Abstract: Irrigated rice production is one of the most essential agricultural activities for sustaining our global population, and at the same time, one of the agricultural sectors considered most eco-unfriendly. This is because it consumes a larger share of available freshwater resources, competing with varied ecosystems as well as other economic sectors; its paddy fields are responsible for significant emission of greenhouse gases; and the reliance on chemical fertilizers and various agrochemicals contributes to pollution of soils and water systems. These stresses on soils, hydrology and atmosphere are actually not necessary for rice production, which can be increased by modifying agronomic practices though more agroecologically-sound management practices. These, combined under the rubric of the System of Rice Intensification (SRI), can reduce requirements of irrigation water, chemical fertilizer and agrochemicals while increasing paddy yields and farmer’s net incomes. Here we discuss how irrigated rice production can be made more eco-friendly for the benefit of farmers, consumers and the environment. This is achieved by introducing practices that improve the growth and functioning of rice plants’ root systems and enhance the abundance, diversity and activity of beneficial soil organisms that live around plant roots and within the plants themselves as symbiotic endophytes.
Abstract: Understanding and managing water quality in drinking water distribution system is essential for public health and wellbeing, but is challenging due to the number and complexity of interacting physical, chemical and biological processes occurring within vast, deteriorating pipe networks. In this paper we explore the application of Self Organising Map techniques to derive such understanding from international data sets, demonstrating how multivariate, non-linear techniques can be used to identify relationships that are not discernible using univariate and/or linear analysis methods for drinking water quality. The paper reports on how various microbial parameters correlated with modelled water ages and were influenced by water temperatures in three drinking water distribution systems.
Abstract: This paper summarizes the deliberations at a meeting convened by the Bill & Melinda Gates Foundation held in Beijing in October 2015. Farm power and mechanization are agricultural production inputs that will be essential to raise the labor and land productivity required if Sustainable Development Goals 1 and 2 (ending poverty and hunger) are to be achieved. The smallholder farm sector demand for mechanization needs to be raised to stimulate the product value chain and activate input supply (that is to raise farm productivity, stimulate value addition, and encourage private sector custom hire service provision). The sustainability of mechanization from a natural resource conservation point of view is discussed with reference to conservation agriculture principles. Mechanization appropriate for the smallholder sector covers the range of possible power sources human, draft animal and motorized. The key is to engage all the stakeholders in the supply chain and offer a range of suitable options from which the user can select. Sustainability of mechanization includes financial and social, as well as environmental factors. Local manufacturers should be supported where feasible as they can provide implements and machines adapted to local conditions—and better technical service and replacement part supply. The public sector role in providing access to mechanization should be restricted to promulgating enabling policies, building technical and business management skills and stimulating demand. The lessons to be learnt from Chinese experience in making mechanization available to smallholder farmers include subsidies, strong extension services, infrastructure development and a solid manufacturing sector that prioritizes the smallholder sector. The implications for sub-Saharan Africa appear to be that group ownership and custom hire service provision are the models to follow. Finally, the relevance of an African Center for Sustainable Agricultural Mechanization, on the model of CSAM in Beijing, is considered and recommended.
Abstract: Groundwater Dependent Ecosystems (GDEs) are increasingly threatened by humans’ rising demand for water resources. Consequently, it is imperative to identify the location of GDEs to protect them. This paper develops a methodology to identify the probability of an ecosystem to be groundwater dependent. Probabilities are obtained by modeling the relationship between the known locations of GDEs and factors influencing groundwater dependence, namely water table depth and climatic aridity index. Probabilities are derived for the state of Nevada, USA, using modeled water table depth and aridity index values obtained from the Global Aridity database. The model selected results from the performance comparison of classification trees (CT) and random forests (RF). Based on a threshold-independent accuracy measure, RF has a better ability to generate probability estimates. Considering a threshold that minimizes the misclassification rate for each model, RF also proves to be more accurate. Regarding training accuracy, performance measures such as accuracy, sensitivity, and specificity are higher for RF. For the test set, higher values of accuracy and kappa for CT highlight the fact that these measures are greatly affected by low prevalence. As shown for RF, the choice of the cutoff probability value has important consequences on model accuracy and the overall proportion of locations where GDEs are found.
Abstract: This study undertook a critical examination of the relationship between perception of environmental harm and consumer willingness to pay for environmental handling fees (EHF). This analysis was supplemented by asking study participants to indicate under what circumstances (and for what materials) they believe a visible fee is appropriate. This study found that there is a statistically significant correlation between willingness to pay environmental handling fees and the perceived environmental harm of the product on which the fee is applied. For items that respondents viewed as “innocuous to the environment” (i.e., “keyboards and mice”), they were relatively unwilling to pay an environmental handling fee. Conversely, for the full range of hazardous waste materials, consumers expressed a willingness to pay EHFs. With respect to fee visibility, respondents indicated that they preferred visible fees (at the sticker) for products that they perceived to be dangerous. There is a strong correlation between perceived environmental harm and whether fees should be visible. Consumers are not necessarily averse to paying an eco fee on products (be they hazardous waste, electronic waste, etc.), but their willingness to do so is almost entirely a function of whether they believe the product is environmentally burdensome. It is the recommendation of this study that promotion and education campaigns for environmental handling fees, particularly those surrounding waste electronics, place greater emphasis on environmental consequences of improper disposal.
Abstract: We determined whole-fish Hg concentrations of 26 female and 34 male adult lake whitefish (Coregonus clupeaformis) from northern Lake Huron captured during November 2010. Subsampling from these 60 fish, Hg concentration was also determined in both somatic tissue and ovaries (n = 5), while methylmercury (MeHg) concentration was determined in whole fish (n = 18). Bioenergetics modeling was used to assess the growth dilution effect on the difference in Hg concentrations between the sexes. Mean whole-fish Hg concentration in females (59.9 ng/g) was not significantly different from mean whole-fish Hg concentration in males (54.4 ng/g). MeHg accounted for 91% of the mercury found in the lake whitefish. Bioenergetics modeling results indicated that the growth dilution effect did not contribute to the difference in Hg concentrations between the sexes. We estimated that females increased in Hg concentration by 17.9%, on average, immediately after spawning due to release of eggs. Using polychlorinated biphenyl (PCB) data for the same 60 lake whitefish from a previous study, we detected a significant interaction between sex and contaminant type (Hg or PCBs), which was attributable to males being significantly higher in PCB concentration than females. Males may be eliminating Hg at a faster rate than females.