Concept of Agricultural Sustainability The idea of sustainability recalls the logic of practice, through which effects viewed as desirable are made to happen rather than a concept built to explain reality. Different meanings have been associated with this notion since the Brundtland Report introduced it to international public debate in 1987 (WCED, 1987). According to AtKisson (1999) sustainability has developed on seven principles, such as:
I. Think long-term: Sustainability is not just about next year or next decade, but about generational timescales. 2. Understand systems: Everything of the natural system is linked together. The dynamics of systems include feedback loops. The effect of one system influences the composition of another system. It is very much difficult to show in one picture. 3. Recognize limits: Once upon a time the human world was small and nature was big. Limits to physical growth were extremely far away. But now the pressure of the human population extends the limit of carrying capacity in the natural system. So, we must recognize the limitations of any action to do. 4. Protect Nature: We depend on nature for life. We should not do any development works ignoring nature. We must protect it for our future generation. 5. Transform business-as-usual: Industrial activities do not follow the sustainability criteria that are needed to follow. It acts just as a business theme. As a result, it hampers real sustainability. We should keep in mind that resources are limited. So, businesses will be run following the sustainability rules. 6. Practice fairness: Sustainability equals fairness over time. If we are truly fair to nature, to each other, and to future generations, sustainability would happen automatically. 7. Embrace creativity: Sustainability compensates for enormous changes that humanity makes, it means embracing the creative imperative. We have to be inventive and creative. Sustainable agricultural systems are an essential foundation for rural development in most of the world. Sustainability requires that systems should be environmentally sound, financially and economically feasible, and socially acceptable. Again, these are characterized as those that can indefinitely meet demands for food and fiber at socially acceptable economic and environmental costs (Diebel et al., 1993).
Methodology of Assessing Sustainability of Agriculture in Bangladesh There are two measures of sustainability to be considered: the economic and the physical. One measure has devoted considerable efforts to the development of economic measures, while another provides an insight into the determination of the physical as related to the soil resource used in agriculture (Francis et al., 1997). Economic measurement of sustainability is difficult, as there are several viewpoints to consider. It is stated that two general views prevail concerning sustainability in agriculture, one by consumers and another is by producers. Consumers view sustainability refers its capacity to provide an abundance of quality food. Producers view sustainability refers as an income-generating activity with economic and social value. The concern they have is maintaining a net return from the sale of agricultural products. In economic terms, consumers assess sustainability in terms of maintaining a level of consumer surplus in the consumption of food over time. On the other hand, in economic terms, producers regard sustainability as the maintenance of a producer surplus or economic rent (return to factors used in production) over time. This dichotomy of interest provides a basis of conflict and attracts attention to the difficulty experienced when trying to measure sustainability. From the consumer's standpoint, the security of the food supply is the uppermost particularly among those who have previously experienced shortages or indeed famine. Measurement of the value of food security becomes almost impossible. Time preference becomes a complicating factor as does try to aggregate the preferences of individuals. The attempt to measure sustainability in terms of food security should be abandoned (Chowdhury et al., 2005). Therefore it is a generalized argument that sustainability may be measured in terms of the flow of income from agricultural production. Because the society regards that the sustainability is means of all the costs and benefits of production. Particular issues that are raised when measuring sustainability are the discount rate; private versus social costs (negative externalities); non-market benefits (positive externalities); economic flexibility; and income/risk preferences. In addition to maintaining a producer, the surplus is the need to sustain farm families. Furthermore, sustainability must be measured taking into account uncertainty. Therefore, the elasticity of supply (the change in output relative to a change in price) may be a relevant indicator of sustainability. Output in response to price changes is impacted by technologies and available inputs.
Factors Influencing the Sustainable Agriculture in Bangladesh Many factors influence the sustainability of agricultural systems, but institutional support systems and technologies are particularly important. Scientists, producers, researchers, and non-governmental organizations (NG0s) have increasingly sought to identify, validate and implement practical farming technologies and methods which meet the sustainability criteria. This has been especially true in developing countries like Bangladesh where chronic rural poverty is often closely linked to a rapidly degrading resource base. In this sense, enhancing the sustainability and productivity of agricultural systems are the key to the conservation of natural resources and to the reduction of rural poverty in coastal Bangladesh (Salequzzaman, 2001). Modern technologies such as improved varieties and chemical inputs have helped spur yields among some farmers, but these do not prevent erosion nor do many 'farmers possess the financial resources to use them. With increasing population and decreasing availability of new land to exploit, maintaining adequate fallows has become increasingly difficult and continuous cropping has become commonplace. This has resulted in a vicious cycle of soil degradation, crop yield declines, further pressure on available lands to generate required food supplies, and often, migration out of agriculture. In addition, it is said that any low-cost innovations, not requiring large capital investments and relatively easy to implement, can help poor farm households become more productive by improving fallow management and increasing yields.
Sustainability Assessment of Coastal Shrimp Aquaculture in Bangladesh The study has identified a set of indicators for shrimp aquaculture sustainability in coastal Bangladesh. These indicators are divided into three sustainability dimensions: economic, social and ecological. These indicators are selected through the analysis of relative availability of data representing the indicators, sensitivity to stress on the system, existence of threshold value and guidelines, productivity, integrability and known response to disturbances, anthropogenic stresses, and change over time (Salequzzaman, 2001). However, the criteria such as the continuity of supply and quality inputs (eg. feed, seed etc), the social, environmental, and economic costs of providing the inputs (eg. depletion of resources), the long term continuity (sustainability) of production, financial viability, social acceptance and impact, environmental impact and efficiency of conversion of resources into outputs have been considered to assess the sustainability the coastal shrimp aquaculture.