河西走廊荒漠区植物生长与水分变化关系分析

The relation between plant growth and soil water in desert district of Hexi Corridor

为了分析荒漠化防治中荒漠植物生长与降水、土壤水和地下水的关系,在河西走廊荒漠区建立了荒漠化综合防治试验站进行长期定位监测,取得了降水、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了分析.结果表明:2006-2014年际变化上,土壤水变化最剧烈,降水、生物量、盖度变化剧烈程度极接近,且也较大,地下水位变化最缓和.盖度呈波动性增大趋势较明显,生物量略有增加趋势,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.在植物生长季的3-11月份期间,土壤各层含水率变化步调基本一致,生物量和盖度变化步调基本一致,降水量、地下水埋深变化步调基本一致,年内变化幅度从大到小依次为降水量>地下水埋深>生物量>平均盖度>土壤质量含水率.盖度、生物量模型均通过了R拟合检验、F方差检验、t回归系数检验,通过模型可预测变差的58.0%、98.7%,准确率可达52.0%、86.2%.研究成果可为荒漠化防治中的水资源管理以及退耕还林、天然林保护、黑河流域综合治理等工程对水资源影响评估等提供科技支撑和参考数据.

In order to explore the response of desert plant growth to soil water in desertification control, the Experimental Station of Desertification Control in Hongshawo had been set up in the desert district of Hexi Corri- dor in order to obtain long-term monitoring data about precipitation, soil moisture, groundwater depth, vegeta- tion biomass and coverage. The algorithm of characteristic parameters, correlation and multiple regression analy- ses had been applied to study the response characteristics of plant growth and annual and monthly water varia- tions. The study has found that： （ 1 ） the change in soil moisture content was very severe, the changes in precipi- tation, biomass and coverage were severe with same extent, but change in groundwater depth was minimal. The change in coverage showed an increasing tendency in the undulation, but changes in biomass slightly increased. The changes in precipitation, soil moisture content and groundwater depth decreased slightly; （2） in the growing season from March to November, the soil moisture content variation was basically in the same step and so did the changes in average vegetation coverage and biomass; （3） the regression equations about coverage and biomass have passed the R fitting test, F test, t test for partial regression coefficient. Through the model, it is possible to predict coverage of 58.0% and biomass of 98.7%, with accuracies of 52.0% and 86.2%, respectively. This study results will be useful for water resource management and for evaluating the effect of desertification control （ such as engineering of returning farmland to forest, natural forest protection and comprehensive reclamation） in the middle reaches of the Heihe River on water resources.