山西农田土壤交换性镁含量、分布特征及其与土壤化学性质的关系

Contents and Distribution of Exchangeable Magnesium and Their Relationship with the Chemical Properties of Main Farm Soils in Shanxi Province,China

采用田间调查与室内分析相结合的方法,研究了山西省农田土壤交换性镁(Mg)含量、分布特征及其与土壤主要化学性质的关系。结果表明,山西省主要农田土壤(0～20 cm)交换性镁含量平均为255.1 mg/kg,变幅为78.1～641.8 mg/kg,其中85%的土壤交换性镁含量在100～400 mg/kg之间,随地区不同而异。土壤剖面(0～100 cm)交换性镁含量为78.1～717 mg/kg,其含量随土壤层次加深呈现出增加的趋势。不同类型土壤交换性镁含量高低依次为潮土>褐土>栗褐土>石灰性褐土>黄绵土>褐土性土。土壤交换性镁含量与土壤pH值、EC值、有机质含量和碱解氮含量呈显著线性正相关,与K/Mg呈显著线性负相关,与全磷含量、速效磷含量、速效钾含量和Ca/Mg呈显著的曲线关系。

The exchangeable magnesium （Mg） contents in soils depended to a large degree upon the soil parent materials, soil physio-chemical properties, the climatic and other environmental conditions, and factitious factors. Using both field investigation and indoor analysis, the soils of 636 samples from the main types of farmland soils in Shanxi Province were sampled and analyzed to investigate the contents and distribution of exchangeable Mg and their relationship with the chemical properties of main types of farmland soils in Shanxi Province, China. The results indica- ted that the average content of exchangeable Mg in top soils （0 -20 cm） of main types of farm- land soils in Shanxi Province was 255.1 mg/kg, varied from 78.1 mg/kg to 641.8 mg/kg. 3.5% of exchangeable Mg contents in total soil samples were below 100 mg/kg, 85% of them were between 100 mg/kg and 400 mg/kg, and 11.5% of them were over 400 mg/kg. The exchangeable Mg contents in top soils varied obviously within different regions, the largest content was 378.5 mg/kg in the areas of Taiyuan City, and the lowest content was 144.2 mg/kg in the areas of Yangquan City. The contents of exchangeable Mg in soft profile （0 - 100 cm） varied from 78.1 rag/ kg to 713.3 mg/kg. As a whole, the exchangeable Mg contents in soil profile had an increasing tendency with deepening of soil layers. The exchangeable Mg contents in the order from high to low in different types of soil were fluvo-aquic soil 〉 cinnamon soil 〉 chestnut-cinnamon soil 〉 calcareous cinnamon soil 〉 loessal soil 〉 cinnamony soil. Correlation analysis between the exchangeable Mg contents and the chemical properties of main types of farmland soils revealed that there were significant positive linear relationships between exchangeable Mg contents and pH value, EC （electric conductivity） value, organic matter content, available nitrogen content in top soils, and the significant negative linear relationship between exchangeable Mg content and the ratio of K/Mg in top soils, as well as the significant curvilinear relationships between exchangeable Mg contents and total phosphorus content, available phosphorus content and available potassium content and ratio of Ca/Mg in top soils. This study demonstrated that the contents of exchangeable Mg are at high level in major farmland soils of Shanxi Province. The exchangeable Mg contents in top soils varied obviously within different types of soils and different regions. There are close relationships between the exchangeable Mg contents in top soils and chemical properties of the major types of farmland soils in Shanxi Province.