Analysis of Nutrient Properties of Effective Microelement in Tobacco-growing Soils with Different Preceding Crops

In order to know the content of effective microelement in tobacco-growing soils with different preceding crops in Zhanyi County,Yunnan province,960 soil samples were collected and the soil microelements were analyzed.The results showed that the contents of available Cu,Fe,Mn and water-soluble chloride ion were very rich,the content of available Zn was in a high level,and the contents of available B and Mo were in a low level.Aiming at the three kinds of microelements with lower contents,the contents of available Zn and available B were the highest and the content of available Mo was the lowest when the preceding crop was wheat.The contents of three kinds of microelement were in a low level when the preceding crops were others which including soybeans,green manure,carrots,peas and corn.