Precision N Management of Spring Wheat: Defining and Assessing Performance Classes.

Increasing N use efficiency (NUE) with precision technologies (e.g. GPS, remote sensing, yield monitors, VRT) will require increased scientific understanding of landscape-scale processes and their impacts on decision-making. We are assessing yield-water-NUE relationships among diverse environments to elucidate site-specific processes that regulate the environmental and economic performance of wheat-based cropping systems. This effort will produce grower-oriented site- and time-specific N management monitoring, decision-aid and evaluation tools required to formulate N efficient and environmentally sound conservation strategies. We are pursuing these goals through the integration of crop (e.g. yield monitoring), soil (e.g. apparent electrical  conductivity), remote sensed (e.g. Rapideye satellite imagery) and economic data using field-scale studies at the WSU Wilke Farm, WSU Cook Agronomy Farm and on-farm locations. Here, we are: (1) measuring site-specific wheat performance and related  variables (yield, protein, economic return, N status, N use efficiency, soil organic matter and inorganic N) required for precision N management decisions; and (2) developing and testing site- and time-specific decision-aid and evaluation tools including an economic assessment required by growers to formulate and assess science-based precision N recommendations. Our expectations are to develop science-based decision aids that improve the application of precision N management strategies in wheat.