 and 45 DAT sampling dates, while the low N rate
was greater at 184 DAT (Table 9). For all sampling dates after 184 DAT the %NRFF
was not statistically different between the two N rates.

For the current research, regardless of N rate, a smaller amount of NDFF and
%NRFF were recovered in thatch than reported by Starr and DeRoo (1981), Miltner et al.

(1996), and Frank (2000). The manner in which thatch layer was defined may be

27

Table 8. Nitrogen derived from fertilizer (NDFF) in Kentucky bluegrass
thatch for the N rate X days after treatment (DAT) interaction.

 

 

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
.......... kg N ha"
15 2. 17131151( 5.14Ab
45 2.06Bb 6.59Aa
184 4.55Ba 6.81Aa
274 1.07Bc 1.93Acd
357 0.86Bc 2.39Ac
549 0.82Bc 1.50Ad
637 0.45Ac 0.56Ae

 

' Means in a row followed by the same capital letter are not
significantly different according to Fischer‘s protected LSD (p=0.05)
IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

Table 9. Percent nitrogen recovered from fertilizer (%NRFF) in Kentucky
bluegrass thatch for the N rate X days after treatment (DAT) interaction.

 

 

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
.............. % --------------
15 8,8413%I 10.48Ab
45 8.4Bb 13.46Aa

184 18.55Aa 13.91Ba
274 4.35Ac 3.93Acd

357 3.53Ac 4.88Ac
549 3 .34Acd 3 .06Ad
637 1.82Ad 1.13Ae

 

' Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

‘Means in a column followed by the same lower case letter are not
Lignificantly different according to Fischer's protected LSD (p=0.05)

28

responsible for the differences in the amount of NDF F reported in this study compared to
Miltner et al. (1996) and Frank (2000). Miltner et al. (1996) defined thatch as the
material between the green tissue and the point below the soil surface where a layer of
rhizomes was reached. The soil in the thatch layer was returned to the soil component.
Frank (2000) included the soil within the thatch layer in the thatch component. It is
unclear, however, what depth into the soil was included in the thatch layer. For the
current research the thatch layer was defined as the plant material above the soil surface
after verdure was removed. Any soil in the thatch layer was removed and defined as the
thatch soil component. The different definitions for the thatch component of Kentucky
bluegrass between each study would lead to differences in the amount of NDFF

recovered in the thatch layer.

Roots

There was a significant N rate X DAT X depth interaction for the amount of
NDFF in roots (Table 10). The 0-5 cm depth, regardless of N rate, contained a greater
amount of NDFF in roots than the 5-10, 10-20, and 20-40 cm depths (Figures 2 and 3).
This result would be expected due to the majority of roots being in the 0-5 cm depth. The
0-5 cm depth, regardless of N rate, averaged 13,451 kg roots ha". The 5-10, 10-20, and
20-40 cm depths combined, regardless of N rate, averaged 2,910 kg roots ha". Although
statistical differences were observed between the 5-10, 10-20, and 20-40 cm depths, the
amount of NDFF recovered in these depths was typically less than 0.15 kg N ha",

regardless of N rate or DAT, and are of little practical significance (Table 11).

29

Table 10. Analysis of variance table for nitrogen derived from fertilizer (NDFF)
and percent N recovered from fertilizer (%NRFF) for Kentucky bluegrass roots.

 

 

 

 

 

Roots
Source df NDFF %NRFF

Pr > F
N rate 1 <.0001 <.0001
DAT'r 4 <.0001 <.0001
N rate X DAT 4 0.1537 0.1541
Depth 3 <.0001 <.0001
N rate X Depth 3 <.0001 <.0001
DAT X Depth 12 <.0001 <.0001
N rate X DAT X Depth 12 0.0027 0.0027
T Days after treatment

 

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When the amount of NDFF for all root depths was summed, there was a
significant N rate X DAT interaction for the total amount of NDFF in roots (Table 12).
The high N rate had a greater total amount of NDFF in roots than the low N rate on 2 of 5
sampling dates (Table 13). The N rate X DAT interaction showed that Kentucky
bluegrass treated at the high N rate had a greater decline in NDFF in roots than at the low
N rate. At 184 DAT, the amount of NDFF in roots for the low and high N rates was 3.66
and 5.14 kg N ha", respectively. By 637 DAT, the amount of NDF F declined to 1.47 and
2.03 kg N ha" for the low and high N rates, respectively. From 184 to 637 DAT, a
decrease of 9 and 13% was observed for the low and high N rates, respectively.

Kentucky bluegrass treated at the high N rate had a greater %NRFF in roots than
the low N rate on 3 of 5 sampling dates (Table 14). Regardless of N rate, the %NRFF
declined significantly from 184 DAT to 637 DAT. At the low N rate the %NRFF
decreased from 14.94% at 184 DAT to 5.99% at 637 DAT. At the high N rate the
%NRFF decreased from 20.99% to 8.28% from 184 to 637 DAT, respectively. These
results were similar to the values reported by Power and Legg (1984), who reported that
the %NRFF in roots in a crested wheatgrass (Agropyron desertorum (Fisch. Ex Link)
Schult.) grassland decreased from 15 to 5% from 1 to 3 years after application,
respectively. The authors concluded that some of the applied labeled fertilizer-N initially
immobilized in the roots was mineralized and would account for a portion of the
cumulative increase of ”N recovered in the “tops” of the plant.

There was not a significant linear effect for the N rate X DAT interaction for the

total amount of NDFF in roots (Figure 4). The negative slope of the regression lines for

34

Table 12. Analysis of variance table for the total amount of nitrogen derived
fi'om fertilizer (NDFF) and percent N recovered from fertilizer (%NRFF) in

 

 

 

 

 

Kentucky bluegrass roots.
Roots
Source df NDFF %NRFF
Pr > F

N rate 1 <.0001 <.0001
DATT 4 <.0001 <.0001
N rate X DAT 4 0.0061 0.0061
T Days after treatment

 

Table 13. Nitrogen derived fiom fertilizer (NDFF) in Kentucky bluegrass roots
when all depths were totaled for the N rate X days after treatment (DAT)

 

 

 

interaction.
N Rate
DAT 98 kg N ha" 245 kg N ha"
---------- kg N ha'1 --------—--
184 3.663“:-I 5.14Aa
274 2.76Ab 3.00Ac
357 2.49Bbc 3.60Ab
549 1.95Acd 1.93Ad
637 1.47Ad 2.03Ad

 

' Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)
IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

35

Table 14. Percent nitrogen recovered from fertilizer (NDFF) in Kentucky bluegrass
roots when all depths were totaled for the N rate X days after treatment (DAT)
interaction.

 

N Rate
DAT 98 kg N ha" 245 kg N ha"

.............. % --------------

184 14.94B*a* 20.99Aa
274 11.25Ab 12.25Ac
357 10.15Bbc 14.69Ab
549 7.95Acd 7.88Ad
637 5.99Bd 8.28Ad

 

' Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly difi‘erent according to Fischer's protected LSD (p=0.05)

36

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53
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37

the amount of NDFF in the roots of Kentucky bluegrass, regardless of N rate, indicates
that the amount of NDFF in roots decreases over time.

For the current research, regardless of N rate, a greater amount of NDF F was
recovered in Kentucky bluegrass roots than reported by Frank (2000). Frank (2000)
reported high ”N enrichments in roots, but the amount NDF F ranged between 0.4 and 1.6
kg N ha" (0.8 and 4.1 %NRFF). Frank (2000) attributed the low percent recoveries to
the low mass of roots on a per hectare basis when compared to soil or thatch. Since mass
is used to determine the amount NDFF in a particular component, a substantially smaller
mass would yield a smaller amount of NDFF, even if ”N enrichments were high. To a
depth of 64 cm, Frank (2000) averaged 6,354 kg roots ha", whereas the current research
to a depth of 40 cm, regardless of N rate, averaged 16,361 kg roots ha". The large
difference in root mass on a per hectare basis is the most likely reason higher percent N

recoveries were observed for the current research as compared to the Frank (2000) study.

Soil

There was a significant N rate X DAT X depth interaction for the amount of
NDFF in soil (Table 15). The 0-5 cm depth, regardless of N rate, had the greatest amount
of NDFF (Table 16). The remaining depths, regardless of N rate, revealed no trends
(Figures 5 and 6). The total amount of NDFF in soil fluctuated among sampling depths
and dates. Miltner et al. (1996) and Frank (2000) noted similar fluctuations and
attributed them to mixing procedures and sample variability.

When the amount of NDFF for all soil depths was summed, there was a

significant N rate X DAT interaction for the total amount of NDFF in soil (Table 17).

38

Table 15. Analysis of variance table for nitrogen derived from fertilizer (NDFF)
and percent N recovered fi'om fertilizer (%NRFF) for Kentucky bluegrass soil.

 

 

 

 

 

Soil.
Source df NDFF %NRFF

Pr > F
N rate 1 <.0001 <.0001
DATT 6 <.0001 <.0001
N rate X DAT 6 <.0001 <.0001
Depth 4 <.0001 <.0001
N rate X Depth 4 <.0001 0.0057
DAT X Depth 24 <.0001 <.0001
N rate X DAT X Depth 24 <.0001 <.0001
1' Days after treatment

 

39

 

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42

Table 17. Analysis of variance table for nitrogen derived from fertilizer (NDFF)
and percent N recovered from fertilizer (%NRFF) in Kentucky bluegrass soil.

 

 

 

 

 

Soil
Source df NDFF %NRFF
Pr > F
N rate 1 <.0001 <.0001
DATT 6 <.0001 <.0001
N rate X DAT 6 <.0001 <.0001
TDays after treatment

 

43

The high N rate had a greater total amount of NDF F than the low N rate for all sampling
dates, except at 274 DAT where they were not different. The highest observed value was
26.63 kg N ha'1 at 15 DAT for the high N rate (Table 18). With respect to %NRFF, the
low N rate usually contained a greater percent of N recovered than the high N rate (Table
19).

The amount of NDFF reported were similar to the values reported by Frank
(2000) and greater than the values reported by Miltner et al. (1996), for similar N rates
applied to Kentucky bluegrass turf. Miltner et al. (1996) reported %NRFF averaging
15.5% for a fall application of 39.2 kg N ha". This value was smaller than the 50.6 and
37.9% averages for the current research at the low and high N rate, respectively. Frank
(2000) reported %NRFF in soil averaging 45.4 and 30.2 % for applications of 24.4 and

48.8 kg N ha", respectively.

Leachate
Nitrogen Derived From Fertilizer

There was a significant N rate X sampling date interaction for the amount of
NDF F in leachate (Table 20). The high N rate had a greater amount of NDFF in leachate
than the low N rate on 10 of 39 sampling dates (Table 21). The amount of NDFF in
leachate for the low N rate ranged from 0.0003 to 0.0788 kg N ha'1 (0.0014 to 0.3215
%NRFF, Table 22). The amount of NDFF in leachate for the high N rate ranged from
0.0131 to 0.7281 kg N ha'1 (0.0268 to 1.486 %NRFF).

When the amount of NDFF from all sampling dates prior to the corresponding

microplot excavation date were summed, there was a significant N rate X DAT

44

Table 18. Nitrogen derived fiom fertilizer (NDFF) in Kentucky bluegrass soil
when all depths were totaled for the N rate X days after treatment (DAT)
interaction.

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
---------- kg N ha“

 

 

15 9.65Bldex 26.63Aa
45 7.36Be 12.28Ae
184 10.57Bcd 14.91Ade
274 13.99Aab 15.62Acd
357 16.3OBa 21.77Ab
549 12.58Bbc 17.69Ac
637 16.35Ba 21.05Ab

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)
IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

Table 19. Percent nitrogen recovered from fertilizer (NDFF) in Kentucky bluegrass
soil when all depths were totaled for the N rate X days after treatment (DAT)
interaction.

 

N Rate
DAT 98 kg N ha" 245 kg N ha"

.............. % --------------

15 39.38316t 54.35Aa
45 30.03Ad 25.07Ad
134 43.13Ac 30.42Bcd
274 57.08Ab 31.88Bcd
357 66.53Aa 44.42131:
549 51.35Ab 36.11Bc
637 66.75Aa 42.97Bb

 

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

45

Table 20. Analysis of variance table for nitrate-nitrogen (NO3-N)
concentration, ammonium-nitrogen (NH4-N) concentration, nitrogen

derived from fertilizer (NDFF), and percent N recovered from fertilizer
(%NRFF) in leachate collected from lysimeters.

 

 

 

Source df NO3-N NH4-N NDFF %NRFF
Pr > F

N rate 1 0.0030 0.3072 0.0071 0.0085

Date 38 <.0001 <.0001 <.0001 <.0001

N rate X Date 38 <.0001 <.0001 <.0001 <.0001

 

46

Table 21. Nitrogen derived from fertilizer (N DF F ) in leachate from
lysimeters for the N rate X sampling date interaction.

 

N Treatment
Date 98 ng ha" 245 kg N ha"
__.......... kg N ha"

11/20/00 000184} 0.0131A
1/10/01 0.0038A 0.0586A
2/9/01 0.011713 0.7281A
2/13/01 0.00618 0.3675A
3/19/01 0.0049A 0.1111A
3/23/01 0.0007A 0.1366A
4/8/01 0.0788A 0.0519A
4/17/01 0.0012A 0.0463A
4/24/01 0.0027A 0.1138A
5/2/01 0.0012A 0.0812A
5/16/01 0.013 113 0.4128A
5/25/01 0.0015A 0.0378A
5/31/01 0.0026A 0.0863A
6/8/01 0.003013 0.09094
6/25/01 0.0003A 0.0640A
8/13/01 0.0008A 0.0304A
10/3/01 0.0034A 0.0329A

10/17/01 0.027413 0.6341A
10/24/01 0.0074A 0.0918A

10/30/01 0.0125A 0.1264A
1 1/20/01 0.0022A 0.0276A
12/3/01 0.0066B 0.1977A

12/21/01 0.01028 0.1908A
1/11/02 0.0094A 0.0896A
2/12/02 0.0088B 0.1536A
3/1/02 0.0148B 0.2786A
3/10/02 0.010713 0.1751A
3/22/02 0.0072A 0.0808A
4/10/02 0.006OA 0.1 140A
5/2/02 0.0056A 0.0770A
5/14/02 0.0053A 0.0655A
5/20/02 0.0035A 0.0772A
6/3/02 0.0045A 0.0920A
6/10/02 0.0058A 0.0678A
7/16/02 0.0131A 0.0826A
7/19/02 0.0040A 0.0602A
7/30/02 0.0049A 0.0804A
8/15/02 0.0054A 0.0452A

12/23/02 0.0044A 0.0210A

 

1 Means in a row followed by the same capital letter are not
iignificantly different according to F ischer's protected LSD (p=0.05).

47

Table 22. Percent nitrogen recovered from fertilizer (%NRFF) in leachate
from lysimeters for the N rate X sampling date interaction.

 

N Treatment
Date 98 kg N ha" 245 kg N ha"
%

1 1/20/00 0.0075Al 0.0268A
1/10/01 0.0153A 0.1196A
2/9/01 0.047713 1.486OA
2/13/01 0.025013 0.7500A
3/19/01 0.0201A 0.2267A
3/23/01 0.0027A 0.2788A
4/8/01 0.3215A 0.1059A
4/17/01 0.0050A 0.0945A
4/24/01 0.0111A 0.2323A
5/2/01 0.0048A 0.1656A
5/16/01 0.053313 0.8424A
5/25/01 0.0060A 0.0771A
5/31/01 0.0108A 0.1761A
6/8/01 0.0121A 0.1855A
6/25/01 0.0014A 0.1307A
8/13/01 0.0034A 0.0621A
10/3/01 0.0137A 0.0671A

10/17/01 011208 1.2941A

10/24/01 0.0303A 0.1873A
10/30/01 0.0511A 0.2580A
11/20/01 0.0089A 0.0563A
12/3/01 0.027013 0.4036A
12/21/01 004153 0.3893A
1/11/02 0.0383A 0.1829A
2/12/02 0.03588 0.3134A
3/1/02 0.0602B 0.5686A
3/10/02 0.043513 0.3574A
3/22/02 0.0295A 0.1649A
4/10/02 0.0247A 0.2327A
5/2/02 0.0228A 0.1570A
5/14/02 0.0215A 0.1336A
5/20/02 0.0141A 0.1575A
6/3/02 0.0184A 0.1877A
6/10/02 0.0235A 0.1384A
7/16/02 0.0535A 0.1686A
7/19/02 0.0162A 0.1229A
7/30/02 0.0200A 0.1640A
8/15/02 0.0219A 0.0923A
12/23/02 0.018OA 0.0429».

 

 

T Means in a row followed by the same capital letter are not
significantly different according to F ischer's protected LSD (p=0.05).

48

interaction for the total amount of NDFF in leachate (Table 23). The high N rate had a
greater total amount of NDFF in leachate than the low N rate for all sampling dates
except the 15 and 45 DAT sampling dates (Table 24). The 15 DAT sampling date
occurred on November 1, 2000, whereas the first lysimeter sampling date occurred on
November 20, 2000, therefore the total amount of NDFF in leachate was zero for both N
rates at 15 DAT due to no sampling dates occurring prior to 15 DAT. At 45 DAT, the
total amount of NDFF in leachate was 0.002 and 0.013 kg N ha'1 for the low and high N
rates, respectively. The low values observed at 45 DAT can be attributed to only one
lysimeter sampling date occurring prior to 45 DAT. At 796 DAT the total amount of
NDF F in leachate for the low N rate was 0.32 kg N ha'l. This value was not statistically
different from zero and accounted for only 1.3% of N recovered from fertilizer (Table
25). The total amount of NDFF in leachate for the high N rate at 796 DAT was 5.33 kg
N ha", or 10.9% of N recovered from fertilizer. This illustrates thattime is an important
factor in moving fertilizer-N into leachate.

There was a significant linear effect for the total amount of NDFF in leachate for
the N rate X DAT interaction (Figure 7). The high N rate had a steep positive slope,
indicative of a rapid increase in the total amount of NDFF in leachate, over time. The
low N rate had a flat slope indicative of little fertilizer-N leaching at this rate.

On the same site as the current research, from 1991 through 1993, Miltner et al.
(1996) applied N as urea at 39.2 kg N ha'l defined by either a spring or fall application
schedule. Miltner et al. (1996) reported 0.18% of applied labeled fertilizer-N from a fall

application was recovered in leachate. For the current research, the low N rate showed a

49

Table 23. Analysis of variance table for nitrogen derived from fertilizer (NDFF)
and percent N recovered from fertilizer (%NRFF) in leachate fiom lysimeters.

 

 

 

 

 

Leachate
Source df NDFF %NRFF
Pr > F
N rate 1 0.0320 0.0362
DATT 7 <.0001 <.0001
N rate X DAT 7 <.0001 <.0001
TDays after treatment

 

Table 24. Nitrogen derived from fertilizer (NDFF) in leachate from lysimeters
for the N rate X days afier treatment (DAT) interaction.

 

 

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
---------- kg N ha"
15 0.000A“aI 0.000Ae
45 0.002Aa 0.013Ae
184 0.110Ba 1.445Ad
274 0.134Ba 2.268Ac
357 0.139Ba 2.477Ac
549 0.262Ba 4.637Ab
637 0.286Ba 5.016Aab
796 0.316Ba 5.332Aa

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

50

Table 25. Percent nitrogen recovered from fertilizer (%NRFF) in leachate from
lysimeters for the N rate X days after treatment (DAT) interaction.

 

 

 

N Rate
DAT 98 kg N ha“ 245 kg N ha"
.............. 0/0 --------------
15 0.000AlaI 0.000Ae
45 0.007Aa 0.027Ae
184 0.449Ba 2.949Ad
274 0.548Ba 4.628Ac
357 0.566Ba 5.054Ac
549 1.069Ba 9.463Ab
637 1.169Ba 10.237Aab
796 1.291Ba 10.882Aa

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)
IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

 

51

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52

similar low amount of NDFF in leachate as reported in the Miltner et al. (1996) study.
The high N rate, however, showed different results than the Miltner et al. (1996) study.
For the duration of the current research, with a similar N rate, 10.9% of labeled fertilizer-

N was recovered in leachate for the high N rate (49 kg N ha'1 rate).

NHrN concentration (mg L'I)

There was a significant N rate X sampling date interaction for the concentration
of NH4-N recovered in leachate (Table 20). The high N rate had a greater concentration
of NH4-N than the low N rate on 1 of 39 sampling dates (Table 26). For the remaining 38
sampling dates, the concentration of NH4-N in leachate was not statistically different
between N rates. The largest concentration of NH4-N was 0.87 mg L'l at the high N rate,
a value 5.5 times greater than the next largest observed value. The remaining
concentrations were typically below 0.07 mg NH4-N L", regardless of N rate. F low-
weighted means for the low and high N rates were 0.04 and 0.13 mg NH4-N L",
respectively (Table 27). These values were similar to the values reported by Miltner et
al. (1996), who reported values for flow-weighted means averaging 0.13 mg L". Brown
et al. (1982) reported that NH4-N losses contributed very little of total N losses from

putting greens and only occasionally exceeded 1 mg L".

N03-N concentration (mg L")
There was a significant N rate X sampling date interaction for the concentration
of NO3-N recovered in leachate (Table 20). The high N rate had a greater concentration

of NO3-N in leachate than the low N rate on 32 of 39 sampling dates (Table 28). The

53

Table 26. Ammonium-nitrogen (NIL-N) concentration (mg L") in leachate
from lysimeters for the N rate X sampling date interaction.

 

N Treatment
Date 98 kg N ha" 245 kg N ha"
mg L’1
1 1/20/00 0.07A* 0.07A
1/10/01 0.02A 0.02A
2/9/01 0.103 0.87A
2/13/01 0.02A 0.02A
3/19/01 0.17A 0.18A
3/23/01 0.10A 0.00A
4/8/01 0.02A 0.02A
4/17/01 0.02A 0.02A
4/24/01 0.03A 0.05A
5/2/01 0.00A 0.01A
5/16/01 0.06A 0.03A
5/25/01 0.02A 0.01A
5/31/01 0.08A 0.04A
6/8/01 0.04A 0.05A
6/25/01 0.00A 0.00A
8/13/01 0.08A 0.00A
10/3/01 0.10A 0.00A
10/17/01 0.00A 0.00A
10/24/01 0.00A 0.00A
10/30/01 0.00A 0.00A
1 1/20/01 0.04A 0.04A
12/3/01 0.08A 0.09A
12/21/01 0.04A 0.07A
1/11/02 0.06A 0.05A
2/12/02 0.06A 0.05A
3/1/02 0.00A 0.01A
3/10/02 0.09A 0.03A
3/22/02 0.02A 0.06A
4/10/02 0.03A 0.05A
5/2/02 0.10A 0.11A
5/14/02 0.08A 0.14A
5/20/02 0.00A 0.00A
6/3/02 0.02A 0.04A
6/10/02 0.04A 0.02A
7/16/02 0.02A 0.03A
7/19/02 0.03A 0.04A
7/30/02 0.02A 0.03A
8/15/02 0.03A 0.03A
12/23/02 0.06A 0.07A

 

l Means in a row followed by the same capital letter are not
iignificantly different according to Fischer's protected LSD (p=0.05).

54

Table 27 . Flow-weighted means of nitrate-nitrogen (NO3-N) and
ammonium-nitrogen (NI-I4-N) concentrations in leachate from lysimeters.

 

N Rate Nitrate-N Ammonium-N
.............. mg L'1--------------
98 kg N ha" 4.12 0.04
245 kg N ha" 20.92 0.13

 

55

Table 28. Nitrate-nitrogen (N 03-N) concentration (mg L'l) in leachate from
lysimeters for the N rate X sampling date interaction.

 

N Treatment
Date 98 kg N ha" 245 kg N ha"
mg L'l

11/20/00 3.013T 12.75A
1/10/01 12.61A 15.88A
2/9/01 3.293 20.52A
2/13/01 3.76B 21.35A
3/19/01 4.173 15.57A
3/23/01 4.18B 17.45A
4/8/01 10.28A 11.67A
4/17/01 2.42A 10.73A
4/24/01 4.213 18.38A
5/2/01 4.233 18.26A
5/16/01 2.57A 9.66A
5/25/01 2.84A 9.96A
5/31/01 3.093 12.29A
6/8/01 2.813 11.99A
6/25/01 2.573 12.47A
8/13/01 2.53A 8.11A
10/3/01 2.773 15.07A
10/17/01 4.373 20.90A
10/24/01 6.88B 28.10A
10/30/01 7.903 31.08A
1 1/20/01 3.05A 8.60A
12/3/01 7.643 25.83A
12/21/01 6.163 35.37A
1/11/02 7.273 34.65A
2/12/02 7.343 38.48A
3/1/02 6.25B 39.51A
3/10/02 5.68B 35.94A
3/22/02 5.403 29.54A
4/10/02 4.233 33.14A
5/2/02 3.213 27.73A
5/14/02 2.953 26.66A
5/20/02 2.913 24.43A
6/3/02 3.013 31.08A
6/10/02 2.973 23.37A
7/16/02 2.78B 21.88A
7/19/02 3.043 19.22A
7/30/02 2.203 19.44A
8/15/02 2.67B 20.25A
12/23/02 3.313 19.29A

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05).

56

NO3-N concentration for the low N rate was less than 5 mg L'1 on 28 of 39 sampling
dates, and exceeded the EPA safe drinking water standard of 10 mg L" on only two
sampling dates. The flow-weighted mean for the low N rate was 4.12 mg NO3-N L'l
(Table 27). The high N rate exceeded the EPA standard on 35 of 39 sampling dates, and
was greater than 20 mg NO3-N L" on 20 sampling dates. On eight sampling dates, the
NO3-N concentration ranged between 30-40 mg L". The flow-weighted mean for the
high N rate was 20.92 mg NO3-N L", which is double the EPA safe drinking water
standard (Table 27).

The findings for the low N rate agree with those of Starr and DeRoo (1981),
Morton et al. (1988), and Miltner et a1. (1996), who stated the leaching of NO3-N from
turfgrass systems posed little risk to groundwater sources. Duff et al. (1997) reported that
N03-N concentrations in leachate were not appreciably greater for older turf sites than
those reported for younger sites. The findings for the high N rate, however, disagree with
the hypothesis that leaching from older turfgrass systems is not a risk to groundwater
sources. From 1991 through 1993, on the same site as the current research, Miltner et al.
(1996) reported that NO3-N concentrations in leachate were generally well below 1 mg
L". For the duration of the current study, with a similar N rate, the concentration of N03-
N rarely dropped below 20 mg L" for the high N rate. These results would support the
hypothesis of Porter et al. (1980) that older turf sites should be fertilized at a reduced N

rate to minimize the potential for NO3-N leaching.

57

Total Nitrogen Recovery

There was a significant N rate X DAT interaction for the total amount of NDF F
recovered in Kentucky bluegrass (Table 29). Kentucky bluegrass treated at the high N
rate contained a greater total amount of NDFF than at the low N rate on all sampling
dates (Table 30). The highest observed value was 39.72 kg N ha" at 15 DAT for the high
N rate. Soil accounted for the greatest amount of NDFF among the turfgrass, soil, and
leachate components, regardless of N rate or sampling date (Table 31). With respect to
%NRFF, the two N rates were similar on four of seven sampling dates (Table 32). The
high N rate was greater on the 45 and 184 DAT sampling dates, while the low N rate was
greater on the 274 DAT sampling date.

The total %NRFF averaged 77.65 and 73.43% for the low and high N rates,
respectively. The highest observed percent recovery was 95.53% at 357 DAT for the low
N rate. The lowest recoveries were at the 45 DAT sampling date, regardless of N rate.
These low recoveries are most likely attributed to missing root data. The average total
percent recoveries for the current research were similar to the values reported by Starr
and DeRoo (1981), Miltner (1996), and Frank (2000). Total recovery of applied
fertilizer-N for these studies ranged from 64 to 90%. These researchers suggested that
denitrification and NH; volatilization losses were responsible for incomplete recovery of
applied l5N. Substantial losses of N can occur through denitrification. In a greenhouse
study, Horgan et a1. (2002) compared denitrification losses from bare soil and Kentucky
bluegrass. Denitrification losses (N2 and N20) accounted for 7 and 19% of applied

labeled fertilizer-N for bare soil and Kentucky bluegrass systems, respectively. Rolston

58

Table 29. Analysis of variance table nitrogen derived from fertilizer (NDFF) and
percent nitrogen recovered from fertilizer (%NRFF) in all components of

 

 

 

 

 

Kentucky bluegrass.
Total Recovery
Source df NDFF %NRFF
Pr > F

N rate <.0001 0.0501
DATT 6 <.0001 <.0001
N rate X DAT 6 <.0001 0.0006
'Days after treatment

 

Table 30. Nitrogen derived fi'om fertilizer (NDFF) in all components of Kentucky
bluegrass for the N rate X days after treatment (DAT) interaction.

 

 

 

N Rate
DAT 98 gN ha" 245 kg N ha"
-------- kg N ha"
15 15.4731ch 39.72Aa
45 13.54Bd 28.00Ad
184 22.83Ba 39.30Aa
274 20.19Babc 27.83Ad
357 23.4lBa 36.28Aab
549 17.36Bbc 31.09Acd
637 20.37Bab 33.93Abc

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)
IMeans in a column followed by the same lower case letter are not
finificantlydifferent according to Fischer's protected LSD (p=0.05)

59

 

8 86 380808800 08 How m038> b02008 Za _ 8888 05 .8 83 05 8 8:00 88 08 0032, 22 80898 88,—. H

8 020 £808 05 88 82.9» 82608 Z: 8888 05 .8 8:0 08 3 8:00 88 08 m0=8> Zn 808898 a.

.382“ 880 wanna no 0088.88 8088080 80888 05 8 00088820

.883 .330 mania 80 80888808 8088080 80888 08 8 30:80.38

 

 

 

 

8038.3. $3386 3308.” 6388.8 5.582 Goduno 5.38: Re
8388.: 64.38; 3:08; 5.90%.: 63:02 $.38: 5.33.4 98
8058.8 $0.388 834388 34.33:” $0.898 84.328 60.843 Sm
@3332 30.388 @3388 3398.2 @3088 80988 3.828 «5
38.8303 A339: 888:; $898.: 2323 $888.2 $.33; 8:
22.588 A8988 . A5388 84.3%..» A3543 $825 We p.828 39
6.238% 89886 92.388 @3338 33:33 . 2 .8:
59:08 $858.0 A8321 $333.2 A3330 second A352; Re
@3300: 99:83 Gasman $058.2 $038.0 38:53 83:: a:
5.3:va A3820 $259.8 5.8302 @0380 5.93 A8391 32
$382.8 $082.0 @3302 $338.2 $088.8 $288.8 A3388 «R
2.3388 388:0 $3.388 5.38.2 $3ch $8.33: 5.38.0 8:
333%.: 20.883 A8382 Aoeéeoa 84.38: 5:82 3 9.22880
588%.: 80.886 $088.8 $an:8 23:88 2 33
3:828
H88,—. 0850801— 8.0803“ Eom A085. 8288/ $88.50 .55 80880:. Z

 

.888 $8388 :8 8 0.88 2 am:— 88 32 08 8 .0080: 38080880 088033 30:80M 8
Emma/go 808—88 80¢ 880,608 80858 8080; 88 b.5975 88:88 808 00,80“. 8&0me Am 058,—.

60

Table 32. Percent nitrogen recovered from fertilizer (%NRFF) in all
components of Kentucky bluegrass for the N rate X days after treatment
(DAT) interaction.

 

N Rate
DAT 98 kg N ha" 245 kg N ha"
.............. % --------------

 

 

15 63.13BTch 81.06Aabc
45 55.28Ad 57.14Ae

184 93.17Aab 90.69Aa

274 82.40Ab 62.9ZBde
357 95.53Aa 81.39Bab
549 70.88Ac 67.39Ade
637 83.14Ab 73.39Abcd

 

T Means in a row followed by the same capital letter are not
significantly different according to Fischer's protected LSD (p=0.05)

IMeans in a column followed by the same lower case letter are not
significantly different according to Fischer's protected LSD (p=0.05)

61

et al. (1982) found denitrification losses to be greatest following irrigation and from
frequently irrigated plots. Mancino et a]. (1988) reported little to no denitrification losses
when the soil was below 80% saturation in combination with low soil temperatures,
however, when saturated soil conditions were combined with high soil temperatures
denitn'fication losses were high. The current research returned 80% evapotranspiration
twice a week, which at least temporarily may have created favorable conditions for
denitrification losses.

Volatilization losses may also have accounted for incomplete recovery of applied
15N. The thatch layer contains large quantities of urease, increasing volatilization losses.
Nelson et al. (1980) reported 5 and 39% of applied N volatilized from Kentucky
bluegrass following urea applications when a thatch layer was not present or was present,
respectively. Bowman et al. (1987) reported that volatilization losses declined
dramatically from Kentucky bluegrass when as little as 1 cm of supplemental irrigation
was applied immediately following urea application. Torello et al. (1983) reported that
approximately three times as much N was lost from Kentucky bluegrass following an
application of solubilized urea as compared to a prilled urea application. The large thatch
layer present at the current research site combined with a solubilized urea application

may have created a favorable environment for volatilization losses.

62

CONCLUSIONS

The total %NRFF in Kentucky bluegrass averaged 77.65 and 73.43% for the low
and high N rates, respectively. These values are similar to the values reported by Starr
and DeRoo (1981), Miltner et al. (1996), and Frank (2000), who reported total %NRFF
ranging between 64 to 90%. The majority of applied labeled fertilizer-N was recovered
in the soil, averaging 50.61 and 37.89% for the low and high N rates, respectively. Porter
et al. (1980) hypothesized that the capacity of the soil to store fertilizer N is a function of
the age of the turfgrass and that older turf sites lose the ability to store additional N in the
soil. In the current research, however, the %NRFF in the soil was much greater than the
values reported by Miltner et al. (1996) from a previous study on the same site 9 years
earlier.

The amount of labeled fertilizer-N recovered in leachate from lysimeters treated
at the high N rate was greater than expected. From October 17, 2000 through December
23, 2002, a period of 796 days, 1.3 and 10.9% of applied labeled fertilizer-N was
recovered in leachate for the low and high N rates, respectively. Flow weighted means
for the low and high N rates were 4.12 and 20.92 mg N03-N L", respectively. The
results for the low N rate were similar to the results reported by Miltner et a1. (1996) at
the same site from 1991- 1993, and indicate that at the low N rate the potential for
groundwater contamination is minimal. At the high N rate, however, the amount of
NDFF and concentration of NO3-N in leachate were substantially greater than the values
reported by Miltner et al. (1996). At the high N rate the NO3-N concentration in leachate
was typically two or more times greater than the EPA safe drinking water standard of 10

mg NO3-N L". These results indicate that urea applied at the low N rate (98 kg N ha";

63

24.5 kg N ha'1 application") to Kentucky bluegrass is a more appropriate than the high N
rate (245 kg N ha"; 49 kg N ha'1 application'l). This research indicates that single dose,
high rate N applications using a water-soluble N source, such as urea, should be avoided
to help minimize the potential for NO3-N leaching. Future research into the fate of N
applied to mature turf stands should determine if:
1) NO3-N concentrations in leachate continue to increase as the age of the
turfstand increases
2) the soil does lose the ability to store additional fertilizer-N as it increases in
age

3) reducing the N rate would lower the NO3-N concentrations in leachate.

64

APPENDIX

65

Table 1A. Mean organic matter concentration (%) of experimental soil.

N Treatment
Demh (cm) 98 kg N ha" 245 kg N ha"
............. % --------------
0-5 5.7 5.3
5-10 3.0 2.5

 

Table 2A. Chemical and physical characteristics of experimental soil.

 

 

Characteristics Marlette
Textural Class fine sandy loam
Taxanomy Fine-loamy, mixed mesic
Glossoboric Hapludalfs
Soil Partical Size .
Sand (%) 65.9
Silt (%) 22.7
Clay (%) 11.4
Bulk Densities (g cm'3)
0-10 cm 1.14
10-20 cm 1.54
20-40 cm 1.58
pH 7.4
Phosphorus (ppm) 17
Potassium (ppm) 78
Calcium (ppm) 1320
Magnesium (ppm) 330
Cation Exchange Capacity (me/ 10L gL 9.5

 

66

Table 3A. Weather and irrigation data for the lysimeter plot area, Hancock
Turfgrass Research Center, East Lansing, MI (October 17, 2000 - 2002).

Continued on pages 67-87.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% BT (cm) (cm)
10/17/2000 17.3 7 .6 ---- ---- 0.50
10/ 1 8/2000 18,7 5 , 5 ---- ---- ----
10/ 19/2000 21 ,3 3 .4 -..-- ---- ----
10/20/2000 23,4 10,3 ---- ---- ----
10/21/2000 20.5 8.2 ---- ---- --..
10/22/2000 20, 1 5 ,4 -..-.. ---- ----
10/23/2000 18.9 8.7 ---- 4.57 ----
10/24/2000 18.1 14.8 ---- 12.70 ----
10/25/2000 192 13 ,0 ---- ---- ----
10/26/2000 23.3 14,3 ---- ---- ----
10/27/2000 22.5 9.2 ---- 6.86 ----
10/28/2000 10,6 0,9 ---- ---- ----
10/29/2000 13,3 -2,7 ---- ---- ----
10/3 0/2000 17, l -22 ---- ---- ----
10/3 1/2000 18, 1 -1 ,3 ---- ---- ----
1 1/1/2000 19. 1 5 , 2 ---- ---- ----
1 1/2/2000 20,5 8,9 ---- ---- ----
1 1/3/2000 16. 1 4,3 m. --..- --..-
1 1/4/2000 1 1,2 .0,6 ---- ---.. ----
1 1/5/2000 15 .4 -0,6 ---- ---.. ----
1 1/6/2000 12.8 0.4 ---- ---- ----
11/7/2000 13.6 7.0 ---- 2.03 ----
1 1/8/2000 14.0 5.2 ---- ---- --..
1 1/9/2000 16.4 6.6 ---- 14.73 ----
1 1/10/2000 9.3 3 .4 ---- 1.02 ----
1 1/1 1/2000 6. 5 3, 1 ---- ---.. ----
1 1/ 12/2000 5 .4 3 . 1 ---.. ---- ----
11/13/2000 5.6 -0.5 ---- 13.72 ----
1 1/14/2000 2.6 —l .6 ---- 1.27 ----
11/15/2000 2.6 -l.1 ---- 3.81 ----
1 1/16/2000 5.6 0.2 ---- 0.51 ----
1 1/17/2000 2.3 -2, 3 ---- ---- ----
1 1/18/2000 -0.5 -3 .2 ---- 0.25 ----
1 1/19/2000 3 ,3 -2, 5 ---- ---- ----

 

 

 

 

 

 

T Evapotranspiration

67

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% ErT (cm) (cm)
11/20/2000 1.6 .4,4 ---- ---- ----
1 1/21/2000 -2. 5 -7_ 5 ---.. ---- ----
1 1/22/2000 -2.4 -1 1.2 ---- ---- ....
11/23/2000 -2.0 .116 an ---.. ----
11/24/2000 3.4 -8.7 ---- ---- ..--
11/25/2000 5.4 -4.1 ---- 1.52 ----
1 1/26/2000 7.4 3.7 ---- 7.62 ----
11/27/2000 5.4 1.2 ---- 0.25 ----
11/28/2000 2.5 -1.5 ---- 0.76 ----
11/29/2000 1.2 -2.3 ---- 1.78 ----
11/30/2000 2.1 -0.4 ---- 3.30 ----
12/1/2000 0. 1 -5 ,3 ---- ---- ----
12/2/2000 -0.1 -92 ---- ---- ----
12/3/2000 19 -115 ---.. ---- ----
12/4/2000 1.1 -6.6 ---- ---- -..-
12/5/2000 1.0 -11.7 ---- ---- ....
12/6/2000 -6.5 -12.6 ---- -..- ----
12/7/2000 -5.9 .104 ---- ---- ----
12/8/2000 -3.5 -13.6 ---- 0.25 ---
12/9/2000 -3,1 -16, 2 an ,---- ----
12/10/2000 0.4 -5,7 ---- ---- ----
12/11/2000 -1.6 -7_2 ---- ---- ----
12/12/2000 -5,1 .119 an ---- ----
12/13/2000 -7.3 .191 ---- ---- ----
12/14/2000 -4.7 -10.8 ---- ---.. ..--
12/ 1 5/2000 -3 ,2 -12, 1 ---- ---- ----
12/1 6/2000 3 .6 -3 .3 ---- 1 1 .43 «~-
12/17/2000 0.7 -145 ---.. ---- ----
12/18/2000 -11.4 -17,4 ---- ---- ----
12/19/2000 -9.0 -l7.4 ---- ---.. ..--
12/20/2000 -5,8 -17_6 ---- ---- ----
12/21/2000 -5,2 -19,2 ---- ....-- ----
12/22/2000 v -13.7 -21,9 ---- ---- ----
12/23/2000 -7.3 -17.6 ---- ---- ----
12/24/2000 -5.7 -159 ---- ---- ----
12/25/2000 -7,5 -259 ---- ---- ----
12/26/2000 -6.4 -12, 2 ---- ---- ----
12/27/2000 -6,9 -16,7 --..- ---- ---..
12/28/2000 -8.3 -210 ---- ---- ---..

 

 

 

 

 

 

68

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
12/29/2000 -4,6 -13,7 ---- ---- ----
12/3 0/2000 -3.6 -9,4 --..- ---- ----
12/31/2000 -1.4 -11.1 ---- 0.25 ----
1/1/2001 -4.3 .196 ---- ---- ----
1/2/2001 -3,3 -228 ---- ---- ----
1/3/2001 -3.9 -139 ---- ---- ----
1/4/2001 -2.7 -65 ---- ---- ----
1/5/2001 2.2 -3 .3 ---- 1.78 ----
1/6/2001 0.2 -3, 1 ---- ---- ----
1/7/2001 10 .43 ---- ---- ----
1/8/2001 .40 -17.8 ---- ---- ----
1/9/2001 -1 .9 -196 ---- ---.. ----
1/10/2001 2.4 -67 ---- ---- ----
1/1 1/2001 4,3 .4, 5 ---- ---.. ----
1/12/2001 3.6 -1,5 ---- ---- ----
1/13/2001 1 .3 -1 ,3 ---- ---- ----
1/14/2001 2.3 -2,4 ---- ---- ---_
1/15/2001 2.5 0.4 ---- 0.25 ----
1/16/2001 1 ,4 -1 ,4 ---- ---- ----
1/17/2001 -0,7 -3,5 ---- ---- ----
1/18/2001 -1 ,6 -5, 1 ---- ---- ----
1/19/2001 .20 -133 ---- ---- ----
1/20/2001 -3,9 -17,8 ---- ---- ----
1/21/2001 -3,7 -12,0 --..- ---- ----
1/22/2001 -0.2 -95 ---- ---- ----
1/23/2001 1 , 1 -3 ,0 ---- ---- ----
1/24/2001 1 ,0 -64 ---- ---- ----
1/25/2001 -2. 1 -8,0 ---- ---- ----
1/26/2001 -1 .7 -9, 5 ---- ---- ----
1/27/2001 -2,3 -9,4 ---- ---- ----
1/28/2001 -3.7 -95 ---- --..- ----
1/29/2001 2.1 -10.2 ---- 6.10 ----
1/30/2001 6.0 -0.1 ---- 6.35 ----
1/31/2001 2.5 -0.2 ---- 4.06 ----
2/1/2001 08 -33 --..- ---.. --..-
2/2/2001 -3 .2 -1 1 ,3 ---- ---- ----
2/3/2001 -3,9 -13.] ---- ---- --....
2/4/2001 1.8 -4. 1 ---- l .02 ----
2/5/2001 1 .3 -2.9 ---- 1 .27 ----

 

 

 

 

 

 

69

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% Etl (cm) (cm)
2/6/2001 -0.4 -3.1 ---- 0.25 ----
2/7/2001 2.0 -8.9 ~-—.- --.... ----
2/8/2001 6.6 -l .9 ---- 5.33 ----
2/9/2001 10.7 -4.8 ---- 27.43 ----
2/10/2001 -4.2 -9.8 ---- ---- ----
2/11/2001 -4.9 -13.5 ---- ---- ----
2/12/2001 2.5 -7.8 ---- ---- ----
2/13/2001 1 .4 0.0 ---- ---- ----
2/14/2001 2.2 -3.3 ---- 3.56 ----
2/15/2001 -1 .7 -6. 1 ---- ---- ----
2/16/2001 -0.4 -7 .2 --- 0.51 ----
2/17/2001 -6.9 -l 1 .9 an ---- --..
2/1 8/2001 -3 .3 -12. 1 ---- ---- ----
2/19/2001 3.2 -55 an ---- ----
2/20/2001 2.3 -5.7 ---- ---- ..--
2/21/2001 -5 . 7 -12. 1 ---- ---- ----
2/22/2001 -2, 1 -12.8 ---- ---- ----
2/23/2001 -0.7 -59 ---- ---- ----
2/24/2001 2.4 -5.3 ---- 24.64 ----
2/25/2001 11.5 -1.1 ---- 5.33 ----
2/26/2001 3.4 -1.4 --.... --.... --....
2/27/2001 0.0 -8.4 ---- ---- ----
2/28/2001 -2.0 -10.0 ---- ---- ----
3/1/2001 4.4 -68 ---- ---- ----
3/2/2001 3.6 -1.6 ---- ---- ----
3/3/2001 8.4 -5.6 ---- ---- ----
3/4/2001 1.5 -5.3 ---- ---- ----
3/5/2001 -3.6 -7 .9 --..- ---- --..
3/6/2001 -0.3 -6.9 ---- 0.25 ----
3/7/2001 4. l -3. 1 ---- ---- ----
3/8/2001 1.6 -3.5 ---- ---- ----
3/9/2001 -0.6 -5. 1 ---- 0.25 ----
3/10/2001 6.0 -85 ---- ---- ----
3/11/2001 4.9 -2.8 ---- 1.52 ----
3/12/2001 4.5 -4.6 ---- 0.51 ----
3/13/2001 5.4 -0.2 ---- 0.76 ----
3/14/2001 9.3 -0.0 ---- ---- ----
3/15/2001 5.0 -0.0 ---- 2.03 ----
3/16/2001 2. 8 -2. 1 ---- 0.25 ----

 

 

 

 

 

 

70

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% Et’r (cm) (cm)
3/17/2001 3.0 .4.1 ---- ---- ----
3/18/2001 8.5 -7 .3 mg ---- ----
3/19/2001 9. 5 -6. 1 ---- ---- ----
3/20/2001 12. 5 -1 .3 ---- ---- ----
3/21/2001 13.2 -3.9 ---.. ---- ----
3/22/2001 12.8 -2.5 ---- ---- ----
3/23/2001 10. 8 -1.0 ---- ---- ----
3/24/2001 1.8 -6.1 ---- 0.25 ----
3/25/2001 -4.3 -12.2 ---- 0.25 ----
3/26/2001 -2. l - 14.5 ---- ---- ----
3/27/2001 1.2 -92 ---- ---- --..-
3/28/2001 7.6 -7.8 ---- ---- ----
3/29/2001 7.8 0.9 ---.. ---- ----
3/30/2001 9.8 0.6 ---- ---- ----
3/3 1/2001 1 1.4 0.8 ---- ---- ----
4/1/2001 3.1 -0.2 0.02 6.10 ----
4/2/2001 12.0 -3. 1 0.09 ---- ----
4/3/2001 10.4 1.5 0.06 0.25 ----
4/4/2001 13.5 -3.2 0.08 ---- ----
4/5/2001 16.2 -2.2 0.09 ---- ----
4/6/2001 18.4 7.0 0.03 12.19 ----
4/7/2001 24.7 7.1 0.09 2.29 ----
4/8/2001 21.9 11.3 0.21 ---- ----
4/9/2001 11.8 4.3 0.10 5.59 ----
4/10/2001 1 1 .2 4. 1 0.04 ---- ----
4/1 1/2001 19.6 8.1 0.05 ---- ----
4/12/2001 21.5 8.6 0.10 ---- ----
4/13/2001 15.7 4.4 0.14 ---- ----
4/14/2001 16.7 -1.0 0.06 ---- ----
4/15/2001 10.2 2.2 0.07 ---- ----
4/16/2001 5.9 -1 .7 0.06 ---- ----
4/17/2001 8.1 -3.0 0.09 0.51 ----
4/18/2001 11.0 -1.5 0.12 ---- ----
4/19/2001 15.4 -3 .3 0.10 ---- ----
4/20/2001 12.7 7.9 0.07 10.41 ----
4/21/2001 23.2 12.5 0.08 12.45 ---
4/22/2001 19.8 8.9 0.08 10.67 ----
4/23/2001 24.5 8.8 0.14 10.92 ----
4/24/2001 12.7 2.8 0.15 0.25 ----

 

 

 

 

 

 

71

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% Etl (cm) (cm)
4/25/2001 16.6 0.6 0.10 ---- ----
4/26/2001 20.3 5.4 0.16 0.25 ----
4/27/2001 17.7 8.8 0.14 0.25 ----
4/28/2001 16.9 0.7 0. 12 ---- ----
4/29/2001 19.4 2.2 0.14 ---- 0.38
4/3 0/2001 27.3 5.8 0.18 ---- ----
5/1/2001 26.5 15.3 0.18 --- ....-
5/2/2001 27.9 16.8 0.17 ---- 0.69
5/3/2001 28.6 16.7 0.00 ---- ----
5/4/2001 24.7 11.9 0.00 0.51 ----
5/5/2001 20. 1 10.0 0.00 ---- ----
5/6/2001 21.3 9.4 0.18 ---- ----
5/7/2001 25.8 11.9 0.16 10.92 0.50
5/8/2001 24.6 10.8 0.13 1.52 ----
5/9/2001 25.3 1 1.9 0.17 ---- ----
5/10/2001 25.8 14.8 0.12 4.57 ----
5/11/2001 19.3 9.2 0.05 4.83 ----
5/12/2001 15.8 5.0 0.00 ---- ----
5/13/2001 19.1 1.2 0.12 ---- ---
5/14/2001 19.3 4.0 0.09 _ 0.25 ----
5/15/2001 15.7 11.2 0.02 54.10 ----
5/16/2001 20.3 11.9 0.06 33.02 ----
5/17/2001 28.1 15.9 0.13 ---- ----
5/18/2001 24.3 12.1 0.14 ---- ----
5/19/2001 24.4 9. 1 0. 17 ---- ----
5/20/2001 24.4 10.1 0.14 ---- ----
5/21/2001 23.5 14.2 0.06 1.02 ----
5/22/2001 17.9 8.1 0.13 ---- ---
5/23/2001 18.5 7.1 0.10 ---- ....
5/24/2001 15.3 7.7 0.05 2.03 ----
5/25/2001 17.5 5.4 0.07 8.38 ----
5/26/2001 17.0 7.3 0.08 4.32 ----
5/27/2001 12.9 10.0 0.03 16.00 ----
5/28/2001 21.0 9.6 0.10 3.30 ---
5/29/2001 18.5 9.5 0.09 ---- ----
5/30/2001 18.3 3 .2 O. 14 ---- ----
5/31/2001 19.8 2.7 0.10 ---- ----
6/1/2001 14.2 8.7 0.09 7.37 ----
6/2/2001 17.6 8.1 0.07 14.99 ----

 

 

 

 

 

 

72

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% Et“ (cm) (cm)
6/3/2001 16.2 7.8 0.06 --—- ----
6/4/2001 18.5 9.4 0.08 ---- 0.50
6/5/2001 17.9 6.4 0.06 0.25 ----
6/6/2001 16.0 12.1 0.04 1.02 ----
6/7/2001 22.4 8.7 0. 13 ---- ----
6/8/2001 25 .0 7.5 0. 14 ---- ----
6/9/2001 25.6 8.8 0.15 ---- ----
6/10/2001 26.3 12.7 0.13 4.06 ----
6/11/2001 28.2 16.9 0.14 1.02 ----
6/12/2001 28.1 17.9 0.15 3.81 ----
6/13/2001 32.7 16.3 0.16 ---- 0.41
6/14/2001 32.4 24.4 0.18 ---- ----
6/15/2001 31.6 17.8 0.15 21.08 0.41
6/16/2001 26.5 14.0 0.14 0.25 ----
6/17/2001 26.9 14.6 0.18 ---- ----
6/18/2001 28.7 15.2 0.14 5.59 ----
6/19/2001 29.3 21.6 0.20 ---- ----
6/20/2001 24. 9 14.7 0. 15 ---- ----
6/21/2001 18.5 12.6 0.04 19.81 ----
6/22/2001 23 .9 13.1 0.14 5.59 ----
6/23/2001 25.5 12.3 o. 12 '
6/24/2001 27 . 1 1 1.4 0.17 ---- ----
6/25/2001 28.6 12.3 0. 16 ---- ----
6/26/2001 28.6 13.5 0.17 ---- ----
6/27/2001 29.9 16.1 0.16 ---- 0.84
6/28/2001 30.8 18.5 0.17 ---- ----
6/29/2001 29.7 16.5 0.15 ---- 0.84
6/3 0/2001 29.8 17 .8 0.15 ---- ----
7/1/2001 24.7 9.6 0.15 ---- ----
7/2/2001 21.5 4.0 0.16 --—- ----
7/3/2001 22.6 13.1 0.10 0.76 0.50
7/4/2001 28.0 14.7 0. 14 ---- ----
7/5/2001 22.4 11.0 0.18 ---- 1.27
7/6/2001 24.7 5 .7 0. 15 ---- --....
7/7/2001 24.9 14.4 0.10 0.25 ----
7/8/2001 31.3 19.1 0.17 ---- ----
7/9/2001 31.6 16.8 0.15 ---- 1.14
7/10/2001 31.1 19.1 0.17 1.27 ----
7/11/2001 24.9 13.7 0.22 ---- ----

 

 

 

 

 

 

73

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
7/12/2001 25.8 12.5 0.14 ---- 1.37
7/13/2001 25.9 9.1 0.17 ---- ----
7/14/2001 28.8 9.1 0.18 ---- -——-
7/15/2001 30.9 11.4 0.14 ---- ----
7/16/2001 30.6 14.3 0.15 ---- 1.65
7/17/2001 29.7 15.5 0.11 0.51 ----
7/18/2001 30.2 16.2 0.12 0.25 ----
7/19/2001 31.0 16.1 0.14 ---- 0.94
7/20/2001 32.6 17 .6 0.15 ---- ----
7/21/2001 28.6 20.5 0.12 4.06 ----
7/22/2001 32.6 19.4 0.15 ---- ----
7/23/2001 28.4 22.2 0.09 1.02 0.94
7/24/2001 3 1.8 21. l 0. 14 ---- --—-
7/25/2001 23 .4 16.9 0.09 7.11 ----
7/26/2001 25.2 13.5 0.14 ---- 0.84
7/27/2001 25 . 8 8 . 9 0. 16 ---- ----
7/28/2001 28.6 10.6 0. 14 ---- ----
7/29/2001 30.6 17.0 0.13 8.64 ----
7/30/2001 29.3 16.5 0.14 ---- ----
7/31/2001 31.9 18.9 0.14 ---- ----
8/1/2001 32.0 19.7 0.14 ---- 0.84
8/2/2001 29.0 22. 1 0.09 ---- ----
8/3/2001 30.0 18.5 0.15 ---- ----
8/4/2001 30. 8 14.6 0. 16 ---- ----
8/5/2001 32.9 14.6 0.16 ---- ----
8/6/2001 32.8 15.7 0.17 ---- 2.54
8/7/2001 33 .6 21.9 0. l6 ---- ----
8/8/2001 35.4 19.7 0.16 ---- 0.84
8/9/2001 33 .0 20.4 0.15 4.83 ----
8/10/2001 26.4 15.3 0.18 0.51 ----
8/11/2001 28.2 12.3 0.14 ---- ----
8/12/2001 28.4 14.9 0.11 ---- —---
8/13/2001 26.1 14.1 0.15 ---- 1.17
8/14/2001 25.9 8.9 0. 14 ---- ----
8/15/2001 27.0 9.5 0. 13 ---- ----
8/16/2001 21.9 16.3 0.05 16.26 ----
8/17/2001 22.4 14.5 0.07 ---- ----
8/18/2001 25.1 14.3 0.08 3.30 ----
8/19/2001 22.4 16.2 0.06 2.54 ----

 

 

 

 

 

 

74

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation
DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
8/20/2001 25.3 15.4 0.1 1 ---- ----
8/21/2001 26.6 9.7 0.1 1 ---- ----
8/22/2001 21.4 15.5 0.05 12.70 ----
8/23/2001 26.6 18. 1 0.06 ---- ----
8/24/2001 26.4 17 . 7 0. 10 ---- ----
8/25/2001 25 .9 1 7 .9 0.06 ---- ----
8/26/2001 26.8 17. 1 0.08 ---- ----
8/27/2001 28.2 13.1 0.12 ---- ----
8/28/2001 26.2 13.4 0.14 0.76 0.66
8/29/2001 27.2 10.2 0.12 ---- ----
8/30/2001 29.2 13.2 0.14 ---- ----
8/31/2001 25.4 12.9 0.11 ---- ----
9/1/2001 22. 1 6.4 0. 13 ---- ----
9/2/2001 25.2 6.8 0. 12 ---- ----
9/3/2001 28.2 12.8 0.12 ---- ----
9/4/2001 23.0 10.8 0.13 ---- 1.91
9/5/2001 25.0 7.5 0.1 1 ---- ----
9/6/2001 27.8 8.7 0.1 1 ---- 0.69
9/7/2001 30.6 18.0 0.13 3.56 ----
9/8/2001 28.5 18.7 0.10 10.16 ----
9/9/2001 25.4 15.4 0.06 17.53 ----
9/10/2001 22.9 12.3 0.1 1 ---- ----
9/1 1/2001 23 .9 9.4 0. 10 ---- ----
9/12/2001 26.9 10.2 0.12 ---- ----
9/13/2001 18.7 8.1 0.09 2.03 0.50
9/14/2001 17 .7 4. 8 0.08 ---- ----
9/15/2001 18.8 5.0 0.07 ---- ----
9/16/2001 22.0 4. 8 0.09 ---- ----
9/17/2001 22.1 7.0 0.06 ---- ----
9/18/2001 23 .6 10.6 0.06 ---- ----
9/19/2001 19.8 14.5 0.02 23.11 ----
9/20/2001 19.1 12.2 0.06 3.81 ----
9/21/2001 19.8 11.1 0.04 19.30 ----
9/22/2001 21.7 8.3 0.06 ---- ----
9/23/2001 22.0 10.0 0.05 13 .97 ----
9/24/2001 14.7 5.8 0.07 0. 51 ----
9/25/2001 6.6 3 .6 0.03 6.10 ----
9/26/2001 10.5 4.8 0.02 2.03 ----
9/27/2001 14. 5 7.2 0.06 ---- ----

 

 

 

 

 

 

75

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
9/28/2001 15.4 8.2 0.04 ---- ----
9/29/2001 19.8 3.9 0.07 ---- ----
9/3 0/2001 21 .9 1 .8 0.00 ---- ----
10/1/2001 22.6 5.6 0.06 ---- ----
10/2/2001 24.4 7 .5 0.08 ---- ----
10/3/2001 25.7 15.1 0.13 ---- ----
10/4/2001 16.1 8.8 0.06 12.45 ----
10/5/2001 9.7 6.0 0.02 19.05 ----
10/6/2001 8.4 1.4 0.05 0.25 ----
10/7/2001 9.7 -2.5 0.04 ---- ----
10/8/2001 14.3 -3.1 0.06 ---- 0.50
10/9/2001 21.3 7 .4 0.10 ---- ----
10/10/2001 18.5 11.9 0.06 1.02 ----
10/11/2001 17.3 10.8 0.02 0.76 ----
10/12/2001 18.2 10.7 0.02 17.02 ----
10/13/2001 21.3 11.4 0.04 1.02 ----
10/14/2001 20.6 7.8 0.02 13.46 --—-
10/15/2001 13.9 6.1 0.05 0.25 ----
10/16/2001 8.7 4.2 0.02 41.15 ----
10/17/2001 9.4 -1.1 0.05 ---- ----
10/18/2001 15 .3 -2.2 0.06 ---- ----
10/19/2001 14.6 2.8 0.06 ---- ----
10/20/2001 18.9 5.3 ---- ---- ----
10/21/2001 17 .7 5.4 0.05 ---- ----
10/22/2001 18.5 4.4 0.05 2.79 ----
10/23/2001 18.6 11.9 0.03 4.83 ----
10/24/2001 21.2 8.5 0.04 13.72 ----
10/25/2001 9.2 0.9 0.12 2.03 ----
10/26/2001 5.2 0.8 0.02 4.57 -—--
10/27/2001 4.7 0.4 0.02 ---- ----
10/28/2001 10.4 -3.7 0.04 ---- ----
10/29/2001 13.2 4.2 0.06 ---- ----
10/30/2001 8.4 2.3 0.03 1.52 ----
10/31/2001 19.3 5.0 0.06 0.76 ----
11/1/2001 18.3 12.1 0.10 ---- ----
11/2/2001 17 .8 7.9 0.04 11.94 ----
1 1/3/2001 14.9 3 .4 0.06 ---- ----
1 1/4/2001 14.5 3 .6 0.06 ---- ----
1 1/5/2001 9.6 -2.5 0.04 ---- ----

 

 

 

 

 

 

76

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% Et'r (cm) (cm)
11/6/2001 15.6 -2.6 0.05 ---- ----
1 1/7/2001 16.3 8.4 0.06 ---- ----
11/8/2001 14.7 2.0 0.03 2.29 ----
11/9/2001 10.2 -2.8 0.03 ---- ---
11/10/2001 12.8 2.7 0.06 ---- ----
11/11/2001 6.4 -3.1 0.06 ---- ----
11/12/2001 11.5 -4.5 0.03 6.35 ----
11/13/2001 15.9 1.7 0.05 ---- ----
ll/14/2001 14.7 10.1 0.04 0.25 ----
11/15/2001 18.0 10.7 0.03 7.62 ----
11/16/2001 15.8 2.9 0.03 ---- ----
11/17/2001 16.3 0.8 0.03 0.25 ----
11/18/2001 16.2 4.6 0.02 ---- ----
11/19/2001 14.1 1.4 0.01 3.56 ----
11/20/2001 5.4 -1.0 0.02 ---- ----
11/21/2001 9.9 -0.2 0.04 ---- ----
11/22/2001 13.5 -1.2 0.03 ---- ....
11/23/2001 16.1 1.0 0.05 ---- ----
11/24/2001 17.1 11.2 0.09 12.70 ----
11/25/2001 13.3 5.2 0.05 0.51 ----
1 1/26/2001 7 .7 4.7 0.02 ‘ --- ----
11/27/2001 12.9 4.2 0.02 2.03 ----
11/28/2001 5.0 3.0 0.03 1.02 ----
11/29/2001 6.0 3.2 0.00 9.65 ---
11/30/2001 11.5 4.1 0.01 12.70 ----
12/1/2001 6.5 1.4 ---- 0.51 ----
12/2/2001 8.6 0.0 ---- ---- ----
12/3/2001 13.1 5.2 ---- ---- ----
12/4/2001 15.2 9.1 ---- 0.51 ----
12/5/2001 20.7 12. 1 ---- ---- ----
12/6/2001 15.8 -0.8 ---- 0.51 ----
12/7/2001 4. 8 -1 .3 ---- ---- ----
12/8/2001 4.9 -0.2 ---- 1 .27 ----
12/9/2001 47 -1 .8 ---- ---- ----
12/10/2001 7 .9 -3 .7 ---- ---- _---
12/1 1/2001 9.7 -4.4 --..- ---- ----
12/12/2001 8.1 1.0 5.59
12/13/2001 8.9 4.4 ---- 0.51 ----
12/14/2001 4.8 -0.2 ---- 7.62 ----

 

 

 

 

 

 

77

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
12/15/2001 0.6 -1.7 ---- 4.32 ----
12/16/2001 5.6 -0.2 ---- 0.76 ----
12/17/2001 5.7 3.5 ---- 4.32 ----
12/1 8/2001 7 .2 1 .9 ---- ---- ----
12/19/2001 4.0 -1.5 ---- 4.06 ----
12/20/2001 2. 7 -3. 1 an ---- ----
12/21/2001 3.3 -63 ---- ---- ----
12/22/2001 6.6 -3.6 ---- 0.25 ----
12/23/2001 7.9 -4.7 ---- 0.51 ----
12/24/2001 -3.2 -73 ---- ---- ----
12/25/2001 -3.8 -8.8 ---- ---- ----
12/26/2001 -5.7 -1 1. 1 ---- ---- ----
12/27/2001 -4. 1 -9. 9 ---- ---- ----
12/28/2001 -3.3 -8.2 ---- 0.51 ----
12/29/2001 -5.4 -9.8 ---- ---- ----
12/3 0/2001 -6.4 -11.9 ---- ---- ----
12/3 1/2001 -5.5 -9. 5 ---- ---- ----
1/1/2002 -0.1 -15.9 ---- 0.51 ----
1/2/2002 -1 .5 -1 5 .3 ---- ---- ----
1/3/2002 -2.6 -128 --.... ---- ----
1/4/2002 04 -9.8 ---- ---- ----
1/5/2002 0.8 -20 ---- ---- ----
1/6/2002 1 .2 -3 .9 ---- 1 .78 ----
1/7/2002 -3.6 -10.6 ---- ---- ----
1/8/2002 24 -7.4 ---- ---- ----
1/9/2002 7 .0 1 .4 ---- ---- ----
1/ 10/2002 5 . 6 -0.4 ---- ---- ----
1/1 1/2002 4.2 -0. 1 ---- ---- ----
1/12/2002 3.5 -0.8 ---- 0.51 ----
1/13/2002 4.0 -3. 1 ---- 0.25 ----
1/14/2002 7 .7 -0.7 ---- 3.81 ----
1/15/2002 1.2 -2.0 ---- 1.78 ----
1/16/2002 0.4 -23 ---- ---- ----
1/17/2002 -0.4 -6.5 ---- ---- ----
1/18/2002 -4.7 -12.8 ---- 0.25 ----
1/19/2002 -2.1 -12.6 ---- 0.51 ----
1/20/2002 1 .2 -3 .9 ---- ---- ----
1/21/2002 1.4 -4.4 ---- 0.51 ----
1/22/2002 10. 1 -4.6 ---- ---- ----

 

 

 

 

 

 

78

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Inigation

DATE (Maximum °C) (Minimum °C) 80% Et'r (cm) (cm)
1/23/2002 8.6 2.3 ---- 0.51 ----
1/24/2002 2.3 -4.6 ---.- ---- ----
1/25/2002 7 .0 -26 ---- ---- ----
1/26/2002 1 1. 1 1.0 ---- ---.. ----
1/27/2002 13.7 2.8 ---- ---- ..--
1/28/2002 13 . 5 1 .5 ---- ---- ----
1/29/2002 1 .8 -1 .7 ---- ---- ----
1/3 0/2002 -1.4 -3.5 ---- --.. ----
1/3 1/2002 -1 . 1 .4. 5 ---- ---- ----
2/1/2002 2.0 -4.2 ---- 1 1.18 ---
2/2/2002 0.3 -9.0 ---- ---- --..
2/3/2002 2.6 -44 um ---- ----
2/4/2002 -4.3 -14.6 ---- ---.. -..-
2/5/2002 -1 .0 -15.5 --- ---- ----
2/6/2002 4.7 -3.9 --- -..- ...-
2/7/2002 3.0 -2.9 ---- ---.. ..--
2/8/2002 5.7 -3.5 ---- ---- ....
2/9/2002 6.6 -3.6 --- ---- ..--
2/10/2002 8.1 -4.7 ---- 0.25 ----
2/1 1/2002 0. 8 -10.4 ---- ---- -..-
2/12/2002 3.6 -6.2 ---- -..- ----
2/13/2002 -0.7 -10.8 ---- ---- ..--
2/14/2002 6.0 -3.9 ---- ---- --..
2/15/2002 6.9 0.5 ---- ---- ----
2/16/2002 2.0 -2.5 ---- 4.06 ----
2/17/2002 0.3 -7.6 ---.. ---- ----
2/18/2002 6.6 -80 ---- ---- ----
2/19/2002 7 .2 1.2 ---- 3.56 «~-
2/20/2002 1 1 .4 2. 8 ---- 13 .72 ----
2/21/2002 2.9 -4.4 ---- 3.56 ----
2/22/2002 -0.5 -78 ---- ---- ----
2/23/2002 5.0 -9.5 ---.. ---- ----
2/24/2002 13 .8 1 .9 ---- ---- ----
2/25/2002 12.7 -1.4 ----- 1 .02 ----
2/26/2002 -1 .0 -5.5 ---- 0.25 ----
2/27/2002 -2.3 -9.2 ---- l .27 ----
2/28/2002 -2.8 -1 1.6 an ---- ----
3/1/2002 1.0 -4.7 ---- 0. 51 ----
3/2/2002 1.8 -2.2 ---- 14.22 ----

 

 

 

 

 

 

79

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
3/3/2002 0.3 -1 1.6 ---- 0.76 ----
3/4/2002 -10.5 -16.4 --_-- 0.25 ----
3/5/2002 -1.5 -129 ---.. ---- ----
3/6/2002 5.6 -5.7 ---- 0. 51 ----
3/7/2002 0. 1 -29 ---- ---- ----
3/8/2002 15.7 -1.0 ---- 2.29 ----
3/9/2002 15.5 -5.3 ---- 1 1.43 ----
3/10/2002 -5. 1 -9.2 ---- ---- ----
3/1 1/2002 2.9 -93 ---- ---- ----
3/12/2002 10.3 -1.6 ---- ---- ----
3/13/2002 15. 1 1 .2 ---- ---- ----
3/14/2002 9.2 0.7 ---- ---- ----
3/15/2002 12.6 -1.2 ---- 2.03 ----
3/16/2002 3.1 -4.0 ---- ---- --_-
3/17/2002 3.4 -4.7 ---- ---- ----
3/18/2002 3.9 -1.9 ---- ---- ----
3/19/2002 8.5 -3.2 ---- ---- ----
3/20/2002 5.0 —1 .7 ---- 0.25 ----
3/21/2002 1.9 -9.7 ---- 0. 51 ----
3/22/2002 -3.9 -105 ---- ---- ----
3/23/2002 6.0 -52 ---- ---- ----
3/24/2002 5 .2 -7. 1 ---- ---- ----
3/25/2002 -2.5 -8.7 ---- ---- ----
3/26/2002 1.2 -6. 1 ---- ---- ----
3/27/2002 7.7 -7.8 ---- ---- ----
3/28/2002 7.7 -5.9 ---- ---- ----
3/29/2002 8.1 -1.1 ---- 8.13 ----
3/30/2002 10.6 -0.8 ---- 0.25 ----
3/31/2002 10.4 -3.3 ---- ---- ----
4/1/2002 4.8 -2.4 0.05 1.02 ---
4/2/2002 5.6 -0.2 0.01 10.92 ----
4/3/2002 4.9 -1.9 0.06 m. ----
4/4/2002 3. 1 -5 .5 0.05 ---- ----
4/5/2002 3.3 -3.7 0.03 ---- --—-
4/6/2002 4.9 -5.0 0.06 ---- ----
4/7/2002 7 .7 —2.0 0.06 ---- ----
4/8/2002 14.5 4.6 0.02 21.34 ----
4/9/2002 14.9 3.0 0.04 3.05 ----
4/10/2002 15.2 -2.3 0.10 ---- ----

 

 

 

 

 

 

80

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation
DATE (Maximum °C) (Minimum °C) 80% Etl (cm) (cm)
4/11/2002 22.8 3.5 0.16 an ....
4/12/2002 21.0 12.0 0.08 2.54 --
4/13/2002 19.1 8.8 0.10 --- ---
4/14/2002 22.3 10.9 0. 10 ---- ----
4/15/2002 29.2 15.4 0. 15 ---- ----
4/16/2002 29.7 18.3 0. 17 ---- ----
4/17/2002 26.5 15.8 0.14 --- 2.11
4/18/2002 29.4 13 .7 0. 14 ---- ----
4/19/2002 24.5 10.6 0.15 2.29 ---
4/20/2002 1 1.9 5.2 0.12 0.25 ---
4/21/2002 7 .0 0.4 0.09 2.54 ----
4/22/2002 5.8 -0. 1 0.03 0.76 ----
4/23/2002 12.3 -2. 1 0. 10 --- --.-
4/24/2002 21.1 3.3 0.15 0.25 0.64
4/25/2002 10.3 2.4 0.22 0.76 ---
4/26/2002 1 1.9 -2.0 0. 10 ---- ---
4/27/2002 1 1.3 -1.3 0.06 4. 57 ---
4/28/2002 13.3 2.3 0.02 5.33 ----
4/29/2002 9.6 1.9 0.05 --- ----
4/3 0/2002 13 .5 3 .8 0. 12 ---- ----
5/1/2002 15.5 -0.7 0.08 ---- ---
5/2/2002 9.8 3.3 0.04 15.24 ----
5/3/2002 12.8 1.3 0.14 ---- ---
5/4/2002 18.0 -1.2 0. 13 --- ---
5/5/2002 23 .9 5.5 0. 18 ---- ----
5/6/2002 18.5 13.6 0.10 3.56 ----
5/7/2002 17 .9 10.8 0.08 ---- ----
5/8/2002 11.4 5.6 0.07 1.78 0.50
5/9/2002 18.1 8.6 0.06 7 . 1 1 m-
5/10/2002 14.9 3.8 0.21 ---- ----
5/11/2002 13.1 0.0 0.05 2.54 ----
5/12/2002 10.8 5.0 0.01 20.32 ----
5/13/2002 10.7 5.8 0.02 0.25 ---
5/14/2002 17.5 5.5 0.14 1.02 ----
5/15/2002 21.0 0.6 0. 14 ---- ----
5/16/2002 20.0 5.4 0.06 24.38 ----
5/17/2002 7. 8 1.2 0.08 ---- ----
5/18/2002 9.3 1.8 0.06 0.76 ----
5/19/2002 10.3 -2. 1 0. 10 ---- ----

 

 

 

 

 

 

81

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% EtT (cm) (cm)
5/20/2002 7.9 -0.3 0.06 ---- ----
5/21/2002 13 .5 2.8 0.10 ---- ----
5/22/2002 18.5 0.6 0. 14 ---- ----
5/23/2002 23 .7 9.0 0. 15 ---- ----
5/24/2002 17.5 7.6 0.13 2.29 0.58
5/25/2002 15.1 3.1 0.06 3 .56 ----
5/26/2002 21.8 4. 1 0. 14 ---- ----
5/27/2002 26.2 6.6 0. 15 ---- ----
5/28/2002 25.6 10.0 0.15 ---- ----
5/29/2002 24.9 16.4 0.09 13 .72 ----
5/30/2002 25.9 16.9 0.11 24.38 ----
5/31/2002 28.3 14.9 0.19 ---- ----
6/1/2002 28.9 13 .6 0.20 ---- ----
6/2/2002 22.6 9. 5 0. 15 ---- ----
6/3/2002 16.5 8.1 0.11 9.40 ----
6/4/2002 22.9 10.3 0.08 27.94 ----
6/5/2002 19.1 12.9 0.03 0.76 ----
6/6/2002 20.9 10.0 0.13 ---- 0. 50
6/7/2002 23 .6 7 .0 0.14 ---- 0.58
6/8/2002 26.9 1 1.8 0. 16 ---- ----
6/9/2002 29.7 12. 8 0. 17 ---- ----
6/10/2002 31.1 17.0 0.18 1.78 0.58
6/11/2002 29.4 20.1 0.15 8.13 ----
6/12/2002 25 .9 16.7 0.1 1 ---- ----
6/13/2002 20.1 14.1 0.09 0.25 ----
6/14/2002 20.7 14.3 0.10 2.29 ----
6/15/2002 21.3 11.7 0.10 1.52 ----
6/16/2002 21.4 11.2 0.12 ---- 0.38
6/17/2002 23 .7 9.3 0.13 1.02 ----
6/18/2002 26. 5 7 .7 0. 16 ---- ----
6/19/2002 29.6 13.5 0.18 ---- ----
6/20/2002 32.0 16. 1 0. 19 ---- 1.27
6/21/2002 27 .9 20.1 0. 1 1 ---- ----
6/22/2002 32.0 20.0 0. 15 ---- ----
6/23/2002 32.1 18.7 0.17 ---- ----
6/24/2002 32.6 18.2 0.15 ---- 1.35
6/25/2002 33.4 16.7 0.15 ---- 0.58
6/26/2002 29.1 20.8 0.14 0.76 ----
6/27/2002 27 .3 20.4 0. 14 ---- ----

 

 

 

 

 

 

82

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation
DATE (Maximum °C) (Minimum °C) 80% Etl (cm) (cm)
6/28/2002 29.1 13 .4 0.16 ---- 1.91
6/29/2002 31. 1 13.8 0. 16 an ----
6/3 0/2002 32.2 16. 8 0.15 ---- ----
7/1/2002 33.6 19.9 0.16 ---- 0.76
7/2/2002 32.9 19.4 0. 18 ---- ----
7/3/2002 33.5 18.7 0.20 ---- 0.50
7/4/2002 32.6 21 .2 0. 18 ---- ----
7/5/2002 24.8 15.0 0.20 -—-- 2. 54
7/6/2002 27 .8 10.7 0.15 ---- 0.64
7/7/2002 31.8 12.5 0. 18 ---- ----
7/8/2002 32.7 15.2 0.17 5.08 1.91
7/9/2002 27 . 1 19.4 0.07 28.96 ----
7/10/2002 24.2 15.5 0. 17 ---- ----
7/11/2002 25.2 10.2 0.15 ---- ----
7/12/2002 26.7 8.4 0.16 ---- 1.27
7/13/2002 30.2 9.7 0.17 ---- ----
7/14/2002 29. 5 1 1 .7 0. 17 ---- ----
7/15/2002 31.3 12.9 0.16 ---- 0.81
7/16/2002 32.4 18.6 0.17 -—-- ----
7/17/2002 30.4 17.9 0.18 ---- 0.81
7/18/2002 29.5 18.1 0.12 ' 8.13 ----
7/19/2002 28. 5 l7 .0 0. 10 ---- ---—
7/20/2002 30.0 14. 5 0. 16 ---- ----
7/21/2002 32.9 18.9 0.13 0.25 ----
7/22/2002 33 . 5 21.9 0.16 4.32 ----
7/23/2002 23.5 13 .9 0.17 ---- 0.69
7/24/2002 25.6 9.4 0. 15 ---- ----
7/25/2002 26.0 12.6 0.15 ---- ----
7/26/2002 29.5 17.8 0.14 17.02 ----
7/27/2002 27.6 18.1 0.08 1.52 ----
7/28/2002 28.6 20.9 , 0.07 9.91 ----
7/29/2002 30.2 20.8 0.10 19.81 ----
7/3 0/2002 29. 8 19. 1 0. 15 ---- ----
7/31/2002 32.2 19.1 0.18 ---- ----
8/1/2002 31.2 19.0 0.15 ---- 0.76
8/2/2002 27.5 16.2 0.17 1.52 ----
8/3/2002 30.4 13 .4 0.16 ---- ----
8/4/2002 31.1 19.7 0.12 0.25 ----
8/5/2002 27.6 18.7 0.12 0.25 0.94

 

 

 

 

 

 

 

83

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% .EtT (cm) (cm)
8/6/2002 21.8 1 1.7 0. 15 ---- ----
8/7/2002 23 .9 8.0 0. 1 1 ---- ----
8/8/2002 25.5 8.1 0.14 ---- 0.94
8/9/2002 27 .6 10.8 0. 14 ---- ----
8/10/2002 29.6 11.2 0.15 ---- 0.38
8/11/2002 31.5 16.7 0.15 ---- ----
8/12/2002 31.4 17 .0 0.15 ---- ----
8/13/2002 30.1 20.3 0.15 6.60 0.64
8/14/2002 23.5 19.2 0.05 10.41 ----
8/15/2002 28.2 17 .3 0.12 ---- ----
8/16/2002 28.3 19.3 0.11 0.51 ----
8/17/2002 28.6 19.1 0.10 ---- ----
8/18/2002 25.2 13.0 0.17 ---- ----
8/19/2002 21.5 12.3 0.06 4.32 ----
8/20/2002 25 .4 10. 9 0. 14 ---- ----
8/21/2002 27.5 11.2 0.14 ---- 0.38
8/22/2002 25.5 19.2 0.14 4.57 ----
8/23/2002 22.1 18.3 0.04 7.1 l ----
8/24/2002 26. 1 17 .9 0.07 ---- ----
8/25/2002 26. 8 13 .9 0. 12 ---- ----
8/26/2002 28.2 13 .8 0. 12 ---- ----
8/27/2002 26.8 14.3 0. 12 ---- ----
8/28/2002 25.2 1 1.7 0.14 ---- ----
8/29/2002 27.4 13 .7 0.12 ---- 0.64
8/3 0/2002 27 . 8 12.6 0.12 ---- ----
8/31/2002 28.8 1 1.9 0.12 ---- ----
9/1/2002 29.7 12.9 0. 14 ---- ----
9/2/2002 28. 1 18.2 0.08 ---- ----
9/3/2002 27.4 14.7 0.15 ---- 0.95
9/4/2002 27 . 1 l 1.6 0.14 ---- ----
9/5/2002 25.9 9.4 0.12 ---- 0.97
9/6/2002 29.8 10.6 0.13 ---- ----
9/7/2002 33.0 10.8 0.14 ---- 0.64
9/8/2002 33 .4 13 .8 0. 14 ---- ----
9/9/2002 32.5 13.8 0.12 ---- 0.76
9/10/2002 32.0 16.2 0.11 0.25 ----
9/1 1/2002 23.7 1 1.4 0.14 ---- ----
9/12/2002 25.4 6.9 0. 1 1 ---- ----
9/13/2002 26.8 9.2 0.10 ---- 0.50

 

 

 

 

 

 

84

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 30% EtT (cm) (cm)
9/14/2002 29.7 10.0 0. 10 ---- ----
9/15/2002 20. 1 1 1 .4 0.06 ---- ----
9/16/2002 24.4 5.6 ---- ---- 0.81
9/17/2002 28. 1 6.6 ---- ---- ----
9/18/2002 25.7 12.2 0.06 1.27 ----
9/19/2002 29.7 18.7 0.09 4.57 ----
9/20/2002 24.8 18.0 0.05 2.79 ----
9/21/2002 26. 5 13 .8 0. 1 1 ---- ----
9/22/2002 16.3 7.2 0.07 3.56 ----
9/23/2002 18.4 4.3 0.07 ---- ----
9/24/2002 17.4 4.8 0.09 ---- ----
9/25/2002 22.2 2.0 0. 10 ---- ----
9/26/2002 23.9 7 .8 0.08 ---— 0.64
9/27/2002 22.6 12.3 0.08 ---- ----
9/28/2002 22.2 7. 8 0. 10 ---- ----
9/29/2002 25.4 13.2 0.10 0.76 ----
9/3 0/2002 29. 5 16.2 0.13 ---- 1.02
10/1/2002 29.9 19.7 0.1 1 ---- ----
10/2/2002 24.5 12.9 0.06 0.25 ----
10/3/2002 15.4 11.1 0.04 3.81 ----
10/4/2002 25.3 14.8 0.02 9.14 ----
10/5/2002 16. 5 5.2 0. 13 ---- ----
10/6/2002 19.5 4.2 0.07 2.54 ----
10/7/2002 12.2 1.7 0. 12 ---- ----
10/8/2002 17 . 1 1.6 0.06 ---- ----
10/9/2002 20.5 5.2 0.08 ---- ----
10/10/2002 21.9 3.6 0.06 ---- ----
10/11/2002 22.2 5.7 0.06 ---- ----
10/12/2002 21.6 5.8 0.04 1.52 ----
10/13/2002 11.9 -1.6 0.08 3.05 ----
10/14/2002 13.7 -0.5 0.06 ---- ----
10/15/2002 17.2 1.0 0.07 ---- 0.50
10/16/2002 9.2 -0.7 0. 1 1 ---- ----
10/17/2002 6.5 -4.4 0.02 2.03 ----
10/18/2002 11.5 3.0 0.02 2.29 ----
10/19/2002 10.9 4.6 0.03 ---- ----
10/20/2002 9.8 -2.0 0.04 ---- ----
10/21/2002 10.4 -4. 1 0.03 ---- ----
10/22/2002 8.9 4.6 0.03 ---- ----

 

 

 

 

 

 

85

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation
DATE (Maximum °C) (Minimum °C) 30% EtT (cm) (cm)
10/23/2002 7 .3 -0.3 0.03 ---- ---
10/24/2002 7.8 -0.7 0.04 --- ----
10/25/2002 5.8 -2.7 0.02 6.60 ----
10/26/2002 8.2 4.2 0.01 0.25 ----
10/27/2002 8.0 3.2 0.03 ---- ----
10/28/2002 8.9 -0.5 0.03 ---- ----
10/29/2002 4.3 -1.4 0.03 ---- ----
10/3 0/2002 8.4 -3.0 0.04 ---- ----
10/3 1/2002 8.3 -4.3 0.02 ---- ----
1 1/1/2002 3 .4 -2.0 0.04 ---- ----
1 1/2/2002 5.2 -2.1 0.03 ---- ----
1 1/3/2002 8.6 -7.0 0.02 ---- ----
1 1/4/2002 9.2 -3.7 0.03 ---- ----
11/5/2002 4.0 -l .5 0.02 4.06 ----
1 1/6/2002 4.6 1.0 0.00 --- ----
1 1/7/2002 10.1 -3.9 0.05 ---- ----
11/8/2002 17.1 7 .4 0.10 -- ---
11/9/2002 15.7 7 .6 0.04 1.78 ----
11/10/2002 18.4 10.9 0.02 11.18 ----
11/11/2002 10.8 3.1 0.02 0.51 ----
1 1/12/2002 4.8 1.0 0.01 ---- ----
1 1/13/2002 9.7 -0.6 0.03 ---- ----
11/14/2002 12.7 0.9 0.05 5.08 ----
* 11/15/2002 1.1 -3.7 0.04 0.76 ----
1 1/16/2002 -0.5 -5.8 0.01 ---- ----
1 1/17/2002 1.6 -4.3 0.02 ---- ---
1 1/1 8/2002 4. 8 -6. 5 0.02 ---- ----
11/19/2002 11.6 1.7 0.04 4.32 ----
11/20/2002 13.4 3.0 0.03 ---- ----
11/21/2002 7.5 -0.4 0.01 3.30 ----
11/22/2002 1.4 -1.0 0.03 0.51 ---—
11/23/2002 4.9 -0.7 0.02 0.25 ----
1 1/24/2002 4.6 -1 .9 0.02 ---- ----
11/25/2002 -0.2 -4.3 0.01 1.78 ----
1 1/26/2002 -1 .2 -5.7 ---- ---- ----
1 1/27/2002 -0.7 -10.3 ---- 0.25 ----
1 1/28/2002 -2. 1 .41 ---- ---- ----
1 1/29/2002 7 .9 -25 ---- ---- ----
1 1/30/2002 4.0 -7 .3 ---- 0.76 ----

 

86

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Air Temperature Air Temperature Precipitation Irrigation

DATE (Maximum °C) (Minimum °C) 80% Et'r (cm) (cm)
12/1/2002 -1 .0 -9. 2 ---- ---- ----
12/2/2002 -1.0 -13.7 .7--- ---- ----
12/3/2002 -3.8 -19.0 ---- 4.06 ----
12/4/2002 -3.0 -205 ---- ---- ----
12/5/2002 -2.0 -121 ---- ---- ----
12/6/2002 -2.8 -8.7 ---- ---- ----
12/7/2002 2.2 .4.7 ---- ---- ----
12/8/2002 -0. 1 -1 5.7 ---- ---- ----
12/9/2002 -3.0 -19.4 ---.. ---- ----
12/10/2002 5.5 -5.8 ---- ---- ----
12/1 1/2002 5.0 -8.0 ---- ---- --..
12/12/2002 6.0 -55 ---- ---- ----
12/ 13/2002 1 .2 -0.6 ---- ---- ----
12/14/2002 1 .8 -1 .0 ---- ---- ----
12/1 5/2002 4. 5 -1 .9 ---- ---- ----
12/16/2002 -1.7 -9.0 ---- ---- ----
12/ 17/2002 0. 1 -7. 5 ---- ---- ----
12/18/2002 8.7 -0.3 ---- 6. 10 «~-
12/19/2002 10.3 0.7 ---- 9.65 ----
12/20/2002 1 .6 -2.4 ---- 1 .52 ----
12/21/2002 -0.1 -3.5 ---- ..-- ----
12/22/2002 -0.2 -2.7 ---- ---- ----
12/23/2002 -1.0 .45 ---- ---- ----
12/24/2002 -2.8 -5.3 ---- ---- ----
12/25/2002 -0.5 -4.7 ---- 1.78 ----
12/26/2002 -0.2 -8.0 ---- 0.76 ----
12/27/2002 -3 .3 -9. 1 ---- ---- --_-
12/28/2002 0. 1 -6. 1 ---- 1 .27 ----
12/29/2002 2.0 .4.7 ---- ---- ----
12/30/2002 1 1.4 -1.7 ---- 0.76 ----
12/31/2002 10.4 -3.7 ---- ---- ----

 

 

 

 

 

 

87

 

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90