Soil water during the drought of 2012 as affected by rye cover crops in fields in Iowa and Indiana

The drought of 2012 provides a unique opportunity to evaluate the effects of cover crop on soil moisture under relatively extreme conditions. The objective of this study was to quantify potential differences in soil moisture due to the presence of a rye (Secale cerale L.) cover crop in a corn (Zea mays L.)-soybean (Glycine max L.) rotation at various locations in the Midwestern United States during the drought of 2012. Soil volumetric water content (.) and soil water storage (SWS) were monitored at three sites in Iowa and Indiana. Daily measurements of soil. were taken at 10, 20, 40, and 60 cm (3.9, 7.9, 15.7, and 23.6 in) soil depths, and SWS was estimated to an 80 cm (31.5 in) depth. Soil water during the drought of 2012 was affected by a rye cover crop in comparison to without a rye cover crop for one (i.e., located in Iowa) of the three sites monitored. At the Iowa site, soil theta was on average 0.041 and 0.033 cm(3) cm(-3) (0.041 and 0.033 in(3) in(-3)) greater at the 10 and 20 cm (3.9 and 7.8 in) depths, respectively, following termination of a rye cover crop than crops without a rye cover crop. Thus, during the 2012 drought, the use of a rye cover crop as compared to without a rye cover crop in a corn-soybean rotation did not significantly lower soil water conditions. The use of a cover crop either had no impact or significantly increased soil water conservation.