The Studies On Simulations Of Phosphorus Leaching In Soil

Phosphorus is one of the main matters of eutrophication, the effect of the moving and leaching of soil phosphorus has become one of the content in environmental soil science. The problems of water pollution and lake eutrophication which is caused by phosphorus leaching are quiet serious. The studies which is about soil phosphorus enrichment leads to water eutrophication have taken a great progress,but many people are concerned about the pathway flow of the earth's surface and soil erode,however the study that phosphorus leaching from cropland leads to water pollution is less. This study, using many simulation measures, proved up the mechanism of soil phosphorus leaching, we want to find out soil phosphorus leaching generally, and establish foundations of fertilization in reason and water eutrophication caused by agricultural contamination. This research adopted the simulations of winter-wheat potted plant,indoor soil column,outdoor field measurement, and we want to know the phosphorus leaching of cinnamon soil in Yangling. I get the conclusions as followed:1,The experiment of winter-wheat potted plant shows : as phosphorus application increased, total phosphorus and the ratio of molybdate reaction phosphorus to total phosphorus increased. Fertilizer application method had a significant effect on phosphorus leaching. Mixing the fertilizer with the soil increased the quantity of phosphorus leached from the soil, especially the quantity of dissolved phosphorus. The form of phosphorus leached from the soil changed across time. Particle phosphorus was first to leach from the soil followed by dissolve organic phosphorus. The largest amount of phosphorus lost from the soil was in the form of molybdate reaction phosphorus. At low levels of phosphorus the largest proportion of phosphorus leached from the soil was in the form of dissolve organic phosphorus. In contrast, as soil phosphorus increased, most phosphorus leached from the soil was in the form of MRP.2,The experiment of indoor soil column indicted: as the increase of concentration of phosphorus solution, the concentration of total phosphorus and total dissolve phosphorus has no enormous changes in leachate, but it tended to increase gradually, the ratio of molybdate reaction phosphorus to TP appearanced peak value with the concentration of phosphorus solution increased. The leaching of phosphorus can obviously augment while the soil horizon is mixed with sand, the dissolve inorganic phosphorus is the main character of leaching.3,The experiment of outdoor field measurement indicted : after pouring the phosphorus solution, the content of phosphorus has increased in each soil horizon, it indicts that the phosphorus in soil is migratory, some partial phosphorus, overpassing soil porosity, can leaching to the bottom of soil horizon. From the spatial distribution, the content of Olsen-P assumes the trend of decrease in outdoor field measurement with the soil horizon deepens, the content of Olsen-P in each soil horizon, compared to controls, assumes the trend of obviously increase, in each soil horizon, water-P and CaCl₂-P are both detected, according to the research of predecessor, the soil can occur eluviation.