Hydrogeochemistry of Two Major Mid-hill Lentic Water Bodies for Irrigation of the Central Himalaya, Nepal

The concentration and composition of different salts in natural water bodies determine the water quality for various purposes. This study assesses the water quality of two mid-mountain lentic water bodies, Lake Phewa and Kulekhani Reservoir. For this purpose, selected physico-chemical parameters along with major ions such as HCO3-, SO42-, PO43-, NO3-, Cl-, Ca2+, Mg2+, Na+, K+, and NH4+ were analyzed. Major ions were analyzed using ion chromatography, anions by DX-600 and cations by Dionex ISC-2500 ion chromatographs. The sources of major ions were determined by using the Gibbs diagram, Piper plot, and Scatter plots. Dissolved oxygen, ammonia and phosphate showed seasonal variations in both lakes. The concentrations of cations are in the order of Ca2+ > Na+ > Mg2+ > K+ in both water bodies. However the trend of anions had small variations for Cl- and SO42- in Lake Phewa (HCO3- > Cl- > SO42- > NO3-) and Kulekhani Reservoir (HCO3- > SO42- > Cl- > NO3-). The Piper plot and equiline plots indicated that the water chemistry is dominantly controlled by the dissolution of carbonate minerals and to a limited extent by weathering of silicate minerals. This is further supported by the Gibbs plot showing bedrock geology as the main source of major ions. The overall study indicates that the hydrogeochemistry of these water bodies is controlled by local geology and is suitable for irrigation purposes

Agricultural intensification in a mid-hill watershed of Nepal : socio-economic and environmental implications

Agricultural intensification is unavoidable due to the food requirements of a growing population, market availability and access to agro-products, and limited productive agricultural areas in Nepal. A shift from cultivating cereal crops towards vegetables and other cash crop has evolved through the process of agricultural intensification in the hills of the Himalayan region. With increased market access and road links to urban centres, settled agriculture in Nepal is becoming transformed into intensified cropping, especially in peri- and semi-urban areas. This study reviewed the historic development of intensification, its evolution and adoption by farmers, and its effects on society and the environment in Ansikhola watershed of Kavre district in Nepal. For the historic and socio-economic aspects, personal interviews, discussion with key farmers, specific case studies, and focus group discussions with different wealth and caste groups where conducted. For the environmental aspects, field erosion plots were established to measure the runoff, soil loss and nutrient losses from agricultural lands. The eroded sediment samples and river water samples were analyzed for major soil nutrients, chemicals, and aquatic macro-invertebrates. The effect of crop intensification on stream water quality is based on the comparison of two mid-hill watersheds with different degrees of intensification

An assessment of good agriculture practices for safe and sustainable vegetable production in mid-hills of Nepal

The vegetable sector provides immediate income, nutrition, and food security and contributes significantly to the economy of Nepal. In recent decades, the sustainability of the vegetable sector has been challenged due to the unsystematic use of agrochemicals for commercializing production. Adopting Good Agriculture Practices (GAP) could reduce the use of agrochemicals in commercial vegetable production. This study conducted the assessment of GAP in Kathmandu Valley. A mixed-method approach, combining quantitative and qualitative methods, was adopted for the study, which included farmers' surveys, key informant interviews, and in-depth interviews. The results showed that farmers were adopting different GAP, such as cropping practices, livestock integration, soil fertility management practices, and integrated pest management practices. Upon adopting these practices, farmers reduced agrochemicals' use by more than 40%. The critical incentives for surveyed farmers to adopt GAP were soil health improvement, farmers' safety, and reduction in the use of agrochemicals while improving the farm's image. Further, the study revealed that farmers faced several challenges in adopting GAP. Management difficulty (I = 0.9) was identified as the most critical problem, followed by no premium price (I = 0.8), knowledge (I = 0.6), access to GAP inputs (I = 0.5), and other risks (I = 0.04). The study's findings imply that adopting GAP helps reduce the use of agrochemicals, consequently motivating farmers toward safe and sustainable vegetable production. The study recommends market-based solutions such as creating mass consumer awareness, ensuring premium prices with quality assurance mechanisms for making the GAP-based production profitable, and promoting its wider adoption. This is supported by facilitating farmers' access to government subsidies, price incentives, and insurance services and increasing access to GAP inputs. This study aims to generate evidence on a safe and sustainable vegetable production model that will be key to institutionalizing GAP in Nepal

Analysing the Environmental Values and Attitudes of Rural Nepalese Children by Validating the 2-MEV Model

The Two-dimensional Model of Ecological Values (2-MEV), developed and verified in Western Europe, successfully explores the environmental values and attitudes of the children (11-16 years old) using questionnaires/items. However, the reliability of the 2-MEV Scale and its bi-dimensionality in a non-industrialised country, such as Nepal, is unexplored. Nepal lies within the monsoon region, which triggers extreme environmental crises such as floods. As environmental values and attitudes are related to pro-environmental/adaptive behaviour, this study analyses not only the values and attitudes of children but also the validity of the 2-MEV Scale in a different geographic and socioeconomic setting. Therefore, the items of the 2-MEV Scale were modified, translated, and validated in two rounds with 200 and 201 children. Results were examined using principal component analysis and confirmatory factor analysis, respectively. The findings validated the two constructs of environmental values (Preservation and Utilisation) with a correlation of -0.93, but the attitude's pattern varied from that found in industrialised countries. Finally, the rural Nepalese version of the 2-MEV was used to measure environmental values. Most children (78.62% from n = 379) show an inclination towards Preservation, 0.26% towards Utilisation, 20.05% towards both values partially, and 1.05% were neutral. In general, the children held pro-environmental values and attitudes.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Changing Trends in Cultivation Practices and Adoption of Climate Adaptive Farming in Eastern Nepal

Climate change impacts are likely to affect the agricultural production leading to further food insecurity. In this context, the trend of cereal production with climate variables was studied in order to understand the linkages between climate change and crop productivity. The study was conducted in three districts of Sagarmatha zone, namely Solukhumbu (mountain region), Okhaldhunga (hill region) and Saptari (Terai region) representing three ecological zones in Nepal. A household survey (295 households), focus group discussions and key informant interviews were used to collect data on the history of the cultivation systems, varieties of crop grown, trends on crop yield, and adaptation to climate change. Results showed farmers’ introduction of high yielding varieties of crops and vegetables due to economic benefit, while traditional varieties are no longer cultivated. The infestation of pest attack is increasingly seen since two decades, while few pests were reported to be disappeared. Although majority of farmers in Saptari and Okhaldhunga districts used pesticides as per the prescribed doses, pesticide use is still random in Solukhumbu district. The multiple comparisons of means showed that there is a significant difference in the average production of rice and maize since 30 years until recently (p<0.05) in these three districts. The average production of rice, maize and wheat increased with decreasing average annual temperature and rainfall in Saptari district since 30 years. In contrast, in Okhaldhunga and Solukhumbu districts, the average production of three cereal crops increased with increasing average annual temperature and rainfall. With the late arrival of the monsoon, farmers have adopted coping strategies particularly for rice cultivation through occasional shift in crop planting dates and selection of shorter duration crop varieties that can be harvested earl

Diatoms as indicators of stream quality in the Kathmandu Valley and Middle Hills of Nepal and India

1. Diatoms are recognised as indicators in temperate streams, but only recently have assessments begun of their value in indicating stream quality in the tropics and sub-tropics. Here, we extend previous studies by assessing stream diatom assemblages in relation to water quality and habitat character in the Kathmandu Valley, and in the Middle Hills of Nepal and northern India. We also assessed whether the U.K. Trophic Diatom Index (TDI) was sufficiently portable to reveal pollution in Himalayan rivers. In the more urbanised and highly agricultural Kathmandu Valley, we compared diatom response to water quality classes indicated by a local invertebrate index, the Nepalese Biotic Score (NEPBIOS). 2. Thirty and 53 streams in the Kathmandu Valley (2000) and Middle Hills (1994–96), respectively, were sampled in October and November during stable flows following the monsoon. Diatoms were collected in riffles, water samples taken for chemical analysis, and habitat character of the stream channel, bank and catchment assessed using river habitat surveys. In the Kathmandu Valley, macroinvertebrates were collected by kick-sampling. 3. In total, 113 diatom taxa were found in the Kathmandu Valley streams and 106 in the Middle Hills. Of 168 taxa recorded, 62 occurred only in the Kathmandu Valley, 56 only in the Middle Hills and 50 were common to both areas. Most taxa found only in the Kathmandu Valley belonged to the genus Navicula while most taxa confined to the Middle Hills were Achnanthes, Fragilaria and Gomphonema. 4. In the Kathmandu Valley, richness and diversity increased significantly with K, Cl, SO4 and NO3, but declined significantly with Al, Fe, surfactants and phenols. Richness here also varied with habitat structure, being lowest in fast flowing, shaded streams with coarse substrata in forested catchments. In all streams combined, richness increased significantly with Si, Na and PO4, but declined significantly with increasing pH, Ca and Mg. 5. Diatom assemblage composition in the Kathmandu Valley strongly reflected water chemistry as revealed by cations (K, Na, Mg, Ca), anions (Cl, SO4), nutrients (NO3, PO4, Si), and also substratum composition, flow character and catchment land use. The commonest taxa in base-poor forested catchments were Achnanthes siamlinearis, A. subhudsonis, A. undata and an unidentified Gomphonema species; Cocconeis placentula and Navicula minima in agricultural catchments; and Mayamaea atomus var. alcimonica, M. atomus var. permitis, and Nitzschia palea at polluted sites near settlements. Diatom assemblages in none-agricultural catchments of the Kathmandu Valley and Middle Hills were similar, but they contrasted strongly between urban or agricultural catchments of the Kathmandu Valley and the less intensively farmed catchments of the Middle Hills. 6. In keeping with variations in assemblage composition, most streams in the Kathmandu Valley had higher TDI values (33–87, median = 64) and more pollution tolerant taxa (0–78%, median = 16) than streams in the Middle Hills (25–82, median 45, 0–26%, median = 2). TDI values correlated significantly with measured PO4, Si, and Na concentrations in the Kathmandu Valley, and with Si and Na concentrations in the Middle Hills. There was some consistency between water quality classes revealed by NEPBIOS and diatoms, but also some contrast. Water quality class I–II sites had lower TDI values and were less species rich than water quality II sites, however, there were no significant differences in detrended correspondence analysis (DCA) assemblage scores and relative abundances of pollution tolerant taxa between NEPBIOS classes. 7. While diatoms in the Middle Hills indicate unpolluted or only mildly enriched conditions, they reveal pronounced eutrophication and organic pollution in the densely populated Kathmandu Valley. In addition, diatoms appear to respond to altered habitats in rural agricultural and urban areas. As demands on water resources in this region are likely to increase, we advocate the continued development of diatoms as indicators using methods based on what appear to be consistent responses in the TDI between Europe and the Himalaya

Microbial community structures in family anaerobic digesters reveal potentially differing waste conversion pathways

Family-scale rural digesters are widely implemented in Nepal for waste management, resource recovery, and environmental stewardship for distributed communities. However, there is little documentation on the microbial community structures in real-world family farm digesters. This work compared microbial community structures in four family digesters to a near-by municipal digester. Included in the family digesters was a high-altitude family digester located on Mt. Everest in Mosi, Nepal (2,634 m elevation). Differences in the community structures included the prevalence in family digesters of Bathyarchaeota MGC-6. MCG-6 is an archaeal population putatively involved in autotrophic acetate generation and conversion of cellulose to sugars. Additionally, Rikenellaceae DMER64, a population thought to degrade sugars, was more prevalent in the family digesters. The ratio of Methanothrix to hydrogenotrophic methanogens was higher in the family digesters. Additionally, the dominant species of syntrophic hydrogen-producing bacteria differed. Syntrophobacter and Syntrophomonas species, documented for their critical roles in waste activated sludge digesters, were not detected. In conclusion, observed differences in microbial community composition suggested a capacity to support different substrate conversion pathways and a major role of Archaea beyond methanogenesis among the studied digesters