Watershed scale precision farming and soil conservation to enhance nutrient use efficiency and profitability

Precision agriculture, together with soil conservation, has considerable potential to better match crop inputs with crop requirements, as they vary over space and time. Both landform and spatial variability of soil properties may affect crop nitrogen (N) response; therefore, implementation of precision farming and soil conservation may enhance crop productivity and nutrient use efficiency (NUE). The objective of this study is to assess the potential for watershed scale precision agriculture and soil conservation to increase NUE and production profitability, and to reduce nutrient losses to the environment. The South Tobacco Creek (STC) watershed in Manitoba, Canada, with more than 25 years of land management data will be used to test the hypotheses that crop NUE and profitability will be improved, and N and phosphorus (P) losses will be reduced, under precision farming and soil conservation systems, as compared with conventional N and P application. The STC watershed fields will be delineated into zones based on historical crop yields, N and P fertilizer inputs, soil and hydrological properties, and land management data. STC dataset will be used to develop NUE, crop yield and cost relationships using multivariate regression estimations, to optimize N and P use for different crops within each zone in the watershed. The relationships developed, and the input-output data collected from both research sites and literature, will be incorporated into an economic simulation model, in order to identify benefits of N and P reduction from precision farming and soil conservation. Preliminary results have shown that fertilizer N accounts for more than 60% of the energy input used in the watershed. Also, a significant amount of applied N and P fertilizer leaves the STC watershed under conventional N and P application, going unrecovered in crops and soil. This suggests that precision farming and conservation management could effectively reduce nutrient losses to the environment.