Effect of long-term fertilization on the content of different forms of phosphorus in wheat

Based on a long-term fertilization experiment, the effect of different fertilizations on the content of different forms of phosphorus in wheat was investigated. The results indicate that under different treatments, the contents of different forms of phosphorus in wheat grain are higher than those in the stem. In wheat grain, lecithoid phosphorus is the highest (1.19 g·kg^-1), followed by labile organic and inorganic phosphorus; whereas the content of unknown forms of phosphorus is lowest (0.348 g·kg^-1). In the stem, the content of labile inorganic phosphorus is highest (0.142 g·kg^-1) while that of labile organic phosphorus is lowest (0.034 g·kg^-1). The content of labile organic phosphorus in wheat stem under organic manure (OM) treatment is significantly lower than in the control treatment. Also the content of the other forms of phosphorus is higher under P (PK, NP, NPK, OM & 1/2OM + 1/2NPK) treatments than under non-P (CK, NK) treatments. Compared with the control treatment, the content of the different phosphorus forms and total phosphorus in wheat grain and labile inorganic P, unknown forms of P and total phosphorus in stems increases significantly under OM treatment. In wheat stem, the content of labile organic phosphorus and lecithoid phosphorus under NP treatment is higher than under other treatments. There is a significant positive correlation between the different forms of phosphorus and total phosphorus content in the grain.