On field precision experimentation (OFPE) applies field-scale experiments using precision-agriculture technology to gain the knowledge to optimize management under the uncertainties associated with large-scale organic production. OFPE is an adaptive management methodology of farmer driven field-scale experiments which helps understand specific within-field drivers of variation in crop production and quality. The aspirations of OFPE in organic settings are to optimize nitrogen inputs from green manure cover crops, to minimize weed impacts, and maximize crop yield, quality, and subsequent profits from following year cash crops. We demonstrated OFPE to organic producers by testing the effect of green manure cover crop seeding rates on following year wheat crops using variable rate seeding equipment. In 2019 we planted (60kg/ha, 90kg/ha and 120kg/ha) peas on a field in Montana and will plant three seeding rates of spring-wheat in 2020. In the same growing season, we applied three seeding rates (150 kg/ha, 180 kg/ha, and 225 kg/ha) of wheat and looked for yield differences across a 175 acre organically managed field in south east Manitoba. Harvest data were collected via combine-mounted yield monitors.
Results/Conclusions
The highest seed density produced the greatest yields, except on hilltops where the lowest seeding density produced highest yields. Based on these results a model was constructed to optimize seeding rates across this field in the future. The net return on the wheat (based on 2013-2019 average organic wheat prices) was increased on average by $6.00 (USD) using the optimized variable seeding rate. Early OFPE results indicate that optimized variable seeding rates outcompete farmer-chosen single field rates. Annual use of OFPE on a field will allow for continual improvement and optimization of field management recognizing that performance will change over time and allow for quantification of uncertainty associated with recommendations. OFPE projects are underway on five organic grain farms in Montana and Manitoba. Continued experiments will test the efficacy on cash crops and nitrogen fixing cover crops, to optimize nitrogen levels in the soil, reduce weed pressure, and maximize producer net returns. We are working with farmers to engage them in the adaptive management approach of OFPE, automating the experimental establishment (stratification of treatments based on previous field performance) and the analysis, but allowing interaction with the experimental process and results through simulation of outcomes given different management scenarios.