Assessing links between crop diversity and food self-sufficiency in three agroecological regions of Nepal

Increasing on-farm crop diversity is one agroecological approach to enhancing food self-sufficiency that helps small-scale farmers keep their food systems stable by reducing risks associated with stressors, such as a pest outbreaks or droughts. But understanding how crop diversity and food self-sufficiency are related is unknown. To explore this complex relation, this study presents household data (n = 1664) from Nepal to test the hypothesis that families with high crop diversity enjoy greater household food self-sufficiency. Data are presented for three districts that are representative of three distinct agroecological regions of the country: (1) Sarlahi, which is affluent, market-oriented, and on the plains; (2) Makwanpur District in the hills, which has well-developed integrated farm production; and (3) the mountainous District of Humla, which has the poorest quality environment and is the most remote. Results show that in the Humla District, families with greater crop diversity were more self-sufficient. In contrast, farmers in Makwanpur, who have already established a high degree of crop diversity based on vegetable production, do not benefit from additional crop diversity in terms of their ability to provide for themselves. Finally, data from Sarlahi show that families’ food self-sufficiency benefits from crop diversification. We conclude that boosting crop diversity is a viable strategy for maintaining stability in food systems, but this varies depending on the accessibility of a farm and, in particular, access to markets.     

Assessing suitability of apple cultivation under climate change in mountainous regions of western Nepal

Mustang, a mountainous region in the Kali Gandaki River Basin in western Nepal, has been increasingly experiencing climatic changes (e.g., higher temperatures). Rising temperatures lead to ecological shifts, which, in turn, can lead to the expansion of the lower limit for the cultivation of apple trees in this area. Apple cultivation can provide opportunities for adaptations under climate change through vulnerability reduction, income source diversification, livelihood improvement, and capacity building for farmers. As there is a lack of a strong basis to justify the expansion of apple cultivation in Mustang, this study examines the biophysical and socioeconomic suitability of apple cultivation in the area. Necessary data and information were collected from both primary and secondary sources. Findings of biophysical suitability using variable and equal weights to the indicators showed that 5.2 and 4.1 % of the areas are highly suitable for apple cultivation, respectively. However, not all potential farming areas are currently in use. Thus, there is the possibility to expand apple cultivation into unplanted areas and to integrate apple crops with other crops on cultivated lands. Increasing temperature may increase the suitable areas for the cultivation of apples in the coming years. High, benefit–cost ratio for land use confirmed the economic suitability of apple farming when compared to other land uses. The social suitability assessment showed no social discords, conflicts, or disagreements with apple cultivation, which is a positive indicator for the expansion of apple cultivation in western Nepal.     

The Sensitivity of PM25 Source-Receptor Relationships to Atmospheric Chemistry and Transport in a Three-Dimensional Air Quality Model

ABSTRACT

Air quality model simulations constitute an effective approach to developing source-receptor relationships (so-called transfer coefficients in the risk analysis framework) because a significant fraction of particulate matter (particularly PM_2.5) is secondary (i.e., formed in the atmosphere) and, therefore, depends on the atmospheric chemistry of the airshed. In this study, we have used a comprehensive three-dimensional air quality model for PM_{2 5} (SAQM-AERO) to compare three approaches to generating episodic transfer coefficients for several source regions in the Los Angeles Basin. First, transfer coefficients were developed by conducting PM_2.5 SAQM-AERO simulations with reduced emissions of one of four precursors (i.e., primary PM, sulfur dioxide (SO₂), oxides of nitrogen (NO_x), and volatile organic compounds) from each source region. Next, we calculated transfer coefficients using two other methods: (1) a simplified chemistry for PM_2.5 formation, and (2) simplifying assumptions on transport using information limited to basin-wide emission reductions. Transfer coefficients obtained with the simplified chemistry were similar to those obtained with the comprehensive model for VOC emission changes but differed for NO and SO emission changes. The differences were due to the parameterization of the rates of secondary PM formation in the simplified chemistry. In 90% of the cases, transfer coefficients estimated using only basin-wide information were within a factor of two of those obtained with the explicit source-receptor simulations conducted with the comprehensive model. The best agreement was obtained for VOC emission changes; poor agreement was obtained for primary PM_2.5.     

Biophysical and anthropogenic controls of forest fires in the Deccan Plateau, India

Forest fires constitute one of the most serious environmental problems in several forested regions of India. In the Indian sub-continent, relatively few studies have focused on the assessment of biophysical and anthropogenic controls of forest fires at a landscape scale and the spatial aspects of these relationships. In this study, we used fire count data sets from satellite remote sensing data covering 78 districts over four different states of the Deccan Plateau, India, for assessing the underlying causes of fires. Spatial data for explanatory variables of fires pertaining to topography, vegetation, climate, anthropogenic and accessibility factors have been gathered corresponding with fire presence/absence. A logistic regression model was used to estimate the probability of the presence of fires as a function of the explanatory variables. Results for fire area estimates suggested that, of the total fires covering 47,043km(2) that occurred during the year 2000 for the entire Indian region, 29.0% occurred in the Deccan Plateau, with Andhra Pradesh having 13.5%, Karnataka 14.7%, Kerala 0.1%, and Tamilnadu 1.15%. Results from the logistic regression suggest that the strongest influences on the fire occurrences were the amount of forest area, biomass densities, rural population density (PD), average precipitation of the warmest quarter, elevation (ELE) and mean annual temperature (MAT). Among these variables, biomass density (BD) and average precipitation of the warmest quarter had the highest significance, followed by others. These results on the best predictors of forest fires can be used both as a strategic planning tool to address broad scale fire risk concerns, and also as a tactical guide to help forest managers to design fire mitigation measures at the district level.     

Rapid immobilization of viable Bacillus pseudomycoides in polyvinyl alcohol/glutaraldehyde hydrogel for biological treatment of municipal wastewater

A new approach for easy synthesis of Bacillus pseudomycoides immobilized polyvinyl alcohol (PVA)/glutaraldehyde (GA) hydrogel for application in a wastewater treatment system is reported. Optimization studies revealed that GA/PVA mass ratio of 0.03 and acidic pH of 2 were required for hydrogel synthesis and eventually for bacterial cell immobilization. The synthesized crosslinked matrix possessed a pore size suitable for microbial cell entrapment while maintaining cell accessibility to external environment for bioremediation. Possible crosslinking and bacterial cell immobilization in the hydrogel were evidenced by FTIR, XRD, and SEM studies, respectively. Further, the extent of crosslinking of GA with PVA was investigated and confirmed by transmittance and permeability experiments. The viability and proliferation of hydrogel embedded cells (after 25 days) was confirmed by confocal fluorescence microscopy which also indicated that acidic pH of polymer solution did not affect the immobilized live cells. B. pseudomycoides immobilized hydrogel were demonstrated to be effective for treatment of municipal wastewater and reduced biochemical oxygen demand (BOD), chemical oxygen demand (COD), and protein content below the recommended levels. Overall, the results from this bench-scale work show that employing bacteria-embedded PVA/GA hydrogel for the treatment of municipal wastewater yield promising results which should be further explored in pilot/field-scale studies.

     

3D MRI measurements of the effects of wind direction on flow characteristics and contaminant dispersion in a model urban canopy

Environmental Fluid Mechanics - Three dimensional velocity fields and contaminant dispersion within an evenly spaced orthogonal array of cubic buildings (height = H) with a central tall...     

Photosynthesis mediated decrease in cadmium translocation protect shoot growth of Oryza sativa seedlings up on ammonium phosphate – sulfur fertilization

Cadmium (Cd) stress responses in seedlings of two Indian rice cultivars, MTU 7029 and MO 16 were investigated under ammonium-based fertilizer amendment. Cd translocation was reduced by fertilizer treatment. An increase in the production of organic acids as well as nitrogenous compounds and maintenance of nutrient status were implicated for decrease in Cd translocation which in turn promoted shoot growth. Fertilizer treatment increased photosynthetic pigments and activity of antioxidant enzymes that ensured steady photosynthetic rate during Cd stress. MO 16 showed Cd exclusion characteristics when compared with MTU 7029. Photosynthesis performance of MO 16 was not affected by Cd treatments. These findings suggest that photosynthesis influenced decrease in Cd translocation enhanced shoot growth of seedlings during ammonium phosphate–sulfur fertilizer supplementation.     

Bond behaviour of bamboo splints in cement-stabilised rammed earth blocks

This paper represents an effort to study the bond characteristics of plain and noded bamboo splints embedded in cement-stabilised rammed earth (CSRE) blocks. A series of CSRE pullout test specimens and two species of bamboo, namely Melocanna Baccifera and Bambusa Balcooa having an average tensile strength of 384 and 310 MPa, respectively, were fabricated using 4–10% Portland cement. These bamboo species are commonly available and widely used for construction in the north-eastern part of India. Besides considering the effects of soil strength, cement content, splint size and type on bond force and slip, the effect of embedded area was also briefly considered as part of the test programme. The test result showed that pullout bond resistance is correlated to rammed earth compressive strength, splint size and type, and embedded area.     

Lytic bacteriophages specific to Flavobacterium columnare rescue catfish, Clarias batrachus (Linn.) from columnaris disease

This investigation was aimed to find out appropriate strategy against antibiotic resistant bacterial fish pathogen, F. columnare. This pathogen was found persistently associated with fishes causing columnaris disease and ensuing mass mortality in hatchery and culture system of Sub - Himalayan region. Nine lytic F. columnare phages (FCP1 - FCP9) specific to its fifteen isolates were isolated from the water and bottom sediments of various geo-climatic regions of North India. The F. columnare phage FCP1 (made of hexagonal head and non contractile long tail belonging to family Podovariedae, a member of DNA virus) exhibited broader host range to lyse 9 out of 15 isolates of F. columnare. Therapeutic ability of FCP1 phage was assessed in C. batrachus inoculated intramuscularly (im) with virulent bacterial isolate FC8 and post inoculated (PI) with FCP1 phage (@ 10(8) : 10(6):: cfu : pfu) through intramuscular (im), immersion (bath) and oral (phage impregnated feed) treatment. Significant (p < 0.001) reduction (less than 10(-3) cfu ml(-1)) in host bacterium in the sera, gill, liver and kidney of challenged fishes was noted after 6 hr of phage treatment. Quantum of phage played a significant role in bringing down bacterial population as in the sera of dose 1 (@ 4.55 x 10(6) pfu ml(-1)) and dose 2 (@ 9.15 x 10(6) pfu ml(-1)) treated fishes mean log10 cfu value reduced by 3 logs (58.39%) and 5 logs (73.77%) at 96 hr, respectively. Phage treatment led to disappearance of gross symptoms, negative bacteriological test, detectable phage and 100% survival in experimentally infected C. batrachus. Result of this study provides evidence of profound lytic impact of FCP1 phage and represents its interesting therapeutic importance against antibiotic resistant F. columnare.