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Constraints and challenges for ensuring food security in the northern and south-western region of Bangladesh: A policy, hazards, and climate change perspectiveAhmed, Zia 10 May 2024 (has links) (PDF)
Achieving food security in Bangladesh remains an arduous task, as the country struggles with several challenges. These challenges include the effects of climate change, occurrence of natural disasters, lack of proper access to credit facilities, and the anthropogenic modification of the agricultural landscape. The vulnerability of agricultural practice in the northern regions to drought, flood, and riverbank erosion, as well as the increased occurrence of coastal surges, waterlogging, cyclones, coastal floods, shrimp aquaculture and soil salinity in the southwestern region, poses a major threat to Bangladesh’s attainment of food security. In this context, we analyze the anthropogenic factors such as land use and land covers change, waterlogging, soil salinity and agriculture credit facilities which combinedly affecting the food security in the southwestern and northern regions of Bangladesh. Findings revealed that in the southwestern regions agricultural lands have decreased because of an increase in shrimp farming. Waterlogging and soil salinity are increasing due to increased shrimp farms also for poor drainage infrastructure and human modification. In our studied three interior coastal districts agricultural land in 2011 was 19,657.12 acres, 12,750.14 acres and 38,774.70 acres which changed to 12,668.70 acres (-36%), 7,151.27 acres (-44%) and 32,809.30 acres (-16%) in 2021. By utilizing CMIP5 data and RCP 4.5 scenarios, we also projected temperature and precipitation in the northern and southwestern regions for the years 2030, 2040, 2050, and 2060 the results indicated substantial variations between pre- and post-monsoon temperatures, with projected maximum, minimum, and mean temperature differences of > 5°C, < 3°C, and < 4°C, respectively. Structural equation modeling reveals that shrimp farming has a significant negative impact on farmers' income and dietary habits. Land use and land cover analyses in the exposed coastal area indicate that agricultural land has decreased by 321.83 km2 over more than thirty years. Structural equation modeling also revealed that agricultural credit influences the food security of marginal farmers. Our study serves as a guide for policymakers in Bangladesh and other developing countries, providing insights into the implementation of effective and sustainable agriculture and climate policies to address the constraints and challenges associated with food security.
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Qualidade da água na carcinicultura na Grande Aracaju - Sergipe, Brasil. / Water quality in cultivation of shrimp in the Great Aracaju - Sergipe, Brazil.Santos, Gracylenne Prata 30 September 2009 (has links)
Known to be essential for human survival, water is one of the most important natural resources of the planet; its quality is of fundamental importance for the sustainability of any agroecosystem. There is a worldwide trend in its preservation, to ensure its availability for various purposes. The aquaculture activity in the cultivation of shrimp has as one of its main problems the disposal of its effluents in aquatic ecosystems. This work aims to analyze, through physico-chemical parameters, the quality of water used in shrimp cultivation in Great Aracaju, in the county of Nossa Senhora do Socorro, SE. The water parameters were measured: pH, temperature, turbidity, suspended solids, total dissolved solids, dissolved oxygen, electrical conductivity, total phosphorus, sulfate, total nitrogen, ammonia, nitrate, nitrite, chlorophyll A, alkalinity, biological and chemical demand of oxygen, total organic carbon and salinity, in three sampling campaigns: October and December, 2008 and January, 2009. Samples were collected at three stations: two nurseries and one spillway. The analyses were conducted in the Laboratório de Química Analítica Ambiental (Laboratory of Environmental Analytical Chemistry) in accordance with Standard Methods. The total phosphorus (nursery: 38.9 mg/L; spillway: 4.3 mg/L), total nitrogen (nursery: 70.3 mg/L; spillway: 60.4 mg/L), total organic carbon (nursery: 19.6 mg / L; spillway: 14.6 mg / L), biological oxygen demand (nursery: 75.8 mg / L; spillway: 66.7 mg / L), dissolved oxygen (nursery: 70.3 mg/L; spillway: 60.4 mg / L) exceeded the limit allowed by Brazilian legislation (CONAMA Resolution 357/2005 and 20/1986) (total P = 0.124 mg / L, total N = 0.40 mg / L,COD <3mg / L, DBO <5mg / L) for brackish water class l. The levels of chemical oxygen demand (nursery: 64.2mg/L; spillway: 80.0 mg/L) were higher than those reported in other studies. The accumulation of nutrients found may be related to the form of management; supplies used such as feed, fertilizers and antibiotics, accumulated organic matter (feed not consumed, excreta); density of shrimp in ponds, the concentration of this nutrient in the composition of the feed used and the utilization of the area as a disposal of domestic sewage in natura. / Conhecida por ser indispensável à sobrevivência humana, a água é um dos recursos naturais mais importantes do planeta, sendo a sua qualidade de fundamental importância para a sustentabilidade de qualquer agroecossistema. Há uma tendência mundial na sua preservação, visando garantir sua disponibilidade para os diversos fins. A carcinicultura, atividade aquícola responsável pelo cultivo de camarão, tem como um dos seus principais problemas o lançamento dos seus efluentes nos ecossistemas aquáticos. Este trabalho tem por objetivo analisar através de parâmetros físico-químico a qualidade da água utilizada na carcinicultura na Grande Aracaju, município de Nossa Senhora do Socorro, SE. Os parâmetros da água medidos foram: pH, temperatura, turbidez, sólidos suspensos, sólidos totais dissolvidos, oxigênio dissolvido, condutividade elétrica, fósforo total, sulfato, nitrogênio total, amônia, nitrato, nitrito, clorofila A, alcalinidade, demanda biológica e química de oxigênio, carbono orgânico total, salinidade, em três campanhas de amostragem: outubro e dezembro de 2008 e janeiro de 2009. Foram coletadas amostras em três estações: 2 viveiros e 1 vertedouro. As análises foram realizadas no Laboratário de Química Analítica Ambiental de acordo com Standard Methods. O fósforo total (viveiro: 38,9mg/L; vertedouro: 4,3mg/L), nitrogênio total (viveiro: 70,3mg/L; vertedouro: 60,4mg/L), carbono orgânico total (viveiro: 19,6mg/L; vertedouro: 14,6mg/L), demanda biológica de oxigênio (viveiro: 75,8mg/L; vertedouro: 66,7mg/L), oxigênio dissolvido (viveiro: 70,3mg/L; vertedouro: 60,4mg/L) excederam o limite permitido pela legislação brasileira (CONAMA Resolução 357/2005 e 20/1986) (P total-0,124 mg/L; N total-0,40 mg/L; TOC ≤ 3mg/L; DBO ≤ 5mg/L) para água salobra classe 1.Os níveis da demanda química do oxigênio (viveiro: 64,2mg/L; vertedouro: 80,0mg/L) foram maiores do que os relatados em outros estudos. O acúmulo de nutrientes verificado pode estar relacionado com a forma de manejo; insumos utilizados como ração, fertilizantes e antibióticos; matéria orgânica acumulada (ração não consumida, excretas); densidade de camarão nos viveiros, a concentração deste nutriente na composição da ração utilizada e a utilização da área como descarte de esgoto doméstico in natura.
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