黄土高塬沟壑区沟头植物群落细根分布特征

Fine Root Distribution Characteristics of Gully Heads Plant Communities in Gullied Region of Loess Plateau

为探明黄土高塬沟壑区沟头植物细根的分布特征,对植被恢复年限为3~35 a,优势植物种分别为猪毛蒿、铁杆蒿、白羊草,主要伴生植物分别为阿尔泰狗娃花、长芒草、达乌里胡枝子的17个具有典型性和代表性的沟头植物群落进行土壤取样,研究了细根平均直径、生物量、根长密度、比根长在0~70 cm土层的分布情况。结果表明:随着植被恢复年限的增加,植物细根平均直径逐渐减小,生物量、根长密度呈逐渐增大的趋势,比根长在恢复初期(3~8 a)增长缓慢、在恢复8~22 a期间显著增大、之后趋于稳定;随土层深度的增加,植物细根平均直径、生物量、根长密度、比根长逐渐减小,超过70%的细根分布在0~40 cm土层中。

In order to find out the vegetation fine root distribution characteristics of gully heads in thegullied loess plateau,17 plant communi ties were selected for soil sampling,and distribution characteristics of fine root mean diameter,fine root biomass,fine root length density and specific root length of 0-70 cm soil layer of these plant communities were studied.These plant communities of gully heads were typical and representative and the vegetation restoration period was 3-35 years.The dominant plant species of these plant communities were Artemisia scoparia,Artemisia sacrorum and Bothriochloa ischaemum,and the main associated plants were Heteropappus altaicus,Stipa bungeana and Lespedeza davuric.The results show that with the increase of vegetation restoration years,fine root mean diameter gradually decreased,and fine root biomass,length density gradually increased.In the early stage of vegetation restoration(3-8 years),specific root length growth is slow,and it increases significantly during the restoration period of 8-22 years and then tends to be stable.With the increase of soil depth,fine root mean diameter,fine root biomass,fine root length density and specific root length gradually are decreased and more than 70%of fine roots distribute in 0-40 cm soil layer.