Short corn rotations do not improve soil quality, compared to corn monocultures

Authors: HOSS, MOLLIE - UNIVERSITY OF ILLINOIS; BEHNKE, GEVAN - UNIVERSITY OF ILLINOIS; DAVIS, ADAM; NAFZIGER, EMERSON - UNIVERSITY OF ILLINOIS; VILLAMIL, MARIA - UNIVERSITY OF ILLINOIS

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2018
Publication Date: 5/3/2018
Citation: Hoss, M., Behnke, G.D., Davis, A.S., Nafziger, E.D., Villamil, M.B. 2018. Short corn rotations do not improve soil quality, compared to corn monocultures. Agronomy Journal. 110(4):1274-1288.

Interpretive Summary: Short corn rotations are widely used in the Midwest, but their long-term impact on soil quality has not been thoroughly examined. Our goal was to compare soil properties under long-term use of the most common crop rotations at several locations in Illinois, to identify those soil properties more sensitive to changes in management that could be used as soil quality indicators for rotations in the state. The physical and chemical properties of soil from continuous corn, corn-soybean, and corn-corn-soybean crop rotations were studied at six Illinois locations after 12 years since establishment. We found that the location of origin was the most important factor in determining soil properties. Crop rotations, on the other hand, regardless of the location considered, did not affect any of the soil properties evaluated. Though these short corn rotations make economic sense, they behave similarly to corn monocultures from the soil quality standpoint, compromising the sustainability of our current agricultural systems and highlighting the need to increase temporal and spatial diversification.

Technical Abstract: Short-duration summer annual crop rotations are widely used in the Midwest, but their long-term impact on soil quality has not been thoroughly examined. Our goal was to compare soil properties under long-term use of the most common crop rotations at several locations in Illinois, to identify those soil properties more sensitive to changes in management that could be used as soil quality indicators for rotations in the state. Crop rotations of continuous corn (CCC), corn-soybean (CS), and corn-corn-soybean (CCS), were arranged in a randomized complete block design (RCBD), with three or four replications at each of six locations, with all phases present each year, and after 12 years since establishment. We measured 21 soil properties on the surface soil and 18 properties at four successive depths rendering a total of 126 and 504 observations available for the multivariate statistical analyses, including principal component analyses (PCA) and canonical discriminant analysis (CDA) in both data sets. We found that our discriminant rules based on the measured soil properties correctly identified the location of origin of the soil samples in more than 95% of cases, representing less than 1% error rates for the crossvalidation results at each location. Crop rotations, on the other hand, regardless of the location considered, did not affect any of the soil properties evaluated, results that were further confirmed by our CDA analyses that showed high error rates for classification. Though these short corn rotations make economic sense, they behave similarly to corn monocultures from the soil quality standpoint, compromising the sustainability of our current agricultural systems and highlighting the need to increase temporal and spatial diversification.