河西走廊盐渍化草地芨芨草“肥岛”对土壤养分空间分布的影响

Effects of Achnatherum splendens tussock fertile island on the spatial distribution of soil nutrient in Salinized-Grasslands of the Hexi Corridor

摘要:

以酒泉盐碱地芨芨草(Achnatherum splendens)草丛为研究对象,选取冠幅相近、生长状况良好、大小适中的芨芨草草丛,对每株芨芨草草丛按4个垂直方位,每个方位按5个距离梯度(草丛中心、距草丛中心20、40、60、100 cm)设置样点,每个样点按5个土层深度(0~10,10~20,20~30,30~40,40~60 cm)进行土壤取样和分析。结果表明,芨芨草中土壤养分呈现如下的空间分布特征:(1)土壤有机质、全氮、全磷、碱解氮、速效磷、速效钾的含量随离草丛中心距离的减少而增加,随土层深度的增加而减少,土壤养分主要富集于草丛下,而且表层土壤更加明显。(2)与草丛外土壤相比,草丛内土壤含水量较高、pH值较低,对盐碱地恶劣的土壤环境治理恢复有重要作用。

Abstract:

There are large areas of saline soils in the Hexi Corridor,the Achnatherum splendens is a salt-tolerant plant,which has an important role in the improvement of dry saline soils.We selected A.splendens tussocks with similar crown size,good growth condition,and moderate size.The sampling sites for each tussock were set up in four vertical orientations with five distance gradients (center of the tussock,20 cm,40 cm,60 cm,and 100 cm from the center of the tussock) and each sampling site at five soil depths (0~10 cm,10~20 cm,20~30 cm,30~40 cm,and 40~60 cm).Soil samples from each site were collected and analysed.The results showed that due to the structural characteristics of A.splendens,the soil nutrients showed the following spatial distribution:(1) The content of soil organic matter,total nitrogen,total phosphorus,available nitrogen,available phosphorus,and available potassium increased with the decrease of distance from the center of the clump and decreased with the increase of soil depth.The soil nutrients were mainly enriched under the clump,particularly in the surface soil.(2) Compared with the outside of the grass,the soil under the grass has higher water content and lower pH,which is important for the management and restoration of the poor soil condition of saline land.