International Journal of Environment

Effect of Climate Change on Agriculture

2020-02-14T12:12:51+00:00

Thank You to Our 2019 Peer Reviewers

2020-02-14T12:09:24+00:00

Levels of Heavy Metals in Banana, Cocoa and Oil Palm Farming Systems in Cameroon

2020-02-14T12:09:25+00:00

The potential accumulation of heavy metals in soils due to rapid urban and industrial development, and increasing reliance on agrochemicals in the last several decades has been of public concern. Excessive heavy metal accumulation in soils may not only result in environmental contamination, but excessive heavy metal uptake by crops may affect food quality and safety. The heavy metal concentrations of soils in banana, cocoa and oil palm farming systems in Fako Division of the South West Region of Cameroon were studied. For soil quality assessment, soil samples were collected at two depths: 0-15 cm and 15-30 cm and analyzed for seven heavy metals (Cd, Cu, Cr, Ni, Mn, Pb and Zn) using inductively coupled plasma optical emission spectrometer (ICP-OES). Cd levels in these soils were below the limits of detection (LOD) at both depths. Average contents of Cd, Cu, Cr, Mn, Ni, Pb and Zn in mg/kg ranged in the order: Cd (< LOD) < Pb (10.7 -17.1) < Cu (59.7-112.7) < Ni (100.2 -174.5) < Zn (129.7-180.4) < Cr (192.7-685.3) < Mn (2731.5-5053.5) for both depths. The soils were all acidic (pH; 4.2-5.5). There were significant variations (p≤0.05) in Cu, Cr, Mn and Zn concentrations within different farming system(s). The soils of the studied farming systems had heavy metal levels within the allowable limits for agriculture. However, the levels of Cu, Cr and Ni were higher in some samples. Although these soils are considered to be unpolluted, care should be taken to avoid high concentrations of heavy metals.

Towards the Promotion of Fuel Briquettes Using Municipal Solid Waste and Residual Biomass in Burundi

2020-02-14T12:09:26+00:00

The issue of domestic energy is still a major concern in developing countries. A sound knowledge of fuel characteristics is a major asset for their acceptability and their distribution. Samples of briquettes made partially with Municipal Solid Waste (MSW) were collected in several companies with unknown characterization. This study intended first to characterize them for physical and chemical properties. Subsequently, energy content of the briquettes and the energy price are presented and compared to those of charcoal and peat, which is typically used by the local population as fuel. To classify the different briquettes according to their quality in terms of rate as well as their level in fire resistance, cooking tests and heating curves have been made. The calorific value of the studied briquettes varied from 12.3 to 18.6 MJ/kg compared to 32.5 MJ/kg for charcoal and 14.7 MJ/kg for peat. Consequently, their value as viable substitutes for charcoal or peat is apparent. However, some samples burn very quickly and do not provide prolonged heating while other samples have a slow rate of combustion and release little energy. Finally, the briquettes using MSW have a low price between $0.16 and $0.19/kg compared to the price of $0.53/kg for charcoal and $0.20/kg for peat. The promotion of these briquettes as a valuable substitution fuel is proved and contribute to sustainable development by reusing MSW and avoiding deforestation.

Evaluation of UASB Reactor Performance During Start-Up Operation Using Glucose Bearing Synthetic Wastewater

2020-02-14T12:09:28+00:00

This research article describes start-up performance of an UASB (Upflow Anaerobic Sludge Blanket) reactor in terms of chemical oxygen demand (COD) removal efficiency, biogas production, sludge loading rate (SLR), volatile fatty acids (VFA), pH, alkalinity, total solids (TS) and volatile suspended solids (VSS), fed with synthetic wastewater with increased concentrations of glucose. The reactor was loaded up to an OLR (Organic Loading Rate) of 15 kg COD m^-3d^-1 and achieved a COD removal efficiency of 82 ±3%. The results showed that digested seed sludge was successfully acclimatized and transformed finally into granular sludge within a period of 120 days. An increase in the accumulation of VFA at high OLRs showed that methanogenesis could be the rate-limiting step in the reactor operation. The SLR and VSS/TS ratio were increased with an increase in OLR. During the initial stages, uniform distribution of VSS concentration and later on maximum VSS concentration were found at port number two at a height of 350 mm. The carbon balance depicts that the maximum percentage of influent COD converted to methane COD. An increase in specific methanogenic activity values with the age of sludge confirmed the transformation of the seed sludge in to a granular sludge.

Monitoring Supraglacial lakes Formation and Risk of Outburst Flooding in the Himalayan Cryosphere of Pakistan

2020-02-14T12:19:08+00:00

The dramatic rise in warm temperatures in the Himalayan region has caused the formation and expansion of numerous supraglacial lakes, some of which pose a serious flood hazard for the downstream communities. In this study, we have investigated the risk of flood hazards associated with supraglacial lakes in the Hindu Kush, Karakoram and Himalayan ranges of Pakistan using Landsat 8 OLI (Operational Land Imager) data of 2013 and field observations. Among the total of 438 supraglacial lakes, the majority were identified in the Karakoram (378) followed by the Hindu Kush range (39). The concentration of lakes was high within 3500-4000 m elevation (168) followed by 4000-4500 m elevation range (116). The lakes had shown more than a two-fold increase during the 2001-2013 period in the three mountain ranges. The increase in lake number was pronounced over valley glaciers likely due to increasing hydro-glacial activity under changing climate. Two types of supraglacial lakes were identified based on geographic characteristics, for example those rolling over glaciers surface away from the margins (called rolling supraglacial lakes ‘RSLs’) and the lakes found near the margins of glaciers mostly stationary in nature (called static supraglacial lakes ‘SSLs’). Most of the glacial lakes outburst flood (GLOF) events have been observed from SSLs in this region. However, the hydrodynamic process exaggerating the risk of GLOF from supraglacial and englacial lakes needs in-depth research for effective disaster risk reduction in this region in future.

Rainfall Runoff Modeling Using HEC-HMS: The Case of Awash Bello Sub-Catchment, Upper Awash Basin, Ethiopia

2020-02-14T12:09:31+00:00

Rainfall runoff modeling is one of the most complex hydrological modeling due to the involvement of different watershed physical parameters. It is essential for the analysis of watershed hydrological response toward the received precipitation under the influence of watershed parameters. As it is a replica of watershed hydrological response, rainfall runoff modeling is essential to evaluate the general characteristics of total surface runoff at catchment’s outlet. The main objective of this study was rainfall runoff modeling using HEC-HMS for Awash Bello sub-catchment. Hydro-meteorological data collected from the National Meteorological Agency and Ministry of Water Resource, Irrigation and Electricity were used for model calibration and validation. SCS-CN, SCS-UH, Muskingum and monthly constant method were used for precipitation loss modeling, transform modeling, flood routing and base flow modeling respectively. Nash Sutcliff Efficiency and coefficient of determination have been selected for model performance evaluation. The model had shown good performance both during calibration and validation with (NSE = 0.855, R²= 0.867) for calibration and (NSE = 0.739, R² = 0.863) for validation respectively. PBIAS for calibration and validation were checked and they were within the acceptable range with a value of 4.59% and 5.67% respectively. By the successful accomplishing of calibration and validation, the peak flood from the model (573.7m³/s) was compared with direct observed flow (546.4m³/s) and model provided nearly the same result with the direct observed flow.

Physiological Effects of Some Pollen Substitutes Diets on Caged Honey Bee Workers (Apis mellifera L.)

2020-02-14T12:09:33+00:00

Nutritional value of four proteinaceous diets and their physiological effects on honey bee workers were evaluated under laboratory conditions. The tested diets were as follows: diet 1 – date (Phoenix dactylifera L.) syrup, skimmed milk powder and dried brewer's yeast, diet 2 – Fenugreek (Trigonella foenum-graecum L.), Turmeric (Curcuma longa L.) powders and dried brewer's yeast, diet 3 – chickpea (Cicer arietinum L.) flour, wheat germ and dried brewer's yeast and diet 4 - soybean meal, skimmed milk powder and dried brewer's yeast, beside a control group (bee bread). Caged Carniolan honey bee workers were used in the experiments. The consumption rate, workers longevity, development degree of hypopharyngeal glands (HPG), and weight of rectal contents were determined. The greatest consumption rate was recorded for the control group while the lowest one was recorded for diet 4. Feeding bees on diet 3 gave the longest longevity (LT₅₀= 27.0 days) among the tested diets and as a second rank after bees in the control group (LT₅₀ = 29.0 days) while diet 4 showed the lowest longevity (LT₅₀ =20.5 days). The highest HPG development degree (3.78) was recorded for 9 days old bees in the control group, followed by diet 3 (3.24) while the lowest degree (2.14) was to diet 4. The weight of rectal contents of honey bee workers was 13.43, 16.03 and 16.12 mg/bee/3 days for diet 3, diet 1 and diet 2, respectively, suggesting the suitability of these diets to bees. In light of this study, diet 3 and 2 have the best physiological effects for bees with good nutritional values.

Assessment of Natural Regeneration Potential of Native Tree Species in a Community Managed Forest of Bangladesh

2020-02-14T12:09:34+00:00

The study was conducted to explore natural regeneration potential of a community managed forest. Village Common Forest (VCF) has been managed as a commo n property resource under the leadership of Mouza Headmen based on traditional resource management pattern. Stratified random sampling method was carried out for the inventory of the regeneration status. The sampling plot size for regeneration was 5m × 5m. About 47 regenerating tree species belonging to 22 families were recorded from the studied village common forest where Grewia nervosa was the dominant regenerated seedlings. Euphorbiaceae was the dominant family with 7 species followed by Moraceae (5 species), Rubiaceae (4 species), Anacardiaceae (3 species), Combretaceae (3 species) and Mimosaceae (3 species). Maximum Importance Value Index (IVI) was found for Grewia nervosa (27.97) followed by Brownlowia elata (21.52), Artocarpus chama (14.74) and Leea macrophylla (12.53). A total of 78% of the regenerating tree species were regenerated from seeds and 22% from coppices. Shannon-Wiener’s Diversity Index was found 3.37 where Simpson’s Diversity Index was 0.055, Moreover, Margalef’s Richness Index was calculated as 8.57 and Species Evenness Index was 0.88. The results depict that the regeneration status of studied VCF has been satisfactory and Village Common Forest still contains dense forests that represents rich biodiversity including rare species. The study might be helpful for increasing conservation importance of this forest. This study suggests further study on vegetation structure and carbon pool assessment to understand more about of this forest for future sustainability.

Role of Intra-Specific Varietal Mixture in Pollination Services: A Case Study in Buckwheat (Fagopyrum esculentum Moench)

2020-02-14T12:09:36+00:00

Buckwheat is one of the crops on which pollination services from honeybees and other insect pollinators are necessary for obtaining quality and higher grain yield. Increasing plant biodiversity is an important strategy to attract and restore pollinators in an agro-ecosystem. Among many ways to increase plant biodiversity, the present study aimed to identify whether the increasing intra-specific crop diversity enhances pollinator diversity in buckwheat (Fagopyrum esculentum Moench). The field experiment was conducted at research field of Hill Crop Research Program, Kabre, Dolakha district, Nepal at an altitude of 1750 m asl during 2016. Thirteen treatments, each representing either a single or combination of two or three buckwheat genotypes were laid out in randomized complete block design (RCBD) with two replications. Pollination diversity or richness as well as their foraging behavior in the buckwheat flowers and associated yield parameters were measured for each treatment. Plots with higher intra-specific varietal mixture were found to attract more pollinators and had higher yield than plots with two or single genotypes. Pollinator visitation was higher during morning hour of the day (9 am to 10 am), which was followed by mid-day (12 noon to 1 pm) and the least visitation was observed during late afternoon (3 pm to 4 pm). The benefit of increasing intra-specific crop diversity on pollination services is not optimized and practiced under current farming practices. Hence, multi-location and multi-season studies are recommended to strengthen the current findings for future endeavors.