Effects Of Mushroom Residues On GHS Emissions From Soils Under Rice-wheat Rotation

CO2, CH4and N2O fluxes and total greenhouse gas emissions were measured from soil under conventional chemical fertilization (CK), a mixture of chemical fertilizer and mushroom residue application (T1) and four different rates of mushroom residue only applications (T2, T3, T4and T5) in a Chengdu Plain rice-wheat rotation field using static chamber-gas chromatographic techniques. This research analyzed the seasonal and daily variations of CO2, CH4and N2O to find out it’s emission characters; This research analyzed the correlation between the flux of agricultural greenhouse gas emissions and environmental factors, soil physical, chemical factors and biological factors to find out the main factor which effect of greenhouse gas emissions. This paper analyzed the difference of the total greenhouse gas emissions and global warming potential of greenhouse gases in different treatments, after this, the affection of mushroom residue application to the field greenhouse gas emission were find out. The main results are as follows:(1) The seasonal rule of CC2,CH4and N2O emissions from field are basically in the same law throughout the experimental period. There were five CO2emission peaks throughout the experimental period, respectively, it’s appeared after fertilization in a rice paddy season, the tillering stage, jointing stage in the drainage rice period, heading and flowering stage when rice growing period of the most productive, two weeks after fertilization in the wheat stage, and the wheat heading and flowering stage; There were only one emission peak of CH4from each treatment over time, its showed a significant change in the in the third week after fertilization of rice (June24), the CH4emissions are maintained at a low level followed by rice flux peek, wheat season CH4emission flux of farmland at a lower level or even negative emissions; There were only one N2O emission peek throughout of the rice-wheat rotation, when at three weeks (November9,2009)after fertilization in wheat stage. The N2O flux decreased rapidly at a low level of after the emission peek; At the rice stage N2O emission were in a very lowe emission levels, and N2O absorption came out in flooded rice fields stage.(2) The different effect between environmental factors, soil physical and chemical factors and biological factors on farmland CO2, CH4, N2O emission fluxes. Temperature s and crops biomass were the main factors which impact of the ecosystem CO2emission. CO2emission fluxes of farmland was increased with crops and temperature; Soil moisture, temperature of5cm under ground, soil content of ammonium and the activity of soil dehydrogenase were the main factors which affected agro-ecosystem flux of CH4emission. CH4emission increased with soil moisture, temperature5cm under ground, soil ammonium nitrogen content and soil dehydrogenase activity. The activity of soil dehydrogenase was the main factor for affecting the agricultural N2O emission. The agricultural N2O emission reduced with soil dehydrogenase activity.(3) This research showed that the application of mushroom residue could reduced agricultural CO2emissions. The CO2emissions from the mushroom residue application treatments (T3, T1, T2and T4) when its more than91.80t/hm2was lower than the chemical fertilizer treatment. Its total CO2emissions of farmland were39444.87,40229.36,41146.76and45132.83kg/hm2,.The CO2emissions for mushroom residue application treatments (T3, T1, T2and T4) were12.96%,11.23%,9.21%and0.41%lower than the control treatment; When the bacteria was higher than91.80t/hm2mushroom residue application, the CO2emissions for mushroom residue application treatments (T5) were significantly higher than conventional chemical fertilizer treatment, its47764.50kg/hm2CO2emissions farmland, and5.39%CO2emissions increase compared with the conventional treatment.(4) The result showed that mushroom residue application could reduce soil CH4emissions from rice-wheat rotation field, and the reducing was increased with the increase of mushroom residue application. Its showed CH4emissions from that treatments which only mushroom residue application (T2, T3, T4and T5) significant lower than the tteatment which applicade mixture that chamical fertilizer and mushroom residue. The reducing of CH4emissions feom treatments which applicad mushroom residue compared with conventional treatment as fallows:T3＞T4＞T5＞T2＞T1, its respectively as follows:34.74%,33.02%,30.97%,24.62%and18.01%.(5) Mushroom residue application could reduce N2O emission in farmland effectively. The N2O emission form field reduced with mushroom application when the mushroom applicated were less than55.10t/hm2. Its showed N2O emissions from that treatments which only mushroom residue application (T2, T3, T4and T5) significant lower than the tteatment which applicade mixture that chamical fertilizer and mushroom residue(T1). The N2O emission form field increased with mushroom application when the mushroom applicated were more than55.10t/hm2. The reducing of N2O emissions feom treatments which applicad mushroom residue compared with conventional treatment as fallows: T3>T2>T1>T4>T5, its respectively as follows:31.94%、29.85%、25.08%、9.52%and0.41%.(6) Mushroom residue application could significantly reduce agricultural greenhouse gases on the global warming potential in three different time scales. Compared with the conventional treatment, the reducing of agricultural greenhouse gases of the global warming potential for mushroom treantments (T1, T2, T3, T4and T5) in the20-year time scale were as fallows:12.86%,12.48%,17.19%,5.46%and0.63%; The reducing of agricultural greenhouse gases of the global warming potential for mushroom treantments (T1, T2, T3, T4and T5) in the100-year time scale compared with the conventional treatment were as fallows:12.28%、11.10%、15.17%、and2.25%; The reducing of agricultural greenhouse gases of the global warming potential for mushroom treantments (T1, T2, T3and T4) in the500-year time scale compared with the conventional treatment were as fallows:13.87%、11.72%、10.03%and0.97%, The agricultural greenhouse gases of the global warming potential for mushroom treantments (T5) in the500-year time scale compared with the conventional treatment were increased4.52%.Considering the agricultural greenhouse gas emissions and crop production, we recommend the application of treatment T3. This treatment consists of the application of40.8t/hm2mushroom residue during the wheat growing phase and14.3t/hm2mushroom residue during the rice growing phase.