湖南郴州烟区土壤有机质和全氮时空变异及其影响因素研究

Spatial and Temporal Variability of Soil Organic Matter and Total Nitrogen and Influencing Factors in Chenzhou Tobacco-growing Area,Hunan Province

为了探明湖南省郴州烟区土壤有机质和全氮的时空变化规律,从而为烟田有机物料投入和氮素养分管理提供科学依据,采用地统计学技术和地理信息技术相结合的方法,对该区2000年和2015年植烟土壤有机质和全氮时间和空间变异特征进行了研究。结果表明,2个年份有机质和全氮含量均十分丰富,2015年土壤有机质(SOM)和全氮(TN)平均含量较2000年分别增加了2.59 g kg^-1和0.04 g kg^-1,变异系数基本稳定,极差变大,Moran’s I下降,SOM块金效应基本稳定,TN块金效应显著增加;有机质"适宜"和"高"等级面积分别下降了12.07%和17.16%",极高"等级面积增加了29.47%;两个年份全氮含量"适宜"及以下的等级均缺失,2015年土壤全氮"高"等级面积下降了5.51%",极高"等级的面积增加了5.51%。上述结果表明郴州植烟土壤SOM和TN含量增加,极差变大,空间自相关性显著下降,而随机变异性增加。植烟土壤SOM与TN呈显著线性正相关。

Based on the methods of GIS and geo-statistics,temporal and spatial variation characteristics of soil organic matter(SOM)and total nitrogen(TN)from 2000 to 2015 in tobacco-planting area of Chenzhou were studied.The results showed that the contents of SOM and TN were very rich in the two years.The mean value of SOM and TN increased by 2.59 g kg^-1 and 0.04 g kg^-1 in 2015 compared with 2000.The coefficient of variation was basically stable,the range became larger,Moran’s I decreased,the lump gold effect of SOM was basically stable,and the lump gold effect of TN increased significantly.The area of SOM with suitable grade was decreased by 12.07%,that with high grade decreased by 17.16%,and that with extremely high grade increased by 29.47%.The areas of TN with suitable grade and below this grade were missing in both years.The area of TN with high grade decreased by 5.51%,and that with extremely high grade increased by 5.51%in 2015.The above results showed that SOM and TN contents in tobacco-growing soils in Chenzhou increased,the range increased,the spatial autocorrelation weakened,and the random variability increased.SOM and TN in tobacco planting soil showed a very significant positive linear correlation.SOM mineralization was a major source of soil TN.