Irrigation Amount and Frequency Effects on Alfalfa Forage Quality.

With the irrigation management used in this study in southwest Kansas, USA, irrigation affected alfalfa forage quality parameters such as crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), and relative feed value (RFV). In general, applying the highest amount of irrigation (i.e., 610 mm during growing season) appears to have lower forage quality in alfalfa than other irrigation treatments. No forage quality difference in alfalfa was found in timing under the same amount of irrigation (i.e., applying irrigation after green-up and between all cuttings vs. none between cuttings 2 and 3). However, there was a slight tendency for lower forage quality at the fourth cutting when irrigation was withheld between cuttings 2 and 3, and higher amounts of water applied prior to the fourth cutting. This tendency was consistent with the forage quality differences across irrigation amount. It appears that total irrigation amounts of 200 mm or less during the growing season maximized forage quality of alfalfa in southwest Kansas.