Where is slash and burn agriculture impacts on soil health


Slash and burn agriculture also results in significant soil erosion and accompanying landslides, water contamination, and/or dust clouds, as without trees and vegetation and their root systems, soil washes away during heavy rains and blows away during droughts.


How does slash and burn lead to soil erosion?

Also, by cutting and burning the trees, field surface remains bare, with no protection against strong winds and rains. Tropical heavy rains can lead to soil saturation and the formation of free water on the surface, which further causes soil erosion even on slightly sloping terrains.

Where is slash and burn agriculture located?

Slash and burn agriculture is most often practiced in places where open land for farming is not readily available because of dense vegetation. These regions include central Africa, northern South America, and Southeast Asia. Such farming is typically done within grasslands and rainforests.

Why is soil depleted of nutrients after slash and burn?

During the first cycle of land exploitation, slash-and-burn releases a large portion of nutrients stored in the above-ground biomass into the soil. Therefore, the gain of nutrient stock in the soil is at the expense of the plant biomass.

Does slash and burn increase soil fertility?

Milpa has been widely related with slash-and-burn farming, which today is considered an unsustainable practice that decreases soil fertility in the long term. Particularly, burning increases soil pH and drastically decreases soil organic matter, which was confirmed in the present study.

Does burning fields help soil?

Intense burns may have detrimental effects on soil physical properties by consuming soil organic matter. Since soil organic matter holds sand, silt, and clay particles into aggregates, a loss of soil organic matter results in a loss of soil structure.

What is slash and burn farming What are its disadvantages?

After the soil loses its fertility, the land is abandoned and the cultivator moves to a new plot. Shifting cultivation is also known as ‘slash and burn’ agriculture. Deforestation, losing fertility of land and soil erosion are the disadvantages of shifting cultivation.

How does burning affect soil?

Physical impacts of fire on soil include breakdown in soil structure, reduced moisture retention and capacity, and development of water repellency, all of which increase susceptibility to erosion.

How does agricultural depletion affect soil?

This practice depletes the soil of nutrients (making the soil less productive over time), reduces organic matter in soil and can cause significant erosion.

How does soil become nutrient deficient?

Unusually low or high soil pH levels can make certain nutrients unavailable to the plant. Poor growing conditions such as excessively wet or dry soils, cold weather, and soil compaction can reduce the roots ability to access sufficient amounts of the nutrients.

Is slash and burn agriculture good or bad?

Slashed and burned areas are experiencing strong negative impact on biodiversity specifically on immobile, small species. However, these effects can be balanced if there is sufficient unaffected area from where re-colonization can re-establish species destroyed in the clearing and cropping phase.

Why is slash and burn good?

It is burned here because the burning process releases nutrients which then fertilize the soil. So, the slash and burn process successfully clears land for agriculture and introduces fertilizing nutrients into the soil, leaving it in excellent condition to grow crops.

Which type of agriculture is slash and burn agriculture?

Slash-and-burn is a type of shifting cultivation, an agricultural system in which farmers routinely move from one cultivable area to another.

What is slash and burn farming?

Slash and burn agriculture—also known as swidden or shifting agriculture—is a traditional method of tending domesticated crops that involves the rotation of several plots of land in a planting cycle. The farmer plants crops in a field for one or two seasons and then lets the field lie fallow for several seasons.

What is slash and burn?

For example, if a swidden rotation is between 5 and 8 years, and the rainforest trees have a 200-700 year cultivation cycle, then slash and burn represents one of what may be several elements resulting in deforestation. Slash and burn is a useful technique in some environments, but not in all. A special issue of “Human Ecology” suggests …

What is the best way to slash and burn?

The Best Conditions for Slash and Burn Agriculture. Slash and burn agriculture works best in low-intensity farming situations when the farmer has plenty of land that he or she can afford to let lay fallow, and it works best when crops are rotated to assist in restoring the nutrients. It has also been documented in societies where people maintain …

How does slash and burn work?

In the meantime, the farmer shifts to a field that has lain fallow for several years and removes the vegetation by cutting it down and burning it—hence the name “slash and burn.”. The ash from the burned vegetation adds another layer of nutrients to the soil, and that, along with the time resting, allows the soil to regenerate.

Does slash and burn agriculture add to deforestation?

Henley discovered that the reality is that swidden agriculture can add to deforestation

Is swidden agriculture bad?

Since the 1970s or so, swidden agriculture has been described as both a bad practice, resulting in the progressive destruction of natural forests, and an excellent practice, as a refined method of forest preservation and guardianship. A recent study conducted on historical swidden agriculture in Indonesia (Henley 2011) documented the historical attitudes of scholars towards slash and burn and then tested the assumptions based on more than a century of slash and burn agriculture.

Is slash and burn a technique?

Slash and burn is a useful technique in some environments, but not in all. A special issue of “Human Ecology” suggests that the creation of global markets is pushing farmers to replace their swidden plots with permanent fields. Alternatively, when farmers have access to off-farm income, swidden agriculture is maintained as a complement …

Where is slash and burn used?

Slash-and-burn agriculture is often used by tropical-forest root-crop farmers in various parts of the world and by dry-rice cultivators of the forested hill country of Southeast Asia. The ash provides some fertilization, and the plot is relatively free of weeds. After several years of cultivation, fertility declines and weeds increase.

What happens after a year of cultivation?

After several years of cultivation, fertility declines and weeds increase. Traditionally, the area was left fallow and reverted to a secondary forest of bush. Cultivation would then shift to a new plot. After about a decade the old site could be reused.

What is the cause of air pollution in Southeast Asia?

In Southeast Asia, slash-and-burn agriculture for oil palm cultivation has been a major source of annual air pollution from smoke. ( See also shifting agriculture .) Slash-and-burn forest clearing in the Amazon.

Does slash and burn produce carbon dioxide?

Although traditional practices generally contributed few greenhouse gases because of their scale, modern slash-and-burn techniques are a significant source of carbon dioxide emissions, especially when used to initiate permanent deforestation. In Southeast Asia, slash-and- burn agriculture for oil palm cultivation has been a major source …

What is slash and burn agriculture?

Slash and burn agriculture is the process of cutting down the vegetation in a particular plot of land, setting fire to the remaining foliage, and using the ashes to provide nutrients to the soil for the use of planting food crops. The cleared area following slash and burn, also known as swidden, …

Where is slash and burn farming practiced?

These regions include central Africa, northern South America, and Southeast Asia. Such farming is typically done within grasslands and rainforests .

How long has slash and burn been around?

Humans have practiced this method for about 12,000 years, ever since the transition known as the Neolithic Revolution—the time when humans stopped hunting and gathering and started to stay put and grow crops. Today, between 200 and 500 million people use slash and burn agriculture, roughly 7% of the world’s population.

What are the negative aspects of slash and burn?

They include: Deforestation: When practiced by large populations, or when fields are not given sufficient time for vegetation to grow back, there is a temporary or permanent loss of forest cover.

Why is slash and burn important?

Slash and burn allows people to farm in places where it usually is not possible because of dense vegetation, soil infertility, low soil nutrient content, uncontrollable pests, or other reasons .

How to slash and burn?

Generally, the following steps are taken in slash and burn agriculture: Prepare the field by cutting down vegetation; plants that provide food or timber may be left standing. The downed vegetation is allowed to dry until just before the rainiest part of the year to ensure an effective burn.

What is the term for clearing a land after a slash and burn?

The cleared area following slash and burn, also known as swidden, is used for a relatively short period of time, and then left alone for a longer period of time so that vegetation can grow again. For this reason, this type of agriculture is also known as shifting cultivation.

Where is slash and burn cultivation?

Slash and burn cultivation (locally called jhum cultivation in India) in progress at Wokha, Nagaland, India. Similarly, the fire works as a natural pesticide, and thus no harmful chemicals are needed prior to planting. Once an area has been burned, it is then planted with the desired crop. Part of the shifting aspect of shifting cultivation, which …

Where is the cultivation of crops after burning?

Cultivation of crops in deforested area after burning in Wokha, Nagaland, India. After the alloted growing seasons, the plot of land is then allowed to fallow, meaning it is left to regrow, and not used for agriculture or cultivated means.

What is shifting cultivation?

Shifting cultivation allows natural habitats to remain, and maintains biodiversity while still yielding crops. Sustainable slash and burn is more commonly known as shifting cultivation, meaning crops and farming rotate in a given area to maintain the soil and natural environment. Slash and burn agriculture is a highly controversial …

How does deforestation affect climate?

It is true that deforestation has had a large and negative effect on climate change. Because forests and trees are such large absorbers of CO2, the removal of these plants has led to an increase of carbon in the Earth’s atmosphere, which in turn has impacted the overall climate and temperature of the planet.

What is stubble burning?

Stubble burning in slash and burn agriculture. Firstly, slash and burn is carefully planned, and certain areas are selected for slashing, rather than targeting an entire forest or field. This is usually around a hectare-sized piece of land. Once an area is established, trees, shrubs and large vegetation are all cut and left to dry out.

Why is shifting cultivation important?

The process of shifting cultivation, however, is based on maintaining a sustainable, balanced form of farming that rotates and “shifts” within a given area, in order to allow the natural habitat to recuperate.

How many seasons does shifting cultivation take?

Part of the shifting aspect of shifting cultivation, which is not found in other types of slashing, is that these crops are usually only planted for two growing seasons. This way, the plants benefit from the nutrient rich soil, without allowing the area to be over-used or completely depleted.

Slash and Burn Definition

What is slash and burn agriculture? Slash and burn farming is a defined agricultural technique which involves cutting down (slashing) and burning existing trees, brush, and other foliage to clear land and prepare it for cultivation. It is a highly efficient practice, first invented and used nearly 12,000 years ago during the rise of agriculture.

Phases of Slash and Burn Agriculture

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.

Environmental Consequences of Slash and Burn Farming

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.

What is slash and burn farming?

Slash and burn farming is a form of shifting agriculture where the natural vegetation is cut down and burned as a method of clearing the land for cultivation, and then , when the plot becomes infertile, the farmer moves to a new fresh plat and does the same again. This process is repeated over and over.

How many farmers are forced to eke out a living on these poor rainforest soils?

Maybe about 250 million farmers (they are not easy to count) are forced to eke out a living like that on these poor rainforest soils. By slashing and then burning the forest, these farmers can usually sustain themselves for only 2 consecutive years on the same patch of soil.

Why does the rainforest lose its fertility?

The soil loses its fertility because the richness of the rainforest is in the trees. As leaves fall or trees die everything is broken down by the soil’s organisms, nutrients are returned to the soil and the tree roots take them up again.

How often do farmers clear new plots?

Indeed quite often they clear a new plot every year. The soil then loses its fertility and the farmer is faced with either a daily walk of several miles to a new patch or, increasingly as the number of landless farmers grows, they may have to uproot their families to move.

Can cash crops be guarded from thieves?

When the plots are far from the dwelling place cash crops cannot be guarded from thieves or wild animals, nor can the family help when there are young children. This too ensures the farmers remain poor. In earlier times when the population density was less, slash and burn worked reasonably well.

How many farmers practice slash and burn agriculture?

Some estimates show that upwards of 300 million farmers practice slash and burn agriculture in …

What is sustainable slash and burn?

According to Mike Hands, “The only truly sustainable system to emerge from our years of scientific research into slash and burn is alley cropping using nitrogen-fixing tree species from the genus Inga.

Why is slash and burn important?

Slash and burn allows for people to farm in places where it usually is not possible because of dense vegetation, soil infertility, low soil nutrient content, uncontrollable pests, or other reasons. ”.

What was Mike’s exposure to slash and burn agriculture?

It was during his work and travels in the tropics that Mike was exposed first hand to slash and burn agriculture. “Particularly when I was in some parts of Africa, walking through miles and miles of burnt Guinea savannah forests, it was just devastating seeing the effects.”.

What are the effects of slash and burn?

The results of continuing on this path of slash and burn are massive deforestation, erosion, decreased biodiversity, nutrient loss, and possibly most significant is the huge net increase in global carbon emissions that result from slash and burn practices. Estimates show that, depending on location, between 4800 and 6200 square miles …

What happens when the land becomes unfertile?

It is when the land becomes unfertile that the farmers turn towards slashing and burning new land. Mike knew that if he was able to figure out how to keep the nutrients in the system he would be well on his way to creating a new technique that would provide an alternative to continuous slash and burn agriculture.

How much carbon is released from deforestation?

From 1850 to 1990, deforestation worldwide released 122 billion metric tons of carbon into the atmosphere, with the current rate being between 1.6 billion metric tons per year (Skole et al. 1998). In comparison, all of the fossil fuels (coal, oil, and gas) burnt during a year release about 6 billion tons per year.”.


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