Crop Rotation and Tillage Effects on Soil Physical and Chemical Properties in Illinois

Recent increases in corn (Zea mays L.) production in the U.S. Corn Belt have necessitated the conversion of rotations to continuous corn, and an increase in the frequency of tillage. The objective of this study was to assess the effect of rotation and tillage on soil physical and chemical properties in soils typical of Illinois. Sequences of continuous corn (CCC), 2-yr corn-soybean [Glycine max (L.) Merr.] (CS) rotation, 3-yr corn-soybean-wheat (Triticum aestivum L.) (CSW) rotation, and continuous soybean (SSS) were split into conventional tillage (CT) and no-till (NT) subplots at two Illinois sites. After 15 yr, bulk density (BD) under NT was 2.4% greater than under CT. Water aggregate stability (WAS) was 0.84 kg kg(-1) under NT compared to 0.81 kg kg(-1) under CT. Similarly, soil organic carbon (SOC) and total nitrogen (TN) were greater under NT than under CT with SOC values for 0 to 60 cm of 96.0 and 91.0 Mg ha(-1) and TN values of 8.87 and 8.40 Mg ha(-1) for NT and CT, respectively. Rotations affected WAS, TN, and K levels with WAS being greatest for the CSW rotation at 0.87 kg kg(-1), decreasing with more soybean years (CS, 0.82 kg kg(-1) and SSS, 0.79 kg kg(-1)). A similar pattern was detected for TN and exchangeable K. Results indicated that while the use of NT improved soil quality, long-term implementation of continuous corn had similar soil quality parameters to those found under a corn-soybean rotation.