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Extractable Soil Boron and Alfalfa Uptake: Calcium Carbonate Effects on Acid Soil
Author(s) -
Su Chunming,
Evans L. J.,
Bates T. E.,
Spiers G. A.
Publication year - 1994
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1994.03615995005800050024x
Subject(s) - chemistry , shoot , soil water , amendment , dry matter , agronomy , salinity , zoology , soil ph , horticulture , biology , soil science , environmental science , ecology , political science , law
Since soil tests for B in fine‐textured soils give inconsistent predictions and the amendment of acidic soils with CaCO 3 is a common practice, the suitability of extractants for plant‐available B in a CaCO 3 ‐amended clayey soil was studied. This research investigated the pH effect on B adsorption, the changes in the amounts of hot‐water‐extractable B (HW‐B), mannitol‐extractable B (MANN‐B), and soil solution B (SOLN‐B) as a result of B and CaCO 3 addition to a silty clay soil (a clayey, mixed, mesic Typic Humaquept) with an initial pH of 4.2. The relationship between the amounts of extractable B and B uptake by alfalfa ( Medicago sativa L.) was also studied. Amounts of extractable B in soil were in the order HW‐B > MANN‐B > SOLN‐B, decreasing with increasing pH and after growth of alfalfa. Addition of 2.5 and 5.0 g CaCO 3 kg −1 increased alfalfa dry matter yield; whereas addition of 0.5 and 1.5 mg B kg −1 had no effect. In the absence of added B, the B concentration in alfalfa shoots decreased with increasing pH. Linear correlations between B concentration in alfalfa shoots and extractable B in soil were significant for all three cuts and for all three extractants. Total uptake of B was significantly correlated with all forms of extractable B except HW‐B for the third cut only. Inclusion of pH improved the relationship for the other cuts. The dilution of B in plant shoots by CaCO 3 ‐stimulated growth may result in B deficiency.