黄土丘陵区不同草本群落生物量与土壤水分的特征分析简

为阐明黄土丘陵区不同草本群落生物量与土壤水分的相关特征,通过野外调查与定点观测,对延河流域内不同演替阶段的5种草本植被（长芒草、铁杆蒿、茭蒿、白羊草、大针茅）群落地上生物量、土壤水分特征及其相关关系进行研究与分析.结果表明：在0～ 500 cm土层内,各演替阶段草本群落土壤含水量的垂直分布规律明显,均表现为浅层（0 ～ 50 cm）减少、中层（50 ～200 cm）增加、深层（200 ～ 500 cm）基本稳定的趋势;植物群落地上生物量均随着演替年限呈先增加后减小趋势,在白羊草群落阶段（退耕演替25 a左右）达到最大值;草本群落地上生物量与土壤含水量整体呈正相关关系,相关程度以0 ～ 200 cm土层较高;植被群落利用土壤水分土层深度随群落演替阶段逐渐加深,表现出对环境更强的适应性.

Aboveground biomass production and soil moisture characteristics of different herb communities in the Loess Hilly-gully Region

The objective of this study is to elucidate the biomass production and soil moisture characteristics of different herb communities at different succession stages in the Loess Hilly-gully Region on the Loess Plateau.After filed investigation and in situ observation,the aboveground biomass,soil moisture and their relationships of five different herbaceous communities （Stipa bungeana,Artemisia sacrorum,A.giraldii,Bothriochloa ischaemum,S.grandis） in Yanhe Watershed were analyzed.Results showed that：soil moisture contents of the five plant communities at different succession stages had obvious vertical distribution characteristics in 0-500 cm soil profile,which decreased in 0-50 cm layer,then increased in 50-200 cm layer,and maintained stable in 200-500 cm layer; aboveground biomass of plant communities showed an increase at early succession stages,reaching the peak at B.ischaemum stage （about 25 years after returning farmland）,and decreased thereafter; there existed positive correlations between aboveground biomass and soil moisture,especially for that in 0-200 cm soil layer; plant communities can make use of soil moisture in deeper layers over succession,showing a strong adaptation to environment.