气候变化对环县退耕还林还草的影响及应对措施

退耕还林还草是环县半干旱区调整产业结构的主方向，也是生态环境建设的一项重要工作，研究气候变化对其影响有重要现实意义。本文采用气候趋势系数、气候倾向率、累积距平、YAMAMOTO检验法分析了环县1957～2012a年连续55a气象资料。结果表明：55a来，环县年平均气温增幅为0.43℃/10a，显著高于全国年平均气温增幅0.22℃/10a的水平，而且年平均气温在1987年存在偏冷向偏暖的突变现象，突变前后平均气温上升了1.2℃；55a来，年降水量呈减少趋势变化，减幅为15.4 mm/10a，年降水日数也呈减少趋势变化；气候暖干化，造成本区热量增加，光照丰富，也致使干旱、山洪、冰雹、霜冻等自然灾害加重，对退耕还林还草工作造成一定的影响。为了更好的应对气候变化带来的影响，建议该地应进行种植结构调整，由以粮为主转为以牧草、林木为主的经营模式，改善生态环境。退耕还林还草应走防护林和经济林相结合，乔、灌、草相结合的路子；应选抗旱性和抗寒性较强本土树种草种；草类、灌木可利用雨季进行直播造林，提高在荒山、荒坡、荒沟等地的造林面积，乔木宜选用植苗造林方式，在春、秋两季选取多株造林、遮阴造林等抗旱造林方法，喷洒增温保墒剂，提高成活率；大力发展“121”雨水集流等水利工程，整地蓄水保墒，以水养林养草。

The impact of climate change on Huan County returning farmland to forest and grass And the Countermeasures

As the half arid area, returning farmland to forest and grassland, which is not only the main direction of adjusting the industrial structure, but also is an important work for the building of the ecological environment in Huanxian county. So, climate- studying has important practical significance to Returning farmland effect. This paper adopts research method of the climate tendency coefficient and climatic trend rate, cumulative anomaly, YAMAMOTO test, by analyzing the consecutive meteorological data from 1957 to 2012. The results showed that: over the past 55 years, the annual average temperature increase 0.43 ℃ / 10a, this is much higher than the national average temperature growth which is 0.22 ℃ / 10a .The annual average temperature is even a mutation phenomenon from cold to warm in 1987, before and after the mutation ,temperature increased by 1.2 ℃; over the 55 years, it showed a trend of decrease of annual precipitation change, the damping is 15.4 mm / 10 a, annual precipitation days also showed a trend of decrease. Climate is warm and dry, it increases in the heat and light and meanwhile, it also causes droughts, floods, hail, frost and other natural disasters, it has a certain influence on returning farmland to forest and grass work. In order to cope with the effects of climate changes, the author suggested that planting structure should be adjusted in this area from food crops to grass and trees, so that improve the ecological environment. Returning farmland to forest and grassland should take shelter forest and economic forest with arbor, irrigation, grass; The native species of tree and grass with drought resistance and cold resistance should be chosen; Grass and shrubs can be directly seed with the rainy season in the barren hills, wasteland and so on. As arbor can plant by stock in the spring and autumn season ,select multiple strains of afforestation, shade reforestation and other methods of drought resistance afforestation and raise survival rate with temperature raising agent; vigorously develop the " 121" rainwater harvesting, water conservancy, so that keep the trees and grass from the water.