Research At Spatial Distribution Characteristic And Migrate Conversion Law Of Phosphorus In Soil In Tongliao's Sewage Irrigation Area

The lack of overall water resources of our country leads to increasingly serious water shortage; especially in arid areas in northern China, Agriculture had to use a large number of sewage irrigating. Sewage contains large amounts of N, P, K and other nutrients, such as phosphorus is necessary for crops to grow as one of the important nutrients.This issue aims at researching phosphorus in the agricultural soil, combining soil phosphorus to wastewater irrigation Investigation and simulation of laboratory soil column experiment getting the following two studies:1,investigate on both sides of the sewers from agricultural soils and the conventional physical and chemical properties and analyze of wastewater irrigation and the spatial distribution of soil phosphorus in the form; 2,do the laboratory soil column experiment; analyze the phosphorus in the soil variation at different concentrations of phosphorus-containing waste water leaching conditions.That is the conclusion:1,Most of the soil total phosphorus concentration among 300～700mg/kg and the Average value is 451.42mg/kg, as a whole belong to low standards.There have two areas with higher phosphorus content, and appear near the kongjiaxiang and qianjiaxiang, which related to the local soil composition and irrigation with sewage so many years.2,With many years of history of sewage irrigation the 7th hole and the 8th hole compared to the 9th hole with year-round using of groundwater for irrigation, soil phosphorus has the similar changes, only phosphorus content of the 7th hole and the 8th hole have a certain distance down than the 9th hole, but no significant difference between the peak size, and the peak was both less than 500mg/kg. With local long-term fertilization and irrigation water for many years of history can be inferred, sewage irrigation on local soil phosphorus accumulation and migration is not significant.3,Spatial variability of soil phosphorus studies of kongjiaxiang have shown that in kongjiaxiang total phosphorus, effective phosphorus, NaOH-Pi and Ca-P have similar spatial distributions, all in all, higher in northern and southern lower. Especially effective phosphorus, sewage irrigation area is 66.49% higher than groundwater irrigated area. 4,Soil column experiments showed that the soil has good stabilizing phosphorus function, when phosphorus-containing waste water into the soil, adsorption and precipitation reactions can trapped phosphorus in the soil. If we irrigate three-year irrigation water volume (24L), the phosphorus content of more than 60cm underground changed significantly, above 60cm little changed, which indicated that phosphorus with water down the rate of migration is lower, this is mainly related to phosphorus as adsorbed state and precipitated state exists in the soil and sediment. Cumulative rate of migration of phosphorus changes along with the concentration of leaching solution, the greater the concentration, the faster rate. Using local sewage treatment plant effluent irrigating soils have little effect on migration and transformation of soil phosphorus. If you increase the concentration of phosphorus leaching solution, you can effectively improve the surface soil effective phosphorus content; therefore, just considering from the perspective of phosphorus, agricultural irrigation water can be appropriately broadened the requirements of phosphorus.