Abstract:

A cutting experiment was conducted in order to explore the suitable cutting time and intensity (i.e., stubble height) for harvesting forage of high yield and good quality and meanwhile maintaining the sustainable use of grassland as soon as possible on the alpine meadow improved by reseeding E. sibiricus in Northwest Sichuan. Yields and nutritional quality of harvesting E. sibiricus, the proportion of number of sexual reproductive individuals in total number of regrowth individuals (PRT), as well as reproductive allocation of regrowth individuals in E. sibiricus were determined under different cutting time (heading stage, flowering stage, milk stage and ripening stage; P1, P2, P3, P4, respectively) and intensities (light, moderate and heavy; H1, H2, and H3 respectively). The results showed that heavy cutting could obtain the highest yield of community and best nutritional quality of E. sibiricus at the flowering stage (P<0.05). Moreover, PRT was not significantly different between heavy cutting and moderate cutting, and cutting at the flowering stage did not reduce reproductive allocation in E. sibiricus significantly. In general, the optimized cutting combination is heavy cutting at flowering stage and once a year for the alpine meadow improved by reseeding E. sibiricus in the Northwest Sichuan.

Key words: E. sibiricus, Cutting time, Cutting intensity, Yield, Nutritional quality, Reproductive allocation

摘要：

本试验在川西北高寒牧区老芒麦（Elymus sibiricus）改良草地，研究不同刈割强度（轻度H1、中度H2和重度H3）和刈割时期（抽穗期P1、盛花期P2、乳熟期P3和蜡熟期P4）下，老芒麦产量、营养品质及其再生植株完成生殖物候比例和生殖分配的变化，以探索既可收获高产优质的牧草，又有利于延长改良草地利用年限的适宜刈割处理。结果表明：盛花期重度刈割（P2H3）下，老芒麦产量和其他植物种总产量均最高（P<0.05），且盛花期老芒麦营养品质最好（P<0.05）；重度和中度刈割下，老芒麦再生植株完成生殖物候的比例无显著差异，且盛花期刈割对老芒麦再生植株的生殖分配无显著不利影响。在川西北高寒补播老芒麦改良的天然草地中，盛花期重度（P2H3）刈割1次是较优的刈割制度。

关键词: 老芒麦, 刈割时期, 刈割强度, 产量, 品质, 生殖分配