Crop rotation influences yield more than soil quality at a semiarid location

Abstract

Winter wheat (Triticum aestivum L.) is often rotated with a fallow in semiarid regions to conserve soil moisture and minimize crop failures. We hypothesized that direct seed systems coupled with intensified and more diverse crop rotations would produce an equivalent or greater annualized grain yield than a traditional winter wheat–fallow (WF) system. Furthermore, continuous cropping would lead to an accumulation of greater soil carbon than the traditional WF. A 6-yr study was conducted to evaluate crop rotations, which included pea (Pisum sativum L.), lentil (Lens culinaris Medik), lentil as a cover crop, spring wheat, or camelina [Camelina sativa (L.) Crantz] in rotation with winter wheat in 2- and 3-yr rotations. The results of this study averaged over 6 yr showed that increased cropping intensity produced an annualized yield equal to that of WF, provided that either a fallow or a cover crop rather than another grain crop was present prior to winter wheat. The soil quality indices showed particulate organic matter (POM) increased with rotations with greater cropping intensity (1.00 vs. 0.67), although the POM of these rotations was not different from that of WF.