Water Use by Cotton From Low and Moderately Saline Static Water Tables1
- L. N. Namken,
- C. L. Wiegand and
- R. G. Brown2
A 4-year lysimeter study was conducted to determine the contribution of low to moderately saline, shallow static water tables to the total water use and yield of cotton grown on deep, permeable soils. Water tables controlled at 91-, 183-, and 274-cm depths contributed 54.4, 26.4, and 17.3% of the total water use under the high moisture treatment and 60.6, 48.9, and 39.2% under the low moisture treatment. Total water use consisted of soil profile depletion, rainfall, irrigations, and additions of water to maintain the water tables. Water uptake from the 274-cm water table was strongly related to the salinity level (electrical conductivity of saturated soil extract, ECe) of the capillary (183- to 274-cm) zone. Lint cotton yields were related to the total amount of water obtained from the table as well as to the salinity level of the capillary zone. Moderate salinity (ECe of 10 to 14 mmhos/cm) of the capillary zone reduced monthly and seasonal water use from the water tables as compared with low salinity (ECe of 2 to 3 mmhos/cm) conditions. The high moisture treatment delayed significant use of water from 183- and 274-cm water tables until late in the season, when irrigations were discontinued and the upper soil profile dried.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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