Suchergebnisse

Classical land rent theories imply that the best land is cultivated first. This principle forms the basis of many land-use studies, but empirical evidence remains limited, especially on a global scale. In this paper, we estimate the effects of agricultural suitability and market accessibility on the spatial allocation of cultivated areas at a 30 arc-min resolution in 15 world regions. Our results show that both determinants often have a significant positive effect on the cropland fraction, but with large variations in strength across regions. Based on a quantile analysis, we find that agricultural suitability is the dominant driver of cropland allocation in North America, Middle East and North Africa and Eastern Europe, whereas market accessibility shows a stronger effect in other regions, such as Western Africa. In some regions, such as South and Central America, both determinants have a limited effect on cropland fraction. Comparison of high versus low quantile regression coefficients shows that, in most regions, densely cropped areas are more sensitive to agricultural suitability and market accessibility than sparsely cropped areas.

Different international plant protection organisations advocate different schemes for conducting pest risk assessments. Most of these schemes use structured questionnaire in which experts are asked to score several items using an ordinal scale. The scores are then combined using a range of procedures, such as simple arithmetic mean, weighted averages, multiplication of scores, and cumulative sums. The most useful schemes will correctly identify harmful pests and identify ones that are not. As the quality of a pest risk assessment can depend on the characteristics of the scoring system used by the risk assessors (i.e., on the number of points of the scale and on the method used for combining the component scores), it is important to assess and compare the performance of different scoring systems. In this article, we proposed a new method for assessing scoring systems. Its principle is to simulate virtual data using a stochastic model and, then, to estimate sensitivity and specificity values from these data for different scoring systems. The interest of our approach was illustrated in a case study where several scoring systems were compared. Data for this analysis were generated using a probabilistic model describing the pest introduction process. The generated data were then used to simulate the outcome of scoring systems and to assess the accuracy of the decisions about positive and negative introduction. The results showed that ordinal scales with at most 5 or 6 points were sufficient and that the multiplication‐based scoring systems performed better than their sum‐based counterparts. The proposed method could be used in the future to assess a great diversity of scoring systems.

International audience ; Aujourd'hui, d'importantes mutations de l'agriculture mondiale sont nécessaires pour produire suffisamment d'aliments sains pour tous, tout en préservant la qualité des terres, de l'air et de l'eau et en sauvegardant la biodiversité. Mais produire suffisamment et préserver en même temps l'environnement est une équation particulièrement complexe à résoudre. Les pratiques agroécologiques, dont un principe essentiel est l'usage de la biodiversité cultivée, constituent une voie prometteuse pour assurer ces mutations. De nombreuses preuves qualitatives et quantitatives montrent leur efficacité sur les plans agricole et environnemental et confirment leur capacité à répondre aux impératifs de production mondiale sur le long terme. Parmi les voies possibles de diversification, l'agroforesterie, les cultures associées et la rotation des cultures permettent d'augmenter significativement la production et favorisent la biodiversité et les services écosystémiques fournis — qualité du sol, contrôle des maladies et ravageurs, qualité et usage de l'eau. Ces preuves permettent de fonder de nouvelles politiques publiques à mettre en œuvre des échelles locales à l'échelle mondiale. La réalisation de telles politiques est cruciale dans les régions vulnérables au changement climatique et dont les besoins alimentaires sont en augmentation, comme l'Afrique subsaharienne.

International audience ; Aujourd'hui, d'importantes mutations de l'agriculture mondiale sont nécessaires pour produire suffisamment d'aliments sains pour tous, tout en préservant la qualité des terres, de l'air et de l'eau et en sauvegardant la biodiversité. Mais produire suffisamment et préserver en même temps l'environnement est une équation particulièrement complexe à résoudre. Les pratiques agroécologiques, dont un principe essentiel est l'usage de la biodiversité cultivée, constituent une voie prometteuse pour assurer ces mutations. De nombreuses preuves qualitatives et quantitatives montrent leur efficacité sur les plans agricole et environnemental et confirment leur capacité à répondre aux impératifs de production mondiale sur le long terme. Parmi les voies possibles de diversification, l'agroforesterie, les cultures associées et la rotation des cultures permettent d'augmenter significativement la production et favorisent la biodiversité et les services écosystémiques fournis — qualité du sol, contrôle des maladies et ravageurs, qualité et usage de l'eau. Ces preuves permettent de fonder de nouvelles politiques publiques à mettre en œuvre des échelles locales à l'échelle mondiale. La réalisation de telles politiques est cruciale dans les régions vulnérables au changement climatique et dont les besoins alimentaires sont en augmentation, comme l'Afrique subsaharienne.

International audience ; Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

Aujourd'hui, d'importantes mutations de l'agriculture mondiale sont nécessaires pour produire suffisamment d'aliments sains pour tous, tout en préservant la qualité des terres, de l'air et de l'eau et en sauvegardant la biodiversité. Mais produire suffisamment et préserver en même temps l'environnement est une équation particulièrement complexe à résoudre. Les pratiques agroécologiques, dont un principe essentiel est l'usage de la biodiversité cultivée, constituent une voie prometteuse pour assurer ces mutations. De nombreuses preuves qualitatives et quantitatives montrent leur efficacité sur les plans agricole et environnemental et confirment leur capacité à répondre aux impératifs de production mondiale sur le long terme. Parmi les voies possibles de diversification, l'agroforesterie, les cultures associées et la rotation des cultures permettent d'augmenter significativement la production et favorisent la biodiversité et les services écosystémiques fournis — qualité du sol, contrôle des maladies et ravageurs, qualité et usage de l'eau. Ces preuves permettent de fonder de nouvelles politiques publiques à mettre en oeuvre des échelles locales à l'échelle mondiale. La réalisation de telles politiques est cruciale dans les régions vulnérables au changement climatique et dont les besoins alimentaires sont en augmentation, comme l'Afrique subsaharienne.

International audience ; Aujourd'hui, d'importantes mutations de l'agriculture mondiale sont nécessaires pour produire suffisamment d'aliments sains pour tous, tout en préservant la qualité des terres, de l'air et de l'eau et en sauvegardant la biodiversité. Mais produire suffisamment et préserver en même temps l'environnement est une équation particulièrement complexe à résoudre. Les pratiques agroécologiques, dont un principe essentiel est l'usage de la biodiversité cultivée, constituent une voie prometteuse pour assurer ces mutations. De nombreuses preuves qualitatives et quantitatives montrent leur efficacité sur les plans agricole et environnemental et confirment leur capacité à répondre aux impératifs de production mondiale sur le long terme. Parmi les voies possibles de diversification, l'agroforesterie, les cultures associées et la rotation des cultures permettent d'augmenter significativement la production et favorisent la biodiversité et les services écosystémiques fournis — qualité du sol, contrôle des maladies et ravageurs, qualité et usage de l'eau. Ces preuves permettent de fonder de nouvelles politiques publiques à mettre en œuvre des échelles locales à l'échelle mondiale. La réalisation de telles politiques est cruciale dans les régions vulnérables au changement climatique et dont les besoins alimentaires sont en augmentation, comme l'Afrique subsaharienne.

International audience ; Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

International audience ; Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

International audience ; Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

International audience ; Aujourd'hui, d'importantes mutations de l'agriculture mondiale sont nécessaires pour produire suffisamment d'aliments sains pour tous, tout en préservant la qualité des terres, de l'air et de l'eau et en sauvegardant la biodiversité. Mais produire suffisamment et préserver en même temps l'environnement est une équation particulièrement complexe à résoudre. Les pratiques agroécologiques, dont un principe essentiel est l'usage de la biodiversité cultivée, constituent une voie prometteuse pour assurer ces mutations. De nombreuses preuves qualitatives et quantitatives montrent leur efficacité sur les plans agricole et environnemental et confirment leur capacité à répondre aux impératifs de production mondiale sur le long terme. Parmi les voies possibles de diversification, l'agroforesterie, les cultures associées et la rotation des cultures permettent d'augmenter significativement la production et favorisent la biodiversité et les services écosystémiques fournis — qualité du sol, contrôle des maladies et ravageurs, qualité et usage de l'eau. Ces preuves permettent de fonder de nouvelles politiques publiques à mettre en œuvre des échelles locales à l'échelle mondiale. La réalisation de telles politiques est cruciale dans les régions vulnérables au changement climatique et dont les besoins alimentaires sont en augmentation, comme l'Afrique subsaharienne.

International audience ; Today, major changes are required in global agricultural systems to produce enough healthy food for all, while preserving the quality of land, air and water and safeguarding biodiversity. But producing enough while simultaneously protecting the environment is a particularly complex equation. Agroecology, a key principle of which is the use of agricultural biodiversity, is a promising pathway to achieve these changes. Extensive qualitative and quantitative evidence demonstrates the agricultural and environmental effectiveness of agroecological practices and confirms their capacity to meet the demands of global production in the long term. Among the possible diversification strategies, agroforestry, intercropping and crop rotation can all significantly increase production and enhance biodiversity and ecosystem services (soil quality, pest and disease control, water use and quality). This evidence can serve as a basis for new public policies to be introduced from the local to the global level. The implementation of such policies is crucial in climate-vulnerable regions where demand for food is growing, such sub-Saharan Africa.

Agricultural price shocks strongly affect farmers' income and food security. It is therefore important to understand and anticipate their origins and occurrence, particularly for the world's main agricultural commodities. In this study, we assess the impacts of yearly variations in regional maize productions and yields on global maize prices using several statistical and machine-learning (ML) methods. Our results show that, of all regions considered, Northern America is by far the most influential. More specifically, our models reveal that a yearly yield gain of +8% in Northern America negatively impacts the global maize price by about –7%, while a decrease of –0.1% is expected to increase global maize price by more than +7%. Our classification models show that a small decrease in the maize yield in Northern America can inflate the probability of maize price increase on the global scale. The maize productions in the other regions have a much lower influence on the global price. Among the tested methods, random forest and gradient boosting perform better than linear models. Our results highlight the interest of ML in analyzing global prices of major commodities and reveal the strong sensitivity of maize prices to small variations of maize production in Northern America.