Effects Of Adding Loess And Other Additives On Ammonia And Greenhouse Gas Emissions From Pig Manure

Climate change has become worldwide concern and one of the most serious environmental problems.At present,due to the changes in the structure of livestock breeding,the rapid growth of animal production and the rising cost of labor,the utilization rate of organic fertilizer resources in china is still at a low level and livestock manure contributes larger quantities of greenhouse gases emissions.Manure storage is an important source of greenhouse gases emissions when considering manure management practices,which also contributes greatly in the loss of carbon and nitrogen of manure.Therefore,reduce greenhouse gas emissions from manure storage is a significant subject worth studying.Chinese farmers have a long history of using manures.In order to maintain cleanliness in livestock breeding,they usually add loess to housing during breeding and use the mixture as a traditional organic fertilizer in Guanzhong Plains,North China.This kind of innovative practice is not only good for better housekeeping of livestock,but also could conserve nutrition in manure.In the past,the researchers mainly focused on the fertility of this organic mixture,there was no relevant research on its environmental effects,which contributes against the sustainable development and the integrated nutrient management.In order to better understand the possible mechanisms of adding loess to livestock housing and study its effects on greenhouse gas emissions,a series of incubation experiments were carried out.Better additives were also selected which are easy to obtain and have better effect during manure storage at the same time,aiming at providing theoretical basis for controlling greenhouse gas emissions and promoting the resource utilization during manure storage.The main conclusions are as follows:?1?Incubation experiment was carried out to study the effects of adding loess and paleosol to pig manure.The results showed that the cumulative release of CO₂ and CH₄decreased by 42.4%-64.3%and by more than 99.8%,respectively.Compared to the control?pig manure without the addition of loess or paleosol?,the loess and paleosol treatments showed a 1.8 to 18.0-fold reduction in the cumulative N₂O emissions because of their soil retention abilities and dilution effects.The global warming potential of loess or paleosol treatments was approximately decreased 33.0%-61.9%compared to the control,indicating an effective reduction in greenhouse gas emissions.When compared to the loess treatment,the paleosol treatment had a greater effect on emission reduction owing to the higher content of physical clay and free iron oxide present in paleosol.We conclude that the selection of a suitable additive has an important impact on reducing greenhouse gas emissions during manure storage.?2?Incubation experiment was carried out to investigate the influence of addition of loess,straw,biochar and bentonite on ammonia and greenhouse gas emissions during pig manure storage.The results showed that the cumulative CO₂ emissions of biochar and bentonite treatments decreased by 15.4 and 20.9%.,respectively.The cumulative N₂O emissions showed a decrease of 19.8%and 37.6%compared to the control?pig manure without additives?.Although NH₃ volatilization in bentonite treatment significantly increased,the global warming potential of biochar and bentonite treatments were both lower than pig manure.The cumulative emissions of CH₄ and NH₃ from straw treatment decreased by 56.8%and 95.8%compared with control,while there was no significant difference in greenhouse gas emissions between the two treatments.Compared with other treatments,the loess addition at the ratio of 1:2 has more reduction effects either in ammonia or global warming potential.The present study suggested that adding loess to livestock housing is an effective method to conserve nutrients and reduce global warming potential from manure.Adding biochar or bentonite additives with less amount could be considered a superior method to manage emissions of greenhouse gases during manure storage.?3?An incubation experiment was carried out to study the greenhouses gas and ammonia emission characteristics of pig manure with 10%biochar,different proportions of loess and acidification during manure storage.The results showed that the cumulative CO_2,CH₄ and NH₃ of biochar treatment decreased by 24.2%,97.5%and 36.3%respectively.Although there was no significant difference in N₂O emission compared to pig manure,the N₂O emissions of biochar treatment was only 4.0%-29.8%of loess treatments.Acidification had a significant effect on reducing CH₄ and NH₃ emissions of manure,but it increased CO₂emissions.The global warming potential was also not significantly different compared to control.The greenhouse gas and ammonia emission characteristics of pig manure was influenced by the rate of loess addition.The global warming potential was decreased by 29.6%and 26.0%by adding 50%and 100%of loess.In summary,adding 10%biochar,50%and 100%loess could significantly reduce the greenhouse effects of pig manure during storage.It was concluded that followed the idea of adding loess to livestock housing,using less biochar instead of loess could ensure the economic and ecology benefits.