Soil Quality in Long-Term Corn and Soybean Rotations.

The objective of this study was to evaluate SQ at successive depths of soils under typical Illinois crop rotations 12 years after establishment. Continuous corn (CCC), corn-soybean (CS), and corn-corn-soybean (CCS) rotations were arranged in a RCBD with three replications at six research sites (locations) around the state, with all phases present each year. The data set included soil bulk density (BD), water aggregate stability (WAS), cation exchange capacity (CEC), soil organic matter (SOM), and a complete set of macro and micro nutrients at the depths of 0-15, 15-30, 30-60, and 60-90cm taken after 12 years of management. We used a 6 x 3 x 4 between-subjects multivariate analysis of variance (MANOVA), followed by factor analysis (FA) as a data reduction technique, and a canonical discriminant analysis (CDA) to investigate the possibility of separating among rotations based on our SQ data set. After detrending the data for the location effect, crop rotations did not seem to affect soil properties even 12 years after establishment. These are critical results as producers seek to mitigate and minimize environmental consequences associated with intensive farming practices.