Characterization of jhum fields and fallow cycles in west garo hills district of Meghalaya using remote sensing and GIS techniques

Abstract

Shifting cultivation is a system of land use involving the slashing and burning of vegetation, few years of cropping followed by a fallow period in which farmers shift to surrounding areas. Shifting cultivation is locally known as jhum in north eastern India, roca agriculture in Brazil. Multi-temporal satellite (Landsat) data were used to identify jhum fields and fallow cycles. The current jhum fields of different years were delineated in Arc-GIS and based on imageries of succeeding years, the different jhum field categories were identified. The data were statistically analyzed using Arc-GIS software and areas were calculated using the geometrical calculation function in the attribute tables for all the years. Results revealed that the area under jhum field ranged from 9665.87 ha in 2008 to 22089.55 ha in 2000 with an average area of 15361.76 ha annually under jhum fields during the study period. More first year crop jhum fields were found to cultivate again for second year cropping as compared to earlier years. Jhum cycle of 4-9 year was found to be more prevalent (68.56%) in the district although jhum cycles of 3-16 years were observed. From the study, it was concluded that the synoptic and multi-temporal remote sensing data provided the best technique for identifying different jhum fallow cycles.