Studies On Unavailable Inorganic Phosphorus Of Main Soil Groups In Mountainous And Hilly Region Of Fujian Province

Phosphorus (P) is one of the necessary elements for the plants, which is mainly from the soil. The available phosphorus in Fujian mountain soils is severely absent, always under 0.1mg/kg. The absence of available phosphorus is always one of the reasons that confine the growth of plants and forest. It is necessary to study the basic character of Fujian main soil groups, especially to realize the distribution circs of inorganic phosphorus. The study can offer theory gist for soil supervising, forest tending and rational fertilizing.On this paper, we study contents of Fe-P, Al-P and O_P in different soils (red soils, yellow soils, latosol, and purple soil) and their rates in total phosphorus, the changes of them with depth at soil profile. Besides, how to increase availability of Fe-P, Al-P and O-P through forest farming is also studied in this paper.The results of the study are:1) The trend of inorganic phosphorus content is: O-P is higher than Fe-P, Al-P is the lowest in the soils in Fujian province.2) The average of the rate in total phosphorus of O-P in red soils is: Shanghang (north latitude24°46'～25°28') is the highest (64.68%),Xiapu(north latitude 26°25'～27°07')is the next (55.92%) ,Shaowu(north latitude 26°55'～27°36') is (39.27%) and Songxi(27°～27°51') is the lowest (30.89%). It means the content of O-P gradually increases in red soils in Fujian province from north to south.3) The content of organic matter has negative correlation with the totality of inorganic phosphorus, so does pH and cation exchange capacity. So we can enhance the availability of phosphorus in soils by increasing the content of organic matter and debasing the acidity in soil.