Assessing the eco-environmental performance of agricultural production in OECD countries: the use of nitrogen flows and balance

Nitrogen balance is increasingly used as an indicator of the environmental performance of agricultural sector in national, international, and global contexts. There are three main methods of accounting the national nitrogen balance: farm gate, soil surface, and soil system. Some studies have provided the comparison among these methods and the conclusion is mixed. The present paper combines these three methods to provide a more detailed auditing of the nitrogen flows and balance. The proposed combination gives more useful information than the individual methods do, especially for the use of nitrogen flows and balance in international comparison of environmental performance. The study investigated the nitrogen flows and balance of OECD countries for years from 1985 to 2003 and used different indicators to assess relative environmental performance of these countries. Some important findings emerge from the empirical exercise. First, on the whole OECD countries had decreased their nitrogen surplus by around 10% between 1990 and 2003. Secondly, OECD nitrogen surplus intensity was still higher than the world level. Thirdly, the environmental performance in the crop sector was better than the livestock sector. Fourthly, the performance varied greatly among member countries and these differences were correlated with many factors such as the use of land and domestic support. Fifthly, the rankings varied depending on the indicators used.