Soil property and soybean yield trends in response to alternative wheat residue management practices in a wheat-soybean, double-crop production system in eastern Arkansas

Abstract

Growing concerns over the long-term sustainability of agricultural systems require investigation of agricultural management practices that may improve and sustain soil quality and crop productivity over time. Over 20% of the soybean [Glycine max (L.) Merr.] area in the highly productive Mississippi River Delta region of the midsouthern United States is in a double-crop rotation with wheat [Triticum aestivum (L.)]. Currently, much of the resulting wheat residue is managed by burning followed by conventional tillage, but this combination may not be environmentally sustainable. Therefore, the objective of this study was to determine the longterm effects of tillage [conventional (CT) and no-tillage (NT)], wheat-residue burning (burn and no burn), wheat-residue level (low and high, achieved with differential N fertilization), and irrigation (irrigated and dry-land) on soybean yield, net economic returns, and soil properties in the top 10 cm of a wheat -soybean, double-crop production system. A field experiment was conducted from 2001 through 2007 in the Mississippi River Delta region of eastern Arkansas on a Calloway silt loam (fine silty, mixed, active, thermic Glossaquic Fraglossudalf). Soil bulk density increased in both CT and NT during the first three years, but at a greater rate under NT (0.12 g cm -3 yr -1 ) than CT (0.08 g cm -3 yr -1 ), followed by a decline at a similar rate in both tillage treatments. Soil pH and Mehlich-3 extractable soil Ca and Mg contents increased, while electrical conductivity decreased linearly over time when all treatments were combined. Soil organic matter (SOM) increased over time in all treatment combinations. Total C (TC) increased at a greater rate in the no burn (0.08 kg C m -2 -1