Purpose: Agricultural land use associated with intensification in plant growing affects the physicochemical parameters of soils and thus soil quality. The aim of this study was to identify the quality of soils in the Peshok catchment in the Eastern Himalayas under different types of land use (tea, horticulture, rice), under high monsoon rainfall conditions. Methods: Physical and chemical analysis were used, e.g. bulk density, pH, TOC, major and trace element content (such as Ca, Fe, K, Mg, Mn, Na, P, Ag, As, Ba, Cd, Co, Cr, Cu, Ga, Li, Mo, Ni, Pb, Sr and Zn) based on AntonPaar Multiwave 3000 microwave system and nitrogen and sulphur content using CNS Elementar Vario MAX cube analyser. In addition, ecotoxicological analyses were performed using the Microtox test. Soil quality was assessed on the basis of chemical indicators related to the mobility of trace elements (risk assessment code, individual contamination factor and global contamination factor); geochemical indicators (geoaccumulation index, enrichment factor, contamination factor, contamination degree, modified contamination degree, pollution load index and improved Nemerow pollution index); and ecological indicators (potential ecological risk coefficient and potential ecological risk index). A statistical package of Statistica v13 was used for statistical analysis. Results: Soils in the analysed catchment are characterised by low contents of macro- and microelements. It was shown that natural factors, such as high precipitation and steep slopes, favour strong leaching of elements from the soil, and farming systems based on natural and chemical fertilisation, terracing and irrigation are not able to balance them fully. The contents of TOC and N as well as pH were determined mainly by the land use. Results of statistical analyses and geochemical indicators revealed the predominantly natural origins of elements. The higher Ga content indicated a relationship with the local geology and the higher Cu content with the use of fertilisers. Indicators showed a low ecological risk related to the presence of trace elements, and soil ecotoxicity to A. fischeri was generally determined by the acidic pH of the tested soils. Low mobility was observed for most elements, and regardless of the land use, the residual fraction predominated. Conclusion: The study showed that use of many indicators can more fully describe soil quality in relation to land use, especially in the case of a low content of trace elements. Moreover, this approach helps to better understand the changes taking place in soil quality under different land uses in mountains with high rainfall.

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).

This study presents an analysis of the influence of climatic conditions and the operation of a dam reservoir on the occurrence of ice cover and water temperature in two rivers (natural and transformed by reservoir operations) located in the Carpathian Mountains (central Europe). The analyses are based on data obtained from four hydrological and two climatological stations. The Extreme Gradient Boosting (XGBoost) machine learning model was used to quantitatively separate the effects of climate change from the effects arising from the operation of the dam reservoir. An analysis of the effects of reservoir operation on the phase synchronization between air and river water temperatures based on a continuous wavelet transform was also conducted. The analyses showed that there has been an increase in the average air temperature of the study area in November by 1.2 °C per decade (over the period 1984–2016), accompanied by an increase in winter water temperature of 0.3 °C per decade over the same period. As water and air temperatures associated with the river not influenced by the reservoir increased, there was a simultaneous reduction in the duration of ice cover, reaching nine days per decade. The river influenced by the dam reservoir showed a 1.05 °C increase in winter water temperature from the period 1994–2007 to the period 1981–1994, for which the operation of the reservoir was 65% responsible and climatic conditions were 35% responsible. As a result of the reservoir operation, the synchronization of air and water temperatures was disrupted. Increasing water temperatures resulted in a reduction in the average annual number of days with ice cover (by 27.3 days), for which the operation of the dam reservoir was 77.5% responsible, while climatic conditions were 22.5% responsible.

We researched local residents' perceptions of a dam and reservoir construction project in the Teesta River catchment basin (Darjeeling Himalayas) within 1.5 years of its completion, using a questionnaire survey. Most survey participants expressed negative perceptions of the project, citing a declining quality of life (loss of jobs and loss of access to river sites that had been important for religious practices and livelihoods) and a sense of insecurity (risk of landslides). These results may help predict attitudes toward similar reservoir projects that are planned for the Teesta basin.