Short Corn Rotations Do Not Improve Soil Quality, Compared with Corn Monocultures

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 around Illinois, and to identify soil quality indicators for rotations in the state. Crop rotations of continuous corn (Zea mays L.) (CCC), corn-soybean [Glycine max (L.) Merr.] (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 for 12 yr. 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 98% of cases, representing <2% error rates for the cross-validation results at each location. Crop rotations, on the other hand, did not affect any of the soil properties evaluated, results 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.

Microbial Signatures in Fertile Soils Under Long-Term N Management

“…As it was observed for the crop rotation, alternating corn and soybean phases seemed to ameliorate the response of the soil microbiota to N fertilization detected in the continuous corn system. This ameliorated response could be further supported by similar levels of SOM and Pa measured across monocropped and rotated corn crops despite obvious differences in amount and quality of residue returned, consistent with previous studies in soils of the region (26,53,55). Across rotations, however, N fertilization had a significant impact on increasing NO − 3 in the soil while reducing pH and available P. The latter is attributed to the enhanced P uptake by crops in rotation, that yielded 10% more grain on average than monocropping (56), as well as to the potential damage to microbial acid phosphatase activities with N-fertilization (57).…”

Agronomic assessment of cover cropping and tillage practices across environments

“…The complete dataset associated to this manuscript is publicly available (Villamil & Nafziger, 2019). Additional examples of the use of multivariate techniques in agricultural studies are provided by Behnke, Pittelkow, Nafziger, and Villamil (2018); Hoss, Behnke, Davis, Nafziger, and Villamil (2018); Huang, Riggins, Rodriguez‐Zas, Zabaloy, and Villamil (2019), whereas Yeater and Villamil (2018) provide a roadmap to the use of multivariate procedures.…”

Soil quality indicators as influenced by 5-year diversified and monoculture cropping systems

“…Corn ( Zea mays L.) and soybean ( Glycine max L.) sequence is the most common agricultural practice in many places worldwide (Hoss et al ., 2018). However, interest in adopting crop diversity has been increasing among producers to enhance crop production.…”