Effects Of Different Fertilization Techniques On The Emission Of Methane And Nitrous Oxide From Single Cropping Rice

Global warming caused by anthropogenic greenhouse gas has become an urgent issue to be solved. CH4 and N2O are two important greenhouse gases preceded only by CO2. Rice field is a major emission source of CH4 and N2O, while single cropping rice in Chaohu area is an important rice production field. But researches on the single cropping rice's discharging of CH4 and N2O are rare, especially researches on technique of fertilization's influence to single cropping rice's discharging of CH4 and N2O, which was hardly ever done.This experiment mainly study in the single cropping rice field, a perennial rice-based cropping system in agricultural non-point source pollution test site, which is located in Tongyang Town, Juque, Hefei City. It uses static chamber-gas chromatograph technique to research in the gap, normal, high yielding, high yielding+urease inhibitor and controlled release fertilizer by the treatment of 5 techniques, which show the rule of discharge of CH4 and N2O and its influencing factor in the whole growth period of rice field; Evaluate the fertilizer practice(including new types of fertilizer), application of inhibitors and all the other aspects of possible environmental and economic influences of the fertilizer emission reduction technology.Through field monitoring, we can reach a conclusion as follows:1. In the growing period of single cropping rice, CH4 season emission rule in different techniques of fertilization treatment is "bimodal" with two peaks changing in the trend "firstly rises and then declines". The peaks appear in the tillering stage and the emission speed of CH4 in the peak in high yielding>normal>control of fertilizer loss>urease inhibitor>empty. Compared to emission of CH4 in different periods of the rice, we can see that single cropping rice emission of CH4 centers on tillering stage and flower booting stage, amounting to 45.23% and 35.06% of the whole growing period of single cropping rice.2. The feature of seasonal emission of N2O of single cropping rice field is basically "unimodal type", the intensive time of emission of N2O of cropping rice field is during and after drying paddy field in sunshine, when the maximum peak emerges, the sequence of emission speed of N2O is:high yielding>routine>loss-control fertilizer>urease inhibitor>empty.The discharge of N2O of single cropping rice field concentrates on the tillering stage and the flowering booting stage, and also some in the filling and ripening stage. The discharges of N2O in the tillering stage reach to 45.86% of that in the whole growth period, with a concentrated discharge after the soil drying.3. Monitor of seasonal emission treated with different fertilization suggested that nitrogen fertilizer would enlarge emission of CH4 of Single Cropping Rice. Calculative CE4single cropping rice emitted with different treatment goes like this:high yielding > regular>loss-control fertilizer> high yielding+urease inhibitor> empty;Compared with the conventional treatment, the CH4treatmented by high yielding and urease inhibitor decrease by 25.8% in a season, the cumulative emissions of the CH4 treatmented by loss-control fertilizer decrease by 15.8% in a season. Both show remarkable difference. Loss-control fertilizer and urease inhibitor can prevent effectively the emission of CH4 in rice field. The emission of N2O treatmented by different fertilizer practice has a little difference. The emission of N2O in single cropping rice shows:high yielding>common practice>loss-control fertilizer> blank >high yielding and urease inhibitor, it hasn't significant difference among these different treatment.4. CH 4 is the major contributors of paddy greenhouse effect. The comprehensive greenhouse effect treatmented by different ways in the whole growth period of single cropping rice shows:high yielding>common practice>high yielding and urease inhibitor>blank, The emission effect of the two kinds of fertilizer measures that treatmented by high yielding+urease inhibitor and loss-control fertilizer have significant difference. Considering the yield factors of each treatment, the per unit output of different treatment's GWP is:convention>high yielding>blank>controlling fertilizer>high yielding+urease inhibitor. The per unit output's GWP of high yielding+urease inhibitor and fertilizer-controlling treatment were respectively 0.89 and 1.03, respectively decreasing 29.9% and 18.9% when compared to conventional treatment, which both made significant difference. To analyse from economic benefits: high yield+urease inhibitor treatment>loss-control fertilizer treatment>high-yielding fertilizer treatment> conventional treatment>blank treatment. Compared with the common practice, the income of per mu controlled-release fertilizer with treatment has increased by 96.81 yuan, while the income of high yielding+urease inhibitor treatment has the largest increase which has reached 11.26 yuan.5. CH4 emission from rice paddies has close relations with 5cm soil temperature. Under the temperature range from 20? to 30?, CH4 emission from rice paddies will increase with the increase of temperature, and CH4 emission has significant positive correlation with temperature. However, N2O emission from paddy fields only has significant correlation with the temperature variation after soil drying.6. The soil pH value and the seasonal variation of single cropping rice's discharge of CH4 and N2O have a good correlation. When the soil pH value is between 5.8 and 6.5, the rice field's discharge of CH4 and soil pH value are significant positive correlation, and single cropping rice's discharge of CH4 will increase along with the increasing of pH value. So is the relationship between single cropping rice's discharge of N2O and soil pH value.