Effect of Physical and Chemical Profile Modification on Soybean and Corn Production

Abstract

Abstract Crop production on highly weathered soils is frequently limited by poor root penetration into the subsoil as a result of highly acid conditions. This results in reduced water uptake from the subsoil and may subject the crop to drought stress. As a result, the possibility of ameliorating the subsoil of a Typic Hapludult, both chemically and physically, was investigated in a field experiment in which four subsoil treatments were compared, namely, control, subsoil mixed to 1 m, subsoil mixed to 1 m with sufficient lime incorporated to neutralize exchangeable Al 3+ , and gypsum incorporated into the surface soil. The crops grown were soybeans [ Glycine max (L.) Merr.] and corn ( Zea mays L. ). Deep incorporation of lime increased yields. Surface‐applied gypsum increased yields only in the 2nd and 3rd yr. Yield improvement resulted from deeper root penetration into subsoils, which was confirmed by water‐depletion measurements. This improved root proliferation was accompanied by a reduction in exchangeable Al 3+ and an increase in exchangeable Ca 2+ .