黑河中游荒漠植物生长与降水、土壤水和地下水的关系

[目的]分析荒漠化防治中植物生长与降水、土壤水和地下水的关系,为荒漠区植被修复与保护提供科学依据。[方法]在黑河中游荒漠区建立荒漠化综合防治试验站进行长期定位监测,取得降水、土壤水、地下水、植物盖度、生物量等数据,采用特征参数算法、相关分析法和逐步多元回归方法,对植物生长和水分的年内、年际变化特征及相关回归模型进行分析。[结果](1)2006—2014年,土壤质量含水率、生物量、盖度变化接近且最大,降水量次之,地下水埋深最小;生物量、盖度呈波动性增大趋势较明显,降水、土壤水、地下水位变化呈波动性略有降低趋势,但不明显。(2)在植物生长季的3—11月期间,土壤各层含水率变化步调基本一致,植物平均生物量和盖度变化步调基本一致,降水量和地下水埋深变化步调基本一致。(3)建立了盖度与0—20cm土壤质量含水率、生物量与0—20cm土壤质量含水率回归方程,且均通过了R拟合检验,F方差检验,t回归系数检验,通过模型预测盖度、生物量的变差分别为99.0%和91.4%,预测盖度和生物量变化的准确率分别可达86.5%,78.9%。[结论]黑河中游荒漠植被的生长与环境水分变化关系十分密切,可通过水资源管理修复植被,也可根据植被生长状况评估水资源管理工作。

Relationship Between Desert Plant Growth and Precipitation, Soil Water and Groundwater in Middle Reaches of Heihe River Basin

[Objective] Analyzing the relationships between plant growth and precipitation, soil water and groundwater in order to provide the scientific basis for vegetation restoration and protection in desertification control.[Methods] We collected precipitation, soil water, groundwater, vegetation biomass and coverage data baseed on long-term locating monitoring in the middle reaches of Hehe river basin. The characteristic parameter algorithm, correlation and stepwise multiple regression analysis was used to investigate the response characteristics of natural desert plant growth and inter-annual and annual variation of soil water content.[Results] (1) The change of soil moisture content, biomass and coverage was the greatest, the change of precipitation was secondary, while the change of groundwater depth was minimum. The biomass and coverage showed an obvious increasing fluctuation trend, while the precipitation, soil moisture content and groundwater depth showed a slight decreasing trend. (2) In the growing season from March to November, the annual variation of soil moisture content in each layer were basically the same, and so were the variations of average vegetation coverage and biomass. (3) The regression equations were established to model the relationship between soil moisture content at 0-20 cm depth and vegetation cover and biomass. R fitting test, F test, t test was used. The partial regression coefficient for vegetation coverage and biomass was 99.0% and 91.4%, respectively. The accuracy of predicted changes in vegetation coverage and biomass was 86.5% and 78.9%, respectively.[Conclusion] There is a close relationship between the growth of desert vegetation and changes of environment water in middle reaches of Heihe river. Consequently, desert vegetation can be recovered by water resources management, and water resources management can be assessed according to the vegetation growing condition.