FACTORS CONTRIBUTING TO CROP RESPONSE ON A DEEP-PLOWED SOLONETZ SOIL

Abstract

Deep plowing was evaluated in the field and simulated in a greenhouse study in an attempt to isolate soil factors responsible for yield effects on a Duagh Solonetz soil. Generally, fertilization provided a more significant yield response than deep plowing in the field or horizon mixing in the greenhouse. In the field, however, deep plowing combination with fertilization produced an additional 542 kg/ha of alfalfa-bromegass forage over fertilization alone (P .ltoreq. 0.01). Also, in fertilized greenhouse treatments, retaining the A horizon on the surface while mixing sub-horizons proved significantly beneficial over mixing all 3 horizons (P .ltoreq. 0.01). The main factor responsible for yield effects appeared to be the Ca enrichment of surface and B horizon areas. An increase in the Ca:Na ratio improved water intake rates and reduced water-logging of the soil, thereby providing a more suitable medium for root development and a more efficient use of indigenous and applied N.