ABSTRACT

Nitrogen (N) management of cotton has arguably not kept pace with other areas of cotton management such as varietal development, minimum-tillage, and subsurface drip irrigation. We present here an update of N management of irrigated cotton, with special reference to the Southern High Plains. Nitrogen fertilizer response in cotton differs by tillage system. For example, conservation-till cotton may require more N than conventional-till cotton. Nitrate soil tests to 2 feet are a useful pre-dictor of cotton response to N in the Western US. The high internal use efficiency of cotton in the Southern Plains means that 40 lb N is required in the cotton plant for every bale of lint produced. More N is probably required per bale for humid areas of the cotton belt. Recovery efficiency of N fertilizer is low in cotton, usually < 50% N of applied throughout the cotton belt. Finally, in-season sensing of N status in cotton, such as the chlorophyll meter and proximal spectral reflectance sensing has potential to guide in-season N fertilization of cotton.