Shifting Cultivation (Jhum): An Unsustainable Agricultural practices in North-East India

Traditional shifting cultivation (Jhum) cycles are characterized by the alternation of cropping and fallow phases, when secondary vegetation grows. At the end of fallow phases, canopies are cut and burnt, and the ashes enrich the soil, thereby allowing a new cropping phase. Slash-and-burn agriculture is considered to be well adapted to tropical climates and soils and accessible to small farmers because of its low cost. It comprises the contiguous Seven Sister States (North-east India)-Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura and the Himalayan state of Sikkim. Slash-and-burn agriculture also known as shifting cultivation, swidden or rotational bush fallow agriculture and as jhum  cultivation, is an ancient method of agriculture that is still practiced by tribal communities in many parts of the world, particularly in the wet tropics. It is regarded as one of the traditional methods for cultivation in hilly areas of tropical regions in which forest vegetation is cut and burned on site. Slash-and-burn agriculture has a rich traditional ecological knowledge base and remains an important component of forested landscape in many parts of north-east India states. The practice involves a series of steps such as selection of a site on the hilly slopes, slashing of primary/ secondary forests; burning the slashed vegetation after drying followed by cultivation of crops of agricultural importance for 1–3years and finally leaving the land fallow. Nonetheless, the productivity of the system depends on the temporary increase in nutrient availability of the soil, the buffering aptitude of ash and the regenerative capacity during the fallow periods. The main difference between the shifting cultivation and practices of present and two three decades back is the increases in the scale and shorting of jhumming period. 

 Cleared forest land for slash-and-burn agriculture

Characteristics of jhum cultivation north-east states

Entertainingly, the time frame for slash-and-burn agriculture are practically strict, specially keep in mind that heavy rainfall of the area, requiring the land be cleared and seed sowed in time for the monsoons. Generally village community chooses where the fields for coming season will be established slashing and subsequent burring are precondition of this traditional forming system. Slashing operation is usually done in last week of November by simply slashing the vegetation to dry in the sun about 3-4 week and then burnt during last week of December. Burning is a fabulous and noisy operation, causing huge flame on the hills reduce visibility and pollute the atmosphere. Following the burning and cleaning of the newly burnt sites sowing and broadcasting of millets and other vegetable crops from January. Each jhum area is generally cultivated for two cropping cycle. Crops totally depend on monsoon due to lack of irrigation facilities. 

Burned Forest land  for shifting cultivation

 This traditional farming system linked with ecological, socio-economic and cultural life of indigenous people and closely concerned to their sacrament and festival that revolve their jhum fields and are organized to make place at various stage of the cultivation. The life of the jhumias (People who involve in slash-and-burn agriculture) comprises many traditional activities throughout the year, revealing their total confinement to agriculture. This traditional farming system usually offers scope for cultivation and on-farm conservation of a wide variety of local agricultural crops. According to the local cropping calendar, the jhumias usually manage their field by distinguishing it into two different phases, as the new field and the old field.

Burned Forest land emitting GHGs

 Perhaps the most important and universal impact of slashing and felling in regard to sustainability is the disruption of natural nutrient cycling and the acceleration of nutrient flow out of the agro ecosystem. This impact is particularly obvious in tropical forested systems where natural nutrient cycles are virtually closed and trees are often credited with removal of insoluble nutrients such as phosphorus from the subsoil. Furthermore, the decay of fine roots immediately follows tree death results in the release of associated nutrients which may leach from the forest soil. Commonly, the presence of slash serves to protect the soil from erosion; however, bare patches of the soil surface may be directly exposed to incoming precipitation and radiation. The loss of a protective plant canopy may cause a sharp increase in surface soil temperatures, thereby stimulating volatilization (i.e. loss of nitrogen to the atmosphere) and increasing rates of organic matter decay. Concentrated human activity during slashing and felling, and the physical impact of falling trees, may result in localized increases in bulk density. Finally, slashing and felling can disrupt populations of soil micro and macro-fauna and favor the germination of seeds from photophyllic opportunists. After clearing, slash is usually allowed to dry before burning. Burning plays an extremely important role in soil fertility. Nutrients released from biomass and even parent material during burning may become available for crop uptake, escape via volatilization, leaching or surface runoff, or remain bound in recalcitrant ash complexes. These outcomes are highly dependent upon the intensity of the burn, which may be the most important factor influencing Jhum soil fertility. The burnt organic matter releases the nutrients which were locked up in the biomass. The soils can be exploited only one to three years before the nutrients are exhausted and the farmers are forced to move to a new site.

 

Paddy in Jhum (Shifting Cultivation) of Garo Hills

Improved slash-burn-agriculture could not only reduce rural poverty, but also contribute to community goals of the north-east India. In tropical agriculture, the key to realizing local and global benefits is seen to lie in agricultural growth and improved fallow management; reduction in the area in cropland while amplification of agricultural production; adoption of agro-forestry; cash crops; expansion of the extent of fallow land or delaying of forest conversion; lengthening of fallows and enhancement of forest species composition; and raising the value of secondary forests through diversification of forest products as well as the commercialization of environmental services improved shifting cultivation systems could not only reduce rural poverty, but also contribute to societal goals of the tribal community of north-east states. In tropical agriculture, the key to realizing local and global benefits is seen to lie in agricultural intensification and improved fallow management; reduction in the area in cropland while intensification of agricultural production; adoption of agro forestry; expansion of the extent of fallow land or delaying of forest conversion; lengthening of fallows and enhancement of forest species composition; and raising the value of secondary forests through diversification of forest products as well as the commercialization of environmental services.

Current Jhum in Nokrek Biosphere Reserve of Garo Hills

 Impact of Slash-and-burn

Land use is an important component to understand global land status. It shows present as well as past conditions of the earth surface and it is a central component and strategy for managing natural resources and monitoring environmental changes. Forest felling and burning are parts of the shifting cultivation cycle that supports thousands of people throughout the north-east India. These practices are also the precursors of permanent agriculture, cash crop, pasture establishment and plantation forestry. Tropical deforestation is of great current concern especially because of its potential impacts on biodiversity and on environmental issues.

 

Sedimentation runoff after rainfall in current jhum land

Slash-and-burn land clearing on sloping land may lead to increased soil run-off following disappearance of the protective vegetative cover. In turn, soil run-off and edge position affects soil fertility and spatial patterns of fertility parameters in a field. Soil erosion is an irreversible phenomenon causing land degradation and deterioration of surface water quality. It is caused due to inappropriate land use and poor management. Therefore, this precious finite resource must be safeguarded against all kinds of degradation and deterioration for sustainability of agricultural production and environment protection. Soil run-off is expressed here as the quantity of downward moving soil that passed the specific location of a flow trap. Existing physical soil run-off barriers and crop performance were scored. Despite serious soil run-off from the steeper upper slopes little soil was actually lost because of the slope form of the field, presence of natural soil run-off barriers, and the planted crop. In contrast, fire is often responsible for large nutrient losses due to particulate movement off the field and volatilization during the fire. Also, nutrients may be lost by soil run-off, which is the process of downward moving of soil caused by water flow and gravity forces. Soil run-off is enhanced by disappearance of vegetative cover and surface litter following the burn.

Slope pattern in current jhum

This farming system may not be productive as it suffers from lack of proper designing and scientific management.  Nevertheless, intervention of proper scientific approach is needed to make such a policy which can provide enough quality food and economic security to the jhumias together with conservation of the traditional crop wealth, sustainability of the production systems and environmental conservation.  If such a step is not taken, then the very livelihood of the farmers would be in danger, as most of the villages of this region are still remote and isolated. Due to increasing agricultural population pressure in the north-east India regions a significant deforestation has been experienced, which brings the new land cover cultivation. Thus, population pressure first exert its impact on expansion of marginal land under cultivation and some extent shortening the fallow, which in turn increase in gross agriculture production as well as exploitation for fodder, fuel wood and timber.