龙山县植烟土壤pH时空变异与影响因子研究

Temporal and spatial variation of soil pH and its influencing factors in tobacco-growing areas of Longshan county

为研究龙山县植烟土壤pH时空变异特征与其影响因子,分别于2000与2015年在龙山烟区采集土壤样品191和300个进行土壤pH与各指标的测定,利用描述性统计、地统计学、相关分析、多重比较、逐步回归与等样本平滑回归对该地区土壤pH的时空变异与其影响因子进行了研究。结果表明:从描述统计来看15年间龙山县植烟土壤pH均值由6.32变为6.03,降幅为4.64%,极低(<5)的样本增加了19.05%,偏低(5.0~5.5)的样本增加了1.1%,适宜(5.5~7.0)的样本降低了19.45%;从时空变化来看,pH在5.0~6.0范围的区域大幅增加,6.0~7.0范围的区域大幅减少,总体呈酸化趋势,但有小部分区域pH呈碱化趋势,有两级分化现象。由相关分析与逐步回归分析得出土壤交换性钙、交换性镁为土壤p H酸化的外在控制因子,有效硫与碱解氮为土壤酸化的外在致酸因子,土壤粘粒为土壤酸化的内在致酸因子,海拔也对pH有重要影响。

In order to study the temporal and spatial variability of soil pH and its influencing factors in tobacco-growing areas of Wuling Mountain and provide reliable basis for the regulation of soil pH in tobacco-growing areas,191 and 300 soil samples were collected from Longshan tobacco-growing areas in 2000 and 2015,respectively,for the determination of soil pH and various indicators.Descriptive statistics,geostatistics,correlation analysis,multiple comparisons and gradual regression were used.The temporal and spatial variability of soil pH and its influencing factors in this area were studied by means of regression analysis.The results showed that the average pH of tobacco-growing soils in Longshan county changed from 6.32 to 6.03 in the past 15 years,with a decrease of 4.64%,an increase of 19.05%in extremely low(<5),an increase of 1.1%in low(5.0~5.5),and a decrease of 19.45%in suitable(5.5~7.0).From the point of view of temporal and spatial variations,the range of pH in 5.0~6.0 increased significantly,and the range of 6.0~7.0 decreased significantly,which showed a trend of acidification in general.But there was a small part of the region with a trend of alkalization,indicating two levels of differentiation.Through correlation analysis and stepwise regression analysis,it was concluded that exchangeable calcium and exchangeable magnesium were the external control factors of soil pH acidification,available sulfur and alkali-hydrolyzed nitrogen were the external acidification factors of soil acidification,clay was the internal acidification factor of soil acidification,and elevation also had an important influence on soil pH.