紫花苜蓿建植期四种刈割频次下的产量、品质及再生性研究

Yield,hay quality and regrowth of establishing Medicago sativa under four harvest schedules

收获制度是苜蓿生产管理的关键环节。为明确不同刈割制度下建植期苜蓿生长规律，本研究利用盆栽试验，通过人工控制苜蓿生长温度、水肥条件，完善测定指标体系，进行苜蓿刈割频次的研究，分析连续生产情况下不同收获制度对不同类型苜蓿建植期产量、品质、再生能力及持续生产力的影响。研究结果表明，高频刈割会显著降低苜蓿的生产力和持久性。连续高频刈割后延长收获间隔可以恢复苜蓿茎密度和再生能力，但不能恢复到适宜刈割频次的水平。不同品种间生育期、耐刈性与再生性、产量分布以及营养价值存在显著差异，并导致相同收获频次下饲草产量、饲草品质以及持续生产力的差异。在建植期及低龄草地，维克多（Ｖｅｃｔｏｒ）和得龙（Ｄｕｒａｎｇｏ）２个国外引进品种适于间隔为２５～３５ｄ高频度刈割；我国东北地区育成低休眠级苜蓿品种公农１号适于间隔为３５～４５ｄ的刈割频度。

Harvest schedule is the key point of Medicago sativa production management. This study measured the response of M. sativa yield, hay quality, regrowth, and persistence to four harvest schedules of three cultivars potted in an appropriate growth environment. A high cutting frequency （20 days） reduced M. sativa pro- ductivity and persistence but stem densities and regrowth ability recovered after a prolonged cutting interval, although they did not reach the same level as those under a proper cutting schedule. There were considerable differences in M. sativa growth stage, cut resistance, regrowth, yield distribution, and feed value of the three cultivars, which resulted in differences of yield, quality and persistence under the same cut frequency. Two foreign M. sativa cultivars, ＇Vector＇ and ＇Durango＇, which have high fall dormancy grades, should be cut at intervals of 25--35 days for establishing stands, while M. sativa ‘Gongnong No. 1＇ （which was bred in the North-East of China） was best suited to a cut schedule of 35--45 days.