Emission Of Greenhouse Gases And Ammonia From Swine Manure Storage

Storage is one of the important steps in livestove manure management. During the manure storage, significant amount of greenhouse gases (GHG) and odorous gases are emitted. Emission of gases during manure composting or biogas production has been widely studied. However, researches concerning about emission during manure storage are relatively lacking. Therefore, greenhouse gases and ammonia emission from manure storage together with the physiochemical properties of swine manure were studied in this study. It is hoped that the result obtained would provide some scientific reference for the greenhouse gases, ammonia emission mitigation, and the greenhouse gases emission inventory preparation. Using the static chamber method, greenhouse gases and ammonia from the swine manure storage were monitored for124days in spring and summer, for66days in fall and winter, repectively. Physiochemical properties of swine manure were analyzed during different storage periods. Based on the measurement data, emission characteristics of greenhouse gases and ammonia were identified. Further, relationship among Physiochemical properties and gas emission was explored. Major conclusions include:1) Variation of GHG and NH3emission with storage time in spring and summer are different from those in autumn and winter. Fluctuation in CO2emission flux is not as significant as other gases, though CO2emissions flux is slightly higher in the early stage of manure storage in spring and summer. CH4emission is much lower than CO2with emission peak appearing at80days, which lasted for a short period. During the first40days of storage, few N2O emission was observed. After that, N2O emssion started to increase and peaked at about90days, followed by the low emission level until the end of storage. High NH3emission was noticed during the first40days and emission in the following days was negligible. In autumn and winter, emissions of CO2, CH4and NH3are higher during the first week of storage, and N2O emission was barely observed during the entire storage period. 2) Physical and chemical properties are correlated with the emission of GHG and NH3. In spring and summer, the temperature was significantly correlated with the emission of GHG and NH3flux; moisture content, NH4+-N content and TKN were significantly correlated with N2O emission flux; TOC content were significantly related with CH4and N2O fluxes. In autumn and winter, the temperature was significantly correlated with the emission of GHG and NH3flux; moisture content was significantly correlated with CO2emissions and correlated with CH4emission; NH4+-N content were significantly correlated with emissions of CO2and CH4.3) The covers did influence the GHG and NH3emission during manure storage.In spring and summer, covering with rice straw increased CO2emission by about19.1%, CH4by31.2%and N2O by35%. On the other hand, NH3emission was decreased by4.3%comparing with uncovered pile. Covering with sawdust increased CO2and CH4emissions by about27.1%and81.9%, respectively. As for NH3and N2O,19.9%and36.8%of decrease were achieved comparing with uncovered pile. In autumn and winter, covering with straw and covering with sawdust reduced43.9%and35.9%of CH4emissions. NH3emission were reduced by around4.7%and12.8%. However, covering with straw and covering with sawdust increased CO2emissions by6.9%and15.4%, respectively.4) Differet pattern of gas emissions were found in different season and different period (early, middle and late). CO2emissions were almost identical in the early and middle stage in spring and summer, and slightly lower in last stage. Howere, CO2emission during the early stage was three times higher than that during the middle and last stage in autumn and winter. In spring and summer, CH4emissions at the middle stage are higher. CH4emissions at the early stage are also much higher than middle and late stage in autumn and winter. In spring and summer, there was no N2O emissions in the early stage, but a lot of emissions in mid and late stage. On the contrary, there are almost no N2O emissions during all three periods in autumn and winter. The NH3emission at early and late period in autumn and winter are higher than sthose in spring and summer. 5) The GHG and NH3emissions in different seasons and with different coverings are significantly different. In spring and summer, highest GHG emission was observed when covered with rice straw, offollowing by covering with sawdust. Lowest GHG emission occurred during storage without any covering. In fall and winter, covering with rice straw seemed to reduce the GHG emissions to a certain extent. On the other hand, covering with sawdust, leads to higher GHG emission comparing with the uncovered storage.