Each spring many farmers are faced with seeding forages, corn, and soybeans, and transplanting tobacco into acid soils. The choices are either to go ahead with planting and do nothing, don\u27t plant, or to try some liming practice and hope that it works. The results from planting without doing anything may be disastrous or result in limited crop performance. While not planting is a viable option for some producers, most cannot afford this choice. The question most often faced is,  Will liming now do any good for this year\u27s crop

Sims, J. L.

Wells, Kenneth L.

English

University of Kentucky

University of KentuckyUKnowledgeSoil Science News and Views Plant and Soil Sciences1989Will Liming Acid Soils Now Be Adequate forSpring Needs?Kenneth L. WellsUniversity of KentuckyJ. L. SimsUniversity of KentuckyRight click to open a feedback form in a new tab to let us know how this document benefits you.Follow this and additional works at: https://uknowledge.uky.edu/pss_viewsPart of the Soil Science CommonsThis Report is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in Soil ScienceNews and Views by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu.Repository CitationWells, Kenneth L. and Sims, J. L., "Will Liming Acid Soils Now Be Adequate for Spring Needs?" (1989). Soil Science News and Views.139.https://uknowledge.uky.edu/pss_views/139UNIVERSITY OF KENTUCKY COLLEGE OF AGRICULTURE COOPERATIVE EXTENSION SERVICE Lexington, Kentucky 40546 Department of Agronomy ii i • s I s Volume 10, No. 3, 1989 Will Liming Acid Soils Now Be Adequate For Spring Needs? K. L. Wells and J. L. Sims Each spring many farmers are faced with seeding forages, corn, and soybeans, and transplanting tobacco into acid soils. The choices are either to go ahead with planting and do nothing, don't plant, or to try some liming practice and hope that it works. The results from planting without doing anything may be disastrous or result in limited crop performance. While not planting is a viable option for some producers, most cannot afford this choice. The question most often faced is, "Wil 1 1 imi ng now do any good for this year's crop?" Determine Acidity Levels Before options can be properly evaluated, it is essential to know the acidity (pH) level present for the field in question. Knowing the degree of acidity will make it easier to decide whether planting now will be a problem. This is particularly true for forage legume and soybean seedings, and tobacco transplanting, all of which can be affected dramatically by soil acidity. Soil testing is the only way to make such a determination. Effect of Acid Soil on Nutrient Availability Soil pH affects the solubility of virtually every nutrient required for plant growth. Below pH 5.5 the availability of calcium, magnesium, phosphorus, and molybdenum are greatly decreased,sometimes to the point of deficiency. Aluminum, hydrogen, iron, and manganese are greatly increased, often reaching levels toxic to plant growth. Soil calcium levels are related to root growth and function. At low soil pH, calcium concentrations must be several times higher than at high pH in order to counteract the adverse effects of high hydrogen concentrations on root elongation. Additionally, in strongly acid soils nutrient toxicity may inhibit root elongation (aluminum) and top growth (manganese) and cause added phosphorus and molybdenum fertilizers to be fixed in forms unavailable to plants. At soil pH above 7.0 other problems with nutrient availability occur. Consequently, soil pH of 6.0 to 6.8 is best for most crops. Tha College of Agriculture is an Equal Opportunity Organization with respect to education and employment and authorization r.o provide .research, e~ucation i.nforma:ion ~nd other services only to individuals and institu1ions that tunctwn without regard to race, color, national origin, sex.,reli_g1on, age and handicap. lnqumes regardmg_comp/1ance with Tltle VI and Title VII of the Civil Righi Act of 1964, Tirle IX of me Educational Amendments. Section 504 of rhe Rehabilrtat1on Act end other related matter should be directed to Equal Opportunity Office, College of Agnculr1;rf!, University of Kentucky, Room S-105, Agricultural Science Building-North, Lexington, Kentucky 40546. UNIVERSITY OF KENTUCKY, KENTUCKY ST ATE UNIVERSITY. US DEPARTMENT OF AGRICULTURE. AND KENTUCKY COUNTIES. CO OPERA TING Effect of Acid Soil on Alfalfa and Clover Soil pH can drastically affect seedling survival and development of these small seeded legumes because of the effect it has on molybdenum availability and other infertility factors in the soil. When soil pH drops below 6.0 to 6.2, molybdenum becomes limiting for needs of the rhizobia bacteria in the nodules on the legume roots which fix nitrogen from the air. Consequently, the legume seedlings will suffer from nitrogen deficiency, often to the point of severe stand loss. Soils should be limed to 6.8 for long term production of alfalfa. Effect of Acid Soil on Tobacco Close monitoring of soil pH in tobacco fields is very important. The large applications of commercial fertilizers used in tobacco production cause soil pH to decrease more rapidly and to a greater extent than for most crops. Soil tests made every other year on continuously cropped tobacco fields will enable producers to monitor soil pH changes that prevent manganese toxicity and molybdenum deficiencies of tobacco. Yield losses to manganese toxicity can range all the way from slight yield reductions with mild toxicity to stand losses with severe toxicity. Besides loss of yield, leaf quality is often lowered because of unsound leaves in the flyings and lug grade groups resulting from loss of interveinal tissue. Lime tobacco soils to 6.6. Effect of Acid Soil on Soybean Growth Soybeans are also affected in the same manner as alfalfa and clovers. As soil pH drops below 6.0 to 6.2, molybdenum availability is decreased in the soil and the plants suffer from nitrogen deficiency. Additionally, if the soil is strongly acid, manganese toxicity may lower yields even further. Soils should be limed to 6.4 for soybeans. Spring Liming Practices In order for spring liming to be effective, (1) There must be adequate amounts of lime which is fine enough to react immediately when mixed into the soil. This can be accomplished by use of a substantial rate of aglime or by a lower rate of finely ground lime (lime finer than 60 mesh); (2) The lime must be mixed thoroughly in the upper 6 to 8 inch layer of soil by disking. Cross-disking may be necessary to get good mixing of lime with the soil in order to hasten reaction of the lime. In addition to lime, use of molybdenum is beneficial when pH of a tobacco field is below 6.6 or if pH for alfalfa, clovers, and soybeans is below 6.2. Also, tobacco responds well to nitrate fertilizer at soil pH below 6.0. Check with your local Agricultural Extension Agent on how to properly use lime, molybdenum, and nitrate fertilizers. Does Spring Liming Work? Table 1 shows results of spring liming practices studied on an acid (pH 5.2) Pope silt loam soil being used for tobacco production. The treatments tested included the recommended 4 T/A applied in the spring of 1978 either plowdown or disk-in. Additionally, a "rescue" treatment of 0.5 T/A fine, bagged lime was tested in 1979 by broadcasting it over young, growing tobacco plants and mixing it into the soil during subsequent cultivations. The bagged lime was finely ground dolomitic limestone and was not burned lime or calcium hydroxide. This treatment significantly increased yield and soil pH over the unlimed control treatment. The same rate (0.5 T/A) was tested as a "rescue" treatment in 1980, using regular aglime. All 1978 spring liming practices tested increased soil pH and tobacco yields as compared to the unlimed treatment over the 3-year study. As shown by the data, the 0.5 rate of aglime did not significantly increase yield over the unlimed control treatment, and it did not raise soil pH. The fine, bagged lime was more effective when used as a "rescue" treatment at 0.5 T/A than aglime used in the same manner at the same rate. Table 1. Effect of Some S~~ing Liming Practices on Soil pH and Yield of Burley Tobacco" .u Rate (T/A) Source 0 Method of Application 1978 Yield pHY (lbs/A) 4.9 2335 1979 1980 Yield Yield pHY (lbs/A) pHY (lbs/A) 4.9 2243 4.4 2025 ------------------------------------------------------------------------------4 Aglime plowdown 5.4 2412 5.5 2637 5.3 2480 4 Aglime disk-in 5.6 2420 5.6 2658 5.3 2557 4 Agl ime 1/2 plowdown 1/2 disk-in 5.6 2716 5.6 2611 5.1 2369 4 Aglime +Mo disk-in 5.5 2380 5.5 2830 5.3 2462 4 fine, bag lime disk-in 5.6 2450 5.8 2892 5.6 2671 0.5 fine,1/ broadcast over bag 1 ime young tobacco 2684 4.9 2503 and cultivated in 0.5 Agl imeil broadcast over 4.4 2172 young tobacco and cultivated in L.S.D. (.10) 0.1 297 0.3 219 0.3 254 11 Wallace, A.M., K.L. Wells, J.L. Sims, and J.D. Grigson. 1982. Yield response of burley tobacco to liming methods and molybdenum treatments on an acid soil. Tob. Sci. 27:66-69. Y All pH measurements on 0-6 inch samples of soil; taken at the end of each ~ 1 season; initial pH in fall 1977 was 5.2. 'f1 Applied only in 1979 :11 Applied only in 1980 COOPERATIVE EXTENSION SERVICE U.S. DEPARTMENT OF AGRICULTURE UNIVERSITY OF KENTUCKY COLLEGE OF AGRICULTURE LEXINGTON, KENTUCKY 40546 OFFICIAL BUSINESS PENAL TY FOR PRIVATE USE, $300 AN EQUAL OPPORTUNITY EMPLOYER BULK RATE POSTAGE & FEES PAID USDA PERMIT No. G268 

Will Liming Acid Soils Now Be Adequate for Spring Needs?

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Will Liming Acid Soils Now Be Adequate for Spring Needs?

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