Greenhouse Gases Emissions and Varies of Carbon and Nitrogen of Manure from Different Lactating Period Cows

Abstract:

Dairy systems are the important greenhouse gases emissions source, in which manure management is one of the three major GHG emission sources. Most researches focused on the effects of external conditions, such as additives, composting materials, composting height, stacking mode, and the frequency of pile up on the greenhouse gas emissions of livestock manure composting process, while a few studies focused on the impact of diet on greenhouse gas emissions frommanure. Different diets were fed to dairy cows during different lactating period, which results in different physical and chemical properties of manure. The objective of the study was to quantify the greenhouse gas emissions and varies of carbon and nitrogen of manure from cows during different lactating periods. Fresh manure from cows during different lactating periods was collected and piled up naturally. Emissions of CO2, CH4 and N2O were measured by using static chamberGC technique, at the same time, the content of TOC, TN, NH+4N and NO-3N were measured. The results showed that there was difference in content of TOC, TN and C/N between manure from different lactating period cows (high group, middle group and low group). At the beginning of piling, manure from high group contained the highest TOC and TN, followed by middle group, then low group, in opposite for the ration of TOC to TN. These differences resulted in accumulative emissions of greenhouse gas differently. The highest accumulative emissions of CH4 and N2O were measured from high cow group, followed by middle group and then low group. The total greenhouse gas emission from low group was significantly low than that from middle group and high group. CO2 accounted for more than half of the total greenhouse gas emission, CH4 and N2O contributed 20%~21% and 17%~21% to the total emissions, respectively. Accumulative emission of N2ON was significantly positive correlation with TN content, in opposite with the ratio of TOC to TN. Accumulative emission of CH4C, CO2C and CO2C+CH4C had no significant correlation with TOC content and the ratio of TOC to TN.