Water Use Efficiency of Double-Cropped Wheat and Soybean
Many studies have demonstrated that double cropping wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.] allows for greater utilization of natural resources by intensifying cropping practices. A 3-yr study was conducted on a Captina silt loam (finesilty, mixed, mesic, typic Fragiudult) to determine the water use efficiency (WUE) of winter wheat and to determine the effects of selected management practices on WUE of double-cropped soybeans. The 3-yr mean grain yield of wheat was 3170 kg ha−1 and the mean cumulative evapotranspiration (ET) after 1 April was 32.8 cm. This translated into an average WUE of 96.6 kg ha−1 cm−1 of water. Shortly after wheat harvest, the effect of irrigation, planting date, and stubble management on soybean water use and yield were determined. Irrigation significantly increased soybean grain yield in 2 of 3 yr. The 3-yr yield mean was 2406 and 1704 kg ha−1 for irrigated and non-irrigated soybean, respectively. When irrigation significantly increased grain yield, irrigated soybean had a highet WUE than non-irrigated soybean. Planting date had a significant effect on soybean yield and WUE in only 1 of 3 yr and only when planting date was confounded with row-spacing. Burning of wheat stubble produced significantly higher soybean yields only when herbicide interference by standing wheat stubble was observed. Stubble management had no effect on soybean ET or WUE. The 3-yr mean WUE for the double cropped wheat and soybean system was 79.3 kg ha−1 cm−1 of water.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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