Paweł Prokop

Natural and human impact on the land use and soil properties of the Sikkim Himalayas piedmont in India

Natural and human causes of change in land use and soil properties were studied in the Sikkim Himalayas piedmont over the last 150 years, with a special emphasis on the period 1930-2010. Analysis of historical reports, combined with the visual interpretation of topographic maps and satellite images, indicates that the land reforms related to the location of tea gardens caused rapid deforestation of the higher elevated terraces in the late 19th century. Continuous population growth between 1930 and 2010 caused a shift in the major land use changes from the terraces to the floodplains. As a consequence, a gradual extension of tea plantation and forestry development helped in stabilizing the land use of the terraces, while the parallel deforestation of mountain catchments and floodplains for rice cultivation intensified fluvial activity. The enlargement of river-channel area by about 42% between 1930 and 2010 excluded a large part of the floodplains from cultivation and increased risk of soil degradation. The replacement of natural forest by monocultural tea and rice cultivation influenced the physical and chemical properties of the soil. Statistically significant changes were observed only in some chemical properties of the topsoil. Tea cultivation reduced the total carbon content by 26% and total nitrogen content by 33% in the surface soil horizon. The influence of rice tillage on the soil properties is masked by the fluvial activity. The combined effect of flooding and rice cultivation is reflected in the lower content of total carbon and nitrogen in the surface of the soil, namely, 76% and 77% respectively. Taking into account the long-term nature of the plantation, the soil still has the capability to support tea production. The productivity of rice depends partly on fertilization levels and partly on the natural deposition of fresh sediment eroded from mountains.

Land Use and Land Cover Changes in the Area with the Highest Rainfall in the World (Meghalaya Plateau, India): Causes and Implications

The Meghalaya Plateau is an area where human activity has caused deforestation which, in the extreme monsoonal rainfall conditions, has led to soil degradation and expansion of grasslands at higher altitudes. The shortening of the shifting cultivation cycle resulting from the demographic growth, is generally considered to be the major cause of deforestation and the degradation of soil in this area. Analysis of the land use and land cover indicates a lack of response of the forest and grassland area to the population increase in the twentieth century. The radiocarbon dating of iron slags and supplemented data from historical reports has led to the formulation of a new hypothesis, connecting the deforestation with the 2000 year-old practice of charcoal production for smelting iron. High rainfall and impoverished soil together with the annual practice of vegetation burning are the causes of the present day stability of the land use and land cover system inherited from the past.

The Meghalaya Plateau: Landscapes in the Abode of the Clouds

The Meghalaya Plateau is a distinct horst located on the northeastern flank of Peninsular India. It is one of the rainiest, most tectonically active areas in the world and hosts the richest types of karst phenomena in India. The combination of its regional uplift, associated river incision, headward erosion and chemical weathering in varied lithology, has facilitated the development of diverse landforms. This has resulted in deep valleys with magnificent waterfalls contrasting with mature undulating hills and karst topography over short distances. Meghalaya is a region of great scenic beauty and is an interesting tourist destination, in addition to its importance as an area for investigating the interaction between climate, tectonics and erosion.

Estimation of soil erosion on cultivated fields on the hilly Meghalaya Plateau, North-East India

The estimation of soil erosion rates in complex subtropical agricultural systems of hilly environment is difficult and most of the traditional methods have serious limitations. The 137Cs technique allows to obtain relatively quickly retrospective medium term soil erosion results. The objective of this study was using 137Cs approach to quantify soil loss under agricultural system which develops under growing human pressure on the hilly terrain of the Meghalaya Plateau. The measured values of caesium inventory for all sampling points are between 2% and 63% of the reference value of caesium inventory. The estimated annual soil loss for sampling points located on the slope are between 29 and 79 Mg·ha−1·yr−1 in the case of an improved mass balance model. It means that soil erosion in this manually tilled agricultural area cannot be neglected.

Socioenvironmental issues of river bed material extraction in the Himalayan piedmont (India)

The present study focuses on the Balason river running through the Himalayan piedmont zone (near Siliguri, India). The objective of the study is an assessment of the environmental effects of river bed material extraction by humans and the dependence of indigenous people on the river and its ecosystem services. The analysis is based on results of field work consisting of geodetic measurements of the river channel and interviews among the local community from the Nimtijot village. Historical hydrological data were also used for the study. The results of the investigation show that the Balason river is heavily affected by excessive exploitation of river bed material during dry season and the replenishment of extracted material in a monsoon season is not always sufficient. It leads to channel deepening. The local community working in the river heavily depends for its livelihood on continuing this activity. A decreasing amount of bed material to be extracted may lead to degradation of the strong relationship between the local community and their natural environment (river).

Reservoir’s Impact on the Water Chemistry of the Teesta River Mountain Course (Darjeeling Himalaya)

Abstract The article presents the role of the newly built reservoir in the formation of the hydrochemistry of water of the Teesta River (a tributary of the Brahmaputra) in its Himalayan course. Field research were performed in the post-monsoon season of the period 2013-2015. Sampling and measuring points were located in five points over 43 km of the Teesta River in the Darjeeling Himalaya. Analysis of water along of river longitudinal profile above and below the reservoir suggest that the reservoir caused decrease most of the basic ions concentrations (Cl−, K+, Na+, Mg2+, NO3− and PO43−). An inverse trend was observed only with respect to Ca2+, SO42− and NH4+. The dam does not influent on the F− concentration. The reservoir causes minor enrichment most of the heavy metals such Cu, Ni, Zn, Cr, Cd and Sr. The lower enrichment of Teesta water below the dam indicates the water self-purification processes for metals by the Teesta Reservoir. The changes of physicochemical properties and concentrations of ions caused by the reservoir are usually normalised by environmental factors before the Teesta River outlet from the Himalayas (within 15 km of the river).

Natural and human impact on land use change of the Sikkimese-Bhutanese Himalayan piedmont, India

Abstract . Natural and human causes of land use transformation were analysed in the Sikkimese-Bhutanese Himalayan piedmont over last 150 years with special emphasize on period 1930-2010. A hydrologic and geomorphic approach was employed to delineate three study areas along river courses on alluvial fans stretching 10 km from the mountain front. The visual interpretation of topographic maps and satellite images combined with logical rules in GIS were used for determination of stable and dynamic areas from the viewpoint of land use changes. Analysis indicates rapid replacement of natural forest through location of tea plantations, crop cultivation and development of settlement in the late 19th century. The shift from natural to human dominated landscape caused increase land use stability through enlargement of areas with monoculture cultivation of tea and paddy between 1930 and 2010. The natural fluvial activity intensified by human induced deforestation of Himalayan margin and clearance of riparian vegetation along foothill channels became the most important factors of present-day land use changes of piedmont.