Thursday, January 11, 2007 - 4:15 PM

Nitrogen Fertilizer Recovery Efficiency of Cotton for Different Irrigation Systems

Kevin F. Bronson, Texas Agricultural Experiment Station, Texas Agricultural Experiment Station, Rt. 3, Box 219, Lubbock, TX 79403, Jeffrey C. Silvertooth, University of Arizona, SWES Dept., Shantz 429, Bldg. #38, Tucson, AZ 85721-0038, and Adi Malapati, Texas AgriLifer Research n, Texas Agricultural Res & Extn Center, 1102 E. FM 1294, Lubbock, TX 79403.

Nitrogen fertilizer recovery efficiency (NFRE) in irrigated cotton is often reported as being low, eg. < 50 %. We present data from West Texas and Arizona of NFRE of cotton for different irrigation systems. Nitrogen content and biomass of cotton was determined at first open boll. Nitrogen fertilizer recovery efficiency averaged 15, 45, and 65 % for furrow irrigation, LEPA (low energy precision -center pivot), and subsurface drip (SDI). The differences in NFRE were attributed not only to the frequency and quantity differences in the various irrigation modes, but also to the fertilizer timing and number of splits. Specifically, N fertilizer was added in one or two splits at the planting and squaring in furrow irrigation. In LEPA, N is fertigated/injected through the irrigation system several times during the season in 30 lb N/ac doses. In SDI 1-3 lb N/ac day were injected on about 30 days over a 5- 8 week period.

Recorded presentation