Improving Nitrogen Fertilizer Use Efficiency in Surface- and Overhead Sprinkler-Irrigated Cotton in the Desert Southwest

Core Ideas Nitrogen use efficiency is low in surface‐irrigated cotton. Canopy reflectance can guide in‐season N management. Deep percolation of rain and irrigation is associated with nitrate leaching. Nitrogen fertilizer use efficiency (NUE) is low in surface‐irrigated cotton ( Gossypium hirsutum L.), especially when adding N to irrigation water. A NO 3 soil‐test algorithm was compared with canopy reflectance‐based N management with surface‐...