Soils of the Indo-Gangetic Plains: their historical perspective and management.

摘要

The Indo-Gangetic Alluvial Plains (IGP) is among the most extensive fluvial plains of the world and cover several states of the northern, central and eastern parts of India. The IGP occupies a total area of approximately 43.7 m ha and represent eight agro-ecological regions (AER) and 14 agro-ecological subregions. The area of the IGP is nearly 13% of the total geographical area of the country, and it produces about 50% of the total foodgrains to feed 40% of the population of the country. Thus the sustainability of the present cropping system and also the health of the soils demand a review on the historical development of the soils and their management that remained associated with the tectonic, climatic and geomorphic history of the IGP since it came into existence due to collision of the Indian and Chinese plates during the Middle Miocene. This review provides a state-of-the-art information on the historical development of soils of the IGP, their tectonic-climate-linked natural degradation during the Holocene, and changes in the levels of carbon in soils under agriculture (mainly rice-wheat cropping system), practised over the years. In view of the vast area of the IGP, research initiatives on benchmark soils are, however, still needed to record the subtilities in pedogenesis, especially their polygenetic history due to climate change during the Holocene. This way a historical soil-climate-crop databank may be established to help in fine-tuning the existing management interventions of the national agricultural research system and also the system-modellers in predicting future projections on the sustainability issue of the rice-wheat cropping system in the IGP.