Sustainable farming practices will vary depending on geographic variables, including local resources like soil type and water availability as well as terrain and climate. Human variables like economic ability to invest in farming infrastructure, technology, and equipment, as well as the size of the land masses available for agriculture will also impact the adequate mix of farming practices that can constitute sustainability in any given region. Soil farming is unlikely to fall out of favor anywhere entirely, although there are some regions of the world that lack soil altogether or which have poor quality soil, Those regions, like atolls in the South Pacific or arid desert regions, would do well to adapt some other farming methods to meet human food needs. Alternatives to soil farming include greenhouses, aquaponics, and hydroponics. Soil-based farming will undoubtedly remain the primary means of cultivating cash crops and staple crops like grains. To be sustainable, soil farming needs to have several features that minimize the dependence on chemicals, while also maximizing the efficiency of water and irrigation. Soil farming that uses crop rotation ensures that the soil remains nutrient rich, as each crop consumes different specific nutrients in the soil. The use of cover crops is a sustainable practice because it prevents soil erosion, prevents the proliferation of weeds thus minimizing dependency on chemicals, and also promotes the integrity...

Soil enrichment with compost promotes the health of the soil, and pest management techniques that are sustainable can create a soil farming practice that is roughly on par with other types of agriculture like greenhouses, aquaponics, and hydroponics.
Greenhouses are not as sustainable as they may seem. Although they "reduce pest infestations and fungal infections," reducing chemical dependency, they do require temperature control -- which consumes electricity. Moreover although greenhouses do allow for regulated water use because of the ability of the farmer to control the amount of water plants get, greenhouses are often poorly insulated and thus unsustainable in some of the climates they are used in. To make greenhouses more sustainable, new technology is being used to help insulate them better, depending on the climate they are being used in (Erdmann, 2009). In developing countries that use greenhouses, such as in the South American flower industry, those upgrades may not be affordable, which is why greenhouses may need to be supplemented by other alternatives.

Defined as "growing plants without…