Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 28, 2001
Publication Date: September 1, 2001
Technical Abstract: Reduced and no-till cropping systems in the central Great Plains have led to increased precipitation storage efficiency and more frequent cropping than the traditional wheat-fallow system. Many producers express concern regarding the effect that more frequent cropping has on soil water content at wheat planting and subsequent yields. The objective of this study was to oquantify the effects of cropping system (crop sequence and fallow weed control method) on soil water at winter wheat planting and subsequent grain yield. The study was conducted over the 1993 through 2000 growing seasons at Akron, CO. Crop rotations evaluated were no-till systems of W-F, W-C-F, W-M-F, and W-C-M, and a W-F conventional till system. Use of conventional tillage resulted in 7.2 cm less soil water at planting in the W-F systems. Lowest water content at planting (10.9 cm) was found in the W-C-M system. Grain yields were correlated with soil water at planting according to the following relationships: kg/ha=285.3+145.2*cm (normal and wet years); kg/ha=897.9+39.7*cm (dry years). Increasing cropping intensity to two crops in three years has little effect on water content at wheat planting and subsequent grain yield, while continuous cropping and elimination of the fallow period reduces soil water at planting by 11.3 cm and yields by 450 to 1650 kg/ha, depending on growing season precipitation.