Sustainable agriculture can be a broad and sometimes vague term without a universally agreed-upon definition. I like to define sustainability in the broadest sense possible, in that sustainability is the ability to carry out practices indefinitely, without having to eventually halt them because of negative impacts on environment, community, or the processes themselves. Sustainable agriculture thus involves more than just environmentally sound farming practices, but also necessarily encompasses both economic considerations (questions of resource utilization) and human considerations as well.Why is sustainability important in agriculture?Unfortunately, the current agricultural production systems in place not only in the U.S. but in many parts of the world are highly unsustainable. Some of the problems with agriculture include the destruction of wild ecosystems, such as the clearing of rainforest and other biomes to make room for farming, nutrient pollution and chemical pollution from agricultural runoff, waterway disruption and aquifer depletion from the use of water for irrigation, and climate destabilization resulting from a combination of factors.What are best practices, with respect to sustainability, in farming and agriculture?People often focus on certain simple issues, like organic farming, or the use of specific harmful chemicals, without looking at the broader picture. Even if everyone in the world were to completely stop using all harmful chemicals in agriculture, and only farm organically, there could still be catastrophic environmental implications of farming.The key issue in sustainability, most important than all other issues, is leaving intact ecosystems, and not clearing or developing more than a certain portion of wild areas for agriculture or human use. The rule of thumb or target that I like to shoot for is to leave 70% of land as intact wild ecosystem. This does not mean that the land is not being used in any way, but only that it is not being directly used for agriculture or other uses (i.e. crops are not being grown there, timber is not being harvested, people are not living there), and that whatever uses of the land only have negligible impacts on the ecosystem.Economic value of wild areas:One argument for continued development is that the development is necessary for economic growth, and growth is necessary for economic health. I find this argument to be fallacious, for two compelling reasons. One is that the paradigm of indefinite economic growth without bound is a flawed one. Resources are always limited, and there is only a certain capacity of goods that can be produced sustainably. Achieving sustainability requires abandoning this old model of economic growth.My second reason, however, is that intact wild ecosystems are actually necessary for sustained economic health, especially in the agricultural sector, but also in virtually all other aspects of society as well.Direct economic benefits of wild areas:In terms of direct effects, intact wild ecosystems provide a buffer which prevents the spread of insects, diseases, and other pests which can destroy crops. Our current unsustainable agriculture system relies on expensive chemical control systems to control pests, which are continually adapting. A sustainable system would rely on natural buffer zones, which not only prevent the spread of disease, but also house predators which feed on insect pests, thus making it unlikely for pests to get established among crops in the first place. The organic farms and gardens that I have worked with which practice crop diversification and the use of wild buffer areas around the operation remark that they typically have almost no problem with pests.Indirect economic benefits of wild areas:Indirect effects, however, are even stronger. Wild ecosystems stabilize climate and weather, which can greatly reduce or even prevent natural disasters like flood, drought, and moderate temperature and humidity, lessening the severity of extreme weather events like cold or hot spells. Wild ecosystems can also produce numerous resources, including foods, which can be sustainably harvested, including wild fish and meat, and plants for food or medicinal use. Wild areas also provide beauty, increasing land value in nearby residential areas, and providing recreation and income to local economies through tourism. Often, an intact wild area can have numerous different uses. And lastly, ecosystems also filter and purify water and air, thus lowering health care costs and lessening the need for burdensome environmental regulations.In summary:Sustainable agriculture is more than just organic agriculture; it encompasses environmental, economic, and human factors together. The single most important issue in organic agriculture is the preservation of intact, wild ecosystems. I set the goal of preserving 70% of all land as wild ecosystems. These lands can provide immense economic value, both for agriculture and society at large, and both through direct and indirect effects.