Modeling long-term dynamics of carbon and nitrogen in intensive rice-based cropping systems in the Indo-Gangetic Plains (India)

Soil organic matter (SOM) is an essential component of any sustainable crop production system, both as a nutrient source for the crop and a physical conditioner for the soil. Land use systems based on (flooded) rice- aerobic upland crop rotations, with their annual cycles of wet and dry soil conditions, puddling and plowing, are unique in their influence on SOM dynamics. Recent reports have related yield ‘stagnation’ in rice-wheat systems in parts of the Indo-Gangetic Plains (IGP) to a decline in SOM quantity and quality. For exploration of the long-term effects of intensive cultivation on soil C and N dynamics, and the consequences for crop yields, a summary model has been developed, based on insights in the underlying processes, to investigate the role of soil organic matter in yield formation in rice-based cropping systems in the IGP and to identify possible reasons for declining yields in the region...