Nitrogen Footprint Analysis Of Scale Pig Breeding Farms In Wuhan

Agriculture activity is the major sources of reactive nitrogen emissions,and livestock activities occupy an important place in reactive nitrogen emissions from agricultural source.N₂O,NH₃ and TKN are the major reactive nitrogen emissions in the process of feeding and manure management,which has caused serious threat to the environment.There is only small proportion of nitrogen applied into the livestock production,most of it emitted into the environment through different approaches.Pig breeding has always been the major part of livestock activities in China,and the amount of pig excrement with high nitrogen content is very huge every year,it becomes the major sources of pig breeding nitrogen emission.Basing on the optimized emission factors from IPCC,this study has studied the nitrogen flow process of pig breeding in Wuhan,analyzed the manure nitrogen footprint transformation rules,the proportion of different nitrogen types and the nitrogen footprint in different districts of scale pig breeding in Wuhan from 1990-2014,generally assess the proportion of nitrogen usage and excrete.The results showed:?1?From 1990 to 1997,the maximum manure N footprint were 6.59×10⁶kgN,the minimum N footprint were 5.95×10⁶kg N;from 1998 to 2014,the maximum N footprint were 6.49×10⁶kg N,and the were 3.51×10⁶kg N.?2?N₂O takes the smallest percentage of c?2.82-13.31%,7 minimum N footprint.48²0.2910⁴ t CO2-eq?,the second is NH₃?20.98-38.11%?,TKN takes the biggest percentage?51.53-76.2%?.The result shows that the N footprint of per carcass pig has positive correlation with fattened weight.?3?From 1990 to 1997,the maximum manure N footprint of per carcass was119.79 g N/kg,the minimum was 92.87 g N/kg;from 1998 to 2014,the maximum manure N footprint per carcass was 95.87 g N/kg,the minimum was 35.61 g N/kg.?4?The manure nitrogen footprint range of the four main scale breeding districts is Huangpi district,Jiangxia district,Xinzhou district and Caidian district.