Study on the Magnesium Content and its Causal Factors in Paddy Soils in Anhui Province

Through the analysis in the paddy soils in Anhui province,the magnesium(Mg) content and its Causal factors were studied.The results were as follows:(1) The total magnesium(T-Mg) contents of the tested paddy soils ranged from 1.86 g/kg to 5.40 g/kg,with an average of 3.11 g/kg which was lower than the average Mg content of farm soils in South China.The exchangeable Mg(Ex-Mg) content of the tested paddy soils was 284 mg/kg in average which showed that the Mg supply capacity of the studied paddy soils was higher.The acid soluble Mg(Acid-Mg) was 2.04 g/kg in average.(2) There had been remarkable defference in the Mg contents derived from different parent materials of Anhui province.The Mg contents in the paddy soils derived from Huaihe river alluvium and Changjiang river alluvium were higher than that derived from river deposition and drift deposit.(3) The soil pH value,clay contents and readily available potassium were major factors affecting Mg content.(4) There had been remarkable correlations between Mg contents of rice plant and soil Ex-Mg,Acid-Mg,T-Mg,which showed that the bioavailabilities of Ex-Mg,Acid-Mg,T-Mg in the studied paddy soils were higher.