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论文以陕西省兴平市为例,采用2009年实测的耕层土壤碱解氮数据,运用地统计学结合GIS技术,建立其最佳半方差函数模型,分析关中盆地农田土壤碱解氮的空间特征、丰缺状况及其含量变化,为土壤培肥和农业生产提供理论基础。结果表明:研究区土壤碱解氮含量介于7.70～82.60 mg.kg-1,多集中在30～40 mg.kg-1,平均37.76 mg.kg-1,较第二次土壤普查下降28.62%。在间距约300 m的采样尺度下,最优理论模型为指数模型,表现为弱的空间相关性,施肥管理、种植制度等随机因素起主导作用。含量高低区域分布明显,大致呈中间高四周低格局。72.67%的农田氮素缺乏,27.33%的农田氮素含量中等。近30 a,原土壤碱解氮1～3级农田区含量显著下降,原5、6级区有所改善,整体集中于4级水平。应进一步实地考察分析具体障碍因素,积极采取分区“补氮”措施。
Taking Xingping City in Shaanxi Province as an example, the best semi-variance function model was established by using geostatistics and GIS technology. The spatial characteristics of soil available nitrogen in the Guanzhong Basin were analyzed. , The status of abundance and deficiency and the change of its content, providing theoretical basis for soil fertility and agricultural production. The results showed that the contents of soil available nitrogen in the study area ranged from 7.70 to 82.60 mg.kg-1, mostly in the range of 30-40 mg.kg-1, with an average of 37.76 mg.kg-1, which was 28.62% lower than the second soil- . Under the sampling scale of about 300 m, the optimal theoretical model is an exponential model, which is characterized by weak spatial correlation, fertilization management, cropping system and other random factors. Regional distribution of high and low content is obvious, roughly the middle of the high four weeks low pattern. 72.67% of the farmland is deficient in nitrogen and 27.33% of the farmlands have medium nitrogen content. In the recent 30 years, the contents of soil alkali-hydrolyzed nitrogen level 1-3 in the original soil decreased significantly, while the levels in the original 5 and 6-level areas improved, concentrating on the level 4. Further investigation and analysis of specific obstacles should be conducted in the field and measures should be taken actively to subarea and “supplement nitrogen”.