Field Measurement of Carbon Dioxide, Methane and Nitrous oxide Emissions from Manure Stockpile and Open Exercise Yard of a Typical Dairy Farm in China by Chamber Technique

Abstract. In typical dairy production and management system of China, outdoor exercise yard and stockpiles play a major role in emissions of pollutants to atmosphere. GHG (CO₂, CH₄ and N₂O) emissions from brick-paved yard and manure stockpiles of a typical dairy farm in Beijing were measured by closed chamber in four different seasons. There are cubicles in the yard and manure in the yard was removed once a day by tractor. CO₂, CH₄ and N₂O emissions from the yard were within the range of 0.2~42 mg m^-2 min^-1, 1~616 ug m^-2 min^-1 and 0.3~129 ug m^-2 min^-1 in different seasons, respectively. GHG emissions from exercise yard showed a seasonal variation. GHG emission rates from different zones (cubicle zone vs. aisle zone) of the lot greatly varied, and the emissions were significantly affected by manure removal strategy (P<0.05). The zone near cubicles on the yard had more excreta and higher CO₂ and CH₄ emissions (P<0.05), while N₂O emissions showed a disparity in different seasons. Compared with the result before manure removal, N₂O emissions were greatly higher after manure removal both at aisle and cubicle zones (P<0.05). Stacking height of the manure stockpiles measured was averaged at 55±12 cm. CO₂, CH₄ and N₂O emissions from manure stockpiles were 4~168 mg m^-2 min^-1, 0.02~1.79 mg m^-2 min^-1 and 0.62~536 ug m^-2 min^-1, respectively. GHG emissions from stockpile also showed a seasonal variation. Volatile solid in manure and temperature were the key factors affecting CO₂ and CH₄ emissions. N₂O emissions were affected by manure storage duration.