COTTON IRRIGATION MANAGEMENT WITH LEPA SYSTEMS
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Irrigations were applied to short-season cotton at Halfway, Texas, using a LEPA irrigation system at intervals of 2, 4, 8 and 12 days in 1986 and at 3, 6, 9, and 18 days in 1987 and 1988. The four interval treatments were grouped for analysis and referred to as 3D, 5D, 9D, and 15D. Irrigation quantities at each interval were 0.4, 0.6, 0.8, and 1.0 times a base irrigation amount (BI) which equalled estimated cotton evapotranspiration (ET) less rainfall. The DRY treatments received preplant irrigations only. The 3D treatments resulted in higher cotton lint yield and seasonal irrigation water use efficiencies than other irrigation intervals. Root length densities in the 3D treatments were higher than in the 15D treatment at both the 04.BI and 1.0BI irrigation quantities. Irrigation interval treatments caused small detectable differences in seasonal soil water content at the 0.4BI irrigation level. Average cotton lint yields were reduced as irrigation amounts increased. The 0.4BI and 0.6BI treatment yields were significantly higher than those of the 0.8BI and the 1.0BI quantities. The 3D×0.4BI treatment produced the highest annual lint yield of 1134 kg/ha from average irrigations totaling 81 mm/yr compared to the 15D×1.0BI (traditional) treatment which yielded 945 kg/ha from 202 mm/yr of seasonal irrigation. Deficit irrigation of short-season cotton using a LEPA system and a 3D interval can enhance lint yield and conserve groundwater on the Southern High Plains of Texas.
author list (cited authors)
BORDOVSKY, J. P., LYLE, W. M., LASCANO, R. J., & UPCHURCH, D. R.