Effect of Cutting Interval and Stage of Maturity on the Digestibility and Yield of Alfalfa2

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Abstract
Chemical composition, digestibility by sheep, and yield of digestible protein and total digestible nutrients per acre were obtained by a series of studies on irrigated alfalfa. In the first study, alfalfa was cut at 21-, 28-, 35- and 42-day intervals for 24 and 25 weeks after the removal of the first cutting. The largest amount of digestible protein was produced by the four-week cutting interval and the most total digestible nutrients by the five-week cutting interval. Plant vigor, as measured by crown and root weights and production and weediness of the first crop the following year, was reduced by the three- and four-week cutting intervals. In the second study, second cutting alfalfa from a different field was harvested by stage of maturity at pre-bud, 1% bud, 62% bud, 11% bloom, 46% bloom and 96% bloom. Digestibility data were obtained for each stage of maturity. To study the yield of alfalfa cut by stage of maturity, a trial was conducted for 4 years in which alfalfa was cut at the pre-bud, bud, 1/10 bloom and ½ bloom stage for 3 years and then all plots cut at the same stage in the fourth year to measure the after effects of the three previous year's treatment. During the 3 years of differential treatment, the greatest dry matter yield was produced by the alfalfa cut at the bloom stages. The greatest protein yield was by that cut at the 1/10 bloom stage. In the fourth season when all alfalfa was cut at the same stage, there was no significant difference in yield despite the difference in treatment during the previous three seasons. When the average annual yield during the three seasons of cutting by stage of maturity is multiplied by the digestibility results from the digestion trial on alfalfa cut by stage of maturity, the largest yield of total digestible nutrients came from the alfalfa cut at the 1/10 bloom stage and the largest yield of digestible protein from the alfalfa cut at the bud stage. Copyright © . .