黄河源区“黑土滩”混播草地牧草植物量及营养动态初探

Dynamics of biomass and nutrition of mixed-sown pasture at'black soil beach' in Yellow River headwater area

黄河源区的极度退化草地——"黑土滩",改建成人工草地是一种恢复退化草地的重要途径,同时可以收获大量饲草。对"黑土滩"混播草地(垂穗披碱草Elymus nutans+中华羊茅Festuca sinensis+碱茅Puc-cinellia distans+冷地早熟禾Poa crymophila+赖草Leymus secalinus)的生产力和营养价值动态进行了研究,分析了放牧对草地生产力的影响。结果表明,从生长高峰期8月到翌年4月,草地生产力自然损失量为144.3 g/m2,损失率为34.9%。这期间放牧利用导致牧草被采食187.2 g/m2。传统的放牧利用,使该类人工草地利用率为45.2%。冷季草地牧草营养价值全都下降,粗蛋白含量降低了69.86%,粗脂肪降低了65.85%。该"黑土滩"混播草地在夏季属碳氮营养型(CN),冬季属碳营养型(C)。因此建议,"黑土滩"混播草地在夏季生长高峰期适度进行人工割草,冬季进行适度放牧利用。

It is an important way to transfer degraded natural grassland into artificial one,for example the extremely degraded grassland at black soil beach in the Yellow River headwater area.The dynamic of productivity and nutritional value in mixed-sown Elymus nutans,Festuca sinensis,Puccinellia distans,Poa crymophilia and Leymus secalinu were studied,and effects of grazing on the forage production were analyzed.The results showed that 34.9% of productivity,144.3 g/m^2,was lost naturally from August to the next year April,in which 187.2 g/m^2 was fed by livestock.In fact,utilization rate of the grassland was 45.2% in traditional grazing way.Nutrition value of forage decreased generally in whole cold season,i.e,69.86% of crude protein and 65.85% of crude fat decreased.So,the grassland belongs to the CN nutritive type in summer and C type in winter.In the case,the grassland would be used by mowing during the growing season in summer and grazing in a moderate intensity in winter.