What does slash and burn mean in terms of agricultural processes? Slash and burn techniques involve cutting down trees, clearing leftover debris, and returning nutrients to the soil in the form of ash. While the main purpose of slash and burn agriculture is to clear land, the end result of burning the cut foliage allows new vegetation the opportunity to grow more healthily in more nutrient-rich soil. In turn, larger populations are able to settle and be fed from the resulting crop surplus. The process can also be completed relatively quickly compared to other methods of farming. The steps involved in slash and burn farming are:
- Slashing and burning the land: Farmland must first be cleared. Smaller vegetation is cut often with hand tools, while larger plants such as trees are chopped down and left to dry. This increases their flammability. The land is burned in a controlled manner, fulfilling the two main objectives of slash and burn farming: clearing land and creating nutrient-rich soil.
- Farming for up to two consecutive years: The cleared land is then cultivated normally for up to two years. After this time period, farmers allow the land to overgrow because the nutrients in the soul begin to deplete, worsening crop growth.
- Moving to another plot of land: While the previously farmed land is overgrowing, farmers move their location to another plot of land which has been slashed and burned more recently. This allows for a steady production of crops, and therefore a steady source of food, to be maintained.
- Repeat the process of slash and burn farming: After a few years, the original plot of land (which was slashed and burned, farmed, and allowed the chance to overgrow), is once again slashed and burned. The process then reverts to step one and repeats.
Where is slash and burn agriculture practiced today? One of the primary locations where slash and burn agricultural techniques are still used is the Amazon rainforest. This dense ecosystem provides soil that is naturally nutrient-rich, but the heavy foliage provides even more nutrients when burned. The soil in the Amazon is highly leached, meaning that plants lose their nutrients as a result of high water runoff. Slash and burn farming has been effective at restoring nutrients to crops and other vegetation in the region. Other locations where slash and burn farming is currently practiced include the grasslands of central Africa and the forests of southeast Asia.
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Although slash and burn farming may be beneficial to farmers and civilizations, a number of environmental consequences take place as a result of the practice. A benefit that slash and burn cultivation provides to the land is the replenishing of nutrients to leached soil via the burning process, especially in regions with high water runoff, such as the Amazon. However, when viewed from a wider perspective, slash and burn agriculture is regarded as a detrimental practice on the environment with mostly negative consequences.
Deforestation is one of the most apparent disadvantages of using slash and burn techniques. Trees in particular are unable to replenish faster than the rate of destruction when slash and burn is practiced. Soil erosion is another concern caused by deforestation and poor farming techniques. Without trees, the soil is not anchored to the ground through root systems and therefore can lose its nutrients more quickly. Biodiversity and uniquely beautiful landscapes and ecosystems are also lost quickly when slash and burn methods are used. A final concern associated with slash and burn cultivation is the high amount of carbon being released into the air from the resulting fires, which has a negative impact on the health of humans and wildlife.
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Farmers have begun to utilize other agricultural methods in place of slash and burn farming. Fertilization is important because it gives plants the nutrients they need to survive and grow in a healthful way. Burning foliage may provide nutrients for the soil which crops use to grow, but artificial fertilizers are less harmful to entire ecosystems when used in moderation. Artificial fertilization and crop rotation practices allow the same land to be continuously used without nutrients being fully exhausted, thus avoiding the negative consequences of slash and burn farming.
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Social consequences also exist as a result of slash and burn farming practices. The original settlements who used slash and burn farming nearly 12,000 years ago may have found the practice to be beneficial, but a number of factors existed then that are not as relevant or realistic to reproducing the practice in the present day. Most notably, the population of settlements during the original uses of slash and burn farming were far smaller than today's global population, or even the population of a single city in any given country. Slash and burn farming cannot sustain extremely large populations because of the amount of land required to be used. In modern contexts, this land is in competition for use by the housing, business, and recreation sectors, meaning that tying it up for use in slash and burn cycles is impractical.
Slash and burn techniques also require land to be abandoned every few years so that it may overgrow to repeat the process. Farmers would need to frequently move to new plots of land in order to sustain the practice of slash and burn agriculture. This would reinforce a cycle of poverty, as a large amount of land would go unused and workers would need to resettle every few years. While slash and burn farming may have been an effective technique during the rise of agriculture, more environmentally friendly and effective agricultural alternatives exist today to better sustain human life.
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Slash and burn farming is an agricultural technique that involves cutting down and burning existing trees, brush, and other foliage to clear land and prepare it for cultivation. It was first invented nearly 12,000 years ago during the rise of agricultural practices. Slash and burn farming was a large influence in allowing agriculture to take place, providing benefits such as the ability for civilizations to be settled, populations to be sustained, and surpluses of food to be stored. The steps involved in slash and burn agriculture include:
- Slashing and burning the land
- Farming for up to two consecutive years
- Moving to another plot of land
- Repeating the process of slash and burn farming
The main purpose of slash and burn farming is to clear land quickly and return nutrients to the soil through the burning process. Slash and burn agriculture, however, is often regarded as a negatively impactful practice in relation to the environment. Deforestation and soil erosion are two primary concerns for ecosystems such as the Amazon rainforest, where slash and burn techniques are currently practiced. Trees regrow more slowly than they are cut down, the natural beauty of ecosystems is lost, and biodiversity decreases as a result of deforestation from slash and burn agriculture. Because of this, more ecofriendly alternatives are typically promoted today.
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Additional Info
The Birth of Agriculture
12,000 years ago, the only way humans could gain food was to either hunt animals or gather wild-growing plants. It was a meager living, requiring small groups of people to regularly move so as not to deplete the resources of an area.
Agriculture, the deliberate growing of food, allows larger numbers of people to settle down, because it can produce far more food than what can be found in the wild. It also allows surpluses to be stored, leaving people less at the mercy of the environment. But the wild first needs to be tamed, and this was first done through slash and burn techniques.
Though in its historical origins slash and burn was practiced in a variety of climates, including woodlands and grasslands, in modern times, slash and burn is commonly utilized in tropical rainforests and grasslands, like those of the Amazon and Southeast Asia.
Clearing and Preparing the Land
Farmland needs to be clear of native plants, which grow everywhere there is fertile soil: the same soil needed for farming. Everything needs to be cut down, generally with common hand tools. Larger plants such as trees need to be cut and left to dry. Eventually everything is burned.
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The burning has a twofold purpose. The first is to clear debris. The second, however, is to return nutrients to the soil via the ash of the fires. These nutrients are what allow the land to produce large quantities of food, which, in turn, make it possible for populations to settle down and build towns.
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Slashing and Burning over Time
Agriculture depletes the soil of nutrients. Without it being replenished, crops can only grow for a couple years. In slash and burn agriculture, plots go through three phases.
1. The first includes the actual slashing and burning of trees and ground cover.
2. The second is farming, and the third is allowing the land to naturally overgrow.
3. After a number of years, the cycle is repeated, with the new growth once more slashed and burned.
Environmental Impact: Erosion and Deforestation
Over time, slash and burn techniques tend to damage the landscape, especially when done in large scale. Trees, in particular, are destroyed at a much greater rate than new ones can grow. Also, soil no longer held together by established root systems is eroded away by the elements.
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This is why, when possible, farmers turn to the use of fertilizers and other methods of returning nutrients to the soil. Fertilization allows the same plot of land to be used over and over without the soil being exhausted, thus avoiding the drawbacks of slash and burn agriculture.
Slash and Burn as Subsistence Agriculture
Fertilization is a far more efficient method of farming, making it more profitable. Most slash and burn agriculture is subsistence farming, meaning those who practice it only expect to produce enough to support themselves rather than producing a large surplus meant for sale.
Lesson Summary
Slash and burn is a type of subsistence farming that generally dies out when agriculture in an area becomes a marketable commodity. It is practiced by cutting down natural grasses, brush and trees and burning the waste. The ash deposits nutrients into the soil to support a few years of cultivation. However, areas have to be abandoned quickly as the nutrients are depleted. This makes the technique fairly inefficient. It also has considerable environmental implications, commonly leading to deforestation and soil erosion.
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