Effect of Irrigation and Row Spacing on Soybean Water Use1
- D. C. Reicosky,
- H. R. Rowse,
- W. K. Mason and
- H. M. Taylor2
A better understanding of the soil-water plant spacing interactions as they affect water-use efficiency and crop yields requires the development of satisfactory methods for determining water use.
The objective of this work was to determine the effect of 25− and 100-cm row spacings on crop water use under irrigated and nonirrigated soybeans [Glycine max (L.) Merr.] on a fine, silty, mixed (calcareous) mesic family of Typic Udorthents soil.
Water use was evaluated by measuring evapotranspiration and soil water extraction. Evapotranspiration (ET) was measured using a portable chamber that utilized psychrometric techniques to determine changes in the water vapor density when the chamber enclosed the crop canopy and the soil surface. Soil water extraction (SYVE) was calculated from changes in gravimetric water content during periods without rainfall and then corrected for the flow of water at the bottom of the root zone.
Irrigation resulted in the expected higher water use rates on both row spacings. The row spacing effect early in the season was related to the leaf area index (LAI). Early in the season, the 25-cm irrigated treatment had a slightly higher ET than the 100-cm irrigated treatment. Later in the season, row spacing effects were not evident. The two methods employed for evaluating crop water use showed only fair agreement.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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