Effect of biochar on the physicochemical properties and nitrogen transport of podzolic soil in a boreal ecosystem

This study is aimed at investigating the effects of biochar on the physicochemical properties and nitrogen transport in podzolic soils. Soil samples were collected from a research site in Pasadena, Newfoundland, Canada. Experimental treatments consisted of three types of soils {top, E-horizon and mixed soil (topsoil 2: E-horizon soil 1)}, two biochar types (granular and powder) and four biochar application rates (0%, 0.5%, 1% and 2% on a weight basis). A total of 210 most relevant and latest research articles were reviewed. Ten important physicochemical parameters of soil were investigated through a total of 72 experimental units and 54 leaching column experiments. Metadata analysis showed that only a few studies were conducted on the boreal podzolic soil. Soil porosity, field capacity and plant available water increased by 2.8%, 10%, and 12.9%, respectively compared to control when the soil was treated with powdered biochar. Nitrate leaching was reduced by 36% compared to control soil. Granular and powdered biochar were found to be hydrophobic and hydrophilic, respectively. A 2% biochar application rate showed greater impact in terms of improving hydraulic properties and reducing nitrogen leaching. The findings would be helpful to improve agricultural practices in the boreal podzolic soil

Geogenic Arsenic and Microbial Contamination in Drinking Water Sources: Exposure Risks to the Coastal Population in Bangladesh

The study aimed to investigate the most usable drinking water sources quality and the dependent population's exposure to potentially contaminated water. The specific area chosen for the study was the coastal area in Satkhira district's Tala Upazila. Six hundred and fourty nine most usable drinking water sources were selected, that included Deep Tubewell (DTW), Shallow Tubewell (STW) and Pond Sand Filter (PSF) for drinking water sampling. Following standard sampling procedures, in-situ measurements were taken for seven important water quality parameters: Arsenic-As, Iron-Fe, Electrical Conductivity-EC, Temperature-Temp, Total Coliform- TC, E-coli, and Fecal Coliform-FC. In addition, semi-structured questionnaire surveys were conducted at corresponding dependent households (HH). Weighted arithmetic water quality index (WQI) was used to calculate the suitability of the derived water for drinking purposes. In the tested water sources, As, Fe and EC range were found 0–500 μg/L, 0–18 mg/L, and 165–8,715 μS/cm, respectively. Of all the tested water sources, 74% exceeded the permissible limit for As, 83% for Fe and 99% for EC, according to WHO standards. Comparatively higher percentages of Point of Uses (PoU) were found to be more contaminated than Point of Sources (PoS), such as TC found in 38% PoS and 54% of corresponding PoU, E. coli found in 24% PoS and 35% of PoU and FC found in 45% PoS and 55% of PoU. WQI suggested that the majority (72%) of most usable drinking water sources were found to be unsuitable for drinking. Thus, 40% of the population (0.12 million) in the study area were directly consuming contaminated water. Dependent household members most frequently suffered from fever, diarrhea and high blood pressure, resulting in the average household spending USD 3–13 per month/HH for health-related expenditures, which is higher than national average. To acquire safe drinking water, the majority (58%) of the dependent HH expressed willingness to pay USD 1 per month/ HH which is costly for them. The situation can be improved by installing a deep tube well for safe drinking water, periodically testing the water quality, educating the public for better hygiene practices, and providing entrepreneurial incentives to help deliver safe water to the public at lower cost

Investigating the Influence of Biochar Amendment on the Physicochemical Properties of Podzolic Soil

Research into biochar, as an amendment to soil, has increased over the last decade. However, there is still much to understand regarding the effects of biochar type and rates on the physicochemical properties of different soil types. This study aimed to investigate the effects of biochar application on the physicochemical properties of podzolic soils. Soil samples were collected from the research site in Pasadena, Newfoundland, Canada. Experimental treatments consisted of three types of soils (topsoil, E-horizon soil and mixed soil (topsoil 2: E-horizon soil 1)), two biochar types (granular and powder) and four biochar application rates (0%, 0.5%, 1% and 2% on a weight basis). Ten physicochemical parameters (bulk density (BD), porosity, field capacity (FC), plant available water (PAW), water repellency (WR), electrical conductivity (EC), pH, cation exchange capacity (CEC), total carbon (TC), and nitrogen (N)) were investigated through a total of 72 experimental units. Biochar morphological structure and pore size distribution were examined using a scanning electron microscope, whereas specific surface area was assessed by the Brunauer−Emmett−Teller method. The result indicated that the E-horizon soil was highly acidic compared to control (topsoil) and mixed soils. A significant difference was observed between the control and 2% biochar amendment in all three soil mixtures tested in this experiment. Biochar amendments significantly reduced the soil BD (E-horizon: 1.40–1.25 > mixed soil: 1.34–1.21 > topsoil: 1.31–1.18 g cm−3), increased the CEC (mixed soil: 2.83–3.61 > topsoil: 2.61–2.70 > E-horizon: 1.40–1.25 cmol kg−1) and total C (topsoil: 2.40–2.41 > mixed soil: 1.74–1.75 > E-horizon: 0.43–0.44%). Water drop penetration tests showed increased WR with increasing biochar doses from 0 to 2% (topsoil: 2.33–4.00 > mixed soil: 2.33–3.33 > E-horizon: 4.00–4.67 s), and all the biochar–soil combinations were classified as slightly-repellent. We found significant effects of biochar application on soil water retention. Porosity increased by 2.8%, FC by 10%, and PAW by 12.9% when the soil was treated with powdered biochar. Additionally, we examined the temporal effect of biochar (0 to 2% doses) on pH and EC and observed an increase in pH (4.3–5.5) and EC (0.0–0.20 dS/m) every day from day 1–day 7. Collectively the study findings suggest 2% powder biochar application rate is the best combination to improve the physicochemical properties of the tested mixed podzolic soil. Granular and powdered biochar was found to be hydrophobic and hydrophilic, respectively. These findings could be helpful to better understand the use of biochar for improving the physicochemical properties of podzolic soils when used for agricultural practices in boreal ecosystems

Groundwater governance in Bangladesh: Established practices and recent trends

Legal framework is very crucial to protect the vital resources, to provide rights to public and administration, to support national policy and to bring technological intervention to ensure equitable distribution, fair management, and effective decision making. In Bangladesh, groundwater is not directly priced (other than pumping costs), perhaps such issue is not surprising that users do not meter the volumes of water usage. Beside the industry, agricultural sector is by far the biggest groundwater consumer of this country, contributing significant amount of annual meter drop in the groundwater table to the annual decline of groundwater table. Additionally, the groundwater resources are severely affected by, pollution, encroachment and overexploitation. National Water Policy (1999) and Bangladesh Water Act (2013) are considered as country's pivotal legal framework but both of these lag behind to provide effective guidelines on permission, extraction limit, monitoring, protection of quality, water harvesting procedure, and recharge mechanism. Existing institutions suffer from consistent crisis, politics, corruption, absence of public participation and coordination of other institutions, mismanagement, and empirical assessment. This study evaluates the existing water related policies and functions of multidimensional institutions, and discusses the key challenges of effective groundwater management. The present paper also provides an overview of established practices around the world to cope with the common challenges. © 2018 Elsevier B.V

Mapping marginality hotspots and agricultural potentials in Bangladesh

Although Bangladesh made some remarkable achievements in reducing poverty and in improving social and economic outcomes in recent decades, about one-third of the rural population still lives below the upper poverty line most of whom depend on agriculture as their primary source of income. One of the reasons for their poverty is the low productivity that results from sub-optimal use of inputs and other technology. To foster agricultural productivity and rural growth, technology innovations have to reach all strata of the poor among small farming communities in rural Bangladesh. For that purpose, technology opportunities need to be brought together with systematic and location-specific actions related to technology needs, agricultural systems, ecological resources and poverty characteristics to overcome the barriers that economic, social, ecological and cultural conditions can create. The first step towards this is to identify underperforming areas, i.e. rural areas in which the prevalence of poverty and other dimensions of marginality are high and agricultural potential is also high since in such areas yield gaps (potential minus actual yields) are high and productivity gains (of main staple crops) are likely to be achieved. The marginality mapping presented in this paper has attempted to identify areas with high prevalence of societal and spatial marginality-– based on proxies for marginality dimensions representing different spheres of life-–and high (un/der utilized) agricultural (cereal) potentials. The overlap between the marginality hotspots and the high (un/der utilized) agricultural potentials shows that Rajibpur (Kurigram), Dowarabazar (Sunamgonj), Porsha (Naogaon), Damurhuda (Chuadanga), Hizla (Barisal), Mehendigonj (Barisal), Bauphal (Patuakhali) and Bhandaria (Pirojpur) are the marginal areas where most productivity gains could be achieved

Water quality information, WATSAN-agriculture hygiene messages and water testing with school students: Experimental evidence for behavioral changes in Bangladesh

This paper attempts to reveal the effectiveness of the package of water, sanitation and hygiene (WASH) interventions with the school students’ network “student brigades” in terms of their impacts on water and sanitation (or WATSAN) behavior of household members both in household and farm level and on their health and productivity outcomes. We conduct Randomized Control Trial (RCT) with students’ brigades in six WATSAN hotspots (sub-districts) of Bangladesh in several phases: a water quality census, baseline survey, treatment implementation at treatment areas and end line survey. Our treatment consists of three actions: informing the households about the prior water testing results, delivering hygiene messages through a poster and equipping the student brigades with water testing toolkits and letting them test water at different points and communicate the results back to their households. Impression from the implemented treatments indicates that the suggested intervention package can be an effective strategy to motivate households and communities, particularly by using school students as the agents of change

Can a specially designed information intervention around the WASH-agriculture linkages make any difference? Experimental evidence of behavioral changes and health impacts

This paper attempts to evaluate the effectiveness of the specially designed packages of water, sanitation and hygiene (WASH) interventions with ‘student brigades’ (student teams tasked with maintaining hygiene in school) on household WASH behavior and practices in both a household and farm setting. In addition, household members’ health and developmental productivity outcomes were also examined. A randomized control trial (RCT) involving student brigades (SBs) was carried out in six sub-districts (hotspots) characterized by comparatively poor WASH indicators. The specially designed WASH-agriculture treatment consisted of three interventions: (1) informing the households about the prior water testing results; (2) delivering hygiene messages with the help of posters; (3) equipping SB members with water quality test kits and asking them to test the water quality at different places and report their findings to their household. Employing the difference-in-difference (DID) multivariate regression technique, the analysis revealed that the BRAC WASH treatment performed well in terms of effecting behavioral changes and improving hygiene practices. In addition, the results suggested that informing households of their drinking water quality and conveying WASH-agriculture hygiene messages to them could have a significant incremental impact over the existing BRAC WASH treatment in changing household hygiene behavior and practices at home and on farms. This research provides evidence that students can act as agents of change in improving water quality, sanitation and health in a rural setting

Can a Specially Designed Information Intervention Around the Wash-Agriculture Linkages Make Any Difference? Experimental Evidence of Behavioral Changes and Health Impacts

This paper attempts to evaluate the effectiveness of the specially designed packages of water, sanitation and hygiene (WASH) interventions with ‘student brigades’ (student teams tasked with maintaining hygiene in school) on household WASH behavior and practices in both a household and farm setting. In addition, household members’ health and developmental productivity outcomes were also examined. A randomized control trial (RCT) involving student brigades (SBs) was carried out in six sub-districts (hotspots) characterized by comparatively poor WASH indicators. The specially designed WASH-agriculture treatment consisted of three interventions: (1) informing the households about the prior water testing results; (2) delivering hygiene messages with the help of posters; (3) equipping SB members with water quality test kits and asking them to test the water quality at different places and report their findings to their household. Employing the difference-in-difference (DID) multivariate regression technique, the analysis revealed that the BRAC WASH treatment performed well in terms of effecting behavioral changes and improving hygiene practices. In addition, the results suggested that informing households of their drinking water quality and conveying WASH-agriculture hygiene messages to them could have a significant incremental impact over the existing BRAC WASH treatment in changing household hygiene behavior and practices at home and on farms. This research provides evidence that students can act as agents of change in improving water quality, sanitation and health in a rural setting