Study On Organic Phosphate Fertilizer And Phytoavailability

In this study, five organic phosphate fertilizers were synthesized and investigated through laboratory and plant experiments to compare their mobility, transformation and phytoavailability with different inorganic phosphate fertilizers. The diffusion of different phosphorus fertilizers, the plant biomass, P uptake, fertilizer utilization efficiency as phytoavailability indexes, and soil Olsen-P and soil organic phosphorus fractionation were determined. The results show as follows:(1)Selected organic waste and inorganic phosphorus in the optimal reaction conditions through physical and chemical reactions. The ultimate synthesis of five kinds of organic phosphate and were treated with OP1, OP2, OP3, OP4 and OP5 said; the content of phosphorus(P2O5)were 9.12%, 9.69%, 11.26%, 11.56%, 12.18%, respectively.(2)With soil depth increase, the diffusive amount of all the phosphorus fertilizers in three soils (sand, cinnamon and red soils) were getting smaller and smaller. The trend of different phosphorus fertilizers depends on different phosphate fertilizers. Inorganic phosphate in three types of soils with super phosphate shortest diffusion distance, the longest relative sodium pyrophosphate, calcium biphosphate between the two; in 20-mm layer in three soils, sodium pyrophosphate diffusion amount was significantly higher than calcium biphosphate and super phosphate. Sodium pyrophosphate diffusion amount in cinnamon and red soil were both significantly higher than calcium phosphate and super phosphate in 40 mm layer. While there was no difference between sodium pyrophosphate and calcium biphosphate in sandy soil, but both of them were significantly higher than super phosphate; apparent diffusion coefficients of sodium pyrophosphate soil were increased 0.42~1.07 times in three soils than super phosphate and calcium biphosphate, otherwise calcium biphosphate were increased 0.07~0.58 fold than super phosphate.(3)The apparent diffusion coefficients for organic phosphate fertilizers were superior to that for inorganic phosphate. The average of diffusion distance for five organic phosphate fertilizers was farther than that for inorganic phosphate with 20.6 mm, the longest was OP1, followed by OP3 and OP2. The average diffusive amounts in 20 mm and 40 mm layers for organic phosphate fertilizers increased from 0.4 to 0.8 times and 1.7~2.8 times compared with inorganic phosphate, respectively. The order of diffusive amounts for different fertilizers were: OP1> OP3≈OP2> OP4≈OP5> inorganic phosphate in both 20 mm and 40 mm layers of three soils, furthermore average diffusive amount of OP1 was the largest and achieved a significant difference with other organic phosphate fertilizers; the apparent diffusion coefficients for organic phosphate fertilizers were increased by 0.32~1.57 fold compared with inorganic phosphate, OP1 was the largest, OP3 was larger than OP2, but little difference in cinnamon and red soils, except the sandy soil. The apparent diffusion coefficient of OP5 was more than OP4 in three soils. (4)Organic phosphate fertilizers in soils mainly existed as highly effective forms and increased soil available phosphorus content in soils. Inorganic phosphates were increased active organic phosphate, medium active organic phosphate, medium stable organic phosphate and high stable organic phosphate to 22.3~75.9%, 5.06~7.79%, 9.41~27.87%, 15.63~43.02% than CK, respectively. Four organic phosphorus content with organic phosphate fertilizers increased by 2.05~46.9%, 6.86~32.9%, 1.07~30.86% and 7.56~35.93% than inorganic phosphate. Soil available phosphorus content was increased by more than 0.96~2.33 times with inorganic phosphate than CK,while organic phosphates fertilizers increased 37.3~135% than inorganic phosphate. Whether high P level or low, the relationships between organic phosphorus fractions and olsen-p content were positively and correlated significantly.(5)Plant biomass for Inorganic phosphate treatments was increased by 0.94~2.1 fold than CK and following order was: sodium pyrophosphate> phosphate> calcium biphosphate. Organic phosphate fertilizers increased 29% than pyrophosphate sodium. Organic phosphate fertilizer provided high effective phosphorus and alredy reached a high level less than half fertilizer application.(6)Organic phosphate fertilizers promote plant uptake of phosphorus and high fertilizer utilization efficiency. Plant uptake of P for three inorganic phosphates per pot, plant phosphorus content and phosphorus utilization raised and was in the order: sodium pyrophosphate maximum, followed by orthophosphoric acid and calcium biphosphate. Plant uptake of P for organic phosphate fertilizers per pot, plant phosphorus content and phosphorus utilization were increased 41.9%, 29.6% and 61.9% compare with sodium pyrophosphate, respectively.To analysis different phosphate mobility, transformation and phytoavailability, it was found that organic phosphate fertilizers were better than inorganic fertilizers.