Abstracts Biological Sciences

Upland Cotton Lint Yield Response to Several Soil Moisture Depletion Levels

by S. Husman

Upland cotton lint yield response to several soil moisture depletion levels was measured in 1996 and 1997 for four Upland cotton varieties including DP 5415, DP 33B, DP 5816, and STV 474. In 1996, depletion of plant available soil water (PAW) irrigation treatments consisted of 35%, 50%, 75%, and 90%. In 1997, treatments were 35%, 50 %, 65 %, and 80% depletion of PAW. In 1996, the 35% and 50% treatments were significantly different than the 75% and 90% treatments (P < 0.05) and resulted in the highest lint yields of 1374 and 1438 lbs. lint/acre respectively. A lint yield reduction was measured with the 75% and 90% PAW treatments of 713 and 329 lbs. lint/acre, respectively. The 75% and 90% treatments were significantly different than the 35% and 50% treatments and were significantly different from each other. In 1997, all PAW depletion treatments were significantly different with the 35% PAW treatment resulting in the highest average lint yield of 1880 lbs. lint/acre. The 50%, 65%, and 80% PAW treatments resulted in 1410, 1123, and 248 lbs. lint/acre respectively. There was no significant (P < 0.05) difference between varieties within all PAW treatments in 1996 or1997.