Agronomy Fact Sheet Series Fact Sheet 7

Liming Materials

Introduction not be able to increase the pH of the . The A material can bring the pH of a soil to inclusion of such inert material will reduce the optimum levels for crop production if used CCE of the material as compared to pure properly. Liming materials also provide materials. (Ca) and/or (Mg) to the soil for plant uptake. In Agronomy Fact Sheets 5 and Table 1: Calcium equivalent (CCE) 6, soil pH and recommendations were of a few common liming materials. discussed. In this Fact Sheet, considerations of Common name Chemical CCE quality, cost, availability, and material formula handling will be discussed to enable selection Calcitic CaCO3 100 of the liming material that best fits the lime Dolomitic limestone CaMg(CO3)2 109 requirements of the farm. Burned lime, quick lime CaO 179 Hydrated or slaked lime Ca(OH)2 136 Liming Material Quality Parameters Assuming 100% pure material. Materials that can cause an increase in pH include , or of Fineness calcium and magnesium. When looking at The rate of reaction of a liming material is liming materials it is often hard to distinguish determined by the particle sizes of the one material from another. Quality standards material; 100% of lime particles passing a used to differentiate liming materials include 100-mesh screen will react within the 1st year Total Neutralizing Value (TNV), Calcium while only 60% of the liming materials passing Carbonate Equivalence (CCE), Fineness, and a 20-mesh sieve (but held on 100 mesh sieve) Effective Neutralizing Value (ENV). is will react within a year of application. Material sometimes added to dry limestone to improve that does not pass the 20 mesh sieve is not the handling characteristics of the ground expected to react within a 1 year following limestone. The moisture content of agricultural application. So, to be of practical use, limestone does not influence its effectiveness limestone CCE equivalents need to be adjusted but a moisture content between 4 and 5% will for the fineness of the material. To determine improve the spreading uniformity and reduces the fineness of a limestone the following the off site movement of very fine particles calculations need to be done: (<100 mesh). o Subtract the % passing a 100 mesh sieve from the % passing a 20 mesh sieve and Total Neutralizing Value (TNV) multiply this difference with 0.60. This is the percentage of the material that can o Add the % passing the 100 mesh sieve and neutralize expressed as the calcium divide the sum by 100. carbonate equivalence (CCE) of the product. Thus, the fineness of a material of which 70% passes a 100 mesh sieve and 97% passes a 20 Equivalence (CCE) mesh sieve is {(97-70)*0.60 +70}/100=0.86. This standard compares the liming material to pure calcium carbonate (CaCO3). Some Effective Neutralizing Value (ENV) materials such as hydrated lime and burned The ENV is the fraction of the material’s CCE lime will have a CCE higher than 100%. Pure that will react with soil acidity in the first year (MgCO3) will neutralize of application. The ENV is calculated by about 1.2 times more acidity than CaCO3 so multiplying a liming material’s CCE and its dolomitic limestone will have a higher CCE fineness. As an example: a liming material than calcitic limestone (Table 7). All liming with CCE of 90% and a fineness of 0.86 has an materials include some inert material that will ENV of 90*0.86= 77.4.

Department of Crop and Soil Sciences 1 College of Agriculture and Life Sciences Liming Material Identification process. Pure calcium has a CCE of In New York, the Department of Agriculture 178% and reacts quickly (powdery lime and Markets (NYSDAM) regulates agricultural material). (MgO) will also be liming materials. Liming materials are defined present if it was present in the ground as “all materials and all calcium and limestone prior to being cooked. Burned lime magnesium products in the oxide, hydrate, must be handled carefully as it quickly reacts carbonate, form or combinations with water creating hydrated lime and thereof and intended for use in the correction releasing large amounts of heat. of soil acidity…”. Liming materials must be registered with the NYSDAM. This process Hydrated lime is calcium (Ca(OH)2). ensures that the product will meet minimum This is a very fast acting and powdery lime quality standards set by NYSDAM: a liming material. This material is caustic and can easily material must have ≥60% CCE, ≥80% must burn plants that are already established. Finely pass a 20 mesh sieve, and ≥30% should pass ground hydrated lime can have an ENV of 120- a 100 mesh sieve (this implies the ENV should 135% and if too much is applied the soil pH be ≥36%). Liming materials sold in bags must could quickly rise beyond the targeted pH. have a label that includes: o Name and address of the company are composed of shell fragments, registering the product. and CaCO3. They are often found and used o Brand name. around coastal areas. Marls tend to react o Type of material (limestone, , oxide, similarly to ground . hydrate, shells, industrial by-products). o TNV as expressed by the CCE. Cost Effectiveness o Minimum fineness at delivery. The best way to economically compare two o Amount and types of foreign material in the lime products is to look at the cost per ton of package if any. ENV obtained by dividing the cost per ton of o If the product has been damaged or limestone by the ENV. If the ENV is not listed otherwise changed after original packaging, (as is the case with some packaged lime a label must be provided explaining the products) the ENV needs to be calculated from kind and degree of alteration. the CCE and particle size distribution. o Net weight being sold. o A guarantee of the weight % of Ca and Mg. In Summary o Particle size distribution (100, 20 mesh). Liming materials vary greatly in quality. To select the most economic liming material, Materials sold in bulk must have: compare products based on cost per ton ENV. o A guarantee of the %ENV. o The weight of the bulk material necessary Additional Resources: to equal one ton of lime with 100% ENV. o Agronomy Fact Sheet #1 (Soil sampling), #5 (Soil pH); #7 (Lime recommendations for field crops): Various Liming Materials http://nmsp.css.cornell.edu/publications/factsheets.asp Ground limestone is usually mined and then o Lime guidelines for field crops in New York: http://nmsp.css.cornell.edu/nutrient_guidelines/. pulverized or ground into finer particle sizes to increase the ENV of the material. Ground For more information limestone usually contains CaCO3 and some impurities. However, some limestones will also include MgCO . Ground limestones make up 3 the majority of lime that is sold in NY. Ground limestone with less than 1-6% Mg is called

“calcitic limestone”. If the limestone has 6% Mg or more it is called “Dolomitic Limestone”. Nutrient Management Spear Program Burned lime (also called quicklime) is ground http://nmsp.css.cornell.edu limestone that has been exposed to high Peter Carey, Quirine Ketterings, and Mike Hunter temperatures to remove dioxide. (CaO) is what remains after the 2006

Department of Crop and Soil Sciences 2 College of Agriculture and Life Sciences