ALFALFA CUTTING FREQUENCY AND DATE OF FALL CUTTING

The traditional viewpoint that fall cutting is often detrimental to alfalfa (Medicago sativa L.) persistence has been challenged. Our primary objective was to determine the effect of a final cut on 1 September, 15 September, or 15 October within two-, three-, and four-cut schedules on forage yield and stand persistence of three alfalfa cultivars. Two adjacent field experiments were conducted on a Tallula silt loam (coarse-silty, mixed mesic Typic Hapludoll) and a Waukegan silt loam (fine-silty over sandy-skeletal, mixed, mesic Typic Hapludoll). A delayed second, third, or fourth cut on 15 September during the traditional 'critical fall period' (1 September to 15 October) or on the average date of the first killing frost (15 October) had no effect on stand persistence or yield for 3 yr following the seeding year. A second or third cut in the third fall on 15 September or 15 October reduced yields (68% average reduction) and stands (57% average reduction) in the spring following a severe winter compared with a final cut on 1 September; however, yields and stands were similar following a fourth cut on 1 September, 15 September, or 15 October. Delaying the second, third, or fourth cut (and consequently increasing the interval between the final two cuts) until 15 September or 15 October before a mild winter increased spring stands 34, 34, and 85% for the two-, three-, and four-cut schedules, respectively, compared with a final cut on 1 September. Yields and stands of cultivars which differed in fall dormancy did not differ consistently in response to cutting treatments during 3 yr of cutting. Following a severe winter, cultivars with greater fall dormancy had greater persistence and yield than a moderately fall dormant alfalfa cultivar. The outcome of fall cutting is influenced by the interaction of stand age, winter weather, cultivar, and cutting frequency. We conclude that there is minimum risk to stand persistence for several years after seeding from delayed second, third, or fourth cuttings on 15 September or 15 October compared with a cutting on 1 September, but decisions by producers to cut in the fall should be made only following an appraisal of their overall management program.