Slash And Burn

  • 7,753 views
Uploaded on

 

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads

Views

Total Views
7,753
On Slideshare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
80
Comments
0
Likes
1

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. I. SLASH AND BURN 1. Concepts Slash and Burn agriculture is considered to be one of the oldest land use sytem (Spencer 1966). It is a method of agriculture primarily used by tribal communities for subsistence farming for about 12,000 years ago, the time when humans stopped hunting and gathering, and started growing crops. More recently McGrath (1987) defined shifting cultivation as “a natural resource management strategy in which the land is in rotation to exploit the energy and nutrients of the soil-plant complex in swidden field”. Over centuries, traditional farmers developed slash and burn agriculture systems as a solution to poverty, soil depletion problems, and managing pests. Although the practice has long disappeared in temperate regions, it is still common in tropical and subtropical areas and is said to be practiced by between 200 and 500 million people, or up to 7% of the world’s population, involving up to 30% of the global exploitable soils (Warner 1991) and nearly one-half of the land area of the tropics. In Vietnam, ……… Slash and burn agriculture is found common in places where there are dense vegetation such as Africa, northern South America, and Southeast Asia, typically within grasslands and rainforests. The practice of slash and burn agriculture is done throughout a process starting with clearing plots of land from the forest, and leaving the cut vegetation to dry out, then burning, and finally planting crops in the ashes. These plots of forestland are used for a few years and then are gradually abandoned to natural vegetation for fallow periods (periods between plantings) of up to twenty or more years. In some areas where there is too much rain or insufficient vegetation for a good burning, the slashed vegetation is left to decompose on its own and cultivated after a long fallow. 2. Slash and Burn Agriculture cycle Generally, the following steps are taken in slash and burn agriculture: 1. Select sites with potentials for farming
  • 2. 2. Prepare the field by cutting down vegetation; plants that provide food or timber may be left standing. 3. The cut vegetation is allowed to dry until just before the rainy season of the year to ensure an effective burning 4. The plot of land is burned to remove vegetation, drive away pests, and provide nutrients for planting. 5. Planting is done directly in the ashes left after the burn. 3. Types of Slash and Burn Agriculture Studies have classified shifting cultivation into 3 different types: Rotational shifting cultivation: this type of cultivation is managed on permanent basis (i) around the established villages in which the local farmers rotate their fields. After about 1- 2 years farming in the first plot, to avoid intensive use of land leading to severe soil fertility depletion and increasing weed infestation, farmers decide to farm the second field in rotation, leaving the first field to lie fallow and naturally regenerate. …? The pioneer shifting system: It involves non-permanent villages that move into the (ii) primary forest for longer periods of intensive cultivation, perhaps 10-15 years. When the soil fertility is severely depleted, the fields are ready for abandon for natural regeneration. Farmers then move to a new location in another area with primary forest. Both types of shifting cultivation require a lot of land since farmers have to move their crops to new fields every years. When more farmers try to farm the land to feed the growing population, they cannot maintain the system of crop rotation. They are forced to clear more and more forest for their crops. For instance, in many parts of the Amazon, the population of an area has grown so much that slash and burn is very destructive to the rain forest. In this sense, many critics claim that slash and burn agriculture contributes to a number of reoccurring problems specific to the environment. Deforestation or loss of forest cover is inevitable when fields are not given
  • 3. sufficient time for vegetation to regenerate. When fields are slashed, burned and cultivated next to each other in rapid succession, roots and temporary water storage are lost and unable to prevent nutrients loss or desertification. Moreover, because shifting agriculture is often practices in tropical regions where biodiversity is extremely high, it could result in biodiversity loss or extinction of the certain species plants and animal. Animal species may be harmed or even destroyed as their habitats are ruined by the fires of slash-and-burn. The burning of forest plots may trap and isolate animals. Also, the continuous fires produce a large amount of smoke and ash which travels through the air and water to be deposited on plants and in soil. One widely held notion is that this method, by its very nature, is damaging to the environment. Prevailing contemporary theories, however, appear to be that this technique is perfectly sustainable and is, in fact, environmentally sensitive as long as population pressure on resources is limited--in other words, there is no drastic reduction in the land available or a sudden increase in the population utilising a given area. These negative aspects are interconnected, and when one happens, typically another happens too. ……to be restricted.. However, there are advocates who argue that when slash and burn agriculture is practiced properly, it can provide communities with a source of food and income. Shifting practice allows people to farm in places where it is usually not possible because of dense vegetation, soil infertility, low soil nutrient content, uncontrollable pests, etc. This system give low productivity per unit area, but give high returns to labor, with low energy requirements.Swidden cultivation was seen to be working with nature, “altering selected components without fundamentally modifying its overall structure” (Harris 1969:4-8). ……………….
  • 4. this system of agriculture is so low-yielding that the highlanders who practise it are all starving or at least suffering from severe malnutrition. Contrary to popular perceptions, the highlanders' way of life offers substantial food security, as various vegetables and fruits are cultivated on hill rice plots and other dietary supplements can be obtained from the forest by gathering leaves, plants, wild fruits, hunting and fishing. At times when rice stocks fall low, villagers eat cultivated tubers and corn or wild tubers from the forest, and in times of severe need there are other traditional methods of security to draw on. according to an increasing number of ecologists, this view is profoundly misguided. A growing body of evidence suggests that rotational shifting cultivation can be both a productive and an environmentally sustainable way of using land in lightly populated areas. Olivier Dubois of the International Institute for Environment and Development (IIED), a research group based in London, says that this type of agriculture could be the most efficient way to use land in places where land is plentiful but labour and capital scarce. He points to studies in Kalimantan that demonstrate that dry rice cultivation by shifting cultivators provides far higher returns on labour- up to 276 per cent-than the wet rice cultivation promoted by Indonesian officials. Elsewhere, shifting cultivation, when it uses long fallow periods, can help to retain high levels of biodiversity. In many parts of the world land scarcity, logging, new markets and aggressive government policies have forced shifting cultivators to shorten the period of fallow, thus turning a sustainable form of land use into an unsustainable one. Do Dinh Sam of the Forest Science Institute in Hanoi estimates that the number of shifting cultivators in Vietnam has fallen to around 1 million. Where the population density is high, fallows have been reduced and food yields have dropped significantly. Replacing the long fallow of shifting cultivation with permanent agriculture inevitably entails further losses of biodiversity.
  • 5. Slash and burn farming is natural…..burning The cleared plot is used for a relatively short period of time, and then left fallow for a longer period of time so that the wild vegetation can grow again before the slash and burn process is repeated. Therefore, this type of agriculture is also known as shifting cultivation, which requires a lot of land for farmers to move their crops to new fields every few years. In this regard, slash and burn agriculture is an ecologically harmonious method of cultivation only when the population density is low and …..Expectations are moderate.
  • 6. II. Slash and burn agriculture in Vietnam At a local level, attitudes to so-called slash-and-burn agriculture do seem to be changing, albeit slowly. quot;Policy makers don't wholly blame shifting cultivators for forest loss now,quot; reflects Sam in Vietnam. Kanok Rerkasem, a coauthor of the IIED study in Thailand, says government officials now realise that shifting cultivation may be the only means some farmers have of maintaining production. There have been positive signs in Indonesia too. Marcus Colchester of the British-based World Rainforest Movement welcomes the fact that the government has blamed plantation and logging companies rather than small farmers for this year's smoke crisis. quot;This is a very important moment,quot; he suggests. quot;At last the focus is on big business.quot; The irony is that virtually everyone now accepts that sustainable forestry is about far more than trees and timber production. Biodiversity, local livelihoods and carbon storage are all seen as important functions of forests-and these, as ecologists are now realising, are precisely the sorts of benefits that agroforestry and rotational shifting cultivation can provide. Charlie Pyo-Smith