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In recent years, the greenhouse gas emissions caused extreme global warming and stratospheric ozone loss has become a major environmental problems facing the world. For climate warming in the atmosphere of greenhouse gases (mainly refers to the increasing concentration of C02, CH4 and N20). Greenhouse gas emissions by farmland ecosystem plays an important role in global warming, greenhouse vegetable part of the farmland ecosystem, and in recent years, the area of ??greenhouse vegetable growing, research facilities, vegetable plots at different fertilization measures and soil CO2 and N2O emissions characteristics and its mechanism in water management, quantitative evaluation of greenhouse vegetable greenhouse gas emissions and the contribution of changes in atmospheric greenhouse gas, is a greenhouse vegetable greenhouse gas emission reduction measures to provide a scientific basis. In this paper, the indoor simulation experiments way, Daxing District, Beijing greenhouse soil by gas chromatography N20 emission flux observations. The trial protocol processing as follows: different water treatments to drought, normal water flooding (30, 60, 90% WFPS); different fertilization treatments for the control, low-fat, fat, high-fat (respectively 0,170.94,341.88, 512.82μN · g-1 dry soil); different nitrogen treatments divided into two groups, one group: the control CK, calcium nitrate CN the ammonium bicarbonate AB, ammonium sulfate, the AS the urea U-; another group of these processing add straw. Observations C02 and N20 emissions. The main findings are as follows: fertilization measures of the same water observation vegetable soil C02 emissions, the results show that, under conditions of drought and normal water, low-fat and CO2 emissions in fertilizer treatment higher higher fertilizer treatment, only under flooded conditions, high-fat processed CO2 emissions is the highest, which is due to waterlogged conditions, organic matter humification process, soil anaerobic conditions, reducing gas increase. Drought, normal water, flood conditions, the average soil C02 cumulative emissions of nitrogen treatments, respectively, compared with the control average increase of 74%, 63% and 28%, respectively. Vegetable soil N20 emissions, regardless of soil moisture in what circumstances, the Greenhouse soil N20 emissions With the increase in the amount of nitrogen increased, and flooding conditions emit more N20. 2, the same fertilization amount under different moisture on the vegetable soil CO2 emissions, the emissions of the peak of the three fertilizer treatments were higher than the control, and the difference is significant. In the indoor simulated conditions, the control treatment, the total CO2 emissions with increasing moisture content increases, the other three fertilization treatments are in the highest emissions under normal moisture conditions. The same fertilization under different moisture vegetable soil N20 emissions control handle moisture conditions throughout the culture period, basic N2O emissions and N20 absorption phenomena, the other three fertilization treatments are in waterlogged conditions soil can emit more N20, about 10-20 times the processing denitrification under anaerobic conditions the process of strengthening, resulting in higher N20. Of NH4-N, N03 - N content of the test, indicating that the N20 generation with both content are closely related. 3, under the same fertilization of different water and vegetable soil C02 and N20 emissions fitting between soil respiration and moisture control treatment presented a significant linear relationship (P lt; 0.01, R2 = 0.8013), with the other the fertilization treatments respiratory no significant relationship. N20 emissions and soil moisture outside, in addition to the control and other treatments showed a highly significant (P lt; 0.01) exponential function, water is an important factor to limit the N20 emissions. 4 indoor simulate different water and fertilizer trials, each treatment (except control outside) the cumulative emissions of CO2 and N2O index or quadratic function was highly significant (P lt; 0.001), low fat drought and high fertilizer normal moisture treatment was the the index equation y = aebx; other processing expressed as y = ax2 bx c a quadratic equation relationship. 5 indoor simulation of different nitrogen sources and straw Add vegetable soil CO2 emissions of different nitrogen in the case of whether or straw, in addition to CN (calcium nitrate) treatment, all treatments of CO2 emissions are significantly higher than CK ammonium nitrogen fertilizer can stimulate the decomposition of organic matter in the soil. Add straw soil CO2 emissions increased about 2-4 times without straw, the reason for the addition of straw increased soil C source, improve the soil C / N. Nitrate fertilizer C02 emissions are lower than the control in the case of whether the straw. Vegetable soil N20 emissions, nitrate fertilizer (CN) easy first reached the the N20 rate of emission peak, ammonium nitrogen fertilizer (AB, AS) and amide nitrogen fertilizer (U), later reached cumulative emissions of N20 size order of AB gt; U gt; AS gt; CN gt; CK. N20 application of ammonium nitrogen fertilizer and the amide nitrogen fertilizer emissions far higher than nitrate fertilizer. No exogenous carbon is added, the N20 emission coefficient of each treatment were 1.01,0.77,0.62,0.42. Add straw after each treatment N20 emission factors were 1.96,1.58,1.34,0.20. In addition to the CN processing plus straw N20 total emissions of nitrogen fertilizer processing are significantly increased. Indoor simulation experiments add different nitrogen sources and straw, straw processing C02 cumulative emissions (y) is not applied to the available the y = aLn (x) b equation fitting relationship with time (x), and facilities straw C02 cumulative emissions (y) and time (x) can be used y = ax b not applied to the N20 the straw and facilities straw cumulative emissions relationship with time (x) (y) (except CK) are y = aLn (x) b fitting, have reached a highly significant correlation (P lt; 0.001). Compared with the control soil pH significantly reduce nitrogen fertilizer, ammonium nitrogen fertilizer ammonium sulfate headed processing even more serious decline in soil pH. Add straw to be able to mitigate this phenomenon, but nitrate fertilizer treatment had no effect.
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