| With the development of Chinese agriculture,output of crops have been continuously improved,and inputs of inorganic fertilizer have been increased year by year,which caused so many problems,such as excessive fertilization,low utilization rate of fertilizer,fertilizer residues and the loss of fertilizer increased,and these problems will result in eutrophication.Planting non-point source pollution problems caused by the loss of nitrogen and phosphorus nutrients are more and more highlighted,that attracted all social people's attention and worries.Tongcheng City is located in the south of Anhui province,the main plant are rice-wheat rotation and rape-rice rotation,it is important to handing characteristics and laws of farmland nutrient loss and pollution in the local rape-rice rotation system for reducing environment pollution which caused by nitrogen and phosphorus loss in agricultural production process,finding out pollution base,marking corresponding reducing technologies and controlling plant non-point source pollution on Tongcheng City.In this study,through monitoring rape-rice rotation site on Zhu Qiao village,XiZi Lake country,Tongcheng City,farmland loss of nitrogen and phosphorus,nitrogen and phosphorus loss coefficient and nitrogen and phosphorus fertilizer utilization by habitual fertilization has been researched,according to records and analysis of the experiment date insist on the following conclusions:1.On Tongcheng City,the amount of direct surface runoff in rape season was significantly greater than which in rice season.According to the data of rainfall,the rice season rainfall is significantly greater than the rape season rainfall;At the same time,the wheat season rainfall in 2013 is greater than which in 2012,as the same as in2014,the rule of each year's difference of surface runoff is the same as the rule of each year's difference of rainfall,it can be concluded that the effect of surface runoff affected by rainfall and the rainfall intensity and other climatic conditions.2.The loss of nitrogen and phosphorus and the loss of nitrogen in rape season in2013 was the largest,on the conditions of conventional fertilizer,the loss of total nitrogen was 15.81kg/hm~2,which has increased by 11.12kg/hm~2 and 10.56kg/hm~2 ascompared with 2012 and 2014,the loss of total phosphorus was 0.23kg/hm~2,which has increased by 0.06kg/hm~2 and 0.16kg/hm~2 as compared with 2012 and 2014;The loss of nitrogen in rice season in 2013 was the largest,on the conditions of conventional fertilizer,the loss of total nitrogen was 8.55kg/hm~2,which has increased by 3.25kg/hm~2 and 1.75kg/hm~2 as compared with 2012 and 2014;The loss of phosphorus in rice season in 2013 was the largest,on the conditions of conventional fertilizer,the loss of total nitrogen was 0.27kg/hm~2,which has increased by0.05kg/hm~2 and 0.06kg/hm~2 as compared with 2012 and 2014,Throughout the year,the loss amount of total nitrogen in 2012 and 2014 were 9.99kg/hm~2 and 12.05kg/hm~2,the loss amount of total phosphorus were 0.39kg/hm~2 and 0.34kg/hm~2,the difference of the total nitrogen loss is equivalent to that of total phosphorus.On the conditions of conventional fertilizer,the loss of nitrogen and phosphorus was mainly in rice season,the loss of phosphorus has been increased obviously after fertilization.3.The loss coefficient of nitrogen and phosphorus.The loss coefficient of total nitrogen from 2012 to 2013 in rape season were 0.75%,2.62% and 0.85%,the loss coefficient of phosphorus were 0.05%,0.07% and 0.02%;The loss coefficient of total nitrogen in rice season were 1.09%,1.41% and 2.21%,the loss coefficient of phosphorus were 0.1%,0.1% and 0.17%;On the condition of rape-rice rotation system and the conventional fertilization mode in Tongcheng City area,loss coefficient of total nitrogen and total phosphorus in rice season was lager than which in rape season.4.By comparing the amount of nitrogen and phosphorus absorption in the economy parts and scrap parts in rape season and in rice season,the absorption of nitrogen,phosphorus and potassium in rice were lager than that in rape,of which the difference of the absorption of potassium was least,the difference of the absorption of phosphorus was medium,the difference of the absorption of nitrogen was largest,the absorption of nitrogen,phosphorus and potassium in rice have increased 43.57 kg/hm~2,22.68 kg/hm~2 and 18.57 kg/hm~2 as compared with that in rape.Therefor,even though the loss of nitrogen and phosphorus in rice was more serious than which in rape,but the absorption of nitrogen and phosphorus in rape was lager than which in rice,the demand and the use of fertilizer in rice was higher thanwhich in rape.5.The utilization rate of fertilizer.The utilization rate of nitrogen in rape season from 2012 to 2014 were 23.14%,14.28% and 16.09%,which shows that the utilization rate of nitrogen in 2012 was the highest,the lowest was in 2013;The utilization rate of phosphorus were 9.24%,14.9% and 7.98%,the highest was in 2013;The utilization rate of potassium were 49.11%,7.59% and 42.1%,the highest was in2012;The utilization rate of nitrogen in rice season from 2012 to 2014 were 27.63%,25.47% and 23.56%,the highest was in 2012,the lowest was in 2013.The utilization rate of phosphorus were 20.78%,24.93% and 19.98%,the highest was in 2013;The utilization rate of potassium were 52.67%,49.68% and 59.31%,the highest was in2014,the lowest was in 2013.The utilization rate of nitrogen in rape was close as that in rice in Tongcheng City,they all in the low lever;The utilization rate of phosphorus had a large difference,the utilization rate of phosphorus in rape was only 10%,which was really lower;Under the utilization rate of potassium,which in rape was higher than which in rice,the utilization rate of potassium in rape season was up to 49.11%,which equal to the lever of developed states' potassium utilization rate.6.According to the output of rape and rice,it shown that no fertilizing will affect crop yield which leaded to significant reduction.Overall test results,use of nitrogen,phosphorus and potassium could significantly increase output.Excluding climate and other factors,the output of crop yield in conventional fertilization obviously increased than that in no fertilizer,and the loss of nitrogen and phosphorus in conventional fertilization was not high.7.In three years six quarter of rice rotation cropping patterns in Tongcheng area,conventional fertilization in rape season annual income increased 8107.5 yuan /hm~2 as compared with no fertilizer annual income,conventional fertilization in rice season annual income increased 9365.3 yuan /hm~2 as compared with no fertilizer annual income,the average annual income was 17472.9 yuan /hm~2. |
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