The effects of three cutting heights on residual leaf area index (LAI), leaf area development, leaf efficiency (LE), mean crop growth rate (CGR), dry‐matter (DM) yield, and total nonstructural carbohydrates (TNC) were studied in 1‐year‐old stands of birdsfoot trefoil (Lotus corniculatus L., cultivar ‘Empire’) in 1965 and 1966. Data were taken during an early and a late‐summer regrowth period, each of 7 weeks in length. The 3.8‐, 7.6‐, and 11.4‐cm cutting heights resulted in minimum effective LAI values of 0.05, 0.37, and 1.10, respectively, for the early summer regrowth. After 7 weeks the net DM yields of the 7.6‐ and the 11.4‐cm treatments were similar and significantly greater than those of the 3.8‐cm treatment. The 3.8‐cm treatment removed leaf area and axillary bud sites, thereby retarding initial regrowth and leaf development. Root and crown diseases were increased in late summer by the 3.8‐cm treatment. The LE increased as stubble height decreased, and decreased over time in all treatments. The CGR values increased with increased cutting height during the first 3 weeks of early summer regrowth. Thereafter, and during the late‐summer regrowth, there was considerable week‐to‐week variation in the CGR. Except for TNC and LE, the late‐summer responses were generally similar to those for early summer, but the values were less. TNC levels increased as residual LAI increased during both regrowth periods. In early summer the differences were small and had nearly disappeared by the 7th week. In late summer the differences were greater than those for early summer and persisted throughout the 7 weeks.
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Greub et al. (1971) studied this question.