Effects of different ratios of base P to dressing P on inorganic phosphorus fractions in paddy soil and rice yield

To seek for the optimal ratio of base P to dressing P for drip irrigation rice, different ratios of base P to dressing P were designed, including CK: no phosphatic fertilizer, T1: 100%, T2: 30% base P + 70% dressing P, T3: 70% base P+30% dressing P, T4: 100% dressing P, the impacts of different ratios of base P to dressing P on soil inorganic phosphorus components and rice yield components were studied by adopting soil stratification sampling, dry matter determination at growth stage and test species after harvest. The results showed that the contents of Resin-P, NaHCO3-P of T1 treatment were the highest, HCl-P of which was the lowest compared with other treatments in the harvest period. Residue-P content of T2 treatment was the highest, NaOH -P content of which was the lowest. Inorganic phosphorus content of each component of T3 and T4 treatment had no regular pattern. The mode of 30% basal application and 70% topdressing of phosphorus could obtain the highest biomass and yield, increasing by 11.67% and 9.92% respectively, compared to CK. There was a similar trend reflecting in the effective panicles, grain number, real grain number, seed rate and grain weight on.