基于不同人为干扰的土壤全量氮磷钾空间变异性研究

采用地统计学与GIS技术相结合的方法，对无人为干扰区25个样本、人为干扰区30个样本土壤全量氮磷钾的空间异质性进行了研究。结果表明：人为干扰区土地多被开发成林地、育苗地，自然植被残体等被移除，土壤腐殖质来源减少，加之由于土层翻动，土壤透气性变好，加快了养分分解与利用，土壤全量氮磷钾含量均值分别降低至0.433、0.902、15.325 g·kg-1，数据间的差异性和分布状态也发生变化;球状模型能较好地拟合无人为干扰区土壤全磷分布,而高斯模型则能较高地拟合两区其余养分指标的分布,两区理论模型的R²介于0.66和0.90之间，拟合精度高;土壤全量氮磷钾的理论模型中，均以无人为干扰区模型的R²高且RSS小;无人为干扰区全量氮磷钾的高值区均在植被覆盖度高的区域内。干扰程度较大的区域，土壤全氮和全磷含量较低，因此应补充适量氮肥和磷肥，满足养分需求。

Spatial variability of total nitrogen, phosphorus, and potassium in soil under different human disturbances

The spatial heterogeneity of soil total nitrogen, phosphorus and potassium in 25 samples from area without human activities and 30 samples from human disturbed area were studied using geostatistics and GIS. The results showed that the land of human-disturbed area was mostly exploited as forest land and nursery field. Due to the removal of vegetation residues by human activity, the source of soil humus was eliminated. For the plowing of the land, the soil was more aerated. As a result, it accelerated the decomposition and utilization of nutrients in soil. So, the average amount of total N, P, and K in the soil decreased to 0.433, 0.902, and 15.325 g·kg^-1, the differences and distributions between the datas also varied. The spherical model well modeled the soil total P distribution in the non-man disturbed area. However, the Gaussian model modeled the distribution of the other nutrients in both areas well. The R² values of models for the two areas were between 0.66 and 0.90, and correlation was high. The theoretical model of total N, P, and K had high R² but low RSS for the undisturbed area. The land with high total N, P, and K in the undisturbed area had high vegetation coverage. In the area with a high intensity of disturbance, the contents of total N and P in the soil were relatively low, therefore, proper amount of N and P fertilization should be added to meet the plant nutrient requirements.