Spatial-temporal character of exchangeable magnesium and its influencing factors at tobacco-growing soil region in Shaoyang

Abstract

In order to understand the distribution of exchangeable magnesium content for tobacco-growing soils in Shaoyang, exchangeable magnesium content and its influencing factors such as pH, organic matter were analyzed using traditional statistics and geostatistics based on 1 790 observed soil samples. The results showed: ①The exchangeable magnesium content in the tobacco-growing soil was in lower level,with a mean of 0.78 cmol/kg and variation coefficient of 51.39%, and about 16.98% of exchangeable magnesium content in the observed soil samples was suitable for tobacco cultivation. ②The exchangeable magnesium content in tobacco-growing soils in Longhui and Shaoyang counties were significantly higher than that of in Xinning county; From the map interpolated by Kriging, the tendency of spatial variation of exchangeable magnesium decreased from north to south; Compared to the results of soil survey in 2002, the exchangeable magnesium in tobacco soils showed a decreased tendency. ③A quadratic curve relationship was found between exchangeable magnesium and soil pH value. If the pH value was lower than 5.0, the exchangeable magnesium was in the state of insufficiency or latent insufficiency; There was no apparent relationship between exchangeable magnesium and organic matter for tobacco-growing soils.