Identifying the factors and status of land degradation in a tropical plateau region

Abstract

The systematic decline of land quality due to the mismatch between land quality and land use is called land degradation. It is the consequences of different physical factors but accelerated by human activities. The processes and factors of land degradation are different in different morpho-climatic regions of the world. Present study is primarily concerned in identifying the factors and status of land degradation in a tropical plateau region. Tropical plateaus are one of the most water erosion related land degraded areas of world. Chotanagpur plateau in tropical eastern India is one of the vulnerable soil degraded areas of the tropical environment. The Precambrian geological formation, undulating topography, immature soil, increasing aridity sets natural settings for land degradation in tropical plateau areas. However, induced degradation results from inappropriate land use, clearance of forest land and heavy land pressure related anthropogenic factors accelerates the processes of land degradation. Kangsabati River basin of eastern Chotanagpur plateau bears all of the above characteristics has been taken for present study as a degraded tropical plateau region. Water erosion and vegetal degradation are the major factors of land degradation in Kangsabati basin. The physical factors responsible for land degradation in the studied area includes physiographic formations, edaphic maturity, hydrologic characteristics, and vegetation cover dynamics etc. This land degradation processes is accelerated by different anthropogenic factors like, land use land cover dynamics, deforestation, agricultural pressure. Multispectral remote sensing data, digital elevation data, thematic maps, recorded climatological data, secondary data and field observation have been utilised to understand the different factors of land degradation in a typical tropical plateau region. The less developed soil profile over Precambrian geology with undulated landforms causes high soil erosion in upper plateau proper regions of the basin. High agricultural pressure, forest and groundwater decline with associated land use land cover dynamics creates decline of land quality in lower basin regions of tropical plateau. The varying intensities of land degraded areas for the basin has been identified through the multiplication of different physical and anthropogenic factor overlaying rasters in GIS environment. Before multiplying, each of these input factor rasters has assigned with weightage after considerable importance of land degradation. The lower basin area with accelerated human interference is the most vulnerable land degraded area for the Kangsabati River basin.