Effects Of Amount,Depth And Fertilization Of Straw Ditch-Buried Returning On Nutrient Leaching In Water Leakage

The conventional ways of straw returning to field would be difficult whole amount of straw to field, returning too shallow that limiting Soil carbon sequestration, and is not conducive to deepening topsoil and other issues. From the perspective of controlling the environmental pollution, improving the soil quality and production potential, and enhancing soil carbon sequestration ability, the article innovatively developed the key technology of " straw ditch-buried returning ". Straw ditch-buried returning is a measure of straw returning ditch buried concentrated after the harvest of crops, which would achieve full amount of straw returning to field deeply and mechanizationly, and achieve less groundbreaking, deep plowing the soil and enhance soil carbon sequestration ability. A pot experiment was conducted in the Nanjing agriculture pailou test base in2010-2012, conducts the research to the rice-wheat rotation loss of nitrogen and phosphorus from the straw volume, buried depth, and fertilization volume. The main conclusions are as follows:1. Wheat straw ditch-buried returning can reduce nitrogen leaching content of water leakageAfter wheat straw ditch-buried returning, soil permeability increased, the quantity of water leakage of rice season and wheat season increased, and the more wheat-straw buried, the greater leakage. Nitrogen leaching from wheat straw ditch-buried returning on rice season and wheat season has obvious interception effect. The management of grass buried depth of35cm and quantity of5kg/m2could significantly reduce the daily average N and total N of seepage of paddy fields. Compared with CK, the daily average N content in2010and2011was reduced by17.20%and12.47%; And the total N was reduced by10.90%and14.07%.The daily average N content in2010and2011was reduced by20.52%and23.91%; And the total N content was reduced by9.56%and16.56%. So the appropriate amount and depth of wheat straw returning can effectively reduce the leaching of N, improve fertilizer utilization efficiency, reduce environmental pollution.2. Rice straw ditch-buried returning can reduce nitrogen leaching content of water leakageThe total N concentration of paddy water leakage were increased firstly and then decreased after fertilization. With the increasing of N fertilizer, the N concentration of paddy water leakage increased, and comparred with no returning straw, rice straw returning reduces the concentration of total N in water. The total N concentration of different levels of leakage water generally shows compete on low trend, bellowing the30cm depth of straw returning treatments the total N concentration was the highest. With the application of N fertilizer and straw, N concentration of the leakage of water can be reduced, and appropriate amount and depth of rice straw returning can effectively reduce the leaching of N, improve fertilizer utilization efficiency, reduce environmental pollution.3. Wheat straw ditch-buried returning can reduce phosphorus leaching content of water leakagePhosphorus leaching from wheat straw ditch-buried returning on rice season and wheat season has obvious interception effect. The management of the buried grass depth of35cm and buried grass quantity of5kg/m2could significantly reduce the daily average P and total P of paddy water leakage. Compared with CK, the daily average P content in2010and2011of the rice season was reduced by29.3%and31.9%. And the total P was reduced by5.4%and23.4%than CK. The daily average P content in2011and2012of the wheat season was reduced by24%and36.1%. And the total P was reduced by5%and41.4%than CK. After wheat-straw ditch-buried returning, the quantity of paddy field leakage increased, and the more wheat-straw buried, the greater leakage. Therefore, appropriate quantity of returning and depth of returning can reduce phosphorus leaching, improve nutrient utilization, and reduce environmental pollution.