Irrigation strategies for cotton under limited water supply
1990
Ganotisi, N.D. | Angeles, H.L. (Cotton Research and Development Inst., Batac, Ilocos Norte (Philippines). Agricultural Engineering Dept.)
The three-year (November 1987-April 1990) study conducted in San Juan, Ilocos Sur [Philippines] sought to determine the influence of moisture deficiency on the growth and yield of cotton; formulate a prediction equation for seedcotton yield as a function of moisture deficiency; and, evolve an irrigation strategy for cotton grown in areas where water shortage may occur during the season. During the first year of implementation, 31 treatments were tested but were reduced to 19 during the second year with the exclusion of less performing treatments. There were 20 treatments during the third year with the employment of a variable duration of wilting days. Results showed that water stress significantly reduced seedcotton yield, bolls produced, plant height, and leaf area index. For single-stress stage, squaring-flowering was the most adversely affected followed by bolling and vegetative stages. For double-stress stage, squaring-flowering and bolling stages were the most critical. Thus, in areas of limited water supply, plants could be subjected to a ten-day temporary wilting condition during the vegetative and bolling stages with the rest of the growing period irrigated based on the 50-55% AM. For moderate water supply, plants could be subjected to temporary wilting condition for five days during the vegetative stage and irrigated later based on the 50-55% AM.
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