Subsistence agriculture
Subsistence agriculture occurs when farmers grow food crops to meet the needs of themselves and their families on smallholdings. Subsistence agriculturalists target farm output for survival and for mostly local requirements, with little or no surplus. Planting decisions occur principally with an eye toward what the family will need during the coming year, and only secondarily toward market prices. Tony Waters, a professor of sociology, defines "subsistence peasants" as "people who grow what they eat, build their own houses, and live without regularly making purchases in the marketplace." Despite the self-sufficiency in subsistence farming, most subsistence farmers  also participate in trade to some degree. Although their amount of trade as measured in cash is less than that of consumers in countries with modern complex markets, they use these markets mainly to obtain goods not to support income for food. This is usually for goods that are not necessary for survival, which may include sugar, iron roofing-sheets, bicycles, used clothing, and so forth. Many have important trade contacts and trade items that they can produce because of their special skills or special access to resources valued in the marketplace. Most subsistence farmers today operate in developing countries . Subsistence agriculture generally features: small capital/finance requirements, mixed cropping, limited use of agrochemicals (e.g. pesticides and fertilizer), unimproved varieties of crops and animals, little or no surplus yield for sale, use of crude/traditional tools (e.g. hoes, machetes, and cutlasses), mainly the production of food crops, small scattered plots of land, reliance on unskilled labor (often family members), and (generally) low yields. History. Subsistence agriculture was the dominant mode of production in the world until recently, when market-based capitalism became widespread. Subsistence agriculture largely disappeared in Europe by the beginning of the twentieth century. It began to decrease  in North America with the movement of sharecroppers and tenant farmers out of the American South and Midwest during the 1930s and 1940s. In Central and Eastern Europe, semi-subsistence agriculture reappeared within the transition economy after 1990 but declined in significance (or disappeared) in most countries by the accession to the EU in 2004 or 2007. Contemporary practices. Subsistence farming continues today in large parts of rural Africa, and parts of Asia and Latin America. In 2015, about 2 billion people (slightly more than 25% of the world's population) in 500 million households living in rural areas of  developing nations survive as "smallholder" farmers, working less than 2 hectares (5 acres) of land. Around 98% of China's farmers work on small farms, and China accounts for around half of the total world farms. In India, 80% of the total farmers are smallholder farmers; Ethiopia and Asia have almost 90% being small; while Mexico and Brazil recorded having 50% and 20% being small. Areas where subsistence farming is largely practiced today, such as India and other regions in Asia, have seen a recent decline in the practice. This is due to processes such as urbanization, the transformation of  land into rural areas, and integration of capitalist forms of farming. In India, the increase in industrialization and decrease in rural agriculture has led to rural unemployment and increased poverty for those in lower caste groups. Those that are able to live and work in urbanized areas are able to increase their income while those that remain in rural areas take large decreases, which is why there was no large decline in poverty.  This effectively widens the income gap between lower and higher castes and makes it harder for those in rural areas to move up in caste ranking. This  era has marked a time of increased farmer suicides and the "vanishing village". Adaptation to Climate Change. Most subsistence agriculture is practiced in developing countries located in tropical climates. Effects on crop production brought about by climate change will be more intense in these regions as extreme temperatures are linked to lower crop yields. Farmers have been forced to respond to increased temperatures through things such as increased land and labor inputs which threaten long-term productivity. Coping measures in response to variable climates can include reducing daily food consumption and selling livestock to compensate for the decreased productivity. These  responses often threaten the future of household farms in the following seasons as many farmers will sell draft animals used for labor and will also consume seeds saved for planting. Measuring the full extent of future climate change impacts is difficult to determine as smallholder farms are complex systems with many different interactions. Different locations have different adaptation strategies available to them such as crop and livestock substitutions. Rates of production for cereal crops, such as wheat, oats, and maize have been declining largely due to heats effects on crop fertility. This has forced many farmers to switch to more  heat tolerant crops to maintain levels of productivity. Substitution of crops for heat tolerant alternatives limits the overall diversity of crops grown on smallholder farms. As many farmers farm to meet daily food needs, this can negatively impact nutrition and diet among many families practicing subsistence agriculture. Types of subsistence farming. Shifting agriculture. In this type of farming, a patch of forest land is cleared by a combination of felling (chopping down) and burning, and crops are grown. After 2–3 years the fertility of the soil begins to decline, the land is abandoned and the farmer moves to clear a  fresh piece of land elsewhere in the forest as the process continues. While the land is left fallow the forest regrows in the cleared area and soil fertility and biomass is restored. After a decade or more, the farmer may return to the first piece of land. This form of agriculture is sustainable at low population densities, but higher population loads require more frequent clearing which prevents soil fertility from recovering, opens up more of the forest canopy, and encourages scrub at the expense of large trees, eventually resulting in deforestation and soil erosion. Shifting cultivation is called "dredd" in  India, "ladang" in Indonesia, "milpa" in Central America and Mexico and "jhumming" in North East India. Nomadic herding. In this type of farming people migrate along with their animals from one place to another in search of fodder for their animals. Generally they rear cattle, sheep, goats, camels and/or yaks for milk, skin, meat and wool. This way of life is common in parts of central and western Asia, India, east and southwest Africa and northern Eurasia. Examples are the nomadic Bhotiyas and Gujjars of the Himalayas. They carry their belongings, such as tents, etc., on the backs of donkeys , horses, and camels. In mountainous regions, like Tibet and the Andes, yak and llama are reared. Reindeer are the livestock in arctic and sub-arctic areas. Sheep, goats, and camels are common animals, and cattle and horses are also important. Intensive subsistence farming. In intensive subsistence agriculture, the farmer cultivates a small plot of land using simple tools and more labour. Climate with large number of days with sunshine and fertile soils, permits growing of more than one crop annually on the same plot. Farmers use their small land holdings to produce enough for their local consumption, while remaining produce  is used for exchange against other goods. It results in much more food being produced per acre compared to other subsistence patterns. In the most intensive situation, farmers may even create terraces along steep hillsides to cultivate rice paddies. Such fields are found in densely populated parts of Asia, such as in the Philippines. They may also intensify by using manure, artificial irrigation and animal waste as fertilizer. Intensive subsistence farming is prevalent in the thickly populated areas of the monsoon regions of south, southwest, and southeast Asia. Poverty alleviation. Subsistence agriculture can be used as a poverty alleviation strategy , specifically as a safety net for food-price shocks and for food security. Poor countries are limited in fiscal and institutional resources that would allow them to contain rises in domestic prices as well as to manage social assistance programs, which is often because they are using policy tools that are intended for middle- and high-income countries. Low-income countries tend to have populations in which 80% of poor are in rural areas and more than 90% of rural households have access to land, yet a majority of these rural poor have insufficient access to food. Subsistence agriculture can  be used in low-income countries as a part of policy responses to a food crisis in the short and medium term, and provide a safety net for the poor in these countries.