Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2016 Influence of source and particle size of agricultural limestone on efficiency at increasing soil pH John David Jones Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Soil Science Commons Recommended Citation Jones, John David, "Influence of source and particle size of agricultural limestone on efficiency at increasing soil pH" (2016). Graduate Theses and Dissertations. 15330. https://lib.dr.iastate.edu/etd/15330 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Influence of source and particle size of agricultural limestone on efficiency at increasing soil pH by John David Jones Jr. A thesis submitted to the graduate faculty in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE Major: Soils (Soil Fertility) Program of Study Committee: Antonio P. Mallarino, Major Professor John Sawyer Allen Knapp The student author and the program of study committee are solely responsible for the content of this thesis. The Graduate College will ensure this thesis is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2017 Copyright © John David Jones Jr, 2017. All rights reserved. ii TABLE OF CONTENTS LIST OF TABLES AND FIGURES iii CHAPTER 1. GENERAL INTRODUCTION 1 Introduction 1 Thesis Organization 2 CHAPTER 2. INFLUENCE OF SOURCE AND PARTICLE SIZE ON AGRICULTURAL LIMESTONE EFFICIENCY AT INCREASING SOIL pH 3 Abstract 3 Introduction 4 Materials and Methods 13 Soils 13 Limestone 13 Incubation 14 Statistics 16 Results and Discussion 17 Soil pH change 17 Soil moisture and pH change 22 Soil CaCl2 measurement 23 Efficiency at increasing soil pH 24 Summary and Conclusions 28 References 31 Tables and Figures 35 CHAPTER 3. GENERAL CONCLUSIONS 49 ACKNOWLEDGEMENTS 50 iii LIST OF TABLES Table 1. Selected soil chemical and physical properties. 35 Table 2. Selected commercial “as-is” aglime and pelleted aglime chemical and physical properties. 35 Table 3. Selected fractioned aglime chemical and physical properties 36 Table 4. Soil pH of three soils as affected by commercial liming sources and the incubation period. 37 Table 5. Soil pH of three soils as affected by liming with different particle sizes of calcitic and dolomitic aglime and the incubation period. 38 Table 6. Efficiency of commercial liming sources at increasing soil pH compared to CaCO3 for three soils and all incubation periods. 39 Table 7. Efficiency of particle size fractions of calcitic and dolomitic aglime at increasing soil pH compared to CaCO3 for three soils and all incubation periods. 41 Table 8. Mean soil pH across three soils for the two longest incubation periods as affected by the liming source and drying/rewetting. 43 Table 9. Equations that describe relationships in Figs 1-3 between soil pH and incubation period length for fourteen lime treatments (means across three soils). 44 iv LIST OF FIGURES Figure 1. Soil pH over time for CaCO3, calcitic aglime, dolomitic aglime, pelleted calcitic aglime, and an untreated control (averages across three soils). 45 Figure 2. Soil pH over time for five fineness fractions of calcitic aglime and an untreated control (averages across three soils). 46 Figure 3. Soil pH over time for five fineness fractions of dolomitic aglime and an untreated control (averages across three soils). 47 Figure 4. Efficiency of different fineness fractions of calcitic and dolomitic aglime at increasing soil pH. Averages for the two longest incubation periods (25 and 30 weeks) and across three soils. 48 1 CHAPTER 1: GENERAL INTRODUCTION Introduction Excessive soil acidity is known to have potential negative impacts on crop production. The chemical and physical characteristics of a liming material determine its capacity to neutralize soil acidity. The calcium carbonate (CaCO3) equivalent (CCE) value and estimates of particle size impact on the efficiency at increasing soil pH are considered when assessing a material’s liming value. Agricultural limestone (aglime) is the most commonly used material used to neutralize soil acidity in production agriculture. Both CaCO3 and magnesium carbonate (MgCO3) in different proportions are the main constituents of aglime. The Soil Science Society of America defines dolomitic limestone as a natural liming material composed mainly of carbonates of Mg and Ca in approximately equal proportions. In production agriculture and limestone trade there is no widely accepted definition, however, an aglime containing more than 70% CaCO3 is usually referred to as calcitic and that containing 10% or more MgCO3 concentration is considered dolomitic. While MgCO3 has a higher acid neutralizing potential than CaCO3 (due to its lower molecular weight), the reaction rate of dolomitic limestone is known to be slower. Recent field experiments in Iowa also showed that the time to reach a certain pH value was longer for dolomitic lime and that sometimes the maximum pH reached also was lower. The degree of reaction of particles within the soil depends largely on the soil pH and the material surface area in contact with the soil. Particle size then influences the speed of reaction, with finer materials allowing for more particles and surface area to react in a given volume of soil, and may also influence the maximum pH reached. The most common method of describing 2 the fineness of aglime is through the use of mesh sieve sizes that are standardized across many industries. The U.S. Tyler Sieve size nomenclature uses a number to describe a specific mesh size. The mesh-number used corresponds to the number of wires that is found in a square inch (2.54 cm2) of the specific sieve. A typical sample of aglime includes multiple particle sizes in varying proportions. An effective liming material has the potential to raise the soil pH to a desired level. An efficient liming material has the potential to raise the soil pH to a desired value with the smallest amount of material applied possible. Cost and availability must be taken into account when deciding to apply a liming material. In spite of extensive previous research on soil acidity and aglime use in production agriculture, the literature shows scarce research describing how different particle size fractions of aglime affect soil pH increases over a period of time. This knowledge is needed to develop methods that appropriately evaluate the value at increasing soil pH of aglime being offered to producers. Therefore, the objective of this study was to evaluate the effect of different particle size fractions on the efficiency of commercially available calcitic aglime, dolomitic aglime, and calcitic pelleted lime at increasing soil pH in various Iowa soils under controlled conditions. Thesis organization This thesis is presented as one paper suitable for publication in scientific journals of the American Society of Agronomy. The title of the paper is Influence of Source and Particle Size on Agricultural Limestone Efficiency at Increasing Soil pH. The paper includes sections for an abstract, introduction, materials and methods, results and discussion, conclusions, references, and tables or figures. This paper is preceded by a general introduction and is followed by a general conclusion section. 3 CHAPTER 2: INFLUENCE OF SOURCE AND PARTICLE SIZE ON AGRICULTURAL LIMESTONE EFFICIENCY AT INCREASING SOIL pH A paper to be submitted to Soil Science Society of America Journal By John D. Jones and Antonio P. Mallarino ABSTRACT Excessive soil acidity is known to have potential negative impacts on crop production. The chemical and physical characteristics of a liming material determine its capacity to neutralize soil acidity. The material CaCO3 equivalent (CCE) and fineness effectiveness estimates are included in effective CCE (ECCE) assessments of a material’s liming value and to decide application rates. The objective of this study was to evaluate the effect of particle size on efficiency at increasing soil pH of commercial calcitic and dolomitic agricultural lime (aglime) compared with pure ground CaCO3 and a commercial calcitic pelleted lime. Both aglime sources were fractionated to pass US Standard Tyler Mesh screen sizes 4 but not 8, 8 but not 20, 20 but not 60, and 60 but not 100, and 100. A rate equivalent to 7.1 Mg CCE ha-1 of the materials was mixed with three Iowa acidic soils having contrasting texture and organic matter, and were incubated for 7, 21, 35, 70, 105, 140, 175, and 210 days at 25 °C and 80% field moisture capacity. Initial soil pH values were 5.20 to 6.01. Materials efficiency at increasing pH relative to pure CaCO3 showed large differences among soils, materials, fineness fractions, and incubation times. Increasing fineness increased the efficiency of the aglime fractions following an exponential trend with decreasing increments. On average across soils and the longest incubation period, calcitic aglime fractions efficiency relative to CaCO3 were 29, 39, 60, 81, and 97% for mesh sizes 4, 8, 20, 60, and 100, respectively. Efficiencies for the dolomitic aglime were lower (10, 20, 43, 66, and 86%). For the last incubation period, the commercial calcitic, 4 dolomitic, and pelleted aglime sources had average efficiencies across all soils of 60, 47, and 90%, respectively. Abbreviations: aglime, agricultural limestone; ANOVA, analysis of variance; CCE, calcium carbonate equivalent; ECCE, effective calcium carbonate equivalent. INTRODUCTION Strong soil acidity limits crop growth and productivity. Therefore, measuring soil pH is critical for a complete assessment of soil productivity and, when needed, lime should be applied to increase pH to an optimum level. The acidity of a soil can be greatly affected by both natural and anthropogenic processes.