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Expansion of aquaculture in the Sundarbans Biosphere Reserve (SBR) is irreversibly replacing agricultural land and the drivers of this change are disputed. Based on in-depth interviews with 67 aquaculture farmers, this paper characterizes major aquaculture types in the SBR, their impacts, and identifies drivers of conversion from agricultural land. Aquaculture types included traditional, improved-traditional, modified-extensive, and semi-intensive systems. Extensive capture of wild shrimp larvae is environmentally harmful but constitutes an important livelihood. Semi-intensive aquaculture of exotic shrimp (Litopenaeus vannamei) has much higher unit-area profitability than other types but involves greater financial risk. Profitability is the main driver for the transition from agriculture, but environmental factors such as lowered crop yields and cyclone impacts also contributed. Many conversions from agriculture to aquaculture are illegal according to the stakeholders. Existing legislation, if enforced, could halt the loss of agriculture, while the promotion of improved-traditional aquaculture could reduce the demand for wild seed. [ABSTRACT FROM AUTHOR]

New agricultural technologies bring multiple impacts which are hard to predict. Two changes taking place in Indian agriculture are a transition from bullocks to tractors and an associated replacement of manure with synthetic fertilisers. This paper uses primary data to model social, environmental and economic impacts of these transitions in South India. It compares ploughing by bullocks or tractors and the provision of nitrogen from manure or synthetic urea for irrigated rice from the greenhouse gas (GHG), economic and labour perspective. Tractors plough nine times faster than bullocks, use substantially less labour, with no significant difference in GHG emissions. Tractors are twice as costly as bullocks yet remain more popular to hire. The GHG emissions from manure-N paddy are 30 % higher than for urea-N, largely due to the organic matter in manure driving methane emissions. Labour use is significantly higher for manure, and the gender balance is more equal. Manure is substantially more expensive as a source of nutrients compared to synthetic nutrients, yet remains popular when available. This paper demonstrates the need to take a broad approach to analysing the sustainability impacts of new technologies, as trade-offs between different metrics are common. [ABSTRACT FROM AUTHOR]