天山南麓山前平原柽柳灌丛地上生物量

Aboveground biomass of Tamarix on piedmont plain of Tianshan Mountains south slope.

基于天山南麓山前平原柽柳灌丛样地调查和实验,研究了柽柳的地上生物量及其分布规律.结果表明,不同地貌带柽柳的地上生物量差异较大.在溢出带,柽柳的地上生物量最大,达1428·53kg·hm-2,其次是三角洲带和洪水剥蚀带,柽柳的平均地上生物量分别为745·97和544·37kg·hm-2,而两河交汇区柽柳的地上生物量最小,仅为111·18kg·hm-2.造成这种差异的主要原因是不同地貌带柽柳的密度不同.在轮台天山南麓山前平原4个地貌样带中,柽柳的地上生物量与表层土壤盐分含量均随地下水埋深的增加而下降,呈良好的相关性,但土壤盐分并不是影响柽柳地上生物量的主要因素,影响柽柳生长的主要生态因子是地下水埋深.

Based on the geo-morphological and hydro-geological characteristics, the piedmont plain of Tianshan Mountains south slope was classified into 4 geo-morphological belts, i. e. , flood erosion belt, groundwater spill belt, delta belt, and the joining belt of piedmont plain and Tarim floodplain. A field investigation on the Tamarix shrub in this region showed that there was a significant difference in its aboveground biomass among the four belts, ranged from 1 428.53 kg · hm^-2 at groundwater spill belt to 111.18 kg · hm^-2 at the joining belt of piedmont plain and Tarim floodplain. The main reason for such a big difference might be the different density of Tamarix shrub on different belts. Both the Tamarix aboveground biomass and the topsoil＇ s salinity were decreased with increasing groundwater level. Groundwater level was the main factor limiting Tamarix growth, while soil salinity was not.