干旱区新垦绿洲防护林体系的防护效益分析——以克拉玛依农业综合开发区为例

Protective Effect of Shelterbelts in New-cultivated Oasis of Arid Area:—Case Study in Karamay Agricultural Development Region

克拉玛依新垦绿洲内部光、热、水、土资源丰富,但生态环境极为恶劣,存在干旱、风沙和盐碱等生态问题,严重阻碍着农业生产的持续发展。通过建立有效的防护林体系来改善种植区生态环境,以保证农业生产的顺利进行。结合野外实地调查资料,对研究区内绿洲防护林林带特征和现有防护林的防风效能、气温、相对湿度等小气候等指标进行了测定比较,结果表明:背风面随着距林带距离的增加,其防风效能呈现递减的趋势,随着防护林的生长,其防风效果也随之提高;在背风面垂直方向上自上而下防风效能呈现递增的趋势,林带有叶期的防风效果明显优于无叶期。林带较之荒漠区具有一定程度的降温增湿作用,同时林带对于防护林内土壤温度和土壤水分的调节作用也很显著。

There are plenty of solar, heat, water and soil resources in Karamay new-cultivated oasis. However, the eco-environment is extremely badly. The problem is mainly showed as serious drought, severe sand blowing and high salt-alkalinity, which seriously hampered the sustainable development of agriculture. By setting up the valid shelterbelt systems to improve the planting condition of plant area so as to guarantee the agricultural production carries on smoothly. According to the data investigated in field and based on the existing the protection forest system, we analyzed the varieties of the windproof efficiency in horizontal and vertical directions both windward and leeward, and analyzed the windproof efficiency of different years. The results indicated that the windproof benefits of shelterbelt leeward more remarkable than windward, the windproof benefits more remarkable in leafed periods than leafless periods. We also discovered with the distance from the shelterbelt increased the windproof efficiency weakened gradually, the wind speed reconverted the field level at 95 m away from the shelterbelt. The analysis of the thermodynamic and hydrologic benefits on shelterbelt showed： the shelterbelts had function on adjusting the air temperature. In sunny daytime, the air temperature and ground temperature near the shelterbelt deeper than reference point, the relative humidity near the shelterbelt higher than the field. The shelterbelts also had distinctively effects on adjusting temperature and soil moisture of the under-shelterbelts.