江苏省农田土壤全氮含量变化及其影响因子

[目的]本文旨在研究江苏省农田土壤全氮含量变化特征及其影响因子。[方法]基于2008和2015年江苏省基本农田质量长期监测点实测数据，运用经典统计学和地统计学分析土壤全氮含量的时空变化，运用多因素方差分析探明成土母质、气候、种植制度、化肥施用等因子对土壤全氮含量变化的影响及不同影响因子间的交互效应。[结果]2015年江苏农田土壤全氮平均含量为1.47 g？kg-1，比2008年增加了8.9%（P<0.01）。2008和2015年，土壤全氮含量空间分布特征保持相对一致，表现为苏南地区高于苏北地区（里下河地区除外），西部地区高于东部地区，沿海地区最低；土壤全氮含量的变化受氮肥施用及氮肥施用与气候交互效应的影响显著，湿润亚热带地区氮肥低投入时土壤全氮含量增加最多，而半湿润温暖带地区氮肥超高投入时土壤全氮含量增加最多；土壤有机质作为协变量对全氮变化影响显著，且解释率最高。[结论]在氮肥低投入及超高投入2种情况下，气候是土壤全氮含量变化的显著影响因子，建议在生产实践中依据气候条件合理施用氮肥。
[Objectives] The paper was aimed to probe the dynamic of soil total nitrogen content on the farmland of Jiangsu Province and its influencing factors. [Methods] The soil quality data were derived from the long-term monitoring network of the basic farmland in Jiangsu Province in 2008 and 2015. Then the classical statistics and geostatistics were employed to analyze the dynamics of soil total nitrogen. The interactive effects of related factors (soil parent materials, climate, planting systems and chemical fertilizers)were analyzed by the multivariate analysis of variance. [Results] The average content of soil total nitrogen was 1.47 g？kg-1 on Jiangsu farmland in 2015, which increased 8.9% in 2008 (P<0.01). The spatial distribution characteristics of soil total nitrogen maintain relative consistency from 2008 to 2015, showing that soil total nitrogen content in South Jiangsu was higher than that of North Jiangsu (except for Lixia River area), and the western area was higher than that of the eastern area, while the coastal area was the lowest. The change of total nitrogen content in Jiangsu Province in 2008 and 2015 was significantly affected by the interaction of nitrogen fertilizer, and its interaction with climate. In humid subtropical region, low nitrogen input caused the highest increase of soil total nitrogen, while in semi-humid warm region, super high nitrogen input was required. As a covariate, soil organic matter exerted a significant impact on total nitrogen and the highest explanation proportion. [Conclusions] Regardless of nitrogen fertilizer level, climate is a key regulating factor in terms of soil total nitrogen. These findings indicate that nitrogen fertilizer application should be based on local climatic conditions