流动沙丘土壤紧实度对沙米生长状况的影响

通过对流动沙丘迎风坡不同部位的沙米种群生长状况和其所对应的主要土壤理化性质测定,分析了其对沙米种群的影响。结果表明,在不同部位,土壤紧实度(F2,87=146.843,P<0.001)和沙米地上生物量(F2,87=324.986,P<0.001)存在显著差异;相反,土壤有机质(F2,12=0.007,P=0.993)和土壤水分(F2,12=11.349,P=0.002)的差异相对不显著。进一步的回归分析显示,土壤紧实度与沙米地上生物量呈负相关。这种关系不仅表现在水平尺度上,而且还表现在垂直尺度上。土壤紧实度对沙米生长状况的影响具有尺度性,其中,在0.013～0.029kg/m₂的范围内,土壤紧实度与沙米的相关关系相对较低;当土壤紧实度变化在0.030～0.113kg/m₂之间,经相关系数置信检查,二者之间存在线性回归关系。

The Influence of Soil Compactibility on Growth Status of Agriophyllum Squarrosum at Mobile Dune

Agriophyllum squarrosum(L.) Moq.is a pioneer species during the community succes,sion process on the mobile dune area in the Horqin sandy land.The growth status of A.squarrosum population is significantly different at the different plots of the windward slope of mobile dune.So,for best understanding the adaptive mechanism of A.squarrosum population at mobile dune area,we set up three plots at the windward slope of the mobile dune,located at bottom,middle,and top sides of the mobile dune,respectively.According to field survey and measurement of the above ground biomass(AGB)of A.squarrosum and soil properties represented by soil hardness,soil moisture,and soil organic matter,the influence of the soil properties upon A.squarrosum has been analyzed by employing one,way ANOVA and regression methods in the Horqin sandy land.Results showed that there was significant variation in soil hardness(F2,87=146.843,P<0.001) and AGB(F2,87=324.986,P<0.001) on different plots of the windward slope of mobile dune which is divided in to bottom,middle,and top windward sides.On the contrary,there was un,significant variation for the soil moisture(F2,12=11.349,P=0.002) and the organic matter(F2,12=0.007,P=0.993) in the same sites.Further regression analysis indic,ated that correlation between the soil compactibility and the AGB was negative.The relation existed not only in horizontal scale(different plots) but also in vertical scale(different soil layers).In addition,the impact of the soil compactibility had threshold,there was less correlation while the soil compactibility changed from 0.013kg/m2 to 0.029kg/m2.Obviously,correlative coefficient check illustrated that there was linear regression while the soil compactibility changed from 0.030kg/m2 to 0.113kg/m2.It is very important to understand that the soil compactibility is not an original characteristic of the windward slope of the mobile dune,but it just reflect erosion or buried degree of soil surface indirectly.