Availability and utilisation pattern of agricultural waste at household level in selected areas of Bangladesh.

The use of organic fertilisers and soil amendments are almost universally recommended for improving the organic matter levels and maintaining soil health, but few studies documenting the actual availability and quality of such materials on smallholder farms are available. We selected a case study of 300 households from northern and southern Bangladesh to assess the types of waste materials available for recycling and their usage patterns at household level and we applied a novel approach to empirically identify household waste as input inefficiency in a production context. Northern districts have highly intensive farming systems whereas southern districts have low intensity farming. The total amount of agricultural waste produced at household level was estimated at 822 kg per month. Cow dung contributed about 65% of the total waste followed by animal feed refusal waste (11%), garbage (7%) and kitchen waste (6%). Most of the farmers utilised cow dung and wastes as organic fertiliser and lesser amounts as cooking fuel. Econometric analysis shows that the number of cattle and small ruminant per holding, total area of cultivated land and family size were significant factors that influence the amount of waste production at household level. Each household can reduce the chemical fertiliser cost by Tk. 1463 (US$ 17.84) per month by using compost prepared from household waste. There were ample opportunities for compost/vermicomposting and potential markets. The Department of Agricultural Extension from the public sector and private sector agents might motivate farmers to harvest the potential benefits of agricultural waste through effective management and utilisation.

Nitrogen fertilization impact on soil carbon pools and their stratification and lability in subtropical wheat-mungbean-rice agroecosystems.

Nitrogen (N) is the prime nutrient for crop production and carbon-based functions associated with soil quality. The objective of our study (2012 to 2019) was to evaluate the impact of variable rates of N fertilization on soil organic carbon (C) pools and their stocks, stratification, and lability in subtropical wheat (Triticum aestivum)-mungbean (Vigna radiata)-rice (Oryza sativa L) agroecosystems. The field experiment was conducted in a randomized complete block design (RCB) with N fertilization at 60, 80, 100, 120, and 140% of the recommended rates of wheat (100 kg/ha), mungbean (20 kg/ha), and rice (80 kg/ha), respectively. Composite soils were collected at 0-15 and 15-30 cm depths from each replicated plot and analyzed for microbial biomass (MBC), basal respiration (BR), total organic C (TOC), particulate organic C (POC), permanganate oxidizable C (POXC), carbon lability indices, and stratification. N fertilization (120 and 140%) significantly increased the POC at both depths; however, the effect was more pronounced in the surface layer. Moreover, N fertilization (at 120% and 140%) significantly increased the TOC and labile C pools when compared to the control (100%) and the lower rates (60 and 80%). N fertilization significantly increased MBC, C pool (CPI), lability (CLI), and management indices (CMI), indicating improved and efficient soil biological activities in such systems. The MBC and POC stocks were significantly higher with higher rates of N fertilization (120% and 140%) than the control. Likewise, higher rates of N fertilization significantly increased the stocks of labile C pools. Equally, the stratification values for POC, MBC, and POXC show evidence of improved soil quality because of optimum N fertilization (120-140%) to maintain and/or improve soil quality under rice-based systems in subtropical climates.