COMPARISON OF WATER USE AND CROP WATER USE EFFICIENCY OF MAIZE, SORGHUM, AND SOYBEAN IN NEBRASKA
Agronomy & Pest Management
Jennifer Rees
Extension Educator
Nebraska Extension
York
Abstract
Water is a crucial resource for agricultural production. As the availability of freshwater resources is decreasing in parts of Nebraska and the world, newer hybrids and varieties have been developed for handling stresses like water-limited conditions. While the trend of losing rainfed sorghum acres to maize acres continues, data lack in terms of water use efficiency between maize, sorghum, and soybean. Field studies were conducted in two rainfed fields in South Central Nebraska to determine crop water use efficiency of these three crops over several years. Watermark granular matrix sensors measured soil water status every 1 ft up to 4 ft for the entire growing season and a general soil water balance equation was used to quantify seasonal crop water use and water use efficiency. In 2009, the evapotranspiration (ET) of maize, soybean, and sorghum was 14.5, 14.0, and 13.7 inches and in 2010, 23.3, 22.0, and 21.3 inches, respectively. By accounting the final grain yields, the overall crop water use efficiency of maize was 6.7 bu/inch in 2009 and 4.3 bu/inch in 2010; for soybean it was 2.4 bu/inch in 2009 and 2.0 bu/inch in 2010; and for sorghum it was 5.6 bu/inch in 2009 and 5.5 bu/inch in 2010. Rainfed maize was most efficient in the drier year of 2009. However, sorghum was the most consistent water use-efficient crop between the two years of varying environmental conditions with rainfall received from crop emergence to physiological maturity of 10.1 inches in 2009 and 16.4 inches in 2010.
Authors: Rees, J.
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Rees, J. Extension Educator, Unl-Extension, Nebraska, 68933