Shifting cultivation, Impact on forest ecosystems
Shifting cultivation:- It is a class of primitive subsistence agriculture. In this, a plot of land is cleared by felling the trees and burning them. The ashes are then mixed with soil and crops are grown. After some time, the land is abandoned and the farmers move to a different place.
> The evil effects of shifting cultivation are devastating and far-reaching in degrading the environment
and ecology of these regions.
> The earlier 15–20 year cycle of shifting cultivation on a particular land has reduced to 2–3 years now. This has resulted in largescale deforestation, soil and nutrient loss, and invasion by weeds and other
species.
> The indigenous biodiversity has been affected to a large extent.
To mitigate the environmental loss and to provide other alternatives of livelihood to the local population, we have made an attempt in this paper to suggest environmental management options for shifting cultivation areas.
Impact of shifting cultivation:- The shifting cultivation is generally practised in the following sequence:
i. Selecting a forest patch and clear fell the vegetation normally in December and January
ii. Burning of the vegetation. Small, cut-trunks portion and roots are normally not removed. The herbs, shrubs and twigs and branches (slashed vegetation) are burnt in February and March.
iii. Sowing of seeds, by dibbling, generally of cereals, vegetables and oil seeds in April – May.
iv. Continuing cultivation for a few years.
v. Abandoning the cultivated site and shifting to other forest sites
vi. Returning to the former site, and once again practise shifting cultivation on it.
- With reduction in jhum cycle from 20–30 years to 2–3 years, the land under shifting cultivation looses its nutrients and the top soil.
- With reduction in crop yield, the families start moving to other virgin areas.
- Now a stage has come that it has already affected 2.7 million ha of land, and each year 0.45 ha of land fall under shifting cultivation, in northeast India.