1,721,406 research outputs found
Sustainable Agriculture Reviews
No full textInternational audienceSustainable agriculture is a rapidly growing field aiming at producing food and energy in a sustainable way for humans and their children. Sustainable agriculture is a discipline that addresses current issues such as climate change, increasing food and fuel prices, poor-nation starvation, rich-nation obesity, water pollution, soil erosion, fertility loss, pest control, and biodiversity depletion. Novel, environmentally-friendly solutions are proposed based on integrated knowledge from sciences as diverse as agronomy, soil science, molecular biology, chemistry, toxicology, ecology, economy, and social sciences. Indeed, sustainable agriculture decipher mechanisms of processes that occur from the molecular level to the farming system to the global level at time scales ranging from seconds to centuries. For that, scientists use the system approach that involves studying components and interactions of a whole system to address scientific, economic and social issues. In that respect, sustainable agriculture is not a classical, narrow science. Instead of solving problems using the classical painkiller approach that treats only negative impacts, sustainable agriculture treats problem sources. Because most actual society issues are now intertwined, global, and fast-developing, sustainable agriculture will bring solutions to build a safer world. This book series gathers review articles that analyze current agricultural issues and knowledge, then propose alternative solutions. It will therefore help all scientists, decision-makers, professors, farmers and politicians who wish to build a safe agriculture, energy and food system for future generations
Nanoscience in Food and Agriculture 5: Sustainable Agriculture Reviews 26
Full text linkInternational audienceChapters: 1. Research Trends and Patents in Nano-food and Agriculture. 2. Politics of Nanotechnologies in Food and Agriculture. 3. Nanosensors for Food and Agriculture. 4. Nanoemulsions for Nutrient Delivery in Food. 5. Nanocarriers for Resveratrol Delivery. 6. Potential of Milk Proteins as Nanoencapsulation Materials in Food Industry. 7. Uptake and Toxicity of Nanomaterials in Plants. 8. Nanomaterial Impact, Toxicity and Regulation in Agriculture, Food and Environment. 9. Nanomaterial Toxicity in Microbes, Plants and Animals. 10. Nanofertilizers for Sustainable Soil Management. 11. Impact of Nanomaterials on the Aquatic Food Chain. 12. Nanoremediation for Sustainable Crop Productio
Phosphorus, Plant Biodiversity and Climate Change
No full textPhosphorus (P) is a major plant nutrient. Its increasing use as a fertilizer has helped to raise crop and fodder production. However, the global reserves and resources of P are finite, demanding an efficient use of P. Under natural conditions, it is often in limited supply. Plants have developed adaptations to small soil P concentrations. Increased P levels can have unwanted side effects like eutrophication and algal blooms. Besides, P concentrations in the soil have often been found to be negatively correlated with plant diversity. For sustainable agriculture, it is essential to understand 1) adaptations of plants to small P concentrations in soils to maintain production with decreasing P reserves, 2) influences of P on phytodiversity to minimize unwanted effects, and 3) future developments of P and phytodiversity in relation to climate change to adjust agricultural practices. P is essential for the energy and sugar metabolism of plants. As it moves in soils by diffusion only, the geometry of the root system is essential for its uptake. Plants have developed different adaptations for P uptake: e.g., localized or overall increases in the number of roots, the development of cluster roots that increase the root surface area by up to 140 times, exudation of different phosphatases and organic acids in reaction to specific forms of P, or symbiosis with mycorrhiza that may be responsible for up to 75% of the P acquired by plants. Gradual differences in these adaptations decrease interspecific competition and facilitate coexistence. Low P concen trations increase plant diversity by favoring stress-tolerant rather than ruderal species or by restricting the growth of competitive grasses more than that of forbs. According to the niche dimension hypothesis, more limiting resources lead to more coexisting species. Worldwide, P limitation is as relevant for plant production as nitrogen (N) limitation. Thus, P could regulate the size of ecological niches by being the main growth-limiting factor or by being coupled to other limiting resources. Global climate change influences soil P availability. Increasing temperatures tend to increase P mineralization of litter. Furthermore, temperature increases by 5 _ºC have been found to double the colonization of roots by mycorrhiza. Nitrogen mineralization was enhanced by on average 48% by temperature increases of between 0.3 and 6.0 _C. Larger amounts of N stimulate phosphatase exudation and plant P uptake. This could result in increased soil P availability, which is further enhanced by increased P mobilization due to human activities. Such a development would reduce phytodiversity and promote the growth of ruderal, fast-growing species. In the long run, this could cause mining of soil P, which would then again increase plant diversity. However, diversity needs a long time to recover from P additions. Therefore, in sustainable agriculture, increases in soil P relative to other factors limiting plant growth have to be prevented to guarantee large phytodiversity
Cocoa in monoculture and dynamic agroforestry
No full textThe growing demand for cocoa beans and products worldwide has been met by expanding the area under cocoa production while productivity per hectare has stagnated at a low level of around 450 kg/ha per year in the last decade. Throughout the tropics cocoa has increasingly been cultivated in full-sun monocultures in order to maximize short-term productivity and profitability, which has been associated with soil erosion and degradation, biodiversity loss, as well as increased susceptibility to climate change impacts and pests and diseases. Dynamic agroforestry systems are an alternative production method which has long been practiced in Latin American countries such as Bolivia. Through mimicking natural forests, these systems offer multiple benefits such as soil fertility enhancement, reduction in pest and disease pressure, erosion control, and revenue diversification. In Côte d’Ivoire, where most cocoa is still produced in monocultures, dynamic agroforestry systems were recently introduced on a small scale.
Here we use different research projects conducted in Bolivia and Côte d’Ivoire as case studies to review productivity, soil fertility as well as pests and diseases in dynamic agroforestry systems and monocultures, and outline factors influencing the adoption of dynamic agroforestry systems from the farmers’ perspective. We found productivity under agroforestry systems to be either similar or higher compared to monocultures. We recorded 161 % higher total system yields in an on-station field trial and an on-farm study in Bolivia, and in an on-farm study in Côte d’Ivoire. Cocoa yields were 12–46 % higher in agroforestry systems compared to monocultures. In addition, cocoa in dynamic agroforestry systems exhibited significantly less incidences of witches’ broom, Moniliophthora perniciosa, compared to monocultures in Bolivia.
Farmers in Bolivia and Côte d’Ivoire observed more soil-related problems and incidences of pests and diseases in monocultures than in agroforestry systems, and they showed high interest to learn dynamic agroforestry management practices. However, adoption was strongly limited to project areas where dynamic agroforestry plots had been installed with farmers’ participation. This highlights the importance of local organizations such as Ecotop, Ecosaf, El Ceibo and Biopartenaire Ltd., who implement such interventions on the ground. However, we found that there is space for improvement in the way organizations interact with farmers, especially in Côte d’Ivoire. Interactive knowledge sharing methods such as farmer field schools may help to stimulate farmers’ protagonism and give scientists and external consultants the role of facilitators who integrate different forms of knowledge and make them visible to different stakeholders. Such a social learning process requires transdisciplinary research for the development of decision support tools which facilitate the determination of both optimal planting densities and shade levels, as well as adequate combinations of trees and accompanying species in order to achieve effective regulation of pests and diseases while ensuring favourable growing conditions
The vine functioning pathway, a new conceptual representation
No full textInternational audienceClimate change, new regulations for preservation of the environment and demands of the markets for speci fi c products, make it increasingly necessary to optimize the choice of cropping practices. The winegrowers take into account the combined in fl uences of environmental factors, plant material and practices, to improve grapes and wine. However, this combined in fl uence has been little studied. A general formalization of these multiple in fl uences at the scale of viticultural terroirs is necessary to better characterize the growth of the vine and its impact on the yearly characteristics of grape and wine. In this article, following a global system approach we review current knowledge about the relationships between environmental factors, plant material, agricultural practices, the growth of the vine and the characteristics of grapes and wine. We propose a conceptual model formalizing the relationships between the systemic variables. The system can be represented as the new concept of ‘the vine functioning pathway’, which we de fi ne as the logical and ordered combination of the effects of environmental factors, plant material and agricultural practices on the levels of vigor and earliness of the vine and the fi nal characteristics of the product. The resulting product of the system model is the grape and then the wine. This conceptual model is less accurate than a functional mathematical model but is the fi rst which takes into account the whole complexity of the vine system. The conceptual model built and implemented by a computer can be used as a support tool for decisions aiding in the optimization of cropping practices based on environmental factors and speci fi c products goals
The environmental impacts of non-food biomass production through land-use changes: Scope, foci and methodology of current research
No full textInternational audienc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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