Effects Of Long-term Fertilization On The Changes Of Different Forms Of Phosphorus In Black Soil

Phosphorus is one of the macronutrient elements necessary for the growth and development of plants.The phosphorus content in the soil is limited.Phosphate fertilizer is an important way to increase the phosphorus content of the soil.However,excessive application of phosphate fertilizer will cause a series of problems such as fertilizer waste and environmental pollution.Black soil has the characteristics of high fertility and strong nutrient supply capacity.Studying the evolution law of soil phosphorus in black soil under long-term fertilization is of great significance to the efficient use of phosphate fertilizer,and at the same time,it also has an important contribution to the protection of black soil.The experiment was based on the Heilongjiang Cultivated Land Conservation and Agricultural Environmental Science Observation and Experimental Station of the Ministry of Agriculture and Rural Affairs（established in 1979）.The experiment selected 8fertilization treatments,namely no fertilization（CK）,organic fertilizer（M）,and single application of phosphate fertilizer（P）.),double phosphate fertilizer（P2）,nitrogen phosphate fertilizer（NP）,double nitrogen phosphate fertilizer（N2P2）,nitrogen phosphorus potassium fertilizer（NPK）,organic fertilizer+nitrogen phosphorus potassium fertilizer（MNPK）,and analyzed the total phosphorus and available phosphorus content of the soil And the changes in the classification of inorganic phosphorus classification.Results showed:1.After 40 years of long-term positioning fertilization test,except for CK and M treatments,all other chemical fertilizer treatments and combined application of organic fertilizers and chemical fertilizers have increased soil total phosphorus and available phosphorus content,of which total phosphorus under CK and M treatments Reduced by about 20.1%and 8.2%,and reduced available phosphorus by about 83.7%and 47.6%;in the phosphate fertilizer treatment,the total phosphorus content increased the most in the N2P2 treatment,which increased by about146.9%,and the NP treatment increased by about 57.5%;the available phosphorus increased the most.It was P2 treatment,about 660.1%,and the smallest increase was NP treatment,about213.2%.In general,long-term application of phosphate fertilizer can effectively increase the total phosphorus content of the soil,and the greater the amount of phosphate fertilizer,the higher the total phosphorus content of the soil.The combined application of organic fertilizers and chemical fertilizers is better than single application of chemical fertilizers..2.The soil phosphorus activation coefficient（PAC）of the treatment without chemical fertilizer（M）was less than 2%;the PAC value of the single application of organic fertilizer was slightly greater than 2%;the PAC value of the two-fold phosphate fertilizer treatment（N2P2,P2）was greater than that of the one-fold phosphate fertilizer treatment（P,NP,NPK,MNPK）,the PAC value of the combined application of organic and inorganic fertilizers is 1 times higher than that of other chemical fertilizers.3.Long-term fertilization has an effect on the relative content of each component of inorganic phosphorus in black soil.After 40 years of long-term fertilization test,compared with CK and M treatments,each phosphate fertilizer treatment obviously added soil Ca₂-P,Ca₈-P,Al-The relative content of P and Fe-P;in the application of chemical fertilizers,the relative content of Ca₁₀-P and OP was significantly lower than other inorganic phosphorus components.In the M and CK treatments,the content of inorganic phosphorus in various forms in the soil was O-P>Ca₁₀-P>Fe-P>Al-P>Ca₂-P>Ca₈-P.In other fertilization treatments,the content of various forms of inorganic phosphorus in the soil was Fe-P>O-P>Al-P>Ca₂-P>Ca₁₀-P>Ca₈-P.4.Long-term fertilization can effectively increase the active inorganic phosphorus and intermediate active inorganic phosphorus components of the soil.Compared with CK,the active inorganic phosphorus component of each phosphate fertilizer treatment is 972.7%～3152.2%more than CK,and the intermediate active inorganic phosphorus component is more than CK400.5%～959.9%more;the higher the application of phosphate fertilizer,the higher the relative content of active inorganic phosphorus and intermediate active inorganic phosphorus.Compared with single application of chemical fertilizer,the relative content of inorganic phosphorus and intermediate active inorganic phosphorus increased slightly..5.In the long-term fertilizer treatment,the content of individual components in the total phosphorus and active inorganic phosphorus and intermediate active inorganic phosphorus in the NP treatment were lower than that in the P treatment,while the above-mentioned phosphorus content in the N2P2 treatment was higher than that in the P2 treatment.