岷江上游干旱河谷白刺花生物量及其与土壤含水量关系研究

岷江上游干旱河谷区是我国长江上游的主要生态功能服务区,而该区域由于“受焚风效应”的影响以及频繁的滑坡、泥石流等地质灾害影响,使该区域也是我国生态环境十分脆弱区。本文以该区域内分布最广泛的灌木——白刺花为对象,研究其生物量、生物量分配格局以及生物量分配与土壤含水量的关系,为干旱河谷区灌丛植被的保护和恢复重建提供理论依据。研究结果表明：①白刺花的地上生物量分配中,阴坡叶片所占地上生物量比例变化范围在36．01％-41．54％,明显高于阳坡（14．35％～21．12％）;AK海拔梯度变化上看,白刺花在阳坡与阴坡的茎枝、叶和种子各部分生物量以及单丛生物量大小变化趋势均呈现“V”字型变化趋势。②白刺花单丛地下生物量则阴坡海拔1860m地最高,达到440．06g,阳坡海拔2280m最高,为436．39g;最低的地下生物量主要在阴坡海拔1730m和阳坡海拔1880m,仅为47．23g和44．61g,最高生物量分别是它们的9．9、9．8和9．8、9．2倍。同时,在阴坡和阳坡的不同海拔梯度上,均表现出粗根和中根生物量占地下部分总生物量50％以上,细根、小根生物量之和在30％以下。③白刺花地上各部分生物量与土壤含水量间相关关系显著,并随土壤含水量的增加而增加。其中白刺花单丛地上部分生物量和枝（干）生物量与土壤含水量的回归曲线方程模型Y=27．581x^1.1473和Y=18．648e^0.3454x。最优,其群分别达到0．9677、0．9464;叶生物量和种子生物量与土壤含水量的回归模型则分别以Y=7．3936x^0.3454x和Y=2．5705e^0.4144x最佳,砰分别为0．7172、0．7446。白刺花各部分根系生物量与土壤含水量的变化趋势总体上也相对一致,即随着含水量的增加而增加。但各径级根系生物量与土壤含水量的回归拟合效果相对地上生物量较差,其中粗根生物量?

A Study of the Relation of Sophora davidiana Biomass and Soil Moisture Content in the Arid Valley of the Upper Minjiang River

Dwing to the foehn, there are 161 km^2 of arid valleys （ 170 km^2） in the upper Minjiang River. The higer evaporatiom and transpiration ,lower precipitation, steep slopes and infertile soils result in an atrocious condition for vegetation in the arid valley. Researches were conducted on the biomass of native species Sophora davidiana and its relations with soil moisture content. It was found that in the above ground biomass in the north facing slope （nfs） the proportion of leaves accounted for 36. 01% - 41.54%, which was obviously higher than that in the south facing slope（sfs） ,which was 14. 35% - 21.12%. The single plant underground biomass was the highest with 440. 06 grams and 436. 39 grams separately at the elevation of 1860 metres of nfs and 2 280 metres of sfs, and it was the lowest with 47.23 grams and 44.61 grams separately at the elevation of 1730 metres of nfs and 1880 metres of sfs. In the underground biomass,the biomass of coarse root and moderate root accounted for more than 50%. The aboveground biomass showed a significant relatedness with the soil moisture content, there were best correlation equations, namely, Y = 27.581 x^1.1473 （ R^2 = 0. 9677） and, Y = 18. 648e^0.3454x （ R^2 = 0. 9464 ）, Y = 7. 3936x^0.957 （R^2 =0. 7172） and Y =2. 5705e^0.4144x （R^2 =0. 7446）, which were separately based on ground biomass , branchs biomass, leaves biomass, seeds biomass with the soil moisture content.