宁夏不同地区农田土壤磷素养分的空间变异特征

在宁夏灌区和旱区30块农田分别采集了0~120 cm深土壤剖面样品,测定了土壤全磷和速效磷含量,分析了土壤磷素养分含量的空间变异性。结果表明,在0~120 cm深土壤剖面中的全磷和速效磷含量,灌区土壤显著高于旱区土壤,在剖面点之间和土壤层次之间存在极显著差异,而且在土层间还存在着正相关。其变异系数总体上是旱区土壤大于灌区土壤,速效磷大于全磷。从地区来看,旱区土壤全磷和速效磷含量的变异系数随剖面深度的增加而增大,灌区土壤全磷量的变异系数在剖面层次之间差别不大,而速效磷的变异系数随剖面深度的增加而呈降低趋势。在0~120 cm深土壤剖面中,土壤全磷和速效磷的累积量灌区较旱区分别高出26.8%和65.0%,在土类间也存在较大差异。

Spatial Variation of Soil Phosphorus of Farmlands in Different Regions of Ningxia

Soil samples of 6 layers from 0 to 120 cm in 30 farmlands with different soil fertility levels of both irrigation and dryland regions in Ningxia province were taken.The contents of both soil total phosphorus and available phosphorus were determined in order to investigate spatial variabilities of soil phosphorus contents.The results showed that the contents of both soil total phosphorus and available phosphorus at depths from 0 to 120 cm in the irrigated soils were significantly higher than that in the dryland soil.There were very significant differences between different soil profiles or different depths.There were obvious positive correlation between the contents of soil phosphorus at different depths.The variance coefficients of soil phosphorus contents in the dryland soil were significantly higher than those in the irrigation soils,and those of available phosphorus was higher than those of total phosphorus as a whole.The variance coefficients of both soil total phosphorus and available phosphorus contents in the dryland soil were increased with soil depths,those of soil total phosphorus in the irrigation soil were hardly changed,and those of soil available phosphorus in the irrigation soil were decreased with soil depths.The accumulated amounts of both soil total phosphorus and available phosphorus from 0 to 120cm depth in the irrigation soil were 26.8% and 65.0% higher respectively than in the dryland soil.In addition the accumulated amounts of soil phosphorus between soil types were relatively different.