喀斯特峰丛洼地土壤综合肥力的空间分异特征及其影响因素

Spatial Variability Characteristics of Soil Integrated Fertility and its Influencing Factors in Karst Peak-cluster Depression Area

利用隶属度函数和因子加权综合法,结合地统计学方法,通过构建土壤综合肥力指数(Integrated Fertility Index,IFI),研究了典型喀斯特峰丛洼地土壤综合肥力的空间分异特征及其主要影响因素。结果表明,各土壤养分因子对土壤综合肥力的贡献大小不一,其中全磷(TP)贡献率最大,权重达到了0.181,pH的贡献率最小,权重只有0.041;土壤IFI的变异系数为0.394,空间变异相对较小。土壤综合肥力空间分布均匀,过渡相对平缓,与单一土壤养分因子的空间分布存在较大的差异,说明单一的土壤养分状况不能代表土壤综合肥力水平;而IFI的总体趋势与单一土壤养分因子相似,均由坡脚向洼地中心递减,说明土壤养分因子对综合肥力的空间分布有一定影响。在土壤综合肥力的影响因子分析中,作物类型与农户管理方式交互作用影响显著,裸岩率与IFI显著相关,说明土壤综合肥力受自然因素与人为因素的共同影响。

Based on membership gr ade function, factor weighted integrated method and geostatic analysis, soil integrated fertility index （IFI） was constructed to investigate spatial distribution of soil integrated fertility and its influencing factors in karst peak-cluster depression area. The results showed that the contributions of the various nutrient factors were different. The weight of total phosphorus （TP） was highest （0.181）, but the contribution of pH was smallest with a weight of 0.041. The spatial variability of IFI was relatively small and its coefficient of variation （CV） was 0.394. The spatial distribution of integrated fertility had a high difference with that of single nutrient factor. However, the general distribution trends of IFI and single nutrient were similar. Both of them decreased from foot of slope to the center of the depression. This indicated that the single soil nutrient could not represent the integrated fertility. The analysis of influencing factors showed that the interaction of crop types and farmer management was significant. The IFI had a significant correlation with the bare rock ratio, indicating that the integrated fertility was influenced by both natural and anthroDo^enic factors.