Research on the Variation of the Soil Fertility in the Planted Young Pinus massoniana Forest and Comprehensive Evaluation of Its Soil Fertility

The soil chemical characteristics were analyzed from the forest land of eucalyptus and from the forest land of Pinus massoniana and wasteland that were planted in the same land of the former-eucalyptus growing after they had been felled in Huanjiang county of Guangxi province.Grey correlation analysis was used to study and evaluate the status of soil fertility changes for Pinus massoniana and wasteland.The results showed that for 4 year-old Pinus massoniana and the wasteland,the content of alkaline solution N,effective P,available K,exchangeable Ca and effective Zn in forest soil increased and the pH value was also improved as before,however,total N,total P,total K,exchangeable Mg and effective Cu decreased.The content of organic matter and effective B decreased in 0~20cm soil layer,but increased in 20~40cm soil layer.The integrated soil fertility was generally poor in different aged Pinus massoniana and the wasteland.After 4 years growth,soil integrated fertility of same soil layer of Pinus massoniana was lower than the wasteland.Except the soil integrated fertility of 4 age wasteland had no any variation in 0~20cm soil layer,and that of 4 the Pinus massoniana and the wasteland degraded,but with the most serious soil fertility of the Pinus massoniana.The research results provide theories for formula fertilization of the planted young Pinus massoniana forest.