Cover crops and no-tillage reduce crop production costs and soil loss, compensating for lack of short-term soil quality improvement in a maize and soybean production system

Abstract

Conservation agriculture has been marketed to producers as a sustainable way to increase soil productivity and buffer the effects of anticipated fluctuations in both climate and the price of fuel and fertilizer. Despite US Farm Bill financial incentives promoting the use of conservation practices such as no-tillage and cover crops among producers, widescale adoption of cover crops in the US remains low. Implementing no-tillage and cover crop use may take years of consistent management to show measurable soil quality improvement. Conversely, costs associated with cover crop planting and management must be incurred immediately and before the accrual of any benefits. Current research has largely focused on the soil quality benefits of cover crops without considering the short-term implementation costs for producers comparing their current production systems to conservation systems they may adopt. To help fill this knowledge gap, soil properties, cash crop yield, and annual production costs were evaluated in a three-year maize /soybean study comparing a conservation system to a conventional production system in Mississippi from 2016 to 2018. The conventional system included frequent tillage and control of winter weeds with a residual soil herbicide (conv. till + bare). We compared five different levels of conservation systems, including a conservation system with no-tillage and cover crops (no-till + cover). We found a lack of consistent improvement in soil properties such as soil organic matter increase or crop yield in the conservation system over the three-year period. The economic benefits of substituting no-tillage and cover crops for expensive conventional inputs were much greater than the modest soil property improvements observed from 2016 to 2018 crops. Though crop yields varied, the cost of cash crop production in the conservation system (no-till + cover) was 43% less than the cost of the conventional system ($29.67 per Mg of crop yield in the conv. till + bare to $17.04 per Mg of crop yield in the no-till + cover system), highlighting a short-term economic incentive for producers to switch to conservation agriculture. The greatest resource benefit from the conservation system was a reduction in estimated soil loss, as mean soil loss in no-till and cover crop decreased by 86% compared to the conventional system (3.5–25.1 t ha-1). These results demonstrate that conservation agriculture has the potential to decrease overall production cost while decreasing the risk of accelerated soil erosion during expected weather extremes associated with climate change, potentially making both farming operations and agroecosystems more resilient.