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Crystèle Léauthaud - One of the best experts on this subject based on the ideXlab platform.
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Agroecology in North African irrigated plains? Mapping promising practices and characterizing farmers’ underlying logics
Regional Environmental Change, 2020Co-Authors: Fatah Ameur, Hichem Amichi, Crystèle LéauthaudAbstract:In the irrigated plains of North Africa, the sustainability of productive resources is subject to multiple threats linked to the prevailing productivist model of irrigated agriculture. These threats, such as soil degradation and unequal access to resources, markets, and information, prompt farmers to mobilize depleting natural resources, including soil and water, in an often environmentally unsustainable way. In order to sustain their Farming systems and consequent incomes, farmers sometimes update their strategies by setting-up Alternative Farming practices. This study aims at mapping and analyzing such existing local Farming practices with agroecological potentials. Our approach is based on direct observations combined with 150 interviews of farmers in three major irrigated plains in North Africa, namely, the Merguellil, Upper Cheliff, and Saiss plains, respectively, in Tunisia, Algeria, and Morocco. This study shows that a wide range of Alternative practices with agroecological potential are emerging (or exist) locally, against the flow of the dominant agricultural model which is rather in favor of intensive practices. The most common practices are developed to improve soil fertility management (production of manure tea, integration of legumes in crop successions), increase per surface agricultural production (relay intercropping, intercropping, agroforestry), or provide multiple ecosystem services (diversification, livestock integration). These practices are jointly used, mostly to (i) increase land-use efficiency, and hence face land fragmentation; (ii) diversify their cropping strategy, and spread out market-related risks; and (iii) reduce expensive production costs related to irrigation and chemical fertilization. The gradient of adoption observed according to national contexts suggests a strong influence of contrasting socio-political and historical factors at the regional to national levels. The analysis of logics in implementing such practices by farmers indicates that economic reasons take precedence over environmental concerns. As such, these practices can be seen as (i) an access to low-cost strategies for small farmers or (ii) a pathway to international markets for agribusiness farmers. Taming the extensive local knowledge related to ecological intensification strategies, as identified in this study, can help to pave the way for a more sustainable agriculture, in this intensively cultivated region of the world.
Fatah Ameur - One of the best experts on this subject based on the ideXlab platform.
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Agroecology in North African irrigated plains? Mapping promising practices and characterizing farmers’ underlying logics
Regional Environmental Change, 2020Co-Authors: Fatah Ameur, Hichem Amichi, Crystèle LéauthaudAbstract:In the irrigated plains of North Africa, the sustainability of productive resources is subject to multiple threats linked to the prevailing productivist model of irrigated agriculture. These threats, such as soil degradation and unequal access to resources, markets, and information, prompt farmers to mobilize depleting natural resources, including soil and water, in an often environmentally unsustainable way. In order to sustain their Farming systems and consequent incomes, farmers sometimes update their strategies by setting-up Alternative Farming practices. This study aims at mapping and analyzing such existing local Farming practices with agroecological potentials. Our approach is based on direct observations combined with 150 interviews of farmers in three major irrigated plains in North Africa, namely, the Merguellil, Upper Cheliff, and Saiss plains, respectively, in Tunisia, Algeria, and Morocco. This study shows that a wide range of Alternative practices with agroecological potential are emerging (or exist) locally, against the flow of the dominant agricultural model which is rather in favor of intensive practices. The most common practices are developed to improve soil fertility management (production of manure tea, integration of legumes in crop successions), increase per surface agricultural production (relay intercropping, intercropping, agroforestry), or provide multiple ecosystem services (diversification, livestock integration). These practices are jointly used, mostly to (i) increase land-use efficiency, and hence face land fragmentation; (ii) diversify their cropping strategy, and spread out market-related risks; and (iii) reduce expensive production costs related to irrigation and chemical fertilization. The gradient of adoption observed according to national contexts suggests a strong influence of contrasting socio-political and historical factors at the regional to national levels. The analysis of logics in implementing such practices by farmers indicates that economic reasons take precedence over environmental concerns. As such, these practices can be seen as (i) an access to low-cost strategies for small farmers or (ii) a pathway to international markets for agribusiness farmers. Taming the extensive local knowledge related to ecological intensification strategies, as identified in this study, can help to pave the way for a more sustainable agriculture, in this intensively cultivated region of the world.
R. P. Zentner - One of the best experts on this subject based on the ideXlab platform.
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improving Farming practices reduces the carbon footprint of spring wheat production
Nature Communications, 2014Co-Authors: Yantai Gan, Colin Campbell, Chang Hai Liang, Reynald Lemke, Qiang Chai, R. P. ZentnerAbstract:Wheat is the world’s second most favoured food source, yet its production has climatic consequences. Here the authors quantify the carbon footprint of wheat production systems and evaluate potential Alternative Farming practices, with a reduced negative impact on climate.
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improving Farming practices reduces the carbon footprint of spring wheat production
Nature Communications, 2014Co-Authors: Yantai Gan, Reynald Lemke, Qiang Chai, Chang Liang, C A Campbell, R. P. ZentnerAbstract:Wheat is one of the world's most favoured food sources, reaching millions of people on a daily basis. However, its production has climatic consequences. Fuel, inorganic fertilizers and pesticides used in wheat production emit greenhouse gases that can contribute negatively to climate change. It is unknown whether adopting Alternative Farming practices will increase crop yield while reducing carbon emissions. Here we quantify the carbon footprint of Alternative wheat production systems suited to semiarid environments. We find that integrating improved Farming practices (that is, fertilizing crops based on soil tests, reducing summerfallow frequencies and rotating cereals with grain legumes) lowers wheat carbon footprint effectively, averaging -256 kg CO2 eq ha(-1) per year. For each kg of wheat grain produced, a net 0.027-0.377 kg CO2 eq is sequestered into the soil. With the suite of improved Farming practices, wheat takes up more CO2 from the atmosphere than is actually emitted during its production.
Hichem Amichi - One of the best experts on this subject based on the ideXlab platform.
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Agroecology in North African irrigated plains? Mapping promising practices and characterizing farmers’ underlying logics
Regional Environmental Change, 2020Co-Authors: Fatah Ameur, Hichem Amichi, Crystèle LéauthaudAbstract:In the irrigated plains of North Africa, the sustainability of productive resources is subject to multiple threats linked to the prevailing productivist model of irrigated agriculture. These threats, such as soil degradation and unequal access to resources, markets, and information, prompt farmers to mobilize depleting natural resources, including soil and water, in an often environmentally unsustainable way. In order to sustain their Farming systems and consequent incomes, farmers sometimes update their strategies by setting-up Alternative Farming practices. This study aims at mapping and analyzing such existing local Farming practices with agroecological potentials. Our approach is based on direct observations combined with 150 interviews of farmers in three major irrigated plains in North Africa, namely, the Merguellil, Upper Cheliff, and Saiss plains, respectively, in Tunisia, Algeria, and Morocco. This study shows that a wide range of Alternative practices with agroecological potential are emerging (or exist) locally, against the flow of the dominant agricultural model which is rather in favor of intensive practices. The most common practices are developed to improve soil fertility management (production of manure tea, integration of legumes in crop successions), increase per surface agricultural production (relay intercropping, intercropping, agroforestry), or provide multiple ecosystem services (diversification, livestock integration). These practices are jointly used, mostly to (i) increase land-use efficiency, and hence face land fragmentation; (ii) diversify their cropping strategy, and spread out market-related risks; and (iii) reduce expensive production costs related to irrigation and chemical fertilization. The gradient of adoption observed according to national contexts suggests a strong influence of contrasting socio-political and historical factors at the regional to national levels. The analysis of logics in implementing such practices by farmers indicates that economic reasons take precedence over environmental concerns. As such, these practices can be seen as (i) an access to low-cost strategies for small farmers or (ii) a pathway to international markets for agribusiness farmers. Taming the extensive local knowledge related to ecological intensification strategies, as identified in this study, can help to pave the way for a more sustainable agriculture, in this intensively cultivated region of the world.
Mizukami Amanda - One of the best experts on this subject based on the ideXlab platform.
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Expansão in vitro de células-tronco mesenquimais cultivadas em biorreator de fibra oca
Programa de Pós-graduação em Biotecnologia, 2011Co-Authors: Mizukami AmandaAbstract:The mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into various types of tissue, a characteristic that makes them interesting for applications in cell therapy. Moreover, cells are anchorage-dependent (ability to adhere to surfaces), easy isolation and rapid expansion in vitro. The traditional cultures of anchorage-dependent animal cells, usually grown in monolayers, resulting in low crop yield and cell recovery, preventing the use of MSCs in therapeutic applications. The need for Alternative Farming techniques for expansion of MSCs in a large scale have led researchers to the use of "bioreactor technology," which has been seconded from the bioreactor, spinner flask with microcarriers and hollow fiber (hollow fiber). The objective of this work was to develop a method of cultivation known as mesenchymal stem cell line hMSC-TERT in spinner flasks with microcarriers for subsequent inoculation into hollow-fiber bioreactor, aiming at the efficient expansion and the subsequent recovery of MSCs so that preserve their differentiation potential in order to be used in cell therapy. In cultured, we used the microcarrier Pronectin ® F 100 mL spinner flasks with culture medium α-MEM with 15% fetal calf serum, kept in a CO2 incubator at 37 ° C and pH between 7.2 and 7.4. In cultures in spinner flasks were adopted strategies such as supplementation of the culture medium, exchanges of culture medium during cultivation, addition of reagents to reduce clusters of microcarriers, to increase productivity for the subsequent cell inoculation in hollow fiber bioreactor. The use of these strategies has increased productivity cell, achieving a best result of cell multiplication factor (MCF) of 5.79. However, obtaining higher FMC was drastically limited by the formation of clusters of microcarriers in a gel matrix.The cell recovery was low maintenance and analysis of the antigenic phenotype by flow cytometry confirmed the conservation of phenotypic characteristics of hMSC-TERT. The hollow fiber bioreactor is an Alternative to the clusters of microcarriers, it allows oxygenation and adequate supply of nutrients. Thus, in experiments carried out in hollow-fiber bioreactor used the α-MEM supplemented with 15% FBS (v / v), 2.0 g / L glucose, 2.50 mM glutamine, 2.60 mM arginine, 0.07% antifoam PPG. The cells were inoculated after 48 hours of cultivation in spinner flasks in a gel composed of collagen, hyaluronic acid, agar (1.5%) in the proportion 0.75: 0.037: 0.21 at pH 7.2 to 7.4 . Thus, the resulting gel was mixed with culture medium in α-MEM 1:3 ratio, to provide better grip on the fibers. The total expansion factor, ie the one calculated from the inoculation of the spinner to the end of cultivation in hollow fiber bioreactor was 11, 2, which can be considered the greatest value achieved in this work. It is clear that this expansion factor can still be easily overcome by adopting strategies to grow more frequent replacement of culture medium. This hypothesis is strengthened by the proven fact that the microcarriers are not yet saturated with cells at the end of the experiment.Universidade Federal de Sao CarlosAs células-tronco mesenquimais (CTMs) são células-tronco multipotentes que podem se diferenciar em diversos tipos de tecido, característica que as torna interessantes em aplicações de terapia celular. Além disso, são células dependentes de ancoramento (capacidade de aderir em superfícies), de fácil isolamento e de rápida expansão in vitro. As culturas tradicionais de células animais dependentes de ancoramento, geralmente cultivadas em monocamadas, resultam em baixo rendimento de cultivo e de recuperação celular, inviabilizando o uso das CTMs em aplicações terapêuticas. A necessidade de técnicas de cultivo alternativas para expansão de CTMs em larga escala têm levado pesquisadores à utilização de tecnologia de biorreatores , na qual tem-se destacado dos biorreatores: frasco spinner com microcarregadores e hollow fiber (fibra oca). Assim, o objetivo deste trabalho foi o de desenvolver uma metodologia de cultivo da linhagem de CTM conhecida como hMSC-TERT em frasco spinner com microcarregadores para posterior inoculação em biorreator de fibraoca, visando a expansão eficiente e a posterior recuperação das CTMs de tal forma que, preservassem seu potencial de diferenciação para poderem ser utilizadas na terapia celular. Nos cultivos, utilizou-se o microcarregador Pronectin®F em frasco spinner de 100 mL com o meio de cultura α-MEM com 15% de soro fetal bovino, mantidos em incubadora de CO2 a 37ºC e pH entre 7,2 e 7,4. Nos cultivos em frasco spinner adotaram-se estratégias como suplementação do meio de cultura, trocas de meio de cultura durante o cultivo, adição de reagentes para diminuição de aglomerados de microcarregadores, visando aumentar a produtividade celular para a posterior inoculação em biorreator de fibra oca. A utilização dessas estratégias permitiram aumentar a produtividade celular, obtendo-se como melhor resultado um fator de multiplicação celular (FMC) de 5,79. Contudo, a obtenção de FMC maiores foi drasticamente limitada pela formação de aglomerados de microcarregadores num gel de matriz extracelular. A recuperação celular foi baixa e a análise da manutenção do fenótipo antigênico por citometria de fluxo comprovaram a conservação das características fenotípicas da hMSC-TERT. O biorreator de fibras ocas é uma alternativa em relação aos aglomerados de microcarregadores, pois permite a oxigenação e suprimento adequado de nutrientes. Sendo assim, nos experimentos realizados no biorreator de fibras-ocas utilizou-se o α-MEM suplementado com 15% SFB (v/v), 2,0 g/L de glicose, 2,50 mM de glutamina, 2,60 mM de arginina, 0,07 % do antiespumante PPG. As células foram inoculadas após 48 horas de cultivo em frasco spinner em um gel composto por colágeno: ácido hialurônico: ágar (1,5%) na proporção 0,75: 0,037: 0,21 em pH = 7,2-7,4. Assim, o gel resultante foi misturado com meio de cultura α-MEM na proporção 1:3, para proporcionar melhor aderência nas fibras. O fator de expansão total, ou seja, aquele calculado desde a inoculação do spinner até o final do cultivo no biorreator de fibra oca, foi de 11, 2, que pode ser considerado o maior valor atingido neste trabalho. Convém esclarecer que este fator de expansão ainda pode ser facilmente superado ao se adotarem estratégias de cultivo com trocas mais frequentes de meio de cultura. Esta hipótese é reforçada pelo fato comprovado de os microcarregadores ainda não estarem saturados de células no final do experimento