Nevada Statewide Greenhouse Gas Emissions Inventory and Projections, 1990 to 2030 slide image

Nevada Statewide Greenhouse Gas Emissions Inventory and Projections, 1990 to 2030

Nevada Statewide Greenhouse Gas Emissions Inventory and Projections, 1990 to 2030 8. 8.1 Agricultural Sector Emissions Overview This section reports CH4 and N2O emissions from agricultural activities in Nevada. Several processes are considered in the agricultural sector, but in this report they are generally categorized as enteric fermentation, management of livestock manure, management of agricultural soils, and agricultural residue burning. Enteric fermentation produces CH4 and is a natural product of animal digestion; ruminants (four-stomached mammals such as cattle, sheep, and goats) are particularly high CH4 emitters because of their unique digestive process. Livestock manure (i.e., animal waste) produces both CH4 and N₂O during the manure's natural decomposition process. Agricultural soils emissions are the result of the release of N2O. This occurs through three main pathways; 1, direct emissions due to the harvesting of plants; 2, direct and indirect emissions from fertilizer application; and 3, direct and indirect emissions due to animal waste in pastures, ranges, and paddocks. Finally, agricultural residue burning emissions (both CH4 and N2O) are the result of burning crop wastes. 34 Depending on their source, emissions associated with energy production for use in the agricultural sector are split between Section 3: Electricity Generation and Section 5: Residential, Commercial, and Industrial Sectors. Emissions from the combustion of fossil fuels used in agricultural equipment are included in Section 4: Transportation. The SIT methodologies were used to estimate GHG emissions. Emissions were estimated by relating estimated livestock populations, crop production, and fertilizer use with process specific emission factors. The sources of the dataset used to estimate agricultural sector GHG emissions are summarized in Table 8-1. Process Table 8-1: Sources Used to Estimate Agricultural Sector GHG Emissions Source Reference 8.2 Emission factors Livestock population data Crop production data Fertilizer use data - SIT - National Agriculture Statistics Service of the USDA National Agriculture Statistics Service of the USDA The Association of American Plant Food Control Officials (AAPFCO) via the SIT Historical Emissions https://www.nass.usda.gov/Quick_Stats/ https://www.nass.usda.gov/Quick_Stats/ http://www.aapfco.org/ Nevada's agricultural sector is a minor source of the state's GHG emissions. Historical agricultural emissions peaked in 2001 with 1.702 MMTCO2eq and this is due largely to emissions from enteric fermentation also peaking in 2001; sector emissions have been in slow decline since. Table 8-2 shows the agricultural sector emissions broken down by sub-sector. Total 2013 agricultural sector emissions were estimated to be 1.436 MMTCO2eq. Overall, emissions from enteric fermentation accounted for roughly 58 percent of total sector emissions; agricultural soil management (including synthetic and 34 The process of agricultural residue burning releases CO2 as well as CH and N₂O, but in accordance with international GHG accounting guidelines, the SIT Agriculture module does not include CO2 emissions from crop residue burning. 34
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