An analysis of the environmental efficiency of pig farms and its determinants—a field study from China

Environmental efficiency (EE) was the efficiency that simultaneously targets economic benefits and environmental protection, requiring producers to provide higher levels of value under the premise of lower material and energy input and lower emissions. Waste treatment systems play an important place in the reduction of pathogen loading and then influence the environmental efficiency of farms. Based on a field study, take chemical oxygen demand (COD) and total nitrogen (TN) excretion as undesirable outputs, the paper aims to measure the EE considering the difference of waste treatment methods of sample pig farms. Technical efficiency (TE) and the contributing factors of environmental efficiency were also estimated. Results show that the environmental efficiency is significantly lower than technical efficiency. Years in the profession, manure treatment income, and receiving manure treatment subsidies had significant positive effects on environmental efficiency.