白鹤滩水电站项目区土壤肥力评价及其空间变异

Assessment of Soil Fertility and Spatial Variation in Project Area of Baihetan Hydropower Station

采用地统计学、地理信息系统(GIS)和模糊数学等方法,系统地调查分析了白鹤滩水电站项目区土壤肥力状况及其空间变异特征。结果显示:研究区碱解氮和有效磷具有较强的空间变异性,有机质和速效钾的空间变异性为中等水平,而阳离子交换量和细菌群落α多样性Chao1指数的空间变异性最小,为较弱水平。在0~10 cm和10~20 cm土层土壤碱解氮、有机质、阳离子交换量、速效钾、速效磷和Chao1指数的平均值分别为14.08 mg/kg、14.02 g/kg、8.04 cmol/kg、98.53 mg/kg、0.65 mg/kg、0.97和12.14 mg/kg、12.70 g/kg、8.02 cmol/kg、109.78 mg/kg、0.74 mg/kg、0.93。其中,碱解氮和速效磷的平均含量低于土壤养分分级标准的6级水平,而有机质含量和阳离子交换量处于4级水平,速效钾含量处于3级水平。10~20 cm土层速效钾在空间上呈现较弱的自相关性,而碱解氮、有机质、阳离子交换量、0~10 cm土层Chao1指数和10~20 cm土层速效磷块金系数均小于25%,在空间上呈现较强的自相关性。通过空间插值图可以看出,研究区土壤综合肥力指标、碱解氮和有机质呈现由西北向东南逐渐降低的趋势,而其他肥力指标则具有不同的空间分布特征。研究区整体土壤肥力水平较低,其中速效磷和碱解氮是主要的限制因素。

Geostatistics,GIS,and fuzzy mathematics methods were used in this study to systematically investigate and analyze soil fertility status and its spatial variability characteristics in the Baihetan hydropower project area.The results showed that available nitrogen(AN)and rapid available phosphorus(RAP)had strong spatial variability,organic matter(OM)and rapid available potassium(RAK)had moderate spatial variability,while cation exchange capacity(CEC)and bacterial communityαdiversity index(Chao1)variation coefficients were the smallest and had weak spatial variability.The average values of AN,OM,CEC,RAK,RAP and Chao1 were 14.08 mg/kg,14.02 g/kg,8.04 cmol/kg,98.53 mg/kg,0.65 mg/kg and 0.97 in 0–10 cm depth,12.14 mg/kg,12.70 g/kg,8.02 cmol/kg,109.78 mg/kg,0.74 mg/kg and 0.93 in 10–20 cm depth,respectively.The average contents of AN and RAP were lower than the 6th levels,OM and CEC were at the 4th levels,and RAK was at the 3rd level of soil property classification standard.10–20 cm RAK showed weak spatial autocorrelation,while AN,OM,CEC,0–10 cm Chao1,and 10–20 cm RAP had nugget coefficients less than 25%and showed strong spatial autocorrelation.Integrated soil fertility index(IFI),AN and OM gradually decreased from northwest to southeast,while other fertility indicators had different spatial distribution characteristics.In conclusion,the overall soil fertility level was low in the study area,with RAP and AN as the main limiting factors.