Industrial Structure and COD Emission of Livestock and Poultry Breeding in Liaoning Province, NE China: Empirical Research on the Panel Threshold Model

Assessing waste from livestock and poultry breeding and clarifying the relationship between industrial structure and livestock and poultry pollution are of critical essence in agricultural non-point source pollution control. This paper estimated the chemical oxygen demand (COD) emissions of livestock and poultry breeding of all 14 prefecture-level cities in Liaoning Province in China. Threshold regression models were applied to analyse whether the industrial structure had the threshold effect on the COD emission of livestock and poultry breeding amongst cities varying in economic levels in Liaoning Province from 2005 to 2015. The results show that the COD emission of livestock and poultry breeding in Liaoning increased from 2.5308 million tons in 2005 to 4.5022 million tons in 2015, with an average annual growth rate of 5.929%. Jinzhou City and Chaoyang City were the main contributors of COD emissions of livestock and poultry in Liaoning Province. Moreover, the industrial structure had the double-threshold effect on the COD emission of livestock and poultry breeding in Liaoning Province, and the double threshold values of the per capita GDP were respectively e(10.841)(51072.425) yuan and e(11.608)(109974.082) yuan. In addition, with the improvement of economic development level, the marginal impacts of industrial structure on COD emissions of livestock and poultry breeding went from negative to positive and from low to high, presenting a V-pattern trend in impacts. Besides, The COD emission of livestock and poultry breeding was in positive correlation with economic density while in negative correlation with financial support in science and technology in all cities. And the preference to primary industry in workforce structure had a positive effect on the COD emissions of livestock and poultry breeding in cities of lower and medium economic development level.