气候变化对青海天然牧草影响研究

The Impacts of Climate Change on the Natural Pasture Grass in Qinghai Province

根据青海省4个牧业气象代表站点1988-2005年天然牧草数据和同期气候资料,分析了青海天然牧草生长发育与气象条件的关系,探讨了气候变化对青海省牧草发育期、高度及产量形成的影响。研究表明:青南东部地区影响牧草返青出现的主要因素是热量条件,而青南西部和环湖地区牧草返青期的早晚主要受制于水分条件;两地区牧草黄枯期出现的迟早与日平均气温稳定通过5℃的终日相接近;在干旱、半干旱地区,天然牧草产量形成的主要因素取决于水分条件,年降水越多,牧草产量越高;青南东部的半湿润地区,温度对产量的影响大于降水对产量的影响。在全球气候变暖的背景下,青海省半湿润牧业区,随气温升高,牧草产量有所增加,草场载畜量有所上升;但在干旱、半干旱牧业区,气候变暖加剧草地水分的散失,牧草的生长发育受阻,产草量下降,同时,优良牧草在草场中的比例下降,杂类草的数量和比例上升,草场朝不良方向演替,呈现退化趋势。

The impacts of climate change on the growth, height and output of the natural pasture grass is discussed, and an analysis has been made in it on the changes of the pasture grass in terms of its height and output in relation to the meteorological conditions, based on both natural grass data from 5 typical livestock-oriented meteorological stations in the Qinghai Province and the climate data from 1971 to 2002. It is concluded that, on the one hand, the climate warming has a greater positive effects on the growth of the pasture grass than its negative impacts, thus giving rise to a higher output and greater grazing capacity in the moist pasturelands across the province. On the other hand, climate warming tend to accelerate evaporation in the arid and semi-arid pasturelands, which in return hinders the growth of the grass, hence decreasing its output. Meanwhile, the proportion of high-quality grass declines while the inferior weeds seemingly gain ground. Furthermore, the total coverage of the natural pasturage is shrinking and areas dominated by desert plants are expanding, consequently the productivity of the natural pasturelands declines significantly with the pasturelands evolving toward negative degradation. The findings of this paper are intended to provide a scientific basis for making a long-term plan of livestock production in the Qinghai Province and in the country as a whole, as well as for the policy-making in implementing the China＇s Grand West Development Strategy.