Soils of HKH Region

Abstract

Soils are dynamic natural bodies comprising the upper layer of the earth. The parent material strongly influences soil composition both through its chemical characteristics, some of which are transferred to the derived soil, and through its physical constitution which influences leaching rate and soil aeration. The climate change, land use change, deforestation, and overgrazing are affecting mountains soils in HKH region. These soils are vulnerable to climatic changes, and the anthropogenic factors support and magnify these changes. Hazards such as floods, landslides, debris flows, and glacial lake outbursts are on the rise in HKH region, especially those areas with rapidly expanding populations and poor infrastructure. Climate change is amplifying the impact of hazards as it increases the frequency of extreme events, causing heavy rainfall, droughts, and glacier melt. Soils found in the Himalayas are diverse in character depending upon altitude, vegetation cover, slope, structure, and stage. The major soils groups in the Himalayas are brown hill soil (600–1700 m amsl), sub-mountain soils (formed under dense forest cover), mountain meadow soils (found in alpine and subalpine zones up to an altitude of 4400 m), and red loamy soils, apart from other less significant types. Most of the soils in the region are acidic in nature. The high-altitude meadow soils are found in high-altitude meadows near the snow line in all parts of the higher and trans-Himalayas. Since the texture of the soils is very coarse with high gravel content, they are prone to displacement due to slides and avalanches. These soils are dark in color having a high content of humus. Desert (Arid) soils are found in the cold desert area of Ladakh (India) and other mountain areas of the region with similar climate and altitude; red and black soils are found in isolated areas of Nepal, Bhutan, and Uttarakhand, and Himachal Pradesh state of India. Podzols are found in Western Himalayas. Apart from the above-mentioned soils, traces of alluvial and lateritic soils are found in some parts of the Himalayas. Mountain soils are highly dynamic and sensitive systems that react to environmental changes such as climate change and intense land use. Human-induced erosion rates are, in some mountain areas, much beyond soil production rates. Extensive erosion rates lead to rapid soil degradation and loss of areas for plant growth which, in turn, also negatively affects carbon sequestration. The Hindu Kush Himalayas is a densely populated area and human activities are the major cause of environmental and land degradation. Soil degradation and forest depletion are the most serious environmental issues in the region. The ecosystem of the great Himalaya Mountains is one of the most important life support systems on the earth. The rivers, which arise from the Himalayas, flow down to the plains and contribute to agriculture, industry, and energy sectors that sustain millions of people. The chapter mostly deals with soils of HKH region according to the new system of soil classification.