AGU hydrology days 2008

2008 annual AGU hydrology days was held at Colorado State University on March 26 - March 28, 2008.Includes bibliographical references.As competition builds for water resources in the Western U.S., limited irrigation strategies for crop production are emerging to conserve agricultural water for other uses or as a way to continue to produce crops under reduced water allocations. Alfalfa is a crop with potential for water savings in a limited irrigation system. The objective of this study was to evaluate potential water saving strategies for alfalfa on the Front Range of Colorado. A field study evaluated four irrigation strategies: Full Irrigation (FI), Stop Irrigation After 2nd Cutting (S2), Spring and Fall Irrigation (SF), and Stop Irrigation After 1st Cutting (S1). Changes in yield, consumptive water use (ET), water-use efficiency (WUE), stand density, and forage quality were measured. Results of the study showed that yield decreased with ET in a fashion similar to previous research. Over the two year period, average yields were reduced by 3.1, 3.5 and 6.5 Mg ha-1 compared to the FI treatment for the S2, SF, and S1 treatments, respectively. Average ET was reduced by 28.2, 27.2, 48.2 cm compared to the FI treatment for the S2, SF, and S1 treatments, respectively. WUE increased as irrigation decreased with an average WUE of 0.251, 0.327, 0.311, and 0.351 Mg ha⁻¹ cm⁻¹ for the FI, S2, SF, and S1 treatments, respectively. Also, the number of crowns m⁻² was higher in the S2 and S1 treatments compared to the FI and SF treatments. Finally, forage quality increased as ET decreased, which may help economically offset the reduced yield. The limited irrigation of alfalfa is an approach to conserve agricultural water to meet changing water demand while still keeping an irrigated agricultural system in production