ARS | Publication request: SUBSURFACE MICROIRRIGATION PLACEMENT EFFECTS ON COTTON LEAF N AND WATER POTENTIAL

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 11, 1996
Publication Date: N/A

Technical Abstract: Optimal cotton (Gossypium hirsutum L.) production practices need to be developed for buried microirrigation systems in the southeast USA. The objective of the research was to evaluate buried tube spacing and N fertilizer management. In 1991 through 1994, cotton was grown over buried tubes placed under every row, placed in the center of alternate midrows, or without irrigation. Nitrogen treatments, applied through the tubing, were one sidedress application of 100 lb/ac, 10 or 20 lb/ac applied as needed based on GOSSYM-COMAX predictions, and five weekly 20 lb/ac applications. Leaf N, petiole N03-N, and leaf water potential were monitored during July and August each year. Differences occurred between rainfed and irrigated cotton for leaf water potential, leaf blade N, and petiole N03-N, but the two buried tubing placements generally did not differ. None of the nitrogen treatments resulted in N deficiency in any year. Irrigation increased lint yield by 19% in 1992 and 62% in 1993. In 1991 and 1994, yields of the irrigated and rainfed cotton did not differ. Tubing placement did not affect cotton yield. Nitrogen application did not impact yield in any year of the study. A wider tubing spacing than in-row placement is adequate to supply water and N to cotton.