Restoring fertility to soils after topsoil stripping for brick production in Bangladesh through harnessing agro-ecosystem waste-streams.

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The striping of topsoil is very common in the agronomic regions abutting urban centres in Bangladesh. As urban centres have been growing exponentially in Bangladesh, particularly around the mega-city of Dhaka, the focus of this study, there are concerns regarding food security due to loss of agricultural land, and the degradation of surrounding agronomic land that has had its topsoil removed. Estimates for the amount of land impacted in peri-urban zones of the Indian-sub-continent through topsoil stripping are 10%. Crop yields from the subsoils left after topsoil removal, even with excess fertilization, decrease by over 50%, impacting subsistence farmers. As clay from soil is the only source of building material, it is unlikely that the practice of stripping soils for brick production will stop or decline in Bangladesh, thus there is a great need to find ways of restoring fertility to impacted soils. We proposed to do this by harnessing nutrient rich agronomic waste streams that are common in Bangladesh agri-ecosystems to rapidly restore impacted soil to full cropping potential. These nutrient rich waste streams include manures, oil cake, rice husks & biomass ash. The grant proposal plans to optimise how these waste streams can be applied to subsoils to fully restore soil sustainability, at a low cost to the farmer, & thereby enhancing the food security of the region. The proposal has two stages. The first is to characterize the nutrient content and quantity of waste streams flowing through Bangladeshi substance rice farming communities and then maximize ways in which to redirect these waste-streams back to the land. The second is to trial, through both wet and dry season rice cultivation, across 9 geographically separated Bangladeshi villages, the utility of these wastes for building up soil health and increasing rice yields, testing common Bangladeshi rice cultivars.