县域农田土壤氮素空间分布特征及其影响因素

采用地统计学与GIS相结合的方法，研究了四川省双流县土壤氮素空间分布特征及其影响因素.结果表明：土壤全氮和碱解氮含量具有中等空间相关性，其空间相关距离分别为15480 m和26980 m.土壤全氮含量高值区主要位于北边的九江、新兴两镇，低值区主要位于东南方向的合江、三星两镇；土壤碱解氮含量从北向南递减趋势比较明显.灰色冲积物上发育的土壤全氮和碱解氮含量均显著或极显著高于紫色岩风化物和老冲积物；水稻土全氮和碱解氮含量均极显著高于黄壤和紫色土；地形条件对土壤全氮和碱解氮含量的影响程度不同，但均以丘陵最低；不同土地利用方式下，水田全氮和碱解氮含量均显著或极显著高于旱地和果园；土壤氮素高值区施肥量明显高于低值区.

Spatial distribution pattern of soil nitrogen in croplands at county scale and related affecting factors

By using geostatistics and GIS, this paper studied the spatial distribution of soil nitrogen in the croplands in Shuangliu County of Sichuan Province, China, and analyzed the related affecting factors. There was a moderate spatial correlation between the contents of total nitrogen (TN) and available nitrogen (AN) in the cropland soils, and the spatial correlation distance was 15480 m for TN and 26980 m for AN. The regions with higher soil TN content were mainly in the north of the County, i.e, Jiujiang and Xinxing towns, while those with lower soil TN content were mainly in the southeast of the County, i.e., Hejiang and Sanxing towns. The soil AN content decreased obviously from north to south. The TN and AN contents in the soils developed from grey alluvium were significantly higher than those developed from purplish rock saprolith and old alluvium. Paddy soil had significantly higher contents of TN and AN than yellow soil and purple soil. Terrain condition affected the soil TN and AN contents todifferent degree, and hilly region had the lowest contents of soil TN and AN. Paddy fields had significantly higher contents of soil TN and AN, compared with dryland and orchards; and the regions with higher soil nitrogen content were applied with obviously higher amount of Nfertilizer, compared to the regions with lower soil nitrogen content.