江苏北部5市土壤表层(0~20cm)全氮含量连云港东北部、淮安南部和盐城西部显著高于其它地区;全磷含量呈现由北到南、自西向东升高的趋势;速效磷含量高值区位于北部的灌云县和南部的金湖县;速效钾含量东部沿海高于其它地区。土壤类型和成土母质对土壤养分产生显著影响:对于土类而言,沼泽土和水稻土养分较高;各成土母质中,湖相沉积物发育的土壤养分含量最高。在研究区1:5万尺度范围内,土壤类型对全氮和全磷的变异起主导作用,而速效磷受成土母质的影响较大,土壤类型和成土母质对速效钾的影响较小,土壤类型和成土母质对全量养分的影响要大于速效养分。

The research on spatial heterogeneity of soil nutrients is considered to be an important topic in utilizing and managing soil resources properly. Based on a 1:50000 soil database, spatial heterogeneity of soil nutrients (including total N, total P, available P and available K) at the surface layer (0-20cm) and their affecting factors in the northern Jiangsu Province were analyzed. The results showed that soil total N in the northeastern Lianyungang County, southern Huai’an County and western Yancheng County were significant higher than those in other areas; the total P content tended to increase gradually from north to south and from west to east; the highest available P content was found in the northern Guanyun County and southern Jinghu County; the available K content in the eastern coastal region was significant higher than those in other areas. Soil properties were significantly affected by soil type and parent material. In terms of soil group, bog soils and paddy soils had high nutrient contents. With regard to parent material, nutrient contents were higher in soils developed from lacustrine deposit than those from other parent materials. It was concluded that, at the scale of 1:50000, soil type was the dominant factor for total N and total P, and parent material was a key factor for available P, while soil type and parent material had a little influence on available K, soil type and parent material had stronger impacts on total nutrients than available nutrients.