SMART TILLAGE TO REDUCE N2O EMISSION FROM ORGANIC AGRICULTURE

The reliance of grain and forage organic production on tillage, manure and cover crops to control weeds and nutrient supply creates challenges to control nitrous oxide emission and nitrogen leaching. Our prior research shows that emissions are high when plowing legume cover crops or when these cover crops are colocated with manure and plowed in. We identified the process that causes the peak emission: denitrification driven by hypoxic conditions caused by high respiration rates. The high availability of nitrate that drives denitrification losses also causes leaching. Land transitioning to organic agriculture, as well as land managed organically or conventionally, must control these harmful N losses, a fact acknowledged by stakeholders through diverse venues. We propose smart tillage to creatively regulate the distribution and concentration of cover crop residues and manure residues in the plow layer, cutting emissions of nitrous oxide by a half during the peak emission phase - the corn phase of the rotation. This is the phase that receives the larget input of both organic nitrogen and organic carbon as cover crop or manure input.Specificallyl, we propose to dilute cover crops residues in a thicker soil layer before inversion tillage, seclude manure from cover crop residues by applying manure after cover crop burial, and by harvesting legume aboveground cover crop biomass when practical and when above a given threshold. We termed all these practices smart tillage.The project includes novel ways of monitoring oxygen and carbon dioxide concentration in the plow layer through imaging, which can produce potent imagery for educational activities. The experiments will be done in an ongoing organic rotational experiment that will be customized to test our hypotheses, conduct field days, and support graduate work. We propose multiple avenues to receive and provide feedback to stakeholders, including testing our smart tillage alternatives in two commercial organic farms. Reducing N losses and preserving productivity is a priority for an environmentally friendly and economically vibrant organic agriculture.