COS 121-5 - CANCELLED - Sparking changes in cover crop adoption in the lower Mississippi River Delta: short-term soil and economic benefits to producers

Background/Question/Methods

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. However, widespread adoption of cover crops in the US remains low, perhaps because costs associated with cover crop planting and management are incurred immediately, with the accrual of any benefits occurring later. 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).

Results/Conclusions

We found a lack of consistent improvement in soil properties, such as soil organic matter, 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. 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 and cover crops have the potential to decrease overall production cost while also decreasing the risk of soil erosion. This may be especially important during expected weather extremes associated with climate change, potentially making both farming operations and agroecosystems more resilient.