Pima and Upland Cotton Response to Irrigation Management1
- D. L. Kittock2
American Pima cotton (Gossypium barbadense L.) traditionally is stressed more for moisture before irrigating than is Upland cotton (G. hirsutum L.). With improved cultivars of each species, many growers now irrigate both in a similar manner. The purpose of this research was to determine if current cultivars of the two species respond differently to irrigation. Upland and Pima cultivars were compared for 4 years under five irrigation regimes at Phoenix, Ariz. Water was metered into closed basins. Treatments consisted of watering every 7, 14, and 21 days for 4 years. Additional treatments for 2 years were watered every 28 days and watered every 7 days at 50% more water than the original 7-day treatment. Highest yield of Pima cotton was from a treatment of one irrigation regime drier than Upland cotton in 3 of 4 years and the same regime for 1 year. Pima cotton lint yield was reduced more by excess water and less by water stress than was the yield of Upland cotton. Higher lint yields were obtained under less frequent irrigation (greater water stress) in years of low productivity. These data suggest that yield of Upland cotton may be increased by more frequent irrigation than is the current practice.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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