Nani Raut

Evolution and future direction of intensified agriculture in the central mid-hills of Nepal

Nepalese mid-hill farmers have shifted from a subsistence-based farming system to an intensified farming system. This paper attempts to describe the evolution of the process of agricultural intensification in the mid-hill region by examining external drivers, trends in fertilizer use, landholding, cropping patterns, irrigation and labour use in the years 1989, 1999 and 2009. Data were obtained by means of structured interviews, focus group discussions, key informant interviews and field observations. The study revealed that modern technology and the involvement of NGOs have facilitated the agricultural intensification process in three ways: (i) by providing access to technology without any financial cost to the farmer, (ii) by increasing the variety and number of crops and encouraging farmers to discontinue crops that had pest problems and (iii) by maximizing the use of chemical fertilizers to increase production. Results showed a significant increase in the application of urea and diammonium phosphate (DAP) and a decrease in the application of farm yard manure (FYM) and muriate of potash from 1989 to 2009 (p < 0.001). The average landholding of 0.76ha in 1989 was reduced to 0.63ha by 2009. The number of crops (rice, maize or millet) cultivated per year increased to at least three crops with the introduction of potatoes and spring rice; however, some crops such as sugarcane and tobacco were not continued as a result of pest problems. Increased nitrogen input could lead to increased N2O emissions; therefore, a better understanding of nitrogen fertilization and quantification of N2O emissions from intensified agriculture is urgently needed to assess the possible environmental impact of input intensification.

Fluxes of CH4, N2O, and kinetics of denitrification in disturbed and undisturbed forest soil in India

Raut, N., Sitaula, B. K., Bakken, L. R. and Dörsch, P. 2014. Fluxes of CH4, N2O, and kinetics of denitrification in disturbed and undisturbed forest soil in India. Can. J. Soil Sci. 94: 237-249. Soil disturbance due to grazing has been severe in Indian forests. This may alter ecosystem functions such as the cycling of nitrogen, and may hence affect the emission of greenhouse gases. We measured fluxes of CH4 and N2O with a closed chamber technique throughout one year in a forest of Western Ghats, Karnataka state, southwest India and determined the product stoichiometry of denitrification under standard anoxic incubations in soil samples from disturbed and undisturbed forest. In both areas, there was a net flux of CH4 from the atmosphere to the soil, and the undisturbed forest soil was a stronger sink for CH4 than the disturbed (P<0.05). The accumulated CH4 uptake averaged for all four seasons was 1.5 times higher in undisturbed than disturbed forest. Contrary to our expectation, the N2O emission was significantly higher for undisturbed than for disturbed forest (P<0.05). The accumulated N2O emission averaged for all four seasons was 1.6 times higher in undisturbed than disturbed forest. Together our data suggest that increase of N2O release and decrease in CH4 sink in soil induced by grazing disturbance can affect the global warming potential (GWP) of forest in this region. The incubation study showed a strong correlation between oxic respiration rate (R) and subsequent denitrification rate (D) and the ratio D/R was 1:3 and 1:6 for soil from undisturbed and disturbed soils, respectively. The N2O/(N2+N2O) product ratio of denitrification tended to be higher in undisturbed than disturbed site, despite lower soil pH.

Advances and Challenges in Flash Flood Risk Assessment: A Review

Flash floods are considered to be one the worst kind of hazard. They are characterized by their suddenness, rarity, small scale, heavy rain and peak discharge, unpredictable, fast and violent movement. It has severe effects on human society in the form life losses, damages to property, roads, communication and on natural settings. Advances in hydrology, meteorology, engineering, using of GIS and remote sensing still not able to increase real time forecast. Researchers from developed countries have stressed to more focus to improve very short time an effective early warning system with collaboration of local communities for flash flood risk supervision. The valid inputs from natural and social science can play a vital role in risk reduction. In the flood hazard risk assessment, the analysis of various morphometric parameters of river basins is very essential. Community based participatory flood hazard mapping provides an essential detail, such as inundation areas, depth information, evacuation centers and routes, critical facilities, communication channels, evacuation criteria, emergency kits and many other items needs for an evacuation in hazard maps. Vulnerability is based on numerous components such as internal (assesses coping capacity of people or systems) and external (exposure of people) side of vulnerability. Risk assessment consists of two main components such as hazard (related to source and pathways) and vulnerability (related to the receptor and consequences). Flood disaster-related risk has increasingly become a global concern, and its vulnerabilities related to changes in demography, socioeconomic conditions, unplanned settlements, environmental degradation, stress on natural resources and climate change.