The Changes Of Phosphorous Fractions In Black Soil Applied Organic Materials

Decomposition of organic materials in the soil need a long time.In this paper,a five years pot experiment was held to explore the long-term dynamic change law of the forms of organic phosphorus in black soil,and set up four kinds of organic materials including pig manure(PM),maize straw(MS),leaf manure(LM),mushroom dreg(MD)and chemical fertilizer only(NPK).This experiment discussed the effect organic material ontransformation of different phosphorus forms combined with the contents of soil total phosphorus,available phosphorus,content of organic phosphorus forms,content of inorganic phosphorus forms and phosphatase activity,and The results shows that:(1)The concentration of total P after applying organic material average for PM > MS > MD > NPK > LM.Soil phosphorus pool is given priority to with inorganic phosphorus,which the percentage of ML-OP and MR-OP in inorganic P pool is approximately 70%,the percentage of O-P and Ca10-P in organic P pool is approximately 50%.The content of available P of PM,MS and MD can by improved in 5 years,5 years and 3 years respectively.The percentage of ML-OP and L-OP increased in PM and LM treatments,and percentage of MR-OP increased in MS and LM treatment.Organic materials(except maize straw)could increase the proportion of Ca2-P?Ca8-P and Al-P,and decrease the proportion of Fe-P and O-P,while has little effect on Ca10-P.the proportion of O-P in MS and O-P treatment was decreased.(2)Compare with applying chemical fertilizer only,concentration of L-OP of PM treatment was significantly higher and continually reduce in 5 years,concentration of MS and LM treatments achieved the highest levels after 3 years,2 years respectively.Application of PM,MS and MD increased concentration of ML-OP.The concentration of ML-OP continue decreased in 5 years after application of PM,while other treatments increased.The concentration of MR-OP are significantly increased at first but decreased year by year after applying organic materials,including straw treatment which was always higher than the rest.HR-OP began to decrease from 2 years or 3 years after of application of organic materials.(3)Application of PM,MS and MD could increase the concentration of Ca2-P,and achieved the highest levels after 1 years,3 years and 2 years respectively;the concentration of Ca2-P PM and MD treatment was significant higher than NPK after 5 years.The PM treatment had the best lifting effect of AL-P,which stay smooth after achieving the highest after 2 years;the MS,MD and LM could increase its' concentration before 2 years,2years and 1years respectively.The trend of Fe-P was similar in each treatment;the content of Fe-P increased in PM and MD treatments while decreased in MS and LM treatments,and MS decreased more than the rest.Organic material average increase the content of O-P at first year,but mushroom residue in the second year,leaves,maize and pig manure content is lower than that of NPK at 4 years.Fertilization of chemical fertilizer is conducive to the accumulation of O-P and the rate slow down year by year.Organic materials tend to impact on the Ca10-P in 2 years,but less affected.(4)Organic materials could improve alkaline phosphatase activities before 2 years after applying,while NPK treatment decrease before 3 years.Neutral phosphatase activity generally decreased in each treatment,but the rate could slow down by organic materials(except leaves).The activity,proportion and activity of P could be improved by PM and MS.(5)Organic materials could activate O-P,and MD was the best,LM followed by.Organic materials could activate steady-state inorganic and organic phosphorus in different extent.But apply chemical fertilizer only promote MR-OP transform into HR-OP and the accumulation of O-P.