Water storage and use by spring wheat under conventional tillage and no-till in continuous and alternate crop-fallow systems in the northern Great Plains

Abstract

ABSTRACT: A five-year study was conducted at two North Dakota locations to evaluate water storage in the 4-foot soil profile and water use by spring wheat under no-till and conventional tillage in continuous and alternate crop-fallow systems. Storage efficiency during the nongrowing season under continuous wheat varied among years and locations, but was similar among tillage systems. Evapotranspiration during the growing season was similar among tillage systems under both continuous and alternate crop-fallow systems. No-till grain yields, hindered in some years by weed competition, foliar disease, and insect damage, were lower than yields for the conventional, spring-plow tillage system at both locations in all years except one. Thus, the spring-plow system resulted in higher water use efficiencies. Gtain yields in the alternate spring wheat-fallow rotation were similar to continuous wheat at one location. Thus, on a land use basis, yields of wheat grown on fallow were half the yields of continuous wheat and 1 bushel/acre less per inch of water when water losi during the fallow counterpart was considered. Fallow wheat yields at the other location were 14 bushels/acre higher than continuous wheat yields. However, on a land use basis, yields of wheat planted after fallow were 8 bushels/ acre less than continuous wheat yields. Continuous wheat, irrespective of tillage system, did not make use of 12% to 24% of the precipitation received. With low water retention by the soil during the summer fallow period, fallow wheat did not make use of 67 7i to 75% of the precipitation received.