中国北方草地生态系统管理问题与对策

草地具有生态意义、资源意义和生物进化场所及文化意义。北方草地表观表现为"三化",草丛对地面的覆盖力和产量是一般采用的判定指标,缺乏生态系统结构要素和功能受损的评价标准,农田化也是草原被破坏或消失的重要因素。放牧是家畜生产途径,也是草地管理手段。放牧干扰状况包括放牧开始时间、放牧强度、放牧频次和持续时间,放牧要素包括啃食、践踏、口液和失衡营养。载畜量或草畜平衡的方程体系中缺少牲畜生长状态参数,草地管理的一项重要内容是管理草地放养的家畜,发展豆科混合半人工草地,以维护土壤肥力,增加牲畜日粮的粗蛋白含量应该是中国北方草地管理当前与今后一段时期内的重要研究内容。草地管理,即草地生态系统管理是由明确目标驱动,由政策和协议及实践而执行,以对生态作用与过程的理解所需的研究和监测为基础,而保持生态系统组分、结构和功能正常运行的管理。

The Problems and Strategies for Grassland Management in Northern China

The grassland in northern China has ecological,resourceful and evolutionary significance.It has problems of degradation and desertification in narrow sense,and saline-alkalization apparently,reclamation(process and result of reclaiming grassland as farmland)also is critical problem.Covering ability to soil is general standard for the three problems,but it lack of damaged or healthy evaluation standard of the ecosystem structure and function.Grazing is an approach for animal production and also is a way to managing the grassland.Grazing as a disturbance factor for grassland ecosystem include some meaningful important regimes:occurrence time of grazing,grazing intensity,grazing frequency,grazing severity and grazing duration and so on.Different regime has different contribution to the problem.At the same time,grazing should be considered as a complex of three animal factors:defoliation,trampling and unbalance of the nutrition in soil at least.Up-coring(destroyed the growth point)in early spring and up-rooting in raining season are seriously event for the problem appearing.And it should be added a parameter to the equation of stocking rate and forage supplying system.The important task for grassland management is to manage the animal grazing/feeding on grassland.Basing on eat-full for the animal on grassland,to develop legume pasture or mixture pasture of grass-legume to increase crude protein in animal intake could get twice the result with half the effort for animal production and grassland protecting.