Environmental Effects Of Crop Fertilization In Wujin District

Fertilizer as an important farming inputs,excessive fertilizer or improper fertilizer can cause nitrogen and phosphorus loss of farmland,it has become one main source of agricultural nonpoint pollution.Therefor studing the characteristics of agricultural nonpoint pollution caused by fertilization is of great significance for the control of nitrogen and phosphorus loss in agriculture.In this study,choose Wujin District where close to the Tai Lake as research object,using the first time census database of agricultural pollution sources,statistical analysis of their towns' planting structure;use of sampling methods,analyze and evaluate the type and amount of fertilizer of the main crops.Meanwhile,set up plot experiments of typical planting patterns to study surface runoff loss rules of nitrogen and phosphorus form 2008 to 2009.On these basis,the calculation of the emission intensity of surface runoff nitrogen and phosphorus of Wujin District was conducted,then using equal standard pollution loading method to evaluate the result of the fertilization on the water environment quality.Eventually measures and recommendations that could slow down the agricultural non-point source pollution due to excessive fertilization and improper fertilization were proposed.Main conclusions indicated that:1.N inputs per unit area of cultivated land was 685.16 kg·hm-2,P inputs 186.13 kg·hm-2,corner garden area N inputs 358.52 kg-hm'2,P inputs 523.83 kg·hm-2.The order of total amount of fertilizer input of cropping patterns is vegetables>Peach>grape>flowers>rice-wheat rotation>rice-rape rotation>single season rice>pear>tea.There was the phenomenon of over-fertilization on rice and wheat planting,50%of the rice production households to excessive fertilize,and 65%of the wheat production households to excessive fertilize.Excessive fertilization on rape cultivation is not obvious.2.Fertilization and rainfall are the two important factors to affect the nitrogen and phosphorus concentration of surface runoff,and low vegetation coverage is easier to produce a greater surface runoff.NO3--N is the main form of nitrogen runoff loss.Fertilization on different cropping patterns has different effects on nitrogen and phosphorus loss of surface runoff.Organic Fertilizer could inhibit nitrogen and phosphorus loss,while excessive fertilization significantly increases the amount of surface runoff loss.On wheat-rice rotation field,the surface runoff loss of TN was 12.30±1.80 kg·hm-2 and the surface runoff loss of TP was 0.03±0.00 kg·hm-2 one year due to fertilizer.Nitrogen loss rate was 2.87%and phosphorus loss rate was 0.05%.On oilseed rape-sweet potato rotation field,the surface runoff loss of TN was 0.99±0.08 kg·hm-2 and the surface runoff loss of TP was 0.39±0.04k kg·hm-2 one year due to fertilizer.Nitrogen loss rate was 0.23%and phosphorus loss rate was 0.34%.On Vegetables growing land,the surface runoff loss of nitrogen was 32.81?44.08 kg·hm-2 and the surface runoff loss of phosphorus was 0.86?1.37 kg-hm"2 one year due to fertilizer.Nitrogen loss rate was 1.07?2.17%and phosphorus loss rate was0.43%?4.63%.3.A total amount of farmland runoff pollution emission to the water caused by fertilization were 354.47 tons of nitrogen per year,and 11.57 tons of phosphorus per year in Wujin District.Among all the towns,the pollution load of Xueyan Town was the highest(0.16),and it's the largest source of pollution due to fertilizer in Wujin District.As it's close to Tai Lake,it had great impact on water environment of Tai Lake.In addition to Luoyang Town where the major pollutant was phosphorus,the major pollutant of the other towns in Wujin District was nitrogen.