Dataset on early growth of cover crops in growth chamber

The data presented in this data paper describe the early growth of cover crop cultivated in growth chamber under non-limiting conditions. Seventeen species of four botanical groups were described after one month of growth. Traits related to plant growth and leaf area development were measured (five traits) and calculated (eight traits). This data set is made available to enable comparisons between dataset, extended analysis and meta-analysis on cover crop traits. The data presented in this article were used on the research article entitled “Leaf area development strategies of cover plants used in banana plantations identified from a set of plant traits'

Management of banana nitrogen fertilization : taking into account nitrogen from organic origin

Les règles de fertilisation azotée en bananeraie prennent rarement en compte l'azote fourni par la minéralisation de la matière organique du sol ou des résidus de culture. Les résultats d'une expérimentation comparant différentes doses d'azote montrent qu'à partir d'un niveau de fertilisation azotée inférieure aux recommandations établies sur la base des prélèvements par la culture il n'y a plus d'augmentation du rendement. Ceci suggère que l'azote des engrais n'est pas la seule source d'azote pour le bananier et l'existence d'une offre d'azote non prise en compte dans la fertilisation conventionnelle. La matière organique du sol fourni des quantités d'azote minéral très variables en fonction du type de sol. Dans les andosols d'altitude des Antilles, les quantités d'azote issues de la minéralisation de la matière organique du sol couvrent une partie importante des besoins du bananier. L'utilisation d'un modèle simulant la dynamique des restitutions organiques et de l'absorption d'azote par le bananier (SIMBA) permet de définir des stratégies de fertilisation garantissant la satisfaction des besoins du bananier tout en limitant les pertes d'azote par lessivage. (Résumé d'auteur

Stochastic Formal Methods for Hybrid Systems

We provide a framework to bound the probability that accumulated errors were never above a given threshold on hybrid systems. Such systems are used for example to model an aircraft or a nuclear power plant on one side and its software on the other side. This report contains simple formulas based on L\'evy's and Markov's inequalities and it presents a formal theory of random variables with a special focus on producing concrete results. We selected four very common applications that fit in our framework and cover the common practices of hybrid systems that evolve for a long time. We compute the number of bits that remain continuously significant in the first two applications with a probability of failure around one against a billion, where worst case analysis considers that no significant bit remains. We are using PVS as such formal tools force explicit statement of all hypotheses and prevent incorrect uses of theorems

Relationships between land use, fertility and andisol behaviour : examples from volcanic islands

Soils developed on voIcanic parent materials have many intrinsic qualities favourable to cropping. Howerer, fertility decreases dramatically when they are badly managed. A short review and case studies from Reunion and Guadeloupe highight the special characteristics of these soils, and their response to management. The interplay of cropping systems and physical characteristics of Andisols is first considered through the example of #Pelargonium# and food crop systems in Reunion. Progressive decrease in production and cropping potential shows in falling yields as well as in the overall decline of the system. The example of banana production in Guadeloupe highights the increase in inputs needed to realise the land's potential and to maintain yields, in particular more tillage and pest treatment. In both cases, these trends are connected to the co-evolution of soil characteristics and cropping systems. They lead to an increase of risks with less security and less scope in the choice of cropping systems. Technical solutions in the form of erosion-control measures, rotation and planting techniques have been developed and prove to be relevant and consistent in their benefit. (Résumé d'auteur

Physico-chemical and physical properties of halloysite rich soils in Guadeloupe

In Guadeloupe, under moderate humid climatic conditions (1800 - 3000mm.), hydrolysis of young andesitic parent rock lead to the pedogenesis of 1:1 lattice clay (halloysite) rich soils (Rusty brown soils). But in the old, highly weathered north-eastern part of the island, covered by ferrallitic soils, halloysite equally appears to be the major mineral soil constituent. For the latter soils, in addition to the dominant 1:1 lattice clay, the presence of accessory 2:1 clay minerals has been noted. In these highly impoverished soils, the presence of such 2:1 minerals causes an important variability of physico-chemical properties, in particular the cation exchange properties and the occurence of exchangeable aluminium. Soil water properties of halloysite rich soils show remarkable differences with regard to water retention, total porosity and shrinkage. In addition to their minera1ogica1 nature, the morphology and size of the halloysite particles, as well as their spatial arrangement seem to play a leading part with regard to the soil's physical behaviour