湘西植烟土壤有机质和全氮时空变异特征研究

为揭示湖南省湘西州烟区土壤有机质(SOM)和全氮(TN)的时空变异特征和为合理施用有机肥和氮肥提供科学依据,采用经典统计学、地统计学和GIS等方法,对湘西州2000年和2015年植烟土壤SOM和TN时空变异特征进行了研究。结果表明:2015年SOM和TN平均含量较2000年分别增加了5.03g/kg和0.31g/kg,增幅分别达21.39%和21.99%,SOM和TN含量的最小值变小,变异系数、最大值和极差变大,Moran’sI指数标准化Z值下降,块金效应增加;SOM和TN含量"低""适宜"等级面积分别下降了3.42%、37.73%和2.04%、44.43%,"高""极高"等级面积分别增加了32.21%、8.94%和35.67%、10.80%。表明湘西植烟土壤SOM和TN含量和变异同时增加,SOM和TN空间自相关性减弱,随机变异性增强。植烟土壤SOM与TN含量表现出极显著的正线性相关,SOM的矿化释放是TN的一个主要来源。

Temporal and Spatial Variability of Soil Total Nitrogen and Organic Matter in Tobacco-planting Area of Xiangxi, Hunan

Based on the methods of classical statistics and geostatistics, the spatiotemporal variation of soil organic matter (SOM) and total nitrogen (TN) from 2000 to 2015 in tobacco-planting area of Xiangxi were studied in order to provide scientific basis for reasonable application of organic and nitrogen fertilizers. ,. The results showed that from 200 to 2015 average SOM and TN increased by 30.90 g/kg and 0.31 g/kg, increased by 21.39% and 21.99%, respectively. for SOM and TN, their minima decreased while variation coefficients, maxima and ranges increased. In the past 15 years, the normalized Z values of Moran ''s I indexes of SOM and TN decreased, nugget effects increased; the "low" and "suitable" grade areas of SOM and TN decreased by 2.04%, 37.73% and 3.42% and 44.43%, respectively; while the "high" and "high" grade areas of SOM and TN increased by 32.21%, 8.94% and 35.67% and 10.94%, respectively. in general, SOM and TN contents and their variations increased significantly in tobacco growing area of Xiangxi, the spatial autocorrelation of SOM and TN were weakened and the random variabilities were enhanced. The SOM and TN of the tobacco planting soil showed a good linear relationship. As the SOM increased, the soil TN increased linearly.