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

在孟加拉国与城市中心毗邻的农区，表层土壤剥离现象非常普遍。由于孟加拉国的城市中心呈指数级增长，特别是在本研究的重点城市达卡周围，人们对农业用地的丧失以及周围表层土壤被拆除的周围农地的退化引起了对粮食安全的关切。据估计，印度次大陆城市周边地区受表层土壤剥离影响的土地数量为10%。去除表土后留下的底土的作物产量，即使在过量施肥的情况下，也会减少50%以上，影响到自给自足的农民。由于土壤中的粘土是建筑材料的唯一来源，孟加拉国不太可能停止或减少剥离土壤用于制砖的做法，因此迫切需要找到恢复受影响土壤肥力的方法。我们建议通过利用孟加拉国农业生态系统中常见的营养丰富的农业废弃物来实现这一点，以迅速将受影响的土壤恢复到完全种植的潜力。这些营养丰富的废物流包括粪便、油饼、稻壳和生物质灰烬。赠款提案计划优化如何将这些废水流应用到底土中，以农民的低成本完全恢复土壤的可持续性，从而加强该地区的粮食安全。该提案分为两个阶段。首先是确定流经孟加拉物质水稻种植社区的废流的营养含量和数量，然后最大限度地将这些废流重新引导回土地。第二个是在孟加拉9个不同的村庄，通过旱季和湿季水稻种植，试验利用这些废弃物来促进土壤健康和提高水稻产量，测试孟加拉国常见的水稻品种。

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.