Research On The Form Changes And Availability Of Organic Phosphorus Long-term Fertilizer

Phosphorus is one of the essential elements for plant growth; organic phosphorus imposes animportant impact on the soil fertility and vegetative availability. In the past, studies on phosphorusavailability was centered on the direct utilization of inorganic phosphorus, other forms ofphosphorus were rarely studied, especially organic phosphorus. In fact, some of organicphosphorus was easy to be mineralized and plays an important role to the supply of phosphorus.Thus, a thorough understanding of the forms and quantity of organic phosphorus has implicationsfor the agricultural production and the supply of phosphorus. Especially on the phosphorusdeficient soils, organic phosphorus may be mineralized and be transformed into availablephosphorus to supply plant. In this case, organic phosphorus becomes an important supplier ofphosphorus to the plant.In this study, four types of soils, the fluvo-aquic soil, paddy soil, red soil and purple soil from"CNSFFELTMN", were taken into consideration as the objects of study. Beginning from fertilizerexperiments (treatments: CK, N, NP, NPK and NPKM) combined with bioavailability experimentsin pot, effects of fertilizer treatments on the organic forms and on the bioavailability of phosphoruswere studied. The results showed that:1 On the typical soils of China, the organic phosphorus contents for every four types was different,the neutral active organic phosphorus dominated the organic phosphorus, followed by the middlestable organic phosphorus, the high stable organic phosphorus and active organic phosphorus.2 Fertilizer treatment effects on the contents of four type organic phosphorus was high, mainly onthe types of active organic phosphorus and neutral organic phosphorus. For the N treatment,changes of contents of four types of organic phosphorus were not remarkable, and changes remainon the inter-transformation between these four types. When phosphorus fertilizer was applied, thecontents of four types of organic phosphorus were all elevated in certain extent, and for thetreatments of NPK and NPKM, the increases in organic phosphorus of all four types wereremarkable, indicating that balanced fertilization benefited the uptake and use of organicphosphorus.3 On the soils of four types, the total organic phosphorus content and the ratio between the fourtypes of organic phosphorus for different fertilizer treatments remained almost stable; theyfluctuated in certain extent without significance.4 On the relationship between organic phosphorus and labile phosphorus, most of the organicphosphorus correlated with labile phosphorus at 0.01 level. In combination of the conclusion that middle active phosphorus' content was highest, accounting for more than 50ï¼…of the total organicphosphorus, the conclusion that middle active phosphorus was the biggest contributor to theavailable organic phosphorus can be drawn; the middle active phosphorus leaded the supply oforganic phosphorus.5 On the plant growth and biomass, organic phosphoric compounds YJL1 and YJL2 increased thegrowth of plant and the accumulation of dry-matter significantly, no phosphorus deficientsymptoms was shown during the entire growing season, showing that these two organic phosphoriccompounds were much better than ordinary phosphorus fertilizers, lecithin and calcium phytate insupplying phosphorus to the plant.6 On the vegetative uptake of phosphorus and the efficiency of phosphorus, treatments of organicphosphoric compounds YJL1 and YJL2 were more prominent than mono-calcium phosphate andcalcium phytate treatments, equivalent to the lecithin treatment. These two organic phosphoriccompounds have certain potential and value and studies is worth to be studied furthered as organicphosphorus fertilizer.