COMPARISON OF TILLAGE AND CHEMICAL SUMMERFALLOW IN A SEMIARID REGION

Abstract

Chemical treatments using contact and systemic herbicides were compared with cultivation for summerfallow preparation on a Wood Mountain clay loam soil from 1964 to 1969, inclusive. Use of chemical alone was equal to cultivation in its effect on soil moisture conservation, soil temperature and yield of wheat. Summerfallow prepared by chemical only conserved 62% of the original crop residue, compared with 35% for normal cultivated fallows. Chemically prepared fallows were less erodible (fewer soil particles < 1 mm in diameter) at die completion of tillage in the autumn than cultivated fallows. However, the chemically fallowed soils exhibited the least aggregation over winter and were slightly more erodible by spring than the cultivated soils. The general trend was for lower NO3-N values in the fall and prior to seeding in the spring for wholly chemical than for wholly cultivated summerfallow, but the differences were not usually significant.