RESIDUE MANAGEMENT PRACTICE EFFECTS ON SOIL PENETRATION RESISTANCE IN A WHEAT-SOYBEAN DOUBLE-CROP PRODUCTION SYSTEM

Abstract

Improving long-term agricultural sustainability requires appropriate soil and residue management practices. Soil cone index (CI), which relates to the resistance to penetration of a cone of specific dimensions, is an important physical property relating to soil and crop productivity, particularly in intensive cropping systems. A study was initiated in 2001 to evaluate the effect of alternative residue management practices on soil penetration resistance in a wheat (Triticum aestivum L.)-soybean (Glycine max [L.] Merr.) double-cropped system in the Mississippi River Delta region of eastern Arkansas. Residue management treatments consisted of tillage (conventional tillage and no-tillage [NT]), residue burning (burn and no burn), and residue level (low and high, achieved by differential N fertilization). Soil CI, as measured using a hand-pushed penetrometer, was determined at 0.05-m intervals to a depth of 0.4 m in 2003, after one, and in 2006, after four complete cropping cycles. The whole-field CI increased with depth in both years. Tillage, burning, and residue level generally did not affect CI in the top 0.20-m in either year. In both years, soil CI was consistently lower under burning than nonburning at all depths below 0.20 m. Compared with after only 1 year, 4 years of NT soybean resulted in a 35% increase in CI at the 0.05-m depth. Soil CI was reduced at the 0.4-m depth under NT and nonburning but increased somewhat under conventional tillage and nonburning after 4 years. Being aware of the potential effects of alternative residue management on soil properties and root growth in relation to soil penetration resistance will be necessary for sustainable soil management practices.