沙漠人工植物群落的根系分布及动态

2004年植物生长季，利用根钻取样研究了沙漠4种不同配置类型油蒿与柠条植物群落的根系分布及生长动态；另外，采用挖沟分层取样研究了半固定沙丘两种植物的粗根剖面结构，结果表明：尽管4个样地高峰值和低峰值出现的时间不一致，但沙漠植物细根的生长动态表现为双峰型；整个生长季纯油蒿样地细根密集分布于0~40 cm，其余样地密集分布于10~60 cm；受一年生植物的影响，9月份4个样地表层（0~30 cm）细根的根长密度和根重密度均出现最大值。采用边灌水边取样的办法获得4个样地300 cm深的根系数据，4个样地90%以上的细根分布在0~200 cm层次，其中纯油蒿样地的根系的最大深度是270 cm，其余3个样地均在300 cm以下；细根的根长密度和根重密度随深度而减小且呈指数递减形式（P<0.01）。除纯油蒿样地外的其他3个样地，根瘤的最高值出现在4月份；粗根的根长密度远远小于细根的根长密度。挖沟分层取样研究表明，与柠条相比油蒿具有较高的根冠比；柠条的粗根长主要分布于0~60 cm，粗根重主要分布在0~40 cm；油蒿的粗根分布比柠条的更浅，粗根长主要分布于0~40 cm，粗根重主要分布在0~20 cm。

Root Distribution and Dynamics of Re-vegetated Communities in Desert Area

In plant growth season of 2004,root system distributions and dynamics of 4 types communities collocated Artemisia ordosica and Caragana korshinskii were sampled by root corer to measure.Simultaneously,coarse root profiles in semi-fixed dunes were investigated with method of digging root system by layers.The results show that the dynamics of fine root of communities can be expressed as two-peak curve though the peak values appear at different date in the 4 quadrats.The fine roots of A.ordosica quadrat mostly distribute in 0~40 cm soil layers,but those of other quadrats densely distribute in 10~60 cm soil layers.The maximums of root length density(RLD) and root weight density(RWD) of 4 quadrats in surface layer(0~30 cm) occur due to annual plants developing.The root system data in depth of 300 cm were gained with method of combined irrigation with sample by root core,it show that 90 percent of fine root of 4 quadrats locate in 0~200 cm layers,and the deepest roots of A.ordosica quadrat arrive to 270 cm and those of other 3 quadrats more than 300 cm.Both of RLD and RWD of fine root minish with depth and the relationships can be described by exponential equation(P<0.01).The root nodules maximums occur in April except for A.ordosica quadrat,and RLD of coarse roots are far little than those of fine roots.The results of digging channel and sampling by layers show that the ratios of root/crown A.ordosica are higher than that of C.korshinskii.The RLD of coarse roots of C.korshinskii mostly distribute in 0~60 cm soil layer and RWD concentrate in 0~40 cm soil layer,both of A.ordosica are not deeper,and distribute in 0~40 cm and 0~20 cm soil layer,respectively.