Effects of Temperature and Application of Urea with N-butyl Thiophosphoric Triamide and Dicyandiaminde on Cotton

Crops are usually known to have low N use efficiency, recovering only 30-35% of the N supplied (Constable and Rochester, 1988; Daberkow et al., 2000). Different practices have been recommended to increase crop N-use efficiency and much attention has been focused on the use of urease and/or nitrification inhibitors to decrease losses of N by volatilization and leaching. Cotton (Gossypium hirsutum L.) yields in the U.S. have been reported to be negatively affected by periods of extreme high temperatures during flowering and boll development (Oosterhuis, 2002). Recently a number of studies have been conducted in the understanding of the physiological responses of cotton to heat stress (Snyder et al., 2009). Application of urease and nitrification inhibitors to crops has also been widely researched; however, there has been limited work on the effects of these inhibitors on the cotton growth and N assimilation physiology under high temperature conditions.