皇甫川流域几种主要植物水分生态特征

A study on the water ecology of some dominant plants in Huangfuchuan Basin

通过在丰水年 (1998年 )和欠水年 (1999年 )连续两个生长季对皇甫川流域几种主要植物 :沙棘 (H ippophae rhamnoides)、沙柳 (Salix psammophyla)、中间锦鸡儿 (Caragana intermedia)、杨树 (Populus simonii)、油松 (Pinus tabulaeformis)、沙打旺(Astragalus adsurgens cv.)、羊柴 (H edysarum leave)、玉米 (Zea mays)和百里香 (Thymus serpyllum)等植物生物学特性、蒸腾特征及土壤水分含量的测定及分析 ,得出以下结果 :几种主要植物蒸腾强度平均值由大到小的排列顺序是 :杨树 >沙柳 >沙打旺>羊柴 >中间锦鸡儿 >玉米 >百里香 >沙棘 >油松 ;在 1998年和 1999年 ,皇甫川流域主要植物蒸腾强度的季节动态基本相同 ,油松、沙棘、中间锦鸡儿以及百里香等植物年平均蒸腾强度较低。无论丰水年还是欠水年 ,生长季内皇甫川流域主要植物蒸腾系数均较高 ,表明了植物的生长是以消耗大量水分为代价 ,水分是其生长的主要限制因子 ;百里香蒸腾系数最小 ,其次是中间锦鸡儿 ,这反映了百里香和中间锦鸡儿能更有效地利用水分进行干物质积累 ;皇甫川流域乔木适宜种为油松、灌木种为中间锦鸡儿和沙棘、半灌木植物为百里香。主要植物群落地段的蒸散量与降雨量的比值在 1左右。但从土壤水分变化角度看 ,皇甫川流域主要植物群?

The paper analyzed the vegetation water status in Huangfuchuan Basin on different spatial, temporal scales and organizational levels. (1) The daily courses of transpiration rate of the dominant plants in Huangfuchuan Basin have two patterns:none-noon depression and noon depression. The arrangement in mean values of transpiration rate of the dominant plants is Populus simonii>Salix psammophyla>Astragalus adsurgens cv.>Hedysarum leave>Caragana intermedia>Zea mays>Thymus serpyllum>Hippophae rhamnoides>Pinus tabulaeformis. In 1998(an abundant water year) and 1999(a deficit water year), the transpiration rate of the dominant plants has similarly seasonal changes. (2) Either in the abundant water year (1998) or in the deficit water year (1999), the increase of aboveground biomass and the increase of water consumption of the dominant plants show no difference. And in growing season, all of dominant plant transpiration coefficients are very high; thus it is concluded that the plant growth is at the expense of vast amount of water content which is one of the main limiting factors. The transpiration coefficient of T. serpyllum is the smallest, followed by C. intermedia, which indicates that T. serpyllum and C. intermedia use water and accumulate dry matter more efficiently than others and so they fit in Huangfuchuan Basin. In Huangfuchuan Basin, the suitable species of tree, shrub and herb are P. tabulaeformis, C. intermedia and H. rhamnoides, and T. serpyllum, respectively. (3) The ratio of evapotranspiration and precipitation is about 1 in the plant community. But in terms of varying of soil water content, soil water is in the deficit state in the plant community area in Huangfuchuan Basin. So these dominant-plants struggle to grow under the condition of water stress. Under the condition of water balance in Huangfuchuan Basin, suitable coverage of P. Tabulaeformis is 36%～47%, P. s simonii is 37%～48%, C. intermedia is 43%～55% and S. psammophyla is 46%～59%. However, the suitable coverages of H. rhamnoides, A. adsurgens cv. H. leave and T. serpyllum are 61%～79%, 50%～65%, 54%～69% and 68%～87% respectively.