Evaluating the effects of perennial cover crops on the soil chemical properties in a wide row corn production system in southern Minnesota

Presenter (s)

Rachel Fischer

Abstract or Description

Cover crop integration has been proposed to eliminate the extended periods of bare soil in intensive corn (Zea mays) production systems and can help reduce the degradation of soil health by decreasing erosion and surface runoff and helping reduce the loss of nutrients. Annual cover crops must be replanted every year in the fall and then killed in the spring to allow land preparation for planting the cash crop (e.g., corn), thus leading to high management costs due to labor and materials. However, perennial cover crops (PCCs) have the potential to increase continuous soil surface cover without needing to be replanted or terminated each year, thus requiring minimal management. There is a lack of research on the effects of PCCs on soil chemical properties. Hence, this study investigated the impacts of PCCs on the soil chemical health indicators in a wide-row (i.e., 60" rows) corn production system in southern Minnesota. The experimental site is a randomized complete block design with four different treatments (three PCCs + one control): i) a control with no PCCs, ii) grass + corn, iii) legume + corn, and iv) grass-legume mix + corn. Each plot has four replications, totaling 16 plots. Soil samples were collected in the spring and fall of 2023 and analyzed after collecting them from 0 to 6” (0-15 cm) depth. Here we present the effect of PCCs on several soil chemical health indicators – potentially mineralizable nitrogen (PMN), inorganic nitrogen content, soil organic matter content (SOM), pH, and the soil macro- and micro-nutrients – and how these indicators vary with time (Spring vs Fall). Analysis of PMN and inorganic nitrogen content is still in progress. Only boron has shown significant differences between the different PCC treatments among all the micro and macro-nutrients. Based on these results we can conclude that PCCs cause very minimal or no short-term changes to the SOM, pH, macro and micronutrient contents of the soil in all the PCC + corn treatments compared to the control treatment and did not support our hypothesis. Patience is needed to observe changes in soil chemical health, even in response to a drastic management change like integration of PCCs to a wide-row corn production system.