菜地土壤养分的空间变异特征

Spatial Variability of Nutrients in Vegetable Soil

通过地统计学、空间分析方法及结合农户施肥调查,对菜地土壤养分的空间变异特征进行研究。结果表明,农户施肥水平差别较大,整体上施磷相对过多,施钾相对较少,土壤OM、NH4+-N、P、K、Ca、Mg和S的变异系数在28.4%～69.2%之间。土壤各养分的空间变异结构有较大区别,土壤OM及NH4+-N的变异具有强烈空间相关性,土壤P、K、Ca、Mg和S养分含量的变异为中等空间相关性。土壤养分的等值线图显示,OM在空间的分布与土壤质地渐变规律相关,NH4+-N呈现南北向的带状分布,P、K、Ca、Mg和S趋于小块状分布。总的来说,施肥等人为因素加剧了土壤矿质养分的空间变异。

Spatial variability of nutrients in vegetable soil was studied by geostatistics and spatial analysis, along with investigation on farmers' fertilization. The result showed that great difference among farmer's fertilization rates was found, and relative too much P was used, whereas K was too less. Variation coefficients of soil OM, (NH_4^+-N), P, K, Ca, Mg and S fluctuated between 28.4% and 69.2%. Soil OM and NH_4^+-N presented strong spatial dependence, and soil P,K, Ca, Mg and S moderate spatial dependence. Isoline maps of soil nutrients indicated that spatial distribution of OM was similar to gradual change of soil texture; NH_4^+-N took on vertical belt distribution from north to south; P, K, Ca, Mg and S tended to be come out as shatters. Conclusively, artificial factors such as fertilization intensified the spatial variability of soil mineral nutrients.