Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. Factors that have contributed to land degradation include:
- Soil erosion.
- Loss of soil fertility.
- Soil structure change.
- Soil pollution.
- Loss of vegetation cover.
- Introduced herbivores such as rabbits and goats.
Consequences of Land Degradation
Increased demand for agriculture commodities generates incentives to convert forests and grasslands to farm fields and pastures. The transition to agriculture from natural vegetation often cannot hold onto the soil and many of these plants, such as coffee, cotton, palm oil, soybean and wheat, can actually increase soil erosion beyond the soil’s ability to maintain itself.
Half of the topsoil on the planet has been lost in the last 150 years. In addition to erosion, soil quality is affected by other aspects of agriculture. These impacts include compaction, loss of soil structure, nutrient degradation, and soil salinity. These are very real and at times severe issues.
The effects of soil erosion go beyond the loss of fertile land. It has led to increased pollution and sedimentation in streams and rivers, clogging these waterways and causing declines in fish and other species. And degraded lands are also often less able to hold onto water, which can worsen flooding. Sustainable land use can help to reduce the impacts of agriculture and livestock, preventing soil degradation and erosion and the loss of valuable land to desertification.
The health of soil is a primary concern to farmers and the global community whose livelihoods depend on well managed agriculture that starts with the dirt beneath our feet. While there are many challenges to maintaining healthy soil, there are also solutions and a dedicated group of people, including WWF, who work to innovate and maintain the fragile skin from which biodiversity springs.
Shifting cultivation is an agricultural system in which a person uses a piece of land, only to abandon or alter the initial use a short time later. This system often involves clearing of a piece of land followed by several years of wood harvesting or farming until the soil loses fertility.
Once the land becomes inadequate for crop production, it is left to be reclaimed by natural vegetation, or sometimes converted to a different long term cyclical farming practice. This system of agriculture is often practised at the level of an individual or family, but sometimes may involve an entire village.
An estimated population exceeding 250 million people derive subsistence from the practice of shifting cultivation, and ecological consequences are often deleterious. Shifting cultivation is a type of farming where people make temporary clearings in the forest to grow food. When the soil is no longer fertile after two to three years, the shifting cultivators abandon the field to look for another suitable plot of land. The first field is left to fallow, or rest, while the cultivators begin the cycle of activities on a new plot of land.The farmers may return to the same plot of land after 20 to 30 years. There are 5 stages in shifting cultivation.
Stage 1: Selecting a plot of land
The headman of the tribe first chooses a plot of land in the forest.Trees in the area are felled and the undergrowth is cleared at the beginning of the dry season.
Stage 2: Burning the felled trees
The trees are left to dry before they are burnt. The ashes of the burnt trees act as fertilisers for the soil.
Stage 3: Planting
Planting is carried out after the ground has cooled. Holes are made witha dibble stick, into which seeds could be dropped.
Stage 4: Harvesting
Harvesting usually takes place during the dry season.
Stage 5: Fallowing
After a few years of cultivation, the soil loses its fertility. Farmers then move on to look for a new plot of land, leaving the first field to fallow or rest. They may return to the same plot of lnf afetr a period of time.
Characteristics of shifting cultivation:
- Shifting cultivation is one of the earliest types of subsistence agriculture. The farmers grow enough food to feed themselves and their family.
- Also practised by trial people residing in forests.
- Even though a small plot of land is cultivated each time, shifting cultivation takes up large areas of forest land because farmers move on to another plot of land every few years.
Hardly any capital is required for shifting cultivation. The farmers use simple tools such as machetes, sickles, axes and sticks. Instead of buying seeds, they use seeds saved from the previous harvest.
Much work is required in the clearing and burning of trees and undergrowth, as well as in the sowimg of seeds. Less work, however, is required durimg the growing process. This is because the crops are not given any special care, other than some weeding by hand. Family members usually provide the labor for this kind of agriculture.
- The output per unit area is low and usually only enough to feed the farmer’s family.
- A small variety of crops are grown. Examples include dryland rice, bananas, maize and tapioca.
- Output is usually only sufficient for survival
Extent of Shifting Cultivation in India
In India, shifting cultivation is still practised in the hill areas of North-Eastern Region, Sikkim, Bihar, Orissa, Andhra Pradesh, Madhya Pradesh, Tamil Nadu, Kerala, Karnataka and Maharashtra. But among all these states, such practices are still prevalent in the hill areas of North-Eastern states, Orissa and Andhra Pradesh. Even though this traditional method of cultivation has been discontinued for more advanced forms of farming, yet it is still being continued in certain parts of the country, apart from North-Eastern states, Orissa and Andhra Pradesh.
Shifting cultivation is known variedly in different regions as slash-and-burn agriculture, migratory primitive agriculture, nomadic agriculture, hoe and burn, forest field rotation, land-rotation agriculture and in north-east India it is known as ‘Jhum’ cultivation or ‘Jhumming’. Due to diminution of fertility, ‘Jhummias’ will have to shift from one area to another area and thus it is known as shifting cultivation.
Report of the Dhebar Commission revealed that nearly 5.41 lakh hectares of area are covered per year by the shifting cultivation and about 25.89 lakh tribal populations are depending on it. Again as per the estimates of Vidyarthi, about 2.6 million tribal people are engaged in shifting cultivation covering nearly 1.35 million acres of land scattered in different parts of India.
In north-eastern region, the estimates framed by the state departments of the region in 1974 reveals that shifting cultivation is prevalent in nearly 2.4 per cent of the total area of the entire NE Region at a point of time. About 2.7 million hectares of area i.e., about 14.19 per cent of the area of the entire NE Region is at present available for shifting cultivation and out of which only 16.8 per cent (i.e., about 4.3 lakh hectares) of the area is cultivated at one point of time leaving the rest area for natural regeneration of fertility. Further, about 4.25 lakh tribal families of the entire NE Region are found engaged in shifting cultivation and total area cultivated per tribal family in the region is 1.07 hectares.
Impacts on Hilly Terrains
In shifting cultivation, cultivation in a particular area for one or two years and then moving into other areas and again returning to the first area for cultivation completes a cycle. Thus, number of years between two consecutive jhum operations constitutes a ‘Jhum Cycle’. The cycle includes number of years an area is under cultivation plus the years the area is kept under forest fallow.
Previously the fallow period was of 30 years and at present due to high pressure of population and heavy erosion of soil this fallow period has declined to 4 to 9 years or even less in different states of our country. Among the North-Eastern states, Meghalaya and Nagaland are having the longest jhum cycle of 9 years, Manipur—6 years and the states like Mizoram and Arunachal Pradesh are having the lowest jhum cycle of 3 to 4 years. It is found that the jhum cycle was very much common to 6 years in some states like Andhra Pradesh, Bihar, Kerala and Madhya Pradesh and the same cycle was 7 years in Orissa.