An Integrated Approach for Nitrogen Management In Upland Cotton Across The U.S. Cotton Belt

Project Summary

Nitrogen (N) is second only to water as a yield-limiting factor in non-legume cropping systems such as corn (Zea mays L.) and cotton (Gossypium hirsutum). Countless research endeavors have sought to unravel the dominant loss mechanisms/pathways in these two crops; however, the end result is that N use efficiency (NUE) remains ~33% worldwide and 40-60% in the U.S. As a result, roughly half to two-thirds of the applied N in non-legume cropping systems can move off-target and into the surrounding environment. To reduce these gaps in NUE, integrated research is needed to understand how N moves, transforms, and is utilized in non-legume cropping systems. This need is particularly urgent in cotton production systems, which represent 5.67 million hectares in the U.S. and required 373,409 metric tons of applied N in 2017.

Previous studies in cotton have focused on N application rates, timing, source, and placement (the 4R’s of nutrient management) in the Mid-South, Southeast, and Texas (High plains/Coastal Bend) regions of the U.S. In contrast, few studies have evaluated 4R’s of N management across the humid portions of the cotton belt, even though these areas represent 89.5% of production. At the same time, new/improved technologies and management strategies such as improved cotton varieties, enhanced efficiency fertilizers (EEF’s), and integrated cover crop solutions offer the potential to regulate N transformations in the soil and reduce N losses to surrounding ecosystems. Still, the ability of these techniques to improve NUE in contemporary cotton systems has not been rigorously examined. This project seeks to fill this important knowledge gap by integrating the 4R’s within a comprehensive agroecosystem perspective to improve NUE in cotton cropping systems, while also enhancing soil chemical and physical properties and decreasing off-target N movement via leaching and volatilization.