Soil Phosphorus Forms and Availability in Coffee Plantations
The forms of phosphorus in coffee garden soils were studied.The results showed that the content of inorganic P was higher than organic P,O-P was the main form in the inorganic P,accounting for 54.63% of the total inorganic P.Moderately labile organic P was the main form in the organic P,accounting for 70.14% of the total organic P.With the increasing of planting years,the differences of total P content was significant,but the variation tendency of total P content was not obvious.Available P,Al-P and Fe-P increased significantly,and total organic P,moderately labile organic P,moderately resistant organic P and highly resistant organic P decreased significantly.Available P was significantly or very significantly correlated with Ca-P,Fe-P and Al-P.The largely accumulated P consisted of Ca-P,Fe-P and Al-P,which had higher availability to crop.