Role of a Dynamic Simulation Tool in Reducing Nitrate Leaching: Research Background and Results from Adapt-N.

Nitrogen management in maize production is often imprecise and inefficient in humid regions due to dynamic, complex and locally-specific interactions among weather, soil and management variables.   N losses are strongly impacted by weather, which generally results in excessive N rates and environmental losses as farmers aim to ensure adequate N availability for most scenarios.  In order to gain more N management precision, computer simulation models can use weather information to simulate soil C and N transformations, water transport and N uptake during maize growth to calculate N fertilizer needs.  The Adapt-N tool focuses on real-time N rate optimization and is a web-accessible cloud-based tool that includes high resolution climate data on a 4x4 km grid, and a readily accessible web-interface that is also mobile enabled.  It incorporates information related to the management of a maize crop, soil properties, rotations, tillage, fertilizer and cover crop management, and manuring.  In addition to N rate recommendations for specific locations and times, it also offers simulation results, including estimated nitrate leaching losses.  It therefore can serve as both an N management decision tool and an environmental assessment tool.  We will present the research background on Adapt-N and demonstrate its ability to effect nitrate leaching reductions, based on results from on-farm trials.