Research On Greenhouse Gas Emission And Mitigation Of Milk Product

Dairy farming is one of the important agricultural sources of greenhouse gas emission. Developing database of the dairy breeding greenhouse gas emissions and mitigation and promoting the low-carbon sustainable development of dairy industry, are the inevitable requirements to respond to addressing climate change and the development of low carbon agriculture. However, at present, the research on greenhouse gas emission of regional dairy farming basing of real production is still insufficient. And there are problems such as confusion of evaluation standard system and lack of basic data. This study aims at assessing greenhouse gas emission of dairy farming in the product（milk product） level in PAS 2050 standard framework using IPCC（2006） tier2 accounting method, taking beijing City as the research object and basing on the actal survey data. In addition, recommendations of greenhouse gas emission mitigation countermeasures and suggestions are proposed, from the point of view of assessing manure management treatment technique in the low-carbon emission. The main conclusions are as follows:（1） Through collation and analysis of Beijing City 19 dairy farms production data after investigation, the average milk yield is 7.91 t per year per cow, and the average daily milk yield is 25.93 kg per day per cow. The average milk fat rate is 3.83% and mature weight is 350 kg. The average level of dairy farms has reached the degree of the scale. The number of adult cows accounts for 49.92% of the total quantity of cows. The structure of herds is reasonable, and the characteristics of each herd are normal. In short, the dairy farms are in normal and healthy operation condition. In terms of feed and feeding, the feeding modes of adult cow, heifer and bred cattle are artificial feeding and mechanical feeding, and the mixed feeding is less. The feeding of female calves is artificial feeding. In terms of manure management, dairy farms have many modes of clearing manure, the highest proportion of which is mechanical desludging. The following is manual clearing. The dung scraping board desludging and water desludging are rarely used. Manure are mainly directly returned to farmland, or to farmland after accumulated fermenting. A small amount of manure is treated using biogas fermentation or dry separation regeneration of bedding material. In terms of energy consumption, the annual power consumption of unit of dairy cows was 401.84 k W·h per cow per year, and the average annual consumption of diesel engine was 46.88 L per cow per year, and the average annual consumption of gasoline was 5.74 L per cow per year, and the annual coal consumption was 0.064 t per cow per year.（2） The greenhouse gas emission baseline of unit of original milk in Beijing city scale dairy farming is 0.74 kg CO₂ e per kg RW. And the emission baseline of unit of fat correeted milk is 0.79 kg CO₂ e per kg FPCM. The emission baseline of unit of energy correeted milk is 0.81 kg CO₂e per kg ECM. The emission baseline of unit of cow is 2.53 kg CO₂ e per cow per year.Analysis of greenhouse gas emissions in different units of cattle and calves was 0.90 kg CO₂ e per cow per year, breeding cattle to 1.33 kg CO₂ e per cow per year, the young cattle to 2.59 kg CO₂ e per cow per year, the adult cows to 3.49 kg CO₂ e per cow per year. Analysis of different aspects of the contribution rate, 23911.07 t CO₂ e enteric fermentation process of greenhouse gas emissions, 67.25% of total emissions accounted for; manure management link emissions for 4272.43 t CO₂ e. 12.02% of total emissions; energy consumption link and emissions for 7373.29 t CO₂ e, 20.74% of total emissions accounted for. Analysis of different greenhouse gases the system contribution rate, methane（CH4） the system contribution rate for 71.72%, including 93.76% from enteric fermentation; nitrous oxide（N₂O） the system contribution rate is 7.54%, including 99.70% from manure management nitrous oxide emissions; carbon dioxide（CO₂） on greenhouse gas emissions contribution rate is 20.74%, which 59.28% from the power consumption, 22.13% from coal consumption.（3） Link storage feces to quantity of amount of livestock on hand 1000 head of cattle farms, for example, from the point of view to research the Beijing 19 family dairy farm production as the base line scenario, solid-liquid separation/aerobic/solid manure management system, the whole system of emission reduction rate was2.44%, feces management link reduction rate was 34.18%; solid-liquid separation/aerobic/compost manure management system, the whole system of emission reduction rate was 3.61% and manure management emission reduction rate was 43.04%; solid-liquid separation/oxygen/methane fermentation manure management system, the whole system of emission reduction rate was 17.07%, manure management links lead to greenhouse gas emissions increase. Single from disposal of feces composting with the best reduction effect, followed by the solid storage; from the farms to the overall emission reduction effect, biogas fermentation processing technology which has a best effect on reducing carbon emissions, far greater than the compost and solid storage and processing technology.