| Mitigate the trend of climate change has become a common responsibility of the global community.Agricultural production is seriously influenced by the change of climate,and it also reacts to the climate change through emission of greenhouse gases.At present,the carbon emission measurement and the screening of the strategies for corresponding energy-saving carbon emissions reduction is one of the research hotspot in this region.It is estimated that the percentage of global agricultural carbon emissions in the total carbon emissions is up to 10%-12%.In China,the agricultural carbon emission is accounts for15%-18%of the total carbon emissions in this country,and it is also accounts for 13%-16%of global carbon emission from agriculture production.As the largest agricultural country worldwide,China's carbon emission from agricultural production processes can not be ignored.Consequently,it is need to deeply understand the current status of China's carbon emissions in agricultural industry,and to precisely quantify the carbon emissions during agricultural-related industries and diverse production processes.Based on this,develop the excellent crop farming systems and animal husbandry production models scientifically.It is believed that reducing of the greenhouse gas emission in agricultural industrial production possesses the important significance for the mitigation of global warming trend.In this study,based on the current situation of agricultural production,relying on agriculture carbon footprint theory and research methods,the carbon footprint of the agricultural industrial production was surveyed in the representative regions:Sichuan Province for rice production and Jiangxi Province for livestock and poultry production.We employed the bottom-up analysis assay for the carbon footprint estimation of both of the agricultural industrial and the screening of the reduction potential.Furthermore,we have also developed the measurement methodology of carbon sequestration and emission reduction methods which are suitable for domestic voluntary carbon emissions,carbon accounting activities for the agricultural industry.The present study will provide the technical support for the energy-saving and carbon emissions reduction in agricultural production.The main results and conclusions obtained in this study are as following:1.In the crop farming system,we chose rice production as representative crop.The average carbon footprint of all stages of rice production was calculated,and the constitution of the carbon footprints during rice production was analyzed under the household or aggregated farms.The results showed that during rice production processes,the carbon footprint of the unit rice yield was 0.35±0.16 tCO2e t-1,and the carbon footprint per unit area was 4.32±1.56 t CO2e ha-1.In household farm,the carbon footprints of the unit yield was 0.44±0.17 t CO2e t-1,which higher than the average level of 25.71%;and the carbon footprints of unit area was 5.12±1.41 t CO2e ha-1,which higher than the average level of18.52%.By contrast,in aggregated farms,the carbon footprints of the unit yield was 0.27±0.09 t CO2e t-1,which lower than the average level of 31.43%,and the carbon footprints of unit area was 3.53±1.31 t CO2e ha-1,which lower than the average level of 18.29%.In addition,we found that the carbon emission caused by production and usage of nitrogen fertilizer contributed the carbon footprints significantly,and the results revealed that the carbon footprint of the production and application of nitrogen fertilizer were 61.76%and13.55%respectively,and the same numbers for the aggregated farms were 58.37%and11.82%.These results demonstrated that the rationalization using the nitrogen fertilizer is the key strategy for reducing carbon emissions in rice production.Furthermore,during rice production system,the cost of carbon of household is 62.96%higher than that of the aggreagated farms,which means that the amount of the emission carbon of the household was 0.17 tCO2e higher than that of aggregated farms for 1000 kilogram rice grains.Furthermore,the carbon intensity of household was 1.95 times than that of aggregated farms.Finally,the carbon efficiency of household is half of the aggregated farms.In a word,the rice yield per unit area and net profit are well correlated with the carbon intensity in rice production processes.Regards to household farm,there is the significantly positive correlation between the yield/net profit and the carbon intensity,that is,the higher yield obtained,the more amount of carbon emission.By contrast,in the aggregated farms,there is the remarkably negative correlation between the yield/net profit and the carbon intensity.These data demonstrated that employing the scale management pattern in crop farming system will achieve to the low-carbon production.2.Through the surveying of the carbon footprint of animal and poultry production,we found that there are differences among different specises,and the order is as following:chicken>pork>egg>milk.In detail,the average carbon footprint per 1000 kilogram pork was 4.84±3.46 tCO2e t-1,and the carbon footprint per adult pig was 0.60±0.50 t CO2e.In the household farms,the carbon footprint per 1000 kilogram pork was 5.48±4.31 t CO2e t-1,which higher than the aggregated farms of 30.17%;the carbon footprint per adult pig under household farms was 0.73±0.65 tCO2e,which higher than the aggregated farms of55.23%.By the farm surveying of the carbon footprint of dairy production,we showed that the carbon footprint per unit yield was 1.07±0.29 tCO2e t-1,and the carbon footprint per adult dairy was 6.18±1.03 tCO2e.In the household farm,the carbon footprint per unit yield was1.01±0.40 tCO2e t-1,which lower than the aggregated farms of 10.62%;the carbon footprint per adult dairy was 5.82±1.25 tCO2e,which lower than the aggregated farms of10.96%.Through examining the carbon footprint of broilers hens,we found that the carbon footprint per unit of production was 13.94±8.99 tCO2e t-1,and the carbon footprint per adult broiler hen was 0.03±0.09 tCO2e head-1.In household farms,the carbon footprint per unit was 20.02±7.18 tCO2e t-1,which higher than the aggregated farms of 154.7%;the carbon footprint per adult broiler hen was 0.04±0.01 tCO2e,which higher than the aggregated farms of 66.67%.By contrast,in aggregated farms,the carbon footprint per unit was 7.86±6.09 tCO2e t-1,which lower than the average level of 43.6%;and the carbon footprint per adult hen was 0.024±0.019 tCO2e,which higher than the average level of20%.For the layer hens,we showed that the carbon footprint per unit yield was 3.58±2.00tCO2e t-1,and the carbon footprint per adult layer hen was 0.06±0.04 tCO2e.In the household farms,the carbon footprint per unit yield was 3.70±0.75 tCO2e t-1,which higher than the aggregated farms of 6.94%;the carbon footprint per adult layer hen was 0.05±0.01 tCO2e,which higher than the aggregated farms of 23.07%.In contrast,in the aggregated farms,the carbon footprint per unit yield was 3.46±2.80 tCO2e t-1,which lower than the average level of 3.4%;and the carbon footprint per adult layer hen was 0.065±0.05 tCO2e head-1,which higher than the average level of 8.3%.3.During pork production procession,composition of carbon emission analysis revealed that the major resources of the green house gas are CO2(64%),followed by N2O(20%)and CH4(16%),separately.Regard to diary production,the composition of carbon emission analysis revealed that the mainly green gas from dairy production is CH4(51%),and followed by CO2(40%)and N2O(9%).Composition of carbon emission analysis demonstrated that N2O(43%and 51%)is the major component of the green house gas during broilers and layer hens production,respectively,and the followed are CH4(34%and23%)and CO2(23%,26%),respectively.4.Further,we invistegated the carbon emission composistion during different growth stages.Regard to the emission sources,90%of the CO2 from pig industrial is caused in feed production stage,whereas the 73%of the feed CO2 was caused by the nitrogen fertilizer production.Thus,reducing of the nitrogen inputs during feed production can attenuate green house gas emission in pig industrial production.In addition,we found that the 33%of N2O and 99%of CH4 emissions came from pig manure processing stages,and during which stage,the N2O emission of the manure in aggregated farms is only 3.8%of the household.On the other hand,the CH4 emission of the manure in household is twice of the aggregated farms.Consequently,the scale management pattern in pig production is conducive to reducing of carbon emission.Duing diary industrial,,the CH4 emissions mainly came from feeding stage(76%)and manure processing stage(24%),and further,the CH4 emissions mainly came from gastrointestinal fermentation processes.On the other hand,85%of the CO2 and 94%of N2O emissions came from fodder development stages,in which the carbon emissions mainly from fertilizer inputs,especially the usage of the cow dung.Therefore,the fertilizer-caused green house gas emission is the main contributor for carbon emission.15%of N2O and 24%of CH4 emissions occurred in manure processing stages,in which,the emissions of N2O and CH4 in aggregated farms were 18%and 0.76%of the household farms,respectively.Therefore,based on these evidences,it is concluded that the scale management pattern in diary production is conducive to reducing of carbon emission.Further,the CH4(100%)and N2O(93%and 92%)mainly came from the manure processing stage,and the emission of aggregated farm is significantly lower than that of household farms.Together,these evidences from broilers and layer hens production also suggested that the scale farming system will decrease the carbon emission.5.At the present of time,in China,the voluntary greenhouse gas emissions trading market has been initially established,but the methodology for the measurement of carbon sequestration and emission reduction methods are largely unknown.In this study,we employed the conservation tillage project and straw curing fuel projects,from diverse aspect of factors,such as the applicable conditions,system boundaries,baseline setting,carbon stocks,greenhouse gas emissions and measurement of carbon sequestration,and developed the methods which are suitable for the carbon measurement on the voluntary carbon market.Finally,conservation tillage solid carbon emissions measurement methodology was build,in which the conservation tillage with straw under conventional tillage is the project background,the farmed land is the project boundary,the ferlizer-caused emissions of N2O,CH4,CO2 and other greenhouse gas emissions from burning of straws are the mainly emissions sources.The other methodology is curing straw fuel emissions measurement methodology,in which the scale straw curing fuel is the project background,the usage of traditional energy and burning of straw are baseline,the production and usage of the straw curing fuel are the project boundary,and the burning of straws and transport are the mainly carbon emission sources.Taken together,these evidences described above demonstrated that,large scale production will achieve to reduce the carbon emission,either in crop farming system or in animal/poultry production.Furthermore,this approach also is indeed consistent with the policy proposed by our country,and at the same time,it helps us achieve to the aim of carbon emission reducing in future.In a word,the scientific and standardized agricultural management modes will achieve to the both goals,in which the negative effects of climate change can be conquered and it is also reduces the carbon emission in agricultural industrial production. |
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