聚乳酸纤维沙障对表层土壤含水量的影响

The effect of PLA sand barrier on the moisture content of surface soil

在乌兰布和沙漠西南缘选择大小、走向相近的裸沙丘分别铺设聚乳酸纤维(PLA)沙障与麦草沙障,设计规格为1 m×1 m、2 m×2 m、3 m×3 m。从2008年开始连续3年对2种沙障不同规格、不同坡位表层土壤含水量进行测定,同时以未铺设任何沙障的裸沙丘作为对照,比较新型材料PLA沙障与传统沙障麦草沙障对表层土壤含水量的长时间影响。结果表明:1)PLA沙障与麦草沙障以及裸沙丘含水量都随年份的增加而增加,2类沙障含水量增长幅度明显优于裸沙丘;2)就沙障规格而言,长时间保持土壤水分,效果最好的是PLA沙障2 m×2 m规格;3)在0～10 cm深度,PLA沙障土壤含水量表现为迎风坡>背风坡>坡顶,麦草沙障与PLA沙障相反;4)在10～20 cm深度,PLA沙障土壤含水量表现为坡顶>迎风坡>背风坡,麦草沙障同样与PLA沙障相反。

At the southwestern margin of Ulan Buh Desert,several bare sand dunes with similar size and direction were selected,which were laid with PLA sand barrier and straw barrier.The designed specifications of the barriers were chosen as 1 m×1 m,2 m×2 m,3 m×3 m.The water content of surface soil protected with different barriers and on different slope positions were measured within 3 successive years since 2008.The long-term effects of PLA and straw sand barrier on the moisture content of surface soil were compared,while bare sand dune without laid barrier was chosen as control.The results showed that soil water content increased with time for both sand dunes protected with PLA or straw barrier and bare sand dunes,the increase of soil water content of protected sand dunes with two kinds of barriers was significantly larger than that of bare sand dunes.To maintain soil moisture for a long time,PLA sand barrier with size of 2 m×2 m performed the best effect.On sand dunes protected with PLA sand barriers,in 0-10 cm depth the soil water contend in the windward slope was larger than that in leeward slope,which was in turn larger than that on slop top.In 10-20 cm depth,the soil water contend on slop top was larger than that in the windward slope,which was in turn larger than that in leeward slope.However,on sand dunes protected with straw barriers,the tendency for two depths was reverse.