Effect of Alternative Soil Acidity Amelioration Strategies on Soil pH Distribution and Wheat Agronomic Response

Agricultural lime is the recommended method for ameliorating soil acidity; however, in-furrow P fertilizer or pelletized lime are also common practices to manage low soil pH. This study evaluated the effects of broadcast incorporated agricultural lime [2.25 or 4.50 Mg effective calcium carbonate equivalent (ECCE) ha(-1)], banded pelletized lime (225 or 450 kg ha(-1) yr(-1)), or banded triple-super-phosphate (28 or 56 kg P2O5 ha(-1) yr(-1)) on bulk soil pH, exchangeable Al [potassium chloride extractable Al (Al-KCl)], Al saturation (Al-sat), spatial pH change in the soil profile, wheat (Triticum aestivum L.) vegetative development, and grain yield. Wheat was sown in October 2009, 2010, and 2011 in a Grant silt loam (fine-silty, mixed, superactive, thermic Udic Argiustoll) with initial soil pH of 4.9. Broadcast agricultural lime at 4.50 Mg ha(-1) increased soil pH to 5.9 and decreased Al-sat by 98%. Changes in soil pH caused by banded pelletized lime were restricted to a region of similar to 1.27 cm surrounding the pellet, while broadcast agricultural lime increased soil pH throughout the incorporated depth. In-furrow P fertilizer increased vegetative growth and plant population homogeneity in all years of the study; broadcast lime provided similar results in 2010-2011 when low soil pH effects were more apparent due to severe drought. Grain yield was not affected by treatment due to low Al-sat (<12%). Data suggest that banded pelletized lime behaves as large lime granules, only ameliorating soil pH at and around the application band; and increased vegetative growth induced by banded P fertilizer or broadcast agricultural lime might not result in increased grain yields when Al-sat < 12%.