Predictive Analysis of Nitrogen Balances Resulting from the Production and Consumption of Livestock Products in the Huang-Huai-Hai Region, China

The purpose of this study is to propose an integrated projection methodology to manage the livestock industry in China sustainably and generate useful data in this context. To achieve this, we constructed a comprehensive set of models, comprising food supply-demand-, nitrogen balance-, and environmental evaluation models respectively. This study focuses on analyzing mediumand long-term projections of the supply-demand balance of nitrogen nutrients in the Huang-Huai-Hai region as well as on the environmental impact due to the influence of livestock products. Discipline: Agricultural environment & Agricultural economic Additional key words: environmental impact, food supply-demand, partial equilibrium, recycling ratios Introduction Economic development, population growth, and rising personal incomes are not only the main catalysts for changes in food preferences and agriculture, but also exert negative impacts on the environment, including the air and water in China. While trends in per-capita grain consumption in China are showing gradual decline, the per-capita consumption of livestock products has tended to soar, in a manner similar to that observed in other countries (FAO:FAOSTAT 2011). However, nitrogen emissions from livestock production have not been seriously considered as industrial emissions; despite the fact livestock contributes more nitrogen than the industrial sector (Li et al. 2000). In addition, nitrogen emissions account for 63-83% of total livestock nitrogen output (Dong et al. 2011); significantly exacerbating the eutrophication of lakes and rivers (Li et al. 2000). The Huang-Huai-Hai plain, one of China’s principal agricultural centers, is an alluvial plain developed by the intermittent flooding of the Huanghe, Huaihe, and Haihe rivers. The target area of this study is defined as the Huang-Huai-Hai (3H) region, which comprises two municipalities and three provinces (Beijing, Tianjin, Hebei, Shandong, and Henan), based on administrative divisions and research feasibility. 2010 statistics show that the 3H region covers a total area of about 539,420 km, 224,318 km of which is cultivated and accounting for 18% of China (NBSC 1991 2011). Although the land area in the 3H region is only 4% of China, its grain and livestock production account for 18 and 29%, respectively, of China’s totals. The population in the 3H region accounts for 21.5% of China’s people, and it has a high population density (5.3 times greater than the national average). In most of the 3H region, nitrogen emissions per unit area exceed 150 kg/ha·y (Wei et al. 2008). In Beijing meanwhile, the Nitrogen Emission Intensity [230 kg/ha·y] (Wei et al. 2008) far exceeds the level stipulated by European regulations [170 kg/ha·y] (DEFRA 2009, Fraters et al 2008), which significantly threatens the aquatic environment. Accordingly, there is a need to identify the structure of nitrogen emissions and project their future evolution, to ease the environmental burden in the region. Based on Material Flow Analysis (Fischer Kowalski 1998), many methods have been created to research the nitrogen cycle. Isermann and Isermann (Isermann & Isermann 1998) developed a nitrogen balance model using statistical data for Germany for the 1995-1998 period, which considers grain, livestock, and waste to analyze the national nitrogen balance. The INITIATOR (De Vries et al. 2003) and STONE models (Wolf et al. 2003, Wolf et al. 2005) focus on regional environmental evaluation, by calculating nitrogen input-output and nitrogen loss, using the proportional distribution principle. The MITERRA-EUROPE model (Oenema et al. 2009, Velthof et al. 2009), which has *Corresponding author: e-mail hirosi98@affrc.go. jp Received 7 June 2103; accepted 15 November 2013.