江西省耕地土壤氮素空间变异特征及其影响因素

为定量探讨省域尺度下土壤氮素空间变异特征及其影响因素。以江西省2012年测土配方施肥项目采集的16 582个耕地表层(0~20 cm)土壤样点数据，运用普通克里格、单因素方差分析与回归分析方法，对土壤氮素空间变异特征及其影响因素进行分析。结果表明：（1）江西省土壤全氮(TN)含量在026~375 g/kg之间，平均值为158 g/kg，变异系数为3101%；碱解氮(AN)含量值域范围为1160~39970 mg/kg，平均值为16431 mg/kg，变异系数为3460%；二者均呈中等程度的变异性。（2）经半方差分析，TN与AN的变程分别为31489和3030 km，TN的空间自相关范围大而AN较小。（3）在空间分布上，高值区主要分布在新余市、抚州市与景德镇市。（4）回归分析与单因素方差分析结果表明，地形因子、耕地利用方式、成土母质、土壤类型和秸秆还田方式对土壤氮素空间变异影响极显著(P<001)。秸秆还田方式对土壤TN与AN空间变异的独立解释能力最高，分别为271%与42%，是影响江西土壤氮素空间变异的主要因素。

Spatial Variability of Farmland Soil Nitrogen of Jiangxi Province and Its Influencing Factors

In order to quantitatively measure the soil nitrogen spatial characteristics of the Jiangxi province,16582 points data collected from the project of 2012 soil-test-based formulated fertilization were analyzed in this study.The analysis methods included ordinary kriging,one-way variance analysis and regression analysis.The results showed:①Total nitrogen (TN) ranged from 0.26 g/kg to 3.75 g/kg,with an average of 1.58 g/kg.The coefficient of variation was 31.01％,indicating a moderately spatial variability.Available nitrogen (AN) ranged from 11.60 mg/kg to 399.70 mg/kg,with an average of 164.31 mg/kg.The coefficient of variation was 34.60％,showing a moderately spatial variability.②The spatial changes of TN and AN were 314.89 km and 30.30 km,respectively;the spatial autocorrelation range of TN is larger and AN is smaller.③In the spatial distribution,the high value areas were mainly included the city of Xinyu,Fuzhou and Jingdezhen.④The terrain factors,farmland-use type,parent material,soil type and straw returning patterns had significant impacts on the spatial variability of soil nitrogen (P ＜ O.O1).Straw returning patterns was the most important factor that influencing on soil nitrogen spatial variation of the Jiangxi province,which could explain 27.1％ of TN spatial variability and 4.2％ of AN spatial variability.