Use of Gypsum for Crop Grain Production under a Subtropical No‐Till Cropping System

Abstract

Gypsum has been used in tropical and subtropical agriculture when subsoil acidity is an important yield‐limiting factor. However, the conditions that promote increased crop yield as a result of gypsum addition in no‐till (NT) systems still remain unclear. A field trial examined the effects of newly and previously surface‐applied gypsum in a long‐term NT system on the soil chemical properties and nutrition and yield of corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] on a clayey Rhodic Hapludox in Parana State, Brazil. Gypsum was surface‐applied at 0 and 6 Mg ha−1 in 2004 on plots that had received gypsum previously at 0, 3, 6, and 9 Mg ha−1 in 1998. Surface‐applied gypsum newly and previously improved exchangeable Ca and SO4–S availability throughout the soil profile, and increased the cumulative grain yield of the crops. Exchangeable K losses through leaching caused by gypsum application were low, and a larger mobility of exchangeable Mg as compared with exchangeable K in soil was found as a result of gypsum addition. An increase in Ca content in the corn, wheat, and soybean leaves, and in S content in the corn and wheat leaves occurred following the gypsum application. The use of gypsum showed economic viability to maximize crop grain production in a long‐term NT soil with a sufficient level of exchangeable Ca (≥8 mmolc dm−3) and low levels of exchangeable Al (≤4 mmolc dm−3) and Al saturation (≤15%) in the subsoil layers (20–60 cm).