THE EFFECT OF LH1E OK THE CKEAICAL COAPOSITIOK OF A CHARLOTTETOWN FINE SANDY LG At;! AND THE EFFECT OF S E V E R N AFEKDIGEKTS OK ITS CONTENT OF YitATER-SOLUBLE BOROK AS SHOWN BY SOIL AND PLAINT ANALYSES By Robert F« Bishop A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Soil Science 19 53 j*CKK OWLEDGEMEK TS The author gratefully acknowledges the guidance of Hr. R. L. Cook, the helpful suggestions of Dr. L. M. Turk the support of the Division of Chemistry, Science Service Canada Department of Agriculture and the co-operation of the Division of Field Husbandry, Experimental Farms Service, Canada Department of Agriculture. ii VITA Robert F r e d e r i c k B i s h o p candidate for the d e g r e e of Doctor of P h i l o s o p h y Dissertation: The Effect of L i m e o n the Chemical Compos­ ition of a C h a r l o t t e t o w n Fine Sandy Loam and the Effect of S e v e r a l Amendments on Its Content of 'Water-Soluble Boron as Shown by Soil and Plant A n a l y s e s Outline of Studies Major subject: Minor subject: Soil S c i e n c e F a r m Crops Biographical Items Born, April 24, 1913, S o m e r s e t , N o v a Scotia Undergraduate Studies, A c a d i a University, 1930-34 Graduate Studies, McGill U n i v e r s i t y , 1944-45, Michigan State College, 1 9 4 9 - 5 0 Experience: School Principal, 1 9 3 4 - 3 8 , Canada Department of Agriculture as A g r i c u l t u r a l Assistant, 1938-45, A g r i c u l t u r a l Scientist, 1945-50, Agricultural R e s e a r c h Officer, 1950 member of the Society of the S i g m a X i , the Agricultural Institute of Canada, the C h e m i c a l I n s t i t u t e of Canada Ill ABSTRACT Field, greenhouse and laboratory experiments were used to determine the results of liming a strongly acid soil and the effect of certain other amendments on its content of water-soluble boron. The soil investigated, a Charlottetown fine sandy loam, is one of the best and most extensive agricultural soils on Prince Edward Island. The field experiment, started in 1931, consisted of a three year rotation of potatoes, barley and clover. Lime­ stone applications of 0, 500, 1,000, 1,500, 2,000 and 3,000 pounds per acre have been made periodically. Commercial fertilizer has been used for each potato crop and, since lt>42, for each barley crop. Chemical determinations made on soil samples taken in 1930, 1946 and 1951 included pH, exchangeable bases, base exchange capacity, total nitrogen and water-soluble boron. Liming decreased soil acidity with the greatest amount of lime changing the pH value from approximately 5.0 to 6.0. Irrespective of the amount of limestone applied, decreases occurred in total nitrogen and exchangeable magnesium while exchangeable potassium increased* ir From 1930 to 1948 water-soluble boron decreased approx­ imately 30 per cent regardless of* the amount of limestone applied. In 1948 a significant difference existed between the water-soluble boron content of limed and unlimed soils but not between soils receiving different rates of lime­ stone . The limestone treatments had little effect on soil acidity below plow depth. Clover and barley yields were significantly increased by liming. This treatment did not affect potato yields but tended to increase the incidence of scab. In a greenhouse experiment liming reduced boron avail­ ability as measured by plant and soil analysis. Two crops of ladino clover were grown and, although the calcium-boron ratios ranged from approximately 550 to 1 to 2,000 to 1, no visual symptoms of boron deficiency were observed. There was e significant correlation between the watersoluble boron in the soil and the boron content of the clover. The effect of calcium carbonate, magnesium carbonate, sodium hydroxide, gypsum, manure and alfalfa, on the water- soluble boron content of soil, was studied in a laboratory experiment. Calcium and magnesium carbonates were eoually effective in decreasing the water-soluble boron in soil. Gypsum was ineffective• V When the pH of the soil was raised from 4.70 to 7.22 with calcium carbonate the water-soluble boron decreased from 0.22 to 0.12 parts per million* The water-soluble boron in soil was increased by appli­ cations of manure or alfalfa hay. The increases were pro­ portional to the rates of application. When expressed as parts per million of water-soluble boron, decreases occurring with calcium carbonate, whether applied alone or with manure or alfalfa hay, tended to be the same for any one rate of application irrespective of the amount of water-soluble boron present. applications of sodium hydroxide, to bring about a range of soil pH values from 4.82 to 9.72, were accompanied by decreases and then increases in water-soluble boron* At comparable pH values of approximately 7.0 or less sodium hydroxide caused a smaller reduction in water-soluble boron than did either calcium or magnesium carbonate* Calcium carbonate, with sodium hydroxide, applied to a soil previously treated caused less reduction in water-soluble boron than where applied in the absence of sodium hydroxide. vi T^BLE OF COKTENTS I INTRODUCTION PAGE ........................................... 1 II LITERATURE REVIEW ..................................... 2 III REG 101. INVESTIGATED ................................... 10 Description of Prince Edward Island ............... 10 B. Description of the Charlottetown Soil Series .... 12 IV EXPERI2AEKTAL P R O C E D U R E ............................... 15 A. Field Studies ........................................ 15 V E. Greenhouse Studies ................................. 19 C. Laboratory Studies ................................. 21 IUETHCDS OF ANALYSIS .............. 23 ............................................... 25 Soils B. Plants II ............................... 24 RESULTS x'-'.D DISCUSSION 25 A. Field Studies ...................................... 25 1. Analysis of Soils .............................. 25 2. Yield Data 43 ...................................... n. Greenhouse Studies on the Effect of Limestone on the Availability ofSoil Boron ................. 58 vii TABLE O F CONTENTS (continued) PAGE C. Laboratory Studies ................................. 67 1. Effect of Calcium Carbonate, Gypsum and M a gnes­ ium Carbonate on the .Vater-Soluble Boron Content of Soil ................................. 67 2. Effect of Manure and Alfalfa, MLone and in Combination with Calcium Carbonate, on the .Vater-Soluble Boron Content of Soil ............ 69 3. Effect of Sodium Hydroxide, Alone and in Combination with Calcium Carbonate, on the Water-Soluble Boron Content of Soil .......... 4. The Water-Soluble Boron Content of Soil VII 72 ...... 74 SUMMARY ................................................. 79 BIBLIOGRAPHY 86 vlii LIST OF TABLES Table Table PAGE I Crop and Year of Lime Application ............. 18 II Chemical Analyses of Soil Samples Collected in 1930 ......................................... Table III Table IV Table V Chemical Analyses of Soil Samples Collected in 1948 ......................................... 27 Average Values of Chemical Analyses of Soils- 34 Change in rfater-Soluble Soil Boron from 1930 to 1948 Table VI VII ................................... 37 V/ater-Soluble Boron Content of the 1948 Soil Samples Table ........... Analysis of Variance of the 40 ater-Soluble Boron Jontent of the 1948 Soil Samples ...... Table Table VIII Chemical Analyses of Subso i l s ............ ... IX Yield of Potatoes .............................. Table Table Table Table Table Table X Analysis of Variance of the Yield Analysis of Variance of the Yield of Barley XIII Yield of Clover ................................ XIV Analysis of Variance of the Yield XV of Clover 41 42 44 46 48 . 50 52 . 55 Average Yields of Potatoes, Barley and Clover from 1940 to 1948 Inclusive Table of Potatoes XI Yield of Barley ............................. XII 26 .......... 56 XVI Yield of Ladino Clover per Pot ............... 59 ix LIST OF TABLES (continued) Table XVII Analysis PAGE of Variance of the Yield of Ladino C l o v e r .................. . ...... Table XVIII 60 Effect of Soil Treatments on the Calcium and Boron Content of Ladino Clover • ..........65 Table XIX Decrease in the Water-Soluble Boron Content of Soil Due to the Application of Calcium Carbonate Table XX Analysis ................................... of Variance of the Decrease in Water-Soluble Boron Content of Soil Due the Application of Calcium Carbonate 75 the to ..... 75 X LIST OF FIGURES Figure PAGE 1. Sketch Map Showing the Location of Prince Edward Island ................................... Figure S. Soil Map of Prince Edward Island (in pocket inside back cover) Figure 3. Plan of Field Experiment with Limestone Treatments in Pounds Figure p e r A c re ................. 11 16 4. Effect of Limestone on Soil pH and Per Cent Base Saturation ................................ . 35 Figure 5. Water-Soluble Boron Content of Soil Samples Taken in 1930 and in 1948 .................... Figure 39 6. Effect of Limestone on Yield of Barley and Glover .......................................... . 57 Figure 7. Effect of Soil Treatments on Yield and Boron Content of Ladino Clover and on the pH Value and Water-Soluble Boron Content of theSoil . . 6 2 Figure 8. Effect of CaC02, C a S O ^ E K g O and MgCOr, on the Water-Soluble Boron Content of Soil.. ........ Figure 68 9. Effect of Manure and Alfalfa, ^lone and in Combination with CaCOr*, on the Water-Soluble Boron Content of Soil .......................... 70 Figure 10. Effect of EaOH, Alone and in Combination with C aC 0 3 , on the Water-Soluble Boron Content of Soil ............................................. 73 INTRODUCTION Lime in the form of marl, chalk or limestone occurs throughout the world and while the liming of agricultural land is far from a recent development the practice has greatly i n ­ creased in the last fifty years. At the present time the use of lime as a soil amendment is generally considered as a major factor in crop production on much of the farm land In the more humid parts of this and other countries. However, recognized that the availability of boron, it is also an essential plant nutrient, may be adversely affected by the application of lime. In recent years the use of lime as a soil amendment has increased considerably in various parts of the Maritime Prov­ inces. This fact, together with reported instances of boron deficiency, makes it desirable to have information relative to liming and the effect of this practice on the availability of soil boron. This investigation, based on field, greenhouse and labor­ atory studies, was carried out to learn what changes have occurred in soil properties and crop yields in a long term liming experiment being conducted at the Dominion Experimental Station, Charlottetown, Prince Edward Island and to determine how changes in pH value as well as applications of different sources of calcium and organic matter, both alone and in com­ bination, affect the water-soluble boron content of soil. II. LITERATURE REVIEW The importance of lime in regard to soil acidity, plant growth, phosphate availability, soil structure, soil formation, fertilizer use and the reclamation of alkali soils has been discussed by Kelley (1940) who considers calcium of greater fundamental significance than nitrogen, phosphorus or potass­ ium. Truog (1948) has indicated that the availability of all plant nutrients in the soil is affected to some extent by the amount of lime present, and Bradfield (1941) considers calcium carbonate part of a system which, directly or indirectly, influences most important reactions in soil chemistry. Fippin (1939) has made reference to the fact that lime is the key to the growth of most legumes and that this is possibly the greatest service of lime in agriculture. according to McCall (1923) if a soil has an unfavorable hydrogen ion concentration, contains soluble iron, aluminum or manganese or has insufficient calcium for nutritive purposes an application of lime will be beneficial. In this connection Peech (1941) has included the direct nutrient effect of calcium and magnesium, the stimulation of microbial activity, ment of the physical condition of the soil, improve­ the neutralization of hydrogen ions and the precipitation of toxic amounts of alum inum, manganese and iron among the beneficial effects to be derived from liming. Fippin (1939) and Truog (1947) have 3 expressed similar views while Salter and Sohollenberger (1939) have stated "'liming increases the efficiency of utilization of the available water and fertility of the soil by correct­ ing some factors unfavorable to plant growth, making possible more economical crop production and tending to conserve the soil." Marshall (1946) has pointed out that the nature of the clay mineral in the soil may have considerable bearing on the response obtained from liming. This is explained by the fact that below 70 per cent saturation montmorillonite clays have a high energy of adsorption for the calcium ion while kaolinite releases calcium with equal ease irrespective of the d e ­ gree of saturation. Cooper, Paden, Garman and Page (1948) have also suggested the importance of the type of clay mineral present in regard to the availability of ions for plant growth while Heed and Cummings (1948) have stated that a higher d e ­ gree of calcium saturation is required for comparable plant adsorption of calcium from soils with a 2:1 type colloid than from soils with a 1:1 type of colloid. ^slander (1952) has attributed the unproductiveness of podzol soils to the absence of plant nutrients rather than to their acid reaction and believes a lasting fertility may be obtained by fertilization without liming. Truog (1918) has also suggested that acidity as such is not ordinarily the limiting factor in acid soils, while IhcCall (1923) considers the intensity of acidity to be of more importance than the quantity. Bryan (1923) believes that the greater the acidity of the substrate the less the power of plants to obtain calcium while Moser (1943) has presented evidence indicating that a liberal supply of available calcium is required for optimum growth in acid soils. Arron and Johnson (1942) have also shown that while acidity was not deleterious to plant growth a high calcium concentration in the nutrient solution was necessary for normal growth at low pH values. While the influence of lime on potassium availability has been studied by various workers there is considerable variation in the results obtained. Harris (1937) has report­ ed that in general increasing fixation occurred with increas­ ing amounts of lime. Peech and Bradfield (1943) believe that in the absence of neutral salts the addition of lime results in the liberation of adsorbed potassium although if the soil contains neutral salts there may be an increase, a decrease or no change in the potassium concentration of the soil sol­ ution as the result will depend on the initial degree of base saturation of the soil. Pierre and Bower (1943) have express­ ed a somewhat similar view. Lucus and Scarseth (1947) have commented on the need for a proper balance between calcium and potassium in the soil while Jenny and Slade (1934) have suggested that microorganisms may be connected with decreased potassium availability following liming* York and Rogers (1947) 5 have stated that as soils vary in their ability to fix applied potassium as well as in the nature and content of native potassium it is difficult to generalize in regard to the effect of lime on potassium availability. Pierre and Browning (1935) as well as Lynd and Turk (1948) have pointed out that excess lime may be detrimental to crop growth while Albrecht and Schroeder (1941) and Albrecht (1946) have shown the importance of adsorbed hydro­ gen in the soil. These workers together with Maclntlre and Hatcher (194E) and haftel (1927a) have referred to the effect of lime on phosphorus availability. From the results reported it would appear that liming may increase, decrease or have little effect on phosphorus availability and as in the case of potassium it would be difficult to generalize in this regard. In addition to the relation of lime to phosphorus and potassium the effect of lime on boron availability has been the object of a considerable amount of investigation since Aarington (1922), Sommer and Lipman (1926) and HcMurtrey (1929) showed boron to be an essential plant nutrient. Although the amount of boron necessary for optimum growth is very small the work of Eaton (1944) shows that different plant species exhibit considerable variation in regard to their boron requirements and tolerances. Harsh (1942) as well as Piland, Ireland and Reisenauer (1944) have indicated that 6 most legumes have a relatively high requirement and that dicotyledonous plants have a greater requirement than do monocotyledonous plants. The function of boron in plants is somewhat obscure although Scripture and McKargue (1943) pointed out that it may be involved with protein metabolism while Cook and Pillar (1949) suggest it regulates the intake of other ions. According to Berger (1949) it is also important in cell d i v ­ ision and seems to be an essential component of the cell wall, tfaringtcn (1934) has indicated that calcium absorption is favored by the presence of boron while Brenchley and Yfarington (1927) have shown a relationship between the boron content of the substrate and the calcium metabolism of the plant. Marsh and Shive (1941) have also reported a relationship between the soluble calcium in plant tissue and the boron content of the substrate as well as between the calcium and boron in the plant. Jones and Scarseth (1944) have stated that plants grow normally only when a certain balance exists between the intake of calcium and boron while Purvis and Davidson (1948) consider a functional relationship to exist between the two with a high intake of either increasing the need for the other. Eaton (1944) has indicated that climatic factors may influence the movement of boron in plants. Berger and Truog (1940) have pointed out that before visable symptoms of boron deficiency are manifest a reduction in 7 yield usually occurs. It has been suggested by Dunklee and I.idgley (1944) that with varying degrees of deficiency plants may show as many as ten different symptoms due to lack of boron. According to Berger (1949) terminal growth is invari­ ably affected by boron deficiency and other symptoms include shortened internodes, blasted flowers and the failure of fruit and seed formation. Visual boron deficiency symptoms of more than seventy plants have been summarized by McMurtrey while Woodbridge (1950) (1948) has similarly summarized deficiency symptoms for various vegetables and tree fruits as reported by a number of Canadian investigators. Although boron deficiency is often associated with a lka­ line and overlimed soils Beeson (1945) has pointed out that it is also found in regions of high rainfall where leaching may be excessive and the soils are strongly acid in reaction. Purvis (1939) considers that cropping practices together with a low original boron content may account for the uns a t i s f a c t ­ ory boron status of many podzol soils while Whetstone, R o b i n ­ son and Byers (194E) believe soils of the Atlantic and Gulf coasts are apt to be deficient in boron. Eaton and Wilcox (1939) have indicated that the boron content of soils may be related to the nature of the soil forming materials and in this connection Whetstone, Robinson and Byers (1942) have reported that soils derived from igneous rocks and unconsoli­ dated sediment have a low content while those derived from 8 alluvium, limestone, shale and glacial drift are high in boron, according to Woodbridge (1950) boron deficiency symptoms have been observed in Canada from the Atlantic to the Pacific al ­ though the Maritime Provinces, Quebec, Ontario and British Columbia are the most seriously affected. In regard to the factor or factors responsible for boron fixation in soils various opinions have been expressed in the literature. Eaton and Wilcox (1929) have suggested that heavy soils may fix boron more readily than light ones and that boron fixation is a relatively slow process and probably due to some kind of a chemical reaction. Midgley and Dunklee (1929) have also considered boron fixation to be of a chem­ ical nature while Olson and Berger (1946) have expressed a similar view and consider it to be rapid, reversible and apparently associated with a group of minerals occurring in the clay fraction of soils. Parks and Shaw (1941) have sug­ gested that fixation may be due to boron replacing aluminum in the aluminum-silicate crystal lattices and Parks (1944) concluded that fixation was due to this rather than to chem­ ical precipitation, adsorption by clay or by organic matter* <2 6" to 12" V/eak reddish-brown or light brown­ ish-red fine sandy loam, weakly developed structure nutlike to small blocky in character, slightly firm, easily permeable. pH 4.6. C lelow 2C" Reddish brown or brownish-red to red, to 24" fine sandy loam to sandy clay loam. Firm but permeable. Contains varying quantities of partially weathered sandstone fragments and the occas­ ional sandstone boulder. pK 4.4. Although the natural fertility of the Charlottetown series is not high these soils respond to good management end are cap­ able of producing satisfactory yields. They are suited to a 14 variety of common farm crops and approximately 60 per cent of the potato acreage of the Province is found on the Charlottetown series. IV. !vXPLRI.:iIi T.tt.L PROCEDURE ■a. Field Studies In the spring of 1921 a field experiment with a three year rotation of potatoes, barley and clover was started at the Dominion Experimental Station, Charlottetown, Prince Edward Island. The experimental area, the soil of which is mapped as Charlottetown fine sandy loam, was divided into three ranges each of which contained three blocks of six plots. The ranges, which carried a different crop in the rotation each year, were separated by 20 foot alleyways. The clots, separated by four foot pathways, were 13.2 feet by 55 feet with an area of one-sixtieth of an acre. A field plen of the experiment is given in Figure 2. Soil treatments. Ground limestone treatments were randomized within each block. The rates used were: (1) Check (2) 500 pounds per acre (2) 1,000 pounds per acre (4) 1,500 pounds per acre (5) 2,000 pounds per acre (6) 2,000 pounds per acre Irior to 1942 limestone was applied every six years. Beginning in 1942 it was applied every three years and that year both the barley and clover crop received limestone. With Range 3 Range 2 Range I I[ 2000 0 2000 2 [ 0 1500 3000 3 [ 1500 3000 1500 4 [ 3000 2000 u o CD 0 1000 500 500 6[ 500 1000 1000 7 1000 1500 1500 8 3000 0 2000 9 2000 ao 3000 0 u o 2000 o CD 500 11 [ 12 1500 1000 3000 500 500 1000 13 [ 3000 14 [ 1500 15 [ 500 1500 0 3000 2000 3 o o 1500 u © 16 1000 l7[ 2000 500 3000 l8[ O I0 0 0 1000 Fig. 3. Block CD o CD 2000 CD ~500~ Plan oF Field experiment with limestone treatments in lb./A. Block 10 2 5[ Block 16 17 this exception limestone was only applied for the barley crop. The crop and year of limestone application is shown in Table I* From 1931 to 1941 inclusive a 4-8-6 fertilizer at 1200 pounds per acre was used for the potato crop. Beginning in 1942 this was changed to a 4-8-10 analysis and in addition 300 pounds per acre of a 2-12-10 analysis was applied to the barley crop. Crop yields. The yields of all crops were recorded each year. In the case of potatoes the crop was examined for scab as in 1930 the experimental area produced scab free potatoes. Yields of this crop were expressed in bushels per acre of marketable tubers. Barley yields were recorded in bushels per acre of threshed grain and clover yields in tons per acre of air dry hay. Soil samples. After the experiment was laid out and before any treatments were applied surface and subsoil samples were taken from plots 3 and 9 in range 1, plots 5 and 13 in range 2 euid plots 3, 9 and 16 in range 3. In 1948 surface soil samples were obtained from each plot in the experiment. In 1951 subsoil samp les, corresponding to those taken at the beginning of the exper iment, were taken. All the samples were of a composite nature with the surface samples representative of the 0-6 inch depth and the subsoil samples representative of the 6-12 inch depth. When the 1948 samples were taken range 1 had received four applications of limestone while ranges 2 and 3 had been limed 18 TABLE I CROP AND YEAR OF LIKE APPLICATION Year _________________Ranges___________________ 3 2 1 1S31 Clover Potatoes Barley (lime) IS 32 Potatoes Barley (lime) Clover 1933 Barley (lime) Clover Potatoes 1S34 Clover Potatoes Barley 1935 Potatoes Barley Clover 1936 Barley Clover Potatoes 1937 Clover Potatoes Barley (lime) 1938 Potatoes Barley (lime) Clover 1939 Barley (lime) Clover Potatoes 1940 Clover Potatoes Barley 1941 Potatoes Barley Clover 1942 Barley (lime) Clover (lime) Potatoes 1943 Clover Potatoes Barley (lime) 1944 Potatoes Barley (lime) Clover 1945 Barley (lime) Clover Potatoes 1946 Clover Potatoes Barley (lime) 1947 Potatoes Barley (lime) Clover 19 48 Barley (lime) Clover Potatoes 19 49 Clover Potatoes Barley (lime) 19 50 Potatoes Barley (lime) Clover 1951 Barley (lime) Clover Potatoe s 19 five times. In 1951, when subsoil samples were obtained, each of the ranges had. received an additional limestone treatment. B. Greenhouse Studies In the fall of 19 50 a greenhouse experiment was init­ iated at Ottawa, Canada. The surface six inches of a Charlotte­ town fine sandy loam soil, obtained from the Dominion Experi­ mental Station at Charlottetown, Prince Edward Island, was screened, mixed and placed in gallon pots. This soil was con­ sidered to be comparable to that in the check plots of the previously described field experiment. The potted soil was not maintained at a definite m o i s t ­ ure content but adequate moisture was provided at all times by surface applications of tap water. There was not, however, enough water applied at any one time to cause leaching through the peat moss plug in the hole at the bottom of the pot. Soil treatments. The experiment consisted of four treatments each of which was replicated three times. The treatments were: (1) Check (2) .an 0-10-10 fertilizer at 800 pounds per acre (2) Calcitic limestone at 2 tons per acre (4) Treatment (2) + Treatment (2) The limestone was mixed with the air dry soil before potting while the fertilizer was applied to the potted soil as a blanket application at a depth of two inches. 20 Seeding and harvesting. In December seven ladino clover seeds were planted in each pot and later thinned to two plants per pot. The clover, which was seeded at the one-hall* inch depth, was cut at the early bloom stage with the last of five cuts being made on October 2, 1951. The material cut from each culture was allowed to air dry before recording the weight. When harvesting was complete the five harvests of the repli­ cates were combined to make a composite sample for each treatment. Soil sampling. Following the fifth cut of clover soil samples were taken with a tube which reached to the bottom of the pot. Three samples were taken from each pot and replicates com­ bined to give composite samples representing each of the four treatments. The second clover crop. The cultures were not watered after the final cut of the 1950-51 crop and further growth was p re­ vented by reworking the surface soil. In December 1951 the soil was removed from the pots and reworked. Other than apply­ ing limestone at 1^ rather than 2 tons per acre the soil treat­ ments as well as the seeding and harvesting procedures were similar to those given for the 1950-51 crop. In the case of the 1951-52 crop the clover was cut four times and composite soil samples were taken from the pots in May 1952. 21 C« Laboratory Studies In August 19 51 a laboratory experiment was set up at the Division of Chemistry, Science Service, Ottawa, Canada* The soil used was representative of the 0-6 inch depth in the check plots in ranges 1 and 3 of the previously described field e x ­ periment at Charlottetown, Prince Edward Island. The plots were sampled in Hay 19 51. Soil treatments. The experiment involved nine series. The treatments within each series were: Series 1 CaC 03 at 0, 1, 2, 4, 6 and 8 tons per acre. Series 2 CaS04 .2Hg0 at 0, 1.72, 3.43, 6.86, 10.30 and 13.73 tons per acre. These rates added the same amount of calcium as was supplied by the CaCO^ in series 1. v Series 3 MgCOr* at 0, 0.84, 1.68, 3.36, 5.04 and 6.74 tons per acre. These rates provided a neutralizing power equivalent to that of the CaCO^ in series 1. Series 4 Manure at 0, 10, 20, 40, 60 and 100 tons per acre* Series 5 CaCO^ and manure together at the rates used in series 1 and 4. Series 6 Alfalfa hay at 0, 10, 20, 40, 60 and 100 tons per acre • Series 7 CaCO^ and alfalfa hay together at the rates used in v series 1 and 6. Series 8 1 .D K a O H at such rates as to give a range of pH values from approximately 5.0 to 9.5. 22 Series 9 Sufficient l.N NaO H to raise the pH value of the soil to approximately 8.5 and then CaC02 treat­ ments as in series 1. The calcium carbonate, gypsum, magnesium carbonate and sodium hydroxide used were boron free. On an air dry basis the manure used contained 17.8 parts per million of total boron and the alfalfa hay 50.8 parts per million. Experimental procedure. The soil was air dried, a 2 mm. sieve, passed through thoroughly mixed and weighed out in 200 gram samples. To facilitate mixing with the soil the manure and alfalfa hay were air dried and ground in a Wiley mill. These materials were added to the soil on the basis of their orig­ inal moisture content. The various materials were thoroughly mixed with the soil which was placed in half pint waxed containers. Water, equal to 50 per cent of the moisture holding capacity of the soil was added and the treated samples allowed to stand until approximately air dry. At that time the samples were thorough­ ly mixed and remoistened. They were maintained in that cond­ ition for two months. At that time they were allowed to air dry and were prepared for chemical analysis. V. IvIETHODS OF A N A L Y S IS ■q.. Solis All analyses except those for nitrogen were made on sam­ ples of air dry soil ground to a fineness of 2 mm. Nitrogen determinations were made on samples ground to 0.5 mm. fineness. A soil water ratio of 1 to 2.5 was used for pH determin­ ations which were made with a glass electrode. Total nitrogen was determined by the Kjeldahl method as given by the Association of Official Agricultural Chemists (19 45) . Exchangeable bases and base exchange capacity were d e ­ termined by the methods of Peech, Alexander, Dean and Reed (1947). In the determination of base exchange capacity the adsorbed ammonia was distilled after extraction with sodium chloride. Licromethods were used in the determination of the exchangeable cations. Aater-soluble boron was determined colorimetrically using tumeric as proposed by Naftel (1929). In this determination 10 grams of soil and 50 ml. of water were boiled under refluxing conditions for five minutes, ^fter cooling to room temp­ erature the water extract was separated from the soil by centrifuging. ^ photoelectric colorimeter was used to deter­ mine the intensity of color developed with the tumeric re- 24 B. Plants The air dry plant material was ground in a Wiley mill prior to analysis* Calcium was determined by dry ashing as given by the association of Official Agricultural Chemists (1950). Total boron was determined colorimetrically using tumeric as proposed by Naftel (1S29). The plant material was dry- ashed in the presence of Ca(0H)2 and the final color comparisons were made with a photoelectric colorimeter* VI. RESULTS AKD DISCUSSIOL A. Field Studies 1. x-nalysis of Soils The results of analysis of seven surface soil samples taken in 1930 are presented in Table II. The strongly acidic nature of the soil is shown by the pH values and the per cent base saturation. While there is considerable variation in r e ­ spect to exchangeable magnesium, and to a lesser extent in the case of exchangeable potassium, the values for nitrogen indicate no great differences in the organic matter content of the experimental area. The analytical data for the 54 surface soil samples c ol­ lected in 1948 are given in Table III. It will be noted that with the exception of those plots which did not receive lime­ stone, the values for exchangeable magnesium are consistently much higher in range 3 than in either range 1 or range 2. It is possible that in one of the years range 3 was limed with dolomitic rather than calcitic limestone. The limestone, dolo mi tic or calcitic, used on Prince Edward Island is imported from Nova Scotia or Lew Brunswick. The data show that the water-soluble boron content of the soil from plots 1, 2 and 3 in range 1 is approximately double that found in any of the other soils. As these three plots occur together at one TABLE II nge *l1 H-' O erf CHEMICAL ANALYSIS OF SOIL SAMPLES COLLECTED IN 1920 pH Exchangeable Cations* Mg Ca K Exchange Capacity* Base Saturation V Nitrogen 1 9 5.4 me 3.54 me 0.30 me 0.20 me 8.29 48.7 $ 0.21 2 13 4.9 3.07 0.60 0.18 8.75 44.0 0.24 2 5 5.2 2.97 0.25 0.22 9.82 35.0 0.21 w 16 4.7 2.29 0.55 0.19 10.54 29.4 0.24 1 u 5.3 3.36 0.40 0.17 8.45 46.5 0.21 u * u 5.2 1.43 0.15 0.11 9.82 17.2 0.22 w 9 5.2 1.35 0.15 0.06 9.80 15.9 0.20 fi * In 100 gm. soil. to T.LiLE III CHEMICAL ANALYSIS OF SOIL SAMPLES COLLECTED IK 1948 Rate of Limestone pH Application Range Plot 1 4 4*6 1 9 4.8 1 14 2 lb./acre 0 Exchangeable Cations* Ca Mg K Exchange Base Capacity* Saturation me 2.39 me 0.12 me 0.29 me 9.88 it 2.30 0.14 0.26 4.7 ft 1.79 0.09 1 4.9 n 2.22 2 8 5.1 « 2 13 5.1 3 2 5.0 % V 10 •X 18 Nitrogen Boron 28.3 r ' 0.19 ppm 0.35 9.60 28.2 0.18 0.34 0.23 9.02 23.4 0.17 0.30 0.14 0.26 9.53 27.5 0.20 0.33 2.94 0.11 0.24 9.31 35.4 0.18 0.34 ft 2.26 0.10 0.32 9.55 28.3 0.18 0.30 rt 2.32 0.18 0.24 9.60 28.5 0.19 0.33 5.1 2.85 0.15 0.28 9.86 WU 4* 0.19 0.35 4.9 1.89 0.13 0.33 9.45 24.9 0.19 0.31 % * In 100 gm. Boil. to ^3 lAbLE III(continued) Range Plot Rate of Limestone pH Application lb./acre 500 Exchangeable Cations* Ca Mg K Exchange Base Capacity* Saturation me 3.11 m6 0.13 me 0.30 me 9.58 " J Nitrogen ppm 0.30 37.0 T 0.19 9.68 36.2 0.20 0.32 0.23 8.15 35.2 0.19 0.27 0.07 0.23 9.06 40.5 0.19 0.28 3.34 0.07 0.26 9.45 38.8 0.19 0.29 ft 3.03 0.09 0.33 9.37 36.8 0.19 0.26 5.4 n 3.38 0.32 0.24 9.88 39.9 0.21 0.33 12 5.4 ft 'Z 'Z'Z 0.24 0.25 9.94 38.4 0.19 0.29 15 5.1 ft 2.07 0.16 0.23 9.25 26.6 0.18 0.28 1 5 4.9 1 10 4.9 M 3.11 0.14 0.25 1 16 5.0 tt 2.52 0*12 2 5 5.3 n •X TO1 o •W 2 12 5.2 ft 2 17 5.1 3 6 w 3 * In 100 gm. soil. “ Boron T A B L E I I I (c o n t i n u e d ) Range Blot Rate of Limestone pH Application lb./acre 1000 Exchangeable Cations* Ca I.lg K Base Exchange Capacity* Saturation me 3.99 me 0.14 me 0.29 me 9.76 Nitrogen Boron 25.1 # 0.20 ppm 0.32 i 1 6 5.1 1 12 5.1 rt 4.19 0.16 0.20 9.47 48.1 0.18 0.30 1 18 5.0 n 2.73 0.12 0.22 9.19 33.4 0.17 0.28 2 6 5.5 n 4.22 0.11 0.29 9.19 50.4 0.20 0.32 2 11 5.4 n 4.23 0.09 0.23 9.68 47.0 0.18 0.29 2 18 5.1 tt 2.76 0.08 0.30 9.19 34.2 0.19 0.28 3 5 5.5 n 3.60 0.41 0.24 10.05 42.3 0.19 0.32 'i u 7 5.6 it 3.92 0.40 0.21 10.00 45.3 0.19 0.32 3 16 5.3 n 2.93 0.33 0.32 9.25 38.7 0.18 0.26 * In 100 gm. soil. to to T.idLE III(continued) Range Plot pH 1 v> 5.4 1 7 5.4 1 12 5.1 2 2 5.6 2 7 5 .5 2 14 5.5 3 5 .6 11 5.5 14 5.5 * Rate of Limestone Application * In 100 gm. soil. Exchangeable Cations* Ca Mg K lb./acre me me me 1500 4.89 0 .13 0.29 4.77 0.11 3.69 tt rt rt it rt tt tt n Base Exchange Capacity* Saturation me Nitrogen Boron ppm 10.17 * 52.4 0.19 0.53 0.25 9.60 53.5 0.19 0.30 0.12 0.22 8 .94 45.2 0 .18 0.27 4.65 C .12 0.16 10.22 48.1 0 .20 0 .31 4.97 0.09 0.25 9.60 55.4 0.19 0 .32 4.52 0.13 0 .27 9.51 5 1.8 0 .18 0.27 4 .2 4 0.46 0.30 9.86 50.7 0.19 0.30 2.29 0 .2 8 0 .22 9.60 39.6 0 .1 8 0 .2 8 3 .70 0 .35 0 .31 9.27 47.0 0 .1 8 0.30 i H B L E I I I (c o n t i n u e d ) Range Hot Rate of Limestone pH application lb./acre 2000 Exchangeable Cations* Ca Mg K Exchange Base Capacity* Saturation Hitrogen Boron me 5.47 me 0.15 me 0.32 me 10.66 55.7 0.19 ppm 0.60 tt 5.45 0.16 0.30 9.64 61.4 0.20 0.33 5.2 tt 3.91 0.08 0.24 8.82 48.0 0.19 0.25 4 6.0 tt 6.71 0.14 0.24 9.82 72.2 0.20 0.30 2 10 5.8 tt 5.60 0.11 0.22 9.92 59.9 0.18 0.31 2 16 5.6 tt 5.75 0.11 0.31 9 .58 64.5 0.19 0.25 'Z w 1 5.7 tt 4.35 0.39 0.24 9.90 50.4 0.20 0.32 3 9 5.9 rt 4.94 0.51 0.29 10.09 56.9 0.19 0.30 w 17 5.5 tt 4.06 0.37 0.35 10.00 47.8 0.18 0.28 1 1 5.3 1 8 5.4 1 15 2 * In 100 gm. soil i $ ..ISLE Iil( c o n t i n u e d ) Range Plot Rate of Limestone pH Application lb./acre 3000 Exchangeable Cation* Ca Iflg K Base Exchange Capacity* Saturation Hitrogen Boron me 5.96 me 0.11 me 0.29 me 10.04 i ■; ft 63.1 0.20 ppm 0.56 1 2 5.6 1 11 5.7 n 6.17 0.14 0.21 9.86 66.0 0.18 0.31 1 17 5.7 n 5.35 0.13 0.22 8.94 63.8 0.18 0.27 2 3 6.3 n 6.94 0.10 0.17 9.74 74.0 0.19 0.25 2 9 6.3 n 7.52 0.14 0.26 10.18 77.S 0.18 0.26 £ 15 5.7 •« 5.25 0.11 0.24 9.60 58.4 0.19 0.25 3 4 6.0 rt O• n. ^o 0.43 0.24 9.88 60.7 0.19 0.31 8 6.2 « 6.14 0.59 0.24 9.72 71.8 0.19 0.31 13 6.1 n 5.76 0.36 0.20 9.90 64.0 0.19 0.30 %j * In 100 gm. soil corner of the experimental area it is thought that sometime since 1930 they had received an application of borax. The average values for the chemical analyses of surface soil samples taken in 1930 and in 1948 are presented in Table IV and the effect of limestone on soil reaction and per cent base saturation is illustrated in Figure 4. In respect to the ex­ changeable magnesium content of the soil there has been a gen­ eral decrease during the 18 year period. If in calculating the average values for this soil constituent the data from range 3 are omitted, a value of 0.12 milliequivalents is obtained for each of the highest rates of limestone application. Thus the relatively high values in range 3 are responsible for the app­ arent increase in exchangeable magnesium with increased rates of limestone application. In contrast to exchangeable magnesium the exchangeable potassium status of the soil has improved. That is, the amount of potassium applied as fertilizer together with that released to the exchangeable form by the soil exceeded the amount of potassium removed by the crops plus that lost by leach­ ing. The values given for total nitrogen indicate a decrease in soil organic matter. There is no indication that the various limestone treatments have influenced the increase in exchange­ able potassium or the decrease in soil organic matter. Ivloschler, Obenshain, Cocke and Camper (1949) working with a Sassafras fine sandy loam have reported that 0, 600, 1,200, 1,800, 2,400 and 3,000 pounds per acre of limestone applied every four years over Ta b l e IV .-yr ..RAGE VALuiiio 0.F CHEi.lIGAL . ANALYSIS OF SOILS Year Sampled Rate of Limestone application pH2 Exchange Capacity1 Base Saturation Litroge 5.16 me 2.57 me 0.34 me 0.16 me 9.35 A 23.8 0.22 lb./acre 1920(7) Exchangeable Cationsl Ga lug K )0 1948(9) 0 4.92 2.L2 0.13 0.27 9.53 28.5 0.19 1948(9) 500 5.11 3.02 0.15 0.26 9.37 36.6 0.19 1948(9) 1000 5.24 3.62 0.20 0.26 9.53 40,6 0.19 1948(9) 1500 5.43 4.30 0.20 0.25 9.64 49.3 0.19 1948(9) 2000 5.53 5.14 0.22 0.28 9.82 57.4 0.19 1948(9) 2000 5.92 6.05 0.24 0.22 9.76 66.6 0.19 1 In 100 gm. soil. 2 Obtained by averaging hydrogen ion concentrations. Figures in brackets refer to the number of values averaged. m 5 75 60 5 50- 50 5 25 40 cent Per Soil base -i 70 pH 6 00 saturation 35 5 00 Base safuration 30 4 75 20 0 500 1000 Rate Fig* 4. of 2000 1500 a p p licatio n in 2500 3000 Ib ./A Effect of limestone on soil pH and per cent base saturation. 36 a 23 year period had little afreet on the potassium status of the soil. Organic matter increased only with the highest rate of limestone. According to Peech (1941) a change in soil reaction from pH 5 to pH 6 may be expected to increase the total content of exchangeable bases, excluding hydrogen, approximately three times. In the present investigation there has been an Increase of approximately two and one-half times. Bear and Toth (1948) have suggested that in an ideal soil 65 per cent of the ex­ change complex should be occupied by calcium, 10 per cent by magnesium, five per cent by potassium and the remainder by hydrogen. They have further stated that in acid soils used for potato production a two to one ratio of magnesium to potassium is important in order that potassium is not taken up by the plants at the expense of magnesium. In general those plots re­ ceiving the highest rate of limestone have approximately 65 per cent of their exchange complex occupied by calcium but only in range 3 does the magnesium to potassium ratio approx­ imate that suggested by Bear and Toth. In view of this it would seem that the use of dolomitic limestone would be pre­ ferable in respect to the conditions under which the-present field experiment is being conducted. The water-soluble boron content of seven samples of sur­ face soil taken in 1920 and of comparable samples taken in 1948, as well as other pertinent data, are presented in Table V. tilth one exception (plot 3 in range 1) there has been 37 TABLE V CHARGE IE ' w a TER-SOLUBLE SOIL BOROK FROM 1930 TO 1948 ppm 0.49 ppm 0.34 69.4 5.1 0.43 0.30 69.8 5.2 5.3 0.41 o • o 73.2 5000 4.7 5.3 0.38 0.26 66.4 or* 6000 5.3 5.4 0.42 0.53 126.2 'K 7500 5.2 5.6 0.42 0.30 71.4 9 100C0 5.2 5.9 0.42 0.30 71.4 9 2 13 2 5 rt lb./acre 0 5.4 ♦ 1 1 Boron 1946 Boron X 100 1930 1946 1930 Boron CD Limestone applied pH Range Plot 1931-1948 1930 1946 4.9 25C0 15 0 7° a rather consistent decrease in content of water-soluble boron. There is no indication that the magnitude of the decrease has been influenced by the apilication of limestone and the result­ ing change in the pH value of the soil. The approximate 30 per cent decrease in the soils from six of the seven plots may be attributed to removal by crops and loss through leaching. Berger (1949) has pointed out that loss of boron by leaching is of particular importance in acid soils. In this connection Kubota, Berger and Truog (194S) as well as Wilson, Lovvorn and •Yoodhouse (1951) have shown that the lighter the texture of the soil the greater the loss by leaching. 38 The change from 1930 to 1948 in the water-soluble boron content of the soil in seven plots is shown graphically in figure 5. The fact that plot 3 in range 1 has a higher content in 1948 than in 1930 lends support to the belief that sometime since the experiment was started this plot, as well as plots 1 and 2 in the same range, received an application of borax. For comparative purposed the water-soluble boron values for the 1948 samples are presented in Table VI. In view of the boron content of plots 1, 2 and 3 in range 1 the block con­ taining these plots was omitted in calculating the treatment means and also in the analysis of variance which is presented in Table VII. The results of analysis of subsoil samples taken in 1930 and of comparable samples obtained in 1951 are presented in Table VIII. There is some indication that the limestone treat­ ments are having a slight effect on the subsoil although the changes recorded are generally small and not consistent. It will be noted however that exchangeable magnesium has decreas­ ed in all cases while no consistent change has occurred in r e ­ spect to exchangeable potassium. On the basis of work report­ ed by Blair and Prince (1934) it would seem that the lack of change in the subsoils may be related to the rates of lime­ stone being used at Charlottetown. This view is further sub­ stantiated by the work of Brown and Llunsell (1938) who found 0 55 930 so m p le s • 1948 samples o soil 0 50 0-35 Boron content of 0 40 0-30 0-25 Range I Plot 9 Range 2 Plot 13 Fig. 5. Range 2 Range 3 Range I Range 3 Plot 5 Plot 16 Plot 3 Plot Range 3 3 Plot 9 Water-soluble boron content of soil samples taken in 1930 and in 1948. M to 40 TABLE VI WATER-SOLUBLE BORON CONTENT OF THE 1948 SOIL SAMPLES Rate of limestone application lb./A 500 1000 1500 2000 3000 Block 0 1 ppm. 0.35 ppm. 0.30 ppm. 0.32 ppm. 0.53 ppm. 0.60 ppm. 0.56 0.443 2 0.34 0.32 0.30 0.30 0.33 0.31 0.317 0.30 0.27 0.28 0.27 0.25 0.27 0.273 4 0.33 0.28 0.32 0.31 0.30 0.25 0.298 5 0.34 0.29 0.29 0.32 0.31 0.26 0.301 6 0.30 0.26 0.28 0.27 0.25 0.25 0.268 7 0.33 0.33 0.32 0.30 0.32 0.31 0.318 8 0.35 0.29 0.32 0.28 0.30 0.31 0.308 9 0.31 0.28 0.26 0.30 0.28 0.30 0.288 0.325 0.290 0.296 0.293 0.293 0.283 Lean* * Block 1 omitted L.S.D. (P.05), for treatment means s 0.017 ~..S.D. (P.05), for block meant = 0*019 Mean 41 TABLE VII ANALYSIS OF VARIANCE OF THE WATER-SOLUBLE BORON CONTENT OF THE 1948 SOIL SAMPLES Source of Variation Degrees of Freedom Mean Square _____ F Value______ Obtained Required P.05 P.01 Blocks 7* 0.00210 7.78 2.29 2.19 Treatments 5 0.00172 6.27 2.49 2.60 Lime vs no lime 1 0.00770 28.52 4.12 7.42 Rates of lime 4 0.00022 0.85 2.64 2.91 Error * Block 1 omitted 25 0.00027 Ta BLE VIII CHEiVICAL ANALYSIS OF SUBSOILS Range H o t Limestone .applied pH 1921-1951 1920 1951 Exchangeable Cations* Ca Mg E 1920 1951 1920 1951 1920 1951 Exchange Base Capacity* Saturation 1920 1951 1920 1951 lb./acre 0 me me 0.22 0.08 me me 0.15 0.17 me me 7.47 6.49 38.3 28.7 5.3 5.2 me me 2.50 1.61 0 5.5 5.3 2.95 1.71 0.15 0.10 0.12 0.14 7.74 6.62 41.6 29.5 5 3000 5.0 5.1 1.54 2.25 0.20 0.06 0.15 0.15 4.66 5.57 40.6 44.5 ** o 16 6000 4.7 5.0 1.27 1.00 0.15 0.10 0.22 0.14 6.52 4.02 25.3 31.1 1 T u 7500 5.3 5.3 3.79 2.62 0.25 0.15 0.11 0.15 8.19 7.15 50.7 43.6 3 9000 4.9 5.1 1.42 1.93 0.20 0.15 0.17 0.14 7.68 7.79 22.4 28.6 9 12000 5.1 5.2 1.30 1.22 0.17 0.10 0.12 0.13 7.89 6.44 20.3 22.5 1 9 2 13 2 3 * In 100 gnu soil. * 43 the time since application and rate of limestone used were important factors affecting the degree and depth to which acidity in the soil was reduced* 2. Yield Data It was considered that by 1940 soil differences, other than those resulting from the application of limestone, would tend to have levelled off and the effect of the limestone treatments on yields could be better evaluated* In view of this as well as the fact that soil samples were taken from all plots in 1948 it was thought that the yields obtained from 1940 to 1948 inclusive would best reflect the influence of liming. During this period each crop occurred three times on each range* Potatoes. The potato yields are shown in Table IX* The low yields recorded for 1941, 1943 and 1945 may be partially attributed to unfavorable weather conditions during the growing season. There was an excess of moisture in 1941 and 1943 while in 1945 the rainfall during July and August was approximately half the usual amount. The analysis of variance, presented in Table X, shows highly significant yield differences between ranges and be ­ tween years within ranges. The limestone treatments have had no significant effect on yield* While Carolus (1944) found that calcium did not seem to be an important factor in the growth and yield of potatoes, Berger (1948) has reported 44 TABLE IX YIELD OF POTATOES (Expressed as bushels per acre) Crop Year Range 1940 2 1941 1942 1942 19 44 •X c<* 1 2 '* X K 0 Rate of limestone application lb./acre 500 1000 1500 2000 18? 149 149 140 149 142 162 149 148 162 161 161 126 144 140 149 140 153 123 120 127 126 152 101 119 110 112 102 102 105 111 104 109 112 98 100 190 200 218 220 257 247 226 228 225 246 274 256 210 200 202 228 O ^ 251 103 97 110 98 106 110 105 111 119 117 121 118 117 100 111 107 118 117 257 300 210 267 297 299 X 201 202 283 205 201 207 260 294 297 232 294 'X 2000 45 TABLE IX (continued) YIELD OF POTATOES (Expressed as bushels per acre) Crop Year Range 0 1945 1 125 120 100 110 100 92 125 115 120 105 95 105 125 120 122 120 115 125 165 135 127 136 106 106 149 147 135 125 159 126 139 151 137 142 O th c\2 Rate of limestone application lb./acre 1000 2000 500 1500 209 200 232 210 189 221 p^ 229 243 216 189 212 254 208 190 251 211 361 375 391 387 375 372 371 382 392 359 368 321 242 347 315 362 371 r*Qr* 1946 2 1947 1948 1 ** 3000 116 46 TABLE X AKALYSI3 OF V a RIALCE OF THE YIELDS OF POTATOES Source of Variation Degrees of Freedom Mean Square F Value Obtained Required P.05 P.01 Ranges 2 149900 *4126 519.72 T r*p 5.29 Years within ranges 6 141260.9691 180.50 2.00 4.82 Treatments within ranges 249.2062 1.27 2.02 2.69 52.2247 0.18 2.52 2.70 498.2469 1.72 2.16 2.98 6 475.4691 1.29 2.25 2.12 20 464.9912 15 5 Treatments Lime vs no lime 1 6.0492 Rates of lime 4 65.0185 10 Treatments x ranges Replications within ranges Years within ranges x Treatments within ranges Years within ranges x Replications within ranges 12 782.62661 Treatments within ranges x Replications within ranges 20 288.42472 Years within ranges x Treatments within ranges x Replications within ranges 60 240.92103 L rt ^ irror mean square for years within ranges. Error mean square for ranges and treatments within ranges* Error mean square for replications within ranges. 47 yield increases from the use of dolomitic limestone. Hawkins, Chucka and Brown (1941) have also reported beneficial results from light applications of dolomitic limestone when a defic­ iency of magnesium caused reduced yields. Reports on the potato crops show the incidence of scab to be increasing with plots receiving the higher rates of lime­ stone being the most seriously affected. Cook and Nugent (1939) found a relationship between soil reaction and scab and co n ­ cluded that calcium compounds affect scab only to the extent that they change soil reaction. Nelson and Brady (1943) grew potatoes in the greenhouse and reported that dolomitic lime­ stone placed at a 1C inch depth increased yield but did not increase scat. '.Vhen the limestone was mixed with the surface soil scab infection was increased. Barley. The yield data for barley are presented in Table XI and the analysis of variance of the data is given in Table X I I . differences in yield between ranges and in years within the same range are highly significant. There is also a sign­ ificant effect from the application of limestone. Both Ahl■?ren (1949) and Klages (1949) have pointed out that barley is sensitive to soil acidity while Webber, Morwick, Heeg, Thomas and Richards (1952) have given 6.5 to 7.6 as a favor­ able pH range for this crop. field notes show that in 1943 and also in 1945 the growth in certain plots v.as apparently retarded by soil moisture 48 TABLE XI YIELD OF BARLEY (Expressed as bushels per acre) Crop Year Range 1940 1 1941 1942 1942 1944 2 7 1 2 Rate of limestone application lb./acre__ 500 1000 1500 2000 3000 25.0 32.5 41.9 45.0 27.5 40.0 22.5 26.9 28.7 43.7 37.5 42.5 22.1 36.9 28.1 r*'X•rrj ou 33.7 43.7 21.2 13.7 18.7 25.0 16.2 16.2 18.7 30.0 26.2 23.7 15.0 13.7 18.7 15.0 12. 5 21.2 15.0 21.2 42.5 47.5 56.2 42.5 42.5 38.7 46.2 48.7 35.0 52.5 47.5 55.0 17.5 32.5 32.5 42.5 40.0 47.5 25.0 31.2 36.2 33.7 25.0 40.0 26 .2 40.0 36.2 21.2 ^ r* n 36.2 26.2 12.5 15.0 35.0 30 .0 21.2 29 .2 26.1 27.5 41.7 42.1 26.1 44. 5 48.6 50 .0 26.1 47.2 45.9 27 .5 22.0 24.7 44.5 42.8 50.0 0 49 TA BLE X I (continued) YIELLS OF EARLEY (Expressed as bushels per acre) Crop Year Range 1S45 w 19 46 1947 1946 ** 1 2 *7 Rate of limestone application lb./acre 500 1000 1500 2000 2000 22.2 22.6 26.4 26.4 22.0 29.2 29 •2 20 .9 24.7 22.0 20.6 27.6 5.6 19.5 18.1 22.2 18.1 29.2 26 .4 27.6 20 .6 26.1 27 .8 45.9 40 .2 26.9 40.2 ^7 c; 'X'X • *x A 44.5 26.4 29 .2 28.9 26 .1 40.2 41.7 16.1 26 .4 26 .4 22.0 27.8 20.6 27.6 20.6 27.5 29 .2 <>*>o •X'X . rx A 29.2 26.4 22.6 26.4 20 .6 27.8 20.6 22.6 29 .2 'X'X 29.2 41.7 22.0 41.7 40 .2 20.6 40.2 24.7 22.4 19 .5 22.4 28.9 27.5 20.6 27.5 0 a 50 TABLE XII ^LALYSIE OF VAn.I*LCE OF TILE YIELDS OF BARLEY Source of Variation Degrees of Freedom Mean Square F Value Obtained Required P.05 P.01 Ranges 2 399 .7420 7 .87 3.32 5.39 Years within ranges 6 1256.4130 19 .74 3.00 4.82 15 76.2876 1.50 2.02 2.69 135.2060 3.84 2.53 3.70 Treatments within ranges 5 Treatments Lime vs no lime 1 639.2692 12.58 4.17 7.56 Rates of lime 4 84.1852 1.66 2.69 4.02 10.66 2.25 3.12 Treatments i ranges Replications within ranges Years within ranges x Treatments within ranges 10 16.8283 6 227.5660 30 19.1619 Years within ranges x Replications within ranges 12 63.75051 Treatments within ranges x Replications within ranges 30 50.80802 Years within ranges x Treatments within ranges x Replications within ranges 60 2 0 .96053 ^ 2 ^ Error mean square for years within ranges. Error mean square for ranges and treatments within ranges. Error mean for replications within ranges. if 51 conditions. This could be partially responsible for the fact that the analysis of variance shows a highly significant d i f f ­ erence between replications within ranges. Wilson (1948) has stated that barley does not do well on wet, poorly drained sandy soils. Although oats are the most important grain crop in the Maritime Provinces, barley production is increasing. According to Shuh (1952) the barley acreage in Prince Edward Island from 1940 to 1949 was approximately two and one-third times as great as it was during the preceding 10 year period. Cowan (1S52) has drawn attention to the fact that the variety most commonly grown in the Maritimes is Charlottetown 80 which orig­ inated from a selection made at the Dominion Experimental Station at Charlottetown, Prince Edward Island. Clover. The clover yields, presented in Table XIII, represent the weight of all plant growth on each plot. Field notes h o w ­ ever, taken during the growing season, show that considerable and rather consistent differences existed in the plots each year with respect to what per cent of the total growth was clover. In the check plots, clover seldom accounted for more than 10 per cent of all growth with the remainder being v o l ­ unteer red top, daisies and weeds. the highest rate of limestone, In the plots, receiving clover represented at least 75 per cent of all growth. Thus it would appear that the lime­ stone treatments have had more influence on this crop than is indicated by the reported yields. 52 TABLE XIII YIELD OF CLOVER (Expressed as tons per acre on an air-dry basis) Crop Year Range 1940 •X u 1941 1942 1942 1944 1 2 ■z 1 0 Rate oron content of ladino clover and on the pH value and natersoluble tioron content of the soil. 0ro 63 soil boron, in terms of the amounts taken up by the crops, was reduced by the application of limestone. Using the values obtained in the two crop years a corre­ lation coefficient of 4-0.76 was found between the watersoluble boron content of the soil and the boron content of the ladino clover. This figure was significant at the 5 per cent level. According to Dregne and Powers (1942) ladino clover has shown indifferent response to boron in Cregon. Ilunsell and Brown (1943) have reported that this legume, grown on a soil containing 0.50 parts per million of "available" boron, had a boron content of 26 and 30 parts per million. When borax was applied at the rate of 20 pounds per acre, the boron content of the clover was 30 and 22 parts per million respectively. These investigators have suggested that ladino is comparable to alfalfa in respect to boron content. Stinson (1953) has given 0.30 parts per million of water-soluble boron as a critical level for the growth of alfalfa on coarse textured sandy soils. He has also considered that, in respect to other legumes, alfalfa is especially sensitive to a shortage of "available" boron. Data given by Rogers (1947) show the crit­ ical level of boron in alfalfa, as reported by various in­ vestigators, exhibits considerable variation. similar sit­ uation may be expected to exist in respect to ladino clover and the critical level in the plant may show some variation with different growing conditions. 64 Jalclum-boron r a tios. The effect of the soil treatments on the calcium and boron content of the ladino clover is shown in Table XVIII. In both crop years the clover grown on soils receiving limestone alone had a higher calcium content than the clover grown on the checks. A similar situation existed between the crops grown with limestone ana fertilizer and those receiv­ ing fertilizer alone. The increase in calcium content was, however, relatively less than the decrease in boron content that occurred in the plants grown on the limed soils. This was especially true in the second crop year. The relative amounts of calcium and boron in the two crops are reflected in the calcium-boron ratios. Although in the first crop year the differences were comparatively small the highest ratios occurred in plants treated with limestone. In the second crop 3/ear there were very marked differences in the ratios found in clover grown on limed and unlimed soils. There were not, however, any visual symptoms of boron defic­ iency observed during either crop year. It is possible that if the plants had been allowed to reach maturity visual symp­ toms of deficiency might have been evident. Stewart and Bear (1951) have pointed out that, while in cases of severe boron deficiency, ladino clover leaves turn red and then yellow, deficiency symptoms for this crop are 65 TABLE XVIII EFFECT OF SwIL TRE^THELT3 OF THE C^LCICE ALX 30RON COL TENT OF LAD IK 0 CLOVER iComposite samples from three replications, 0rop Year 1550-51 1551-52 air-dry basis) ____ Ladlno Clover B C a :B Ratio Soil Treatment pH Check 5.10 ppm. 21400 ppm. 35.8 598:1 Limestone 5.90 22400 31.0 723:1 C-10-10 5.00 206C0 36.4 566:1 Limestone ic 0-10-10 6.CO 22 400 33.0 679:1 Check 4.7e 2780C 45.8 558:1 Limestone 6.49 28900 20.1 1438:1 0-10-10 4.70 240 00 30.4 789:1 Limestone cc 0-10-10 6.47 2 56 0 C 12.8 2078:1 Ca 66 not easily recognized in the field. From data given by these investigators an average calcium-boron ratio for ladino clover grown in I\ew Jersey was calculated to be 272 to 1, The diff­ erence between this calcium-boron ratio and those reported in the present investigation was chiefly due to differences in the boron rather than the calcium content of the clover. 67 C. Laboratory Studies 1. Effect of Calcium Carbonate, Gypsum and Magnesium Carbonate on the ViTater-Soluble Boron Content of Soil The effect of calcium carbonate, g y p s u m and magnesium carbonate on the water-soluble boron content of soil is ill­ ustrated in Figure 8. Calcium carbonate. The application of increasing rates of c al­ cium carbonate resulted in decreased contents of water-soluble boron. The decreases in boron, which were consistent with the increased rates of calcium carbonate and increased soil pH values, ranged from 6.3 per cent with a one ton application to 59.4 per cent with eight tons. A highly significant corre­ lation coefficient of -0.98 existed between the amount of cal­ cium applied and the water-soluble boron content of the treated soils. Gypsum. The gypsum treatments, while accompanied by slight increases in soil acidity, resulted in negligible changes in water-soluble boron. The greatest decrease in boron content was 5.9 per cent and occurred with an intermediate rate of gypsum. There was no change with the smallest application and in three instances the decrease was only 2.9 per cent. The correlation coefficient between the amount of calcium applied and the water-soluble boron content of the treated soils was -0.56. This was not significant. 68 Series I — Co CO, 4 70 ... 1 00 5 18 2 00 5 62 400 rTTTTTTTTTTTTTT 6 42 6 00 7- 17 8 00 7 38 OIO Woter Se ri e s 0 20 0-30 soluble boron — p. p . m . Soil pH O 0-40 2 — CaS04 2 H - 0 4 80 Soil pH 4 64 6 87 0-31 4-48 0 IO Water O 20 0-30 soluble boron — p. p . m . Series 3 0-40 Mg CO. 0-84 I -68 3 36 6 28 504 OIO Woter Fig. 8. 0 20 soluble boron 0-30 — p. p . m . Effect of CaC03 . CaS04 .2HzO and N^COj on the water-soluble boron content of soil. 0 40 Soli pH 5 28 69 Magnesium o a r b pnate . The decreases in water-soluble boron, which occurred with applications of magnesium carbonate, were almost identical with those resulting from the use of calcium carbonate. The range in pH values was similar in both inst­ ances. There was a 6.1 per cent reduction in boron content with the lowest rate of magnesium carbonate and a 57.6 per cent decrease with the highest rate. A highly significant correlation coefficient of —0.98 was found between the amount of magnesium applied and the water-soluble boron in the treated soil. 2. Effect of Manure and Alfalfa, Alone and in Combination with Calcium Carbonate, on the Water-Soluble Boron Content of Soil The effect of increasing amounts of manure and alfalfa, both alone and in combination with increasing amounts of c al­ cium carbonate, on the water-soluble boron content of soil is illustrated in Figure 9. Manure. The application of increasing amounts of manure in ­ creased the water-soluble boron content of the soil although acidity was somewhat reduced. The increases in boron, while small with the lower rates of manure, were consistent and ranged from 3.1 to 40.6 per cent. A highly significant corre­ lation coefficient of +0.99 existed between the rates of m a n ­ ure applied and the water-soluble boron content of the treated soils. Series 4 — Manure A lfalfa 0 10 4-98 10 4 75 20 4 96 < 20 4-89 ..................................... uai 4 83 i . i n n . i . A i . i i . i . . . 1.... /.V.VtV.V.V.VAV. \ n m i n i i i u i i m n n m ^ rm i TiTin 5 40 510 (A m m i i n n i i m r T n i H U M M m n n n i n 60 CL .............................................. i , , 508 60 i . j Soil 507 40 x pH 1111fi III11 II I11 II11 111 H 6 - 482 0 < Series .................. 514 ...■ . ■ ■ . . . .. ■ ■ . . .. . ■ . . . n i.u i. i. i. t m . i w iim iii 1 1 mi i i 1 1 1 1 1 1 1 1 » 1 1 m1 1 1 1 1 1 1 1 1 1 ii1 1 1 1 1 1 1 1 1 u hi 1 1 uniu111nr/ n ..iin in 100 5 20 0 1 1 1 010 0-20 0 30 100 5 42 . . . .1 0-40 0 10 Water soluble boron - p.p.m . Water Series Series 5 - Manure + CaCO, 0 4-83 0-40 soluble 030 060 0 70 0-80 b o ro n -p .p .m 7 - Al f al f a + CaCO, 0 4-82 1 5-40 5-95 nimiimmni 40 — 6-72 - 60 < •O tn s 1- 20 2 5 73 40 4 7-35 60 6 7-53 100 8 662 IIfIIVIT1 7-28 pH 20 10 X Q. Soil 5 46 T T f . I .i.M .I < 0 0-30 IIMVVIMMailVIMIIIIIIIIIJI 10 \ 0 20 PIMMVflllMllllllllliMIII 100 0 Water 0 10 0-20 soluble 0-30 0 40 b o ro n .p p.m. Fig. 9. 7-38 .................... .............a 0 10 020 Water 030 0 40 soluble 0 50 0 60 070 080 b o ro n -p .p .m . Effect of manure and alfalfa alone and in combination with CaCOj, on the water-soluble boron content of soil. o 71 Manure and calcium carbonate. The water-soluble boron content of the soil was decreased by applications of manure and cal­ cium carbonate. The decreases, calculated in terms of soil receiving similar manure treatments, ranged from 11.8 to 45.0 per cent and showed some inconsistencies in respect to the rates of calcium carbonate applied. It was found that a sign­ ificant correlation coefficient of -0.87 existed between the pH value and water-soluble boron content of the treated soils. ■tt-lfalfa. The consistent increases in water-soluble boron con­ tent of the soil that occurred with this treatment ranged from 12.9 to 154.8 per cent. The larger additions of alfalfa also resulted in appreciable decreases in soil acidity. A highly significant correlation coefficient of +0.99 was found between the rate of alfalfa applied and the water-soluble boron con­ tent of the treated soils. alfalfa and calcium carbonate. In no case did the combined alfalfa and calcium carbonate treatments reduce the watersoluble boron of the treated soils to the level of the check, however, in terms of soil receiving similar amounts of alf­ alfa, the addition of calcium carbonate was accompanied by reductions in boron ranging from 2.9 to 34.2 per cent. A significant correlation coefficient of +0.84 existed between the pH value and water-soluble boron content of the treated soils. 72 2. Fffect of Sodium Hydroxide, ^loiie and in Combination with Calcium Carbonate, on the i/ater-Soluble Boron Content of Soil The effect of increasing amounts of sodium hydroxide and of a constant amount of sodium hydroxide in combination with increasing amounts of calcium carbonate, on the water-soluble boron content of soil is illustrated in Figure 10. Sodium hydroxide. Increasing amounts of sodium hydroxide r e ­ sulted in decreased contents of water-soluble boron until the pH of the soil reached approximately 8.0. From this point, up to a pH value of 9.72, the boron content of the soil increas­ ed. At pH values of 7.50 and 7.75 decreases in boron content amounted to 21.5 per cent. '.Vhen the pH value of the soil was 2.72 the increase, in terms of the check, was 15.6 per cent. The correlation coefficient between the pH value and watersoluble boron content of the treated soils was +0.22. This was not significant. Sodium hydroxide and calcium carbonate. The application of increasing amounts of calcium carbonate, to a soil previous­ ly treated with sodium hydroxide, resulted in decreased con­ tents of water-soluble boron. The decreases, which showed some inconsistencies in respect to the amounts of calcium carbonate applied, ranged from 2.4 to 24.1 per cent and were accompanied by increased pH values, a significant correlation coefficient of -0.8c existed between the pH value and watersoluble boron content of the treated soils. The correlation 73 Series 8 - NoOH 4 82 i i M i m i i r i i i n u n iiin ir iu i n 5 78 5 5 6 53 8 5 702 130 7 50 15 O 7 75 20 0 8 50 ? 250 8 87 2 300 9 32 iiT '1 1i n i n 1 11 1 1 11 1i i i i ni 1 1 1i i i n n i 1 1 1n t 1 11 1i'i 1 1 1 1ii 1 1 1 1i'i 35 0 9 45 40 0 9-72 0 10 Woter Series O 20 soluble boron 9 - NoOH + 0 30 p.p.m. - O 40 CaCO, 8-23 8-84 pH 8 53 9 02 Soil NoOH / 200 gm. soil 2 5 pH 5 32 Soil 10 918 9-20 O IO Water Fig. 10. 0 20 soluble boron - 0-30 p p m Effect of NaOH alone and in combination with C a C O s on the water-soluble boron content of soil. 0-40 74 coefficient of -0.77, found between the amount of calcium applied and the water-soluble boron in the treated soils, failed to reach significance, 4, The Water-Soluble Boron Content of Soil The decreases that occurred in the concentration of watersoluble boron with applications of calcium carbonate, alone or in combination with manure or alfalfa, either are shown in Table XIX. The values given for the original soil were obtain­ ed from series 1 while those for the manured soil represent the differences between series 4 and series 5. In the case of the alfalfa treated soil differences between series 6 and 7 are given. It will be noted that any one rate of calcium car­ bonate tended to result in the same decrease irrespective thewater-soluble boron of content of the soil. The analysis of variance, presented in Table XX, shows that the application of calcium carbonate has resulted in hig h ­ ly significant decreases in the water-soluble boron content of soil, although Drake, Sieling and Scarseth (1941) found the addition of lime had no effect on the water-soluble boron con­ tent of a silt loam soil, other investigators, including Cook and killar (1939), Muhr (1940), Schaller (1948) and Davis (1949) have reported decreased boron availability with liming. The results the of the present investigation, in respect to influence ofgypsum on boron availability, are in agreement 75 TABLE XIX DECREASE IE THE WATER-SOLUBLE BORON CONTENT OF SOIL DUE TO THE APPLICATION OF CALCIUM CARBONATE Soils 1 Calcium carbonate T/A 2 4 6 8 Mean Original ppm. 0.02 ppm. 0.07 ppm. 0.12 ppm. 0.17 ppm. 0.19 0.114 Original ♦ manure 0.04 0.04 0.10 0.18 0.19 0.110 Original 4 alfalfa 0.01 0.04 0.10 0.16 0.27 0.116 Mean 0.050 0.107 0.170 0.217 L.S.D. 0.023 (P.05), for treatment means = 0 .050 TABLE XX il.AYolS OF VARIANCE OF THE DECREASE IN THE WATER-SOLUBLE BORON CONTENT OF SOIL DUE TO THE APPLICATION OF CALCIUM CARBONATE Source of V&riation Degrees of Freedom Mean Square Soils 2 0.000047 Treatments 4 0.019534 Error 8 0.000713 F Value Obtained Required P.05 P.01 27.40 3.84 7.01 A 76 with findings reported by Truninger (1944), Wolf (1940) and Smith (1949). Parks and Shaw (1941), using pure chemical systems under laboratory conditions, have shown that boron may be precipit­ ated in combination with various ions including silicon and aluminium. Also the boron content of the precipitates tended to be increased by the presence of calcium and at pH values of 7 and above the boron in the precipitates was completely insol uble in hot water. Thus pH differences may account for the re­ sults obtained in the present investigation when equivalent amounts of calcium were applied as calcium carbonate and as gypsum. A further indication that pH plays an important part in boron fixation is provided by the results obtained with tigCOg. Midgley and Dunklee (1939) have reported calcium and magnesium carbonates to be equally effective in causing the fixation of boric acid, according to Olson and Berger (1946) the alkalinity produced by bases has more influence on boron fixation than do the cations of the bases. Differences in the form in which boron exists in manure and alfalfa, in the relative rates of decomposition of the two materials and in their boron content could be responsible for the fact that additions of alfalfa produced the greater in­ creases in the water-soluble boron content of soil. Olson and Berger (1946) have observed that th6 oxidation of organic matter resulted in and increase in available boron. Brown and King (1939) have reported that boron deficiency in alfalfa 77 appeared to have been somewhat reduced by the application of manure. In respect to boron availability Berger and Truog (1945) have indicated the final effect of organic matter is less than that of pH. The results obtained in series 1 and series 8 show that at similar pH values calcium carbonate produced a greater d e ­ crease in water-soluble boron than did sodium hydroxide. C oop­ er (1947) has pointed out that sodium tetraborate is consider­ ably more soluble than calcium metaborate. He has also suggest­ ed that liming may decrease boron availability by the form­ ation of relatively insoluble calcium borate. According to Colwell and Cummings (1944) there is a fundamental difference in the behavior of aqueous solutions of calcium and sodium metaborates with the former dissolving very slowly. Thus the nature of the cation associated with a change in the pH value of soil may have a bearing on boron availability. Another factor in the case of soils treated with sodium hydroxide is the amount of organic matter subsequently brought into sol­ ution by extraction with boiling water. Since boron exists in both organic and inorganic forms the presence of sodium h yd r ­ oxide could conceivably result in the release of boron held in organic form. This would not be the case with a weak base such as calcium hydroxide. The addition of calcium to a soil previously treated with sodium hydroxide caused some decreases in content of water-soluble boron. The reductions were, however, cons 78 less than occurred with c a l c i u m carbonate treatments alone* While the resulting soil pH values differed considerably the presence of sodium i ons apparently reduced the effect of the calcium carbonate. According to Cook and Millar (1929) and Muhr (1940) s o d i u m carbonate was ineffective in preventing boron toxicity in soybeans. Wolf (1940) has also observed that the nature of the cation employed in changing the pH of a soil has an important bearing on the availabil­ ity of soil boron. 79 VII SUMMARY Field, greenhouse and laboratory experiments were used to study the results of liming a strongly acid soil and the effect of certain other treatments on its content of watersoluble boron. The soil investigated, a Charlottetown fine sandy loam, is one of the best and most extensive agricult­ ural soils on Prince Edward Island. The field experiment, located at the Dominion Experi­ mental Station, Charlottetown, Prince Edward Island, was started in 1931. It consisted of a three year rotation of potatoes, barley and clover. Prior to 1942 a 4-8-6 fert­ ilizer at 1,200 pounds per acre was used for the potato crop and limestone treatments of 0, 500, 1,000, 1,500, 2,000 and 3,000 pounds per acre were applied every sixth year. Since 1942 limestone has been applied every third year, a 4 -8 - . 0 fertilizer has been used for the potato crop and the barley has received 300 pounds per acre of a 2-12-10 fertilizer. In 194e composite soil samples, taken at the 0 to 6 inch depth, were obtained from each plot in the experiment. Chemical determinations made on these, as well as on seven samples taken in 1930, included pH value, exchangeable bases base exchange capacity, total nitrogen and water-soluble boron. 80 In 1951 seven subsoil samples, taken at the 6 to 12 inch depth, were taken from plots where similar samples had been taken in 1950* Yifith the exception of total nitrogen and watersoluble boron the same chemical determinations were made on these as on the surface soil samples* In 1948 the plots that had received limestone at the rate of 3,000 pounds per acre had an average pH value of 5.92 as against 4*92 for the check plots in the surface six inches* Corresponding values for per cent base saturation were 66*6 and 28.5. Apparently the base exchange capacity of the samples, which in general approximated 9.5 milliequivalents per 100 grams of soil, was not affected by the limestone treatments. In the case of the seven surface samples collected in 1930 the average values for total nitrogen and exchangeable potassium were 0.22 per cent and 0.16 milliequivalents re ­ spectively. The corresponding values for comparable samples ta.-cen in 1948 were 0.19 per cent and 0.29 milliequivalents. The results of analyses also indicated a decrease in ex­ changeable magnesium during the 18 year period. These changes were rather consistent although the plots involved received different limestone treatments. The water-soluble boron content of the 1930 samples ranged from 0.38 to 0.49 parts per million. By 1948 a rather consistent decrease of approximately 30 per cent had occurred. This decrease did not appear to be related to the amounts of I 81 limestone applied and may be attributed to loss by leaohing and removal by crops. The 1948 samples showed that there were no significant differences in the boron content of soils which had received different amounts of limestone. There was, however, a sign­ ificant difference in the boron content of limed and unlimed soils. The limestone applications had little effect on the re ­ action of the subsoils. While exchangeable magnesium decreas­ ed during the 31 year period, exchangeable potassium remained rather constant. Yield data, as recorded from 1940 to 1948 inclusive, were treated statistically. The limestone treatments had no effect on potato yields but resulted in significant increases in the yields of the other two crops in the rotation. The average yield of potatoes on unlimed plots was 191 bushels per acre as compared, to 190 bushels per acre from plots which had re­ ceived the highest rate of limestone application. Barley yields under similar conditions were 28.2 and 35.5 bushels per acre respectively. In the case of clover unlimed plots yielded 0.873 tons per acre as against 1.611 tons where lime­ stone was used at the rate of 3,000 pounds per acre. In recent years the incidence of potato scab has tended to increase on those plots receiving the higher rates of limestone • 82 The effect of limestone on boron availability, as deter­ mined by soil and plant analyses, was investigated in a green­ house experiment. Ladino clover, grown on soil containing 0.36 parts per million of water-soluble boron, had a boron content of 36.4 parts per million. The pH value of the soil was 5.0. When the soil was limed to a pH of 6.0 its water-soluble boron content was reduced approximately one-third and the boron content of the clover to 0.33 parts per million. A second crop of clover, grown on the same soil after it was limed to a pH of 6.47, contained 12.8 parts per million of boron. The water-soluble boron content of the soil at that pH was 0.15 parts per million. The correlation between the water-soluble boron in the soil and the boron content of the ladino clover was sign­ ificant. In the first clover crop calcium-boron ratios ranged from 566 to 1 to 723 to 1. In the second crop the largest ratio was 2078 to 1. No visual symptoms of boron deficiency were observed in either crop. The effect of calcium carbonate, gypsum, magnesium carb­ onate, manure, alfalfa and sodium hydroxide, on the water- soluble boron content of soil, was studied in a laboratory experiment• Calcium carbonate, applied at 0, 1, 2, 4, 6 and 8 tons per acre, resulted in a range of pH values from 4.70 to 7.38. M 83 The untreated soil contained 0.32 p a r t s per million of watersoluble boron as compared with 0 . 1 3 parts per million where 8 tons of calcium carbonate was a p p l i e d . A highly significant negative correlation existed b e t w e e n the amounts of calcium applied and the water-soluble b o r o n content of the treated soils. Reductions in water-soluble soi l boron resulting from applications of gypsum were n e g l i g i b l e . cium added were the same as where The amounts of cal­ c a l c i u m carbonate was applied. Soil acidity was slightly increased by the gypsum treatments. The correlation b e t w e e n the amounts of calcium added and the water-soluble boron c o n t e n t of the treated samples was not significant. Decreases in water-soluble soil boron, ing magnesium carbonate, were almo s t obtained by apply­ identical with those re­ sulting from the use of calcium c a r b o n a t e . The range in pK values was similar. The negative c o r r e l a t i o n between the amounts of magnesium applied and the water-soluble boron con­ tent of the treated soils was h i g h l y significant. applications of manure or of alfalfa, 20, 40, 60 and 100 tons per acre, at rates of 10, increased bcron content of the soil. The increases, 40.6 per cent with manure and from 12.9 the water-soluble ranging from 3.1 to to 154.6 per cent with alfalfa, varied directly with the r a t e s of application. 84 Decreasing amounts of water-soluble boron were found in soils treated with increasing rates of manure and calcium car bonate. This was also true when alfalfa was used in place of manure• All combinations of manure and calcium carbonate re ­ sulted in lower values for water-soluble soil boron than occurred in the check soil. Where alfalfa and calcium carbon­ ate mixtures were applied, no combination reduced the watersoluble soil boron content to the level found in the check soil. When expressed as parts per million of water-soluble boron the reductions that occurred with calcium carbonate, whether applied alone or in combination with manure or alf­ alfa, tended to be the same for any one rate of application irrespective of the amount of water-soluble boron present. Increasing amounts of sodium hydroxide were used to ob­ tain a range of soil pH values 1rom 4.82 to 9.72. The in­ creasing pH values were accompanied by a reduction and then an increase in water-soluble boron. The greatest decrease amounted to 31.3 per cent and occurred at pH values of 7.50 and 7.75. .at a pH value of 9.72 the soil contained 15.6 per cent more water-soluble boron than was found in the check soil. The correlation between pH value and content of watersoluble boron was not significant. The addition of increasing amounts of calcium carbonate to a soil previously treated with sodium hydroxide resulted in decreased contents of water-soluble boron. On a percentage f i 85 basis the decreases, which showed some inconsistencies in respect to the amounts of calcium carbonate applied, were less than those that occurred where the soil had not been previously treated with sodium hydroxide. The pH values of soils receiving both sodium hydroxide and calcium carbon­ ate ranged from 8,22 to 9.20. There was a significant n e g ­ ative correlation between these pH values and the watersoluble boron in the soil. The negative correlation b e ­ tween the amounts of calcium applied ana the water-soluble boron in the soils was not significant. BIBLIOGRAPHY -tHilgren, Gilbert H, (1949) Forage Crops, ed. 1. McGraw-Hill Book Company, Inc,. New York, 418 pp, ^.lbrecht, Wm. A, (1946) Plant nutrition and the hydrogen ion, V, Relative effectiveness of coarsely ground and finely pulverized limestone, Boil Sci. 62.: 265-271, and R. A. Schroeder, (1941) Plant nutrition and the hydrogen ion. I, Plant nutrients used more effectively in the presence of hydrogen ions. Soil Sci. S o c . Amer. Proc. 6.: 195-196. Arron, D. I., and C. M. Johnson. (1942) Influence of hydrogen ion concentration on the growth of higher plants under controlled conditions. Plant Physiol. 17: 525-529. ^slander, Alfred. (1952) Standard fertilization and liming as factors in maintaining soil productivity. Soil Sci. 7j4: 181-195. ..ssooiation of Official Agricultural Chemists (1945) Official and Tentative Methods of Analysis, ed. 6. Washington, D.C. (1950) Official Methods of Analysis, ed. 7. Was hington, D.C. Bear, F. E . , and S. J. Toth. (1948) Influence of calcium on the availability of other soil cations. Soil Sci. 65: 69-74. Beeson, K. C. (1945) The occurrence of mineral nutritional diseases of plants and animals in the United States. Soil Sci. 60: 9-12. Berger, K. C. (1948) Soil fertility investigations with potatoes in 'Wisconsin. Amer. Potato Jour. 25: 277-386. (1949) Boron in soils and crops. Norman, A. Editor. Advances in Agronomy, Vol. 1. Academic Press Inc., New York, 1949. 439 pp. and E. Truog. (1940) Boron deficiencies as revealed by plant and soil tests. Jour. Amer. Soc. Agron. 32: 297-301. and ____ (1945) Boron availability in relation to soil reaction and organic matter content. Soil Sci. Soc. Amer. Proc. 10: 113-116. Blair, A. W. , and A. L. Prince. (1934) The influence of lime on the reaction of subsoils. Jour. Agr. Res. 48: 469-473. Boulet, L. J., and Lucien Choiniere. (1952) Phosphate end potash effects on ladino clover swards Better Crops with Plant Food 3J7: 6-14, cont., 39-46. Bradfield, Richard. (1941) Calcium in the soil* I Physico-chemical relations. Soil Sci. Soc. Amer. Proc. 6: 8-15. Brenchley, W. E . , and Katherine Warington. (1927) The role of boron in the growth of plants. Ann. Bot. 41: 167-187. Brown, B. A., and ^PLlan King. (1939) Soil conditions under which alfalfa responded to boron. Soil Sci. Soc. Amer. Proc. 4: 310-313* and R. I* Munsell* (1938) Soil acidity at various depths as influenced by time since application, placement and amount of limestone Soil Sci. Soc. Amer. Proc. 3: 217-221. Bryan, 0. C. (1923) Effect of reaction on growth, nodule formation, and calcium content of alfalfa, alsike clover and rad clover* Soil Sci* 15: 23-35* Colwell, W. E * , and R* W. Cummings* (1944) Chemical and biological studies on aqueous solutions of boric acid and of calcium, sodium and potassium metaborates. Soil Sci. 57: 37-49. ee Carolus, R. L. (1944) Influence of nitrogen, phosphorus, potassium and calcium on tuber and foliage weight of potatoes. Amer. Potato Jour. 21: 199-203. Cook, R. L., and C. E. Millar. (1939) Some soil factors affecting boron availability. Soil Sci. Soc. Amer. Proc. 4: 297-301. and ____ . (1949) Plant nutrient deficiencies. Michigan Agricultural Experiment Station, East Lansing, Special Bull. 353, 80 pp. Cook, H. T . , and T. J. Nugent. (1939) The influence of acid-forming and non-acid-forming fertilizer on the development of potato scab. Amer. Potato Jour. 16: 1-5. Cooper, H. P. (1947) Minor plant nutrients. Commercial Fertilizer 74: 14-19, cont., 42-44. VY. R. Paden, W. K. Carman, and N. R. Page. (1948) Properties that influence availability of calcium in the soil to plants. Soi Sci. 65: 75-96. Cowan, P. R. (1952) The development of barley varieties in Canada. Agricultural Institute Review )7: 23-24. Davis, Franklin L. (1949) Effects of liming on response to minor elements of crimson clover, soybeans and alyce clover. Agron. Jour. 41: 368-374. Drake, M., D. H. Sieling, and G. D. Scarseth. (1941) Calcium-boron ratio as an important factor in controlling the boron starvation of plants. Jour. Amer. Soc. Agron. 33: 454-462. Dregne, H. E . , and W. L. Powers. (1942) Boron fertilization of alfalfa and other legumes in Oregon. Jour. Amer. Soc. Agron. 34: 902-912. Dunklee, D. E . , and A. R. Midgley. (1944) The need for borax on fourteen crops. Better Crops with Plant Food 28: 15-19, cont., 43-49. 89 Eaton, F. M. (1944) Deficiency, toxicity, and accumulation of boron in plants. Jour. Agr. Res. 69: 237-277. and L. V. Wilcox. (1939) The behavior of boron in soils. United States Department of Agriculture, Washington, Tech. Bull. 696. 58 pp. Fippin, Elmer 0. (1939) Soil acidity and liming and some factors that should determine the standards for lime for the soil. Symposium on Lime. Columbus Regional Meeting. American Society for Testing Materials. Gidaens, Joel, and Stephen J. Toth. (1951) Growth and nutrient uptake of ladino clover grown on red and yellow and grey-brown podzolic soils containing varying ratios of cations. Agron. Jour. 43: 209-214. Hanna, W. J., and E. R. Purvis. (1941) Effect of borax and lime on activity of soil microorganisms in Norfolk fine sandy loam. Soil Sci. 52: 275-281. Harris, H. C. (1937) Effect of lime on the availability and fixation of potash in soils. Soil Sci. 44: 265-275. Hawkins, A., J. Ghucka and B. E. Brown. (1941) Minor element studies on potatoes in Maine. Amer. Potato Jour. 19_: 234-239. Jenny, H . , and E. R. Slade. (1934) The potassium lime problem in soils. Jour. Amer. Soc. Agron. 26>: 162-170. Jones, H. E., and G. D. Scarseth. (1944) The Ga-B balance in plants as related to boron needs. Soil Sci. 57: 15-24. Kelley, W. P. (1940) The agronomic importance of calcium. Soil Sci. 40: 103-109. 90 Klages, K. H. W. (1949) Ecological Crop Geography. The Macmillan Company, New York. 615 pp. Kubota, J., K. C. Berger, and E. Truog. (1949) Boron movement in soils. Soil Sci. Soc. Amer. Proc. 1 3 : 130-134. Lucas, R. E., and C. D. Scarseth. (1947) Potassium, calcium and magnesium balance and reciprocal relationship in plants. Jour. Amer. Soc. Agron. 39: 887-897. Lynd, J. <*,. , and L. M. Turk. (1948) Overliming injury on an acid sandy soil. Jour. Amer. Soc. Agron. 40: 205-215. Maclntire, '.7. H., and B. W. Hatcher. (1942) Evidence in support of a new concept as to the end product of superphosphate in limed soils. Soil Sci. 53: 43-54. Marsh, R. P. (1942) Comparative study of the calcium-boron metabolism of representative dicots and monocots. Soil Sci. 53: 75-78. and J. W. Shive. (1941) Boron as a factor in the calcium metabolism of the corn plant. Soil Sci. 51: 141-151. Marshall, C. E. (1948) Ionization of calcium from soil colloids and its bearing on soil-plant relationships. Soil Sci. 65: 57-69. McCall, G. (1923) The influence of acidity itself on plant growth without regard to other factors. Jour. Amer. Soc. Agron. 15: 290-297. M c M u rtrey, J. E. Jr. (19 29) The effect of boron deficiency on the growth of tobacco plants in aerated and unaerated solutions. Jour. Agr. Res. 38: 371-380. (1948) Chap. VIII. Visual symptoms of malnutrition in plants. Hermine B. Kitchen, Editor. Diagnostic Techniques for Soils and Crops, The American Potash Institute, Washington, D.C. 308 pp. 91 Midgley, A. R., and D . E. D u n k l e e . (1929) The effect of lime on the fixation of borates in soils. Soil Sci. Soc. -Amer. P r o c . 4: 302-207. Moschler, .V. W. , S. S. Obenshain, R. P. Cocke and H. M. Camper. (1949) The effect of varying amounts of ground limestone on the pH and base exchange properties of Sassafras fine sandy loam. Soil Sci. Soc. Amer. Proc. 14: 122-125. looser, E. (1943) Calcium nutrition at respective pH levels. Soil Sci. Soc. Amer. Proc. 7: 329-244. ixluhr, G. R. (1940) Available boron as affected by soil treatments. Soil Sci. Soc. Amer. Proc. 5: 220-226. ...unsell, R. I., and B. Brown. (1942) The boron content of certain forage and vegetable crops. Jour. Amer. Soc. Agron. 25: 401-408. ..'.aftel, J. A. (1927a) Soil liming investigations. III. The influence of calcium and a mixture of calcium and magnesium carbonates on certain chemical changes in soils. Jour. Amer. Soc. Agron. 2£: 526-526. (1927b) The influence of excessive liming on boron deficiency in soils. Soil Sci. Soc. ^mer. Proc. 2: 282-284. (1929) Colorimetric microdetermination of boron. Ind. and Eng. C h e m . , Aral. Ed. 11: 407-408. Aelson, -i Roy*!* Pt A llarbyP l Bdid Hi • t. mw / ' ' Bunburv ^ B rilnnl Pi Shipvw d ■Thsriti Fi i w O u r t m SOIL MAF W een P i r OF PRINCE COUNTY g*r.tiri HI PRINCE ED WARD IS LA ND Shemod? MiltaR ,1,. -2 n u l~ o . 1 iiu'li <-r ! I J B ? J W ebb* Pi (ontiHirinterval2'I* — -■' Sunbury roir.l n e tm Pi biufqli mi fcfcTtoMldPt REFERENCE Bouqu* f'- / Gordon r PoitBoMCTI Bcfderi fta nt CampM. down andp iJ d u W fc» lA« Kzpmm*m f N m r ,l i u m m i . mI * p » T 0 # n t i i f bd»»r '" SOU. MAP PRINCE EDWARD QUEENS i . k c ; k n d COUNTY ISLA> I H V. W ; | O t ) C 1W>< W«