Sustainable agriculture is the use of farming systems and practices which maintain or enhance the economic viability of agricultural production, the natural resource base and other ecosystems which are influenced by agricultural activities.
At present the world’s agricultural output exceeds demand, leading to widespread hunger in parts of the world. Sustainable agriculture is necessary to ensure that we have enough to feed not only the present but the future generations too.
 Utilizes planet's resources
It is an important element of the overall effort to make human activities compatible with the demands of the earth's ecosystem. Sustainable agriculture stresses the need to utilize the planet's resources wisely.
This calls for reduction of purchased inputs and managing on-farm resources. Reliance on biologically-fixed nitrogen from legumes as against manufactured nitrogen fertilizers is an example of managing on-farm resources. Low-input agriculture is one of several alternative farming systems whose methods are adaptable to sustainable agriculture.
Of prime importance in sustainable agriculture is stewardship of human and natural resources. The former includes social responsibilities such as working and living conditions of labourers, maintaining communities and improvement of consumer health and safety. Stewardship of natural resources involve long-term enhancement of vital resource base.
The key features of sustainable Sustainable agriculture are:
Cultivated landscapes that are complex, diverse are created and sustained. Producers use practices that conserve and restore resources.
Humane Animal Management
Animals are allowed to engage in the natural behaviors that are important to their well-being, and are harvested in ways that minimize stress to the animals and the environment.
Producers operate within a framework of sound business planning and pursue integrated and proactive approaches to marketing and sales.
Producers and their employees receive fair and reasonable compensation and work in a safe and respectful environment.
 Need for genetic diversity
Historically farmers have confined themselves to growing only the fastest and most productive plants. Such practices can result in growing crops without the genetic diversity found in wildlife. This lack of diversity makes crop susceptible to disease and failure.
Among the many methods of sustainable farming discussed by scientists and farmers are growing a diverse number of perennial crops in a single field, each growing in separate seasons to avoid competing with each other for natural resources. This way there will not only be replication of the biodiversity already found in a natural environment, but will also result in greater disease resistance and reduced effects of erosion and loss of nutrients in soil.
 Replenishing nutrients
While harvesting crops, some of the nutrients of the soil get removed. Unless these nutrients are replenished, land would become unusable for further farming. In sustainable agriculture soil is replenished with the minimum use of non-renewable resources, such as natural gas (used in converting atmospheric nitrogen into synthetic fertilizer), or mineral ores (e.g., phosphate).
Nitrogen is made available from renewable sources which would last indefinitely. These processes include recycling human and livestock manure and crop waste.
- Sustainable Agriculture Educational Project
- Towards a Sustainable Agriculture
- What is sustainable agriculture?