Jhum: Slash and Burn Cultivation

The increasing agricultural yields of the last few decades in India were possible through industrialisation of agriculture involving heavy subsidies. Though these modern agro-ecosystems are efficient in terms of human time and labour, they are not so as far as ecology is con cerned. The obvious limitations of such systems as models of development in an energy-limited world have renewed scientific interest in traditional systems of agriculture since they are considered to be ecologically efficient. The forest farmer in the humid tropics has managed his shifting agriculture for centuries with optimum yield on a long term basis, rather than trying to maximise production on a short term. It has been considered possible to increase agricultural produce without departing too much from this traditional system. Jhum is seen as an important component of sustainable agricultural tribal development. Shifting agriculture or jhum as the tribals call it, is a major economic activity of the humid tropics in the north-eastern regions of India. This highly organised agro-ecosystem is based on empirical knowledge accumulated over the centuries. Jhum is in harmony with the environment as long as the jhum cycle (the interim fallow period between two successive croppings) is long enough to recover the forest and the soil fertility that is lost during the cropping phase. This land-use system of north-eastern India, involves slashing the vegetation, burning the dried slash before the onset of the monsoon, raising a mixture of crops on a temporarily nutrient enriched soil for a year or two, fallowing the plot for regrowth of natural vegetation, and eventually returning to the same plot for another cropping phase after a few years. The time interval between successive croppings would be one shifting agriculture cycle. Until a few decades ago the time span for this cycle was 20 years or more. It has now come down