Research highlights ► Long term changes in soil quality and crop productivity with fertilizer and tillage. ► Soil Quality Index (SQI) developed using ponents Approach. ► Improved soil quality in No-till, Reduced pared to conventional management. ► Conservation management improves nutrient availability, soil stability and structure. ► Soil quality concord with microbial nitrogen processing, nitrogen use and leaching. A scoped approach to traceability management Original Research Article Journal of Systems and Software This paper proposes a structural VAR model which extends the frameworks of Hoffmaister and Roldós [Hoffmaister, A. W., & Roldós, J. E. (2001). The sources of macroeconomic fluctuations in developing countries: Brazil and Korea. Journal of Macroeconomics, 23, 213–239] and Prasad [Prasad, . (1999). International trade and the business cycle. Economic Journal, 109, 588–606]. The model is then used to analyse the sources of China's trade balance fluctuations in the period of 1985–2000. Efforts are made to distinguish the forces which underlie the long-run trend in trade balance from those with transitory impacts. The effects of four types of shock are examined—the foreign supply shock, the domestic supply shock, the relative demand shock and the nominal shock. Among other findings, two emerge as important. First, the movements in China's trade balance are large