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759 results on '"Frossard, E."'

4. Allometric Models for Estimating Above-Ground, Below-Ground and Total Biomass of Tea (Camellia sinensis (L.) O. Kuntze) Plants Grown in Uva and Up Country, Sri Lanka.

Author

Rathnayaka, R. A. A. S., Jananey, B., Maduranga, H. P. N., Sivananthawerl, T., Amarasena, P. G. D. S., Frossard, E., Mohotti, A. J., Mohotti, K. M., and Suriyagoda, L. D. B.

Subjects
BIOMASS estimation, NONLINEAR regression, TEA growing, TEA, NONLINEAR analysis
Abstract

This study was conducted to identify the dendrometric variables highly correlating with above-ground (AGB), below-ground (BGB) and total (TB) biomass of tea grown in Uva and Up Country Sri Lanka, develop allometric models to estimate AGB, BGB and TB of tea plants, and to investigate the applicability of already developed allometric models in other countries to Sri Lanka. Twelve experimental plots from TRIORCON field experiment at Tea Research Institute of Sri Lanka, and 18 farmer fields in Uva region, Sri Lanka were selected as the study sites. Representative tea plants were uprooted from the selected sites and seven dendrometric variables were measured. Fresh and dry AGB and BGB of the tea plants were determined. The best allometric models to predict AGB, BGB and TB using dendrometric variables were developed using multiple linear and non-linear regression analyses. Non-linear allometric models fitted best when predicting AGB and TB. Over 64% of total variability of AGB and TB was explained by these models using collar diameter at the soil level. Linear allometric fitted best when predicting BGB. Over 92% of total variability of BGB was explained by linear regression models using collar circumference, mainstem circumference, mean length and circumference at end of the primary branches. Leave-one-out cross validation showed strong positive (AGB and TB) and moderate positive (BGB) correlations between observed and predicted biomass values. Developed linear allometric models in comparison to those in literature showed better fit to data collected under Sri Lankan conditions and precisely estimated AGB, BGB and TB. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Utilization of research knowledge in sustainable development pathways: Insights from a transdisciplinary research-for-development programme

Author

Jacobi, J., Llanque, A., Bieri, S., Birachi, E., Cochard, R., Chauvin, N. Depetris, Diebold, C., Eschen, R., Frossard, E., Guillaume, T., Jaquet, S., Kämpfen, F., Kenis, M., Kiba, D.I., Komarudin, H., Madrazo, J., Manoli, G., Mukhovi, S.M., Nguyen, V.T.H., Pomalègni, C., Rüegger, S., Schneider, F., TriDung, N., von Groote, P., Winkler, M.S., Zaehringer, J.G., and Robledo-Abad, C

Published
2020
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10. L'approche energetique en mecanique des materiaux granulaires

Author

Frossard, E.

Subjects
Physics - Fluid Dynamics
Abstract

This communication establishes first, that basis of discontinuous granular materials mechanics, are the explicit result of a new approach of the physics of energy dissipation by friction, and second, that these mechanics of discontinua, transposed to the equivalent continuous media, as used in geomechanics, is directly responsible for a large set of practical properties of these materials, part of the fundamentals of Soil Mechanics. These physics of energy dissipation are developped on the original concept of energy rate tensor of internal actions., Comment: 57 pages

Published
2012

13. Soil phosphorus supply controls P nutrition strategies of beech forest ecosystems in Central Europe

Author

Lang, F., Krüger, J., Amelung, W., Willbold, S., Frossard, E., Bünemann, E. K., Bauhus, J., Nitschke, R., Kandeler, E., Marhan, S., Schulz, S., Bergkemper, F., Schloter, M., Luster, J., Guggisberg, F., Kaiser, K., Mikutta, R., Guggenberger, G., Polle, A., Pena, R., Prietzel, J., Rodionov, A., Talkner, U., Meesenburg, H., von Wilpert, K., Hölscher, A., Dietrich, H. P., and Chmara, I.

Published
2017

19. Higher than expected: Nitrogen use efficiencies over 35 years of organic and conventional cropping

Author

Oberson, A., Jarosch, K.A., Frossard, E., Hammelehle, A., Fliessbach, A., Mäder, P., Mayer, J., Oberson, A., Jarosch, K.A., Frossard, E., Hammelehle, A., Fliessbach, A., Mäder, P., and Mayer, J.

Abstract

Organic and conventional cropping systems differ in type and amount of nitrogen (N) inputs, which may affect efficiency and sustainability of N use. Organic N fertilizers such as animal manure differ from mineral N fertilizers in the supply of available N over time. Nitrogen budgets based on field data records of long-term experiments enable the determination of Use be crops over decades.

Published
2023

30. Towards circular phosphorus:The need of inter- and transdisciplinary research to close the broken cycle

Author

Stamm, C., Binder, C.R., Frossard, E., Haygarth, P.M., Oberson, A., Richardson, A.E., Schaum, C., Schoumans, O., Udert, K.M., Stamm, C., Binder, C.R., Frossard, E., Haygarth, P.M., Oberson, A., Richardson, A.E., Schaum, C., Schoumans, O., and Udert, K.M.

Abstract

Phosphorus (P) is an essential element to all living beings but also a finite resource. P-related problems center around broken P cycles from local to global scales. This paper presents outcomes from the 9th International Phosphorus Workshop (IPW9) held 2019 on how to move towards a sustainable P management. It is based on two sequential discussion rounds with all participants. Important progress was reported regarding the awareness of P as finite mineable resource, technologies to recycle P, and legislation towards a circular P economy. Yet, critical deficits were identified such as how to handle legacy P, how climate change may affect ecosystem P cycling, or working business models to up-scale existing recycling models. Workshop participants argued for more transdisciplinary networks to narrow a perceived science-practice/policy gap. While this gap may be smaller in reality as illustrated with a Swiss example, we formulate recommendations how to bridge this gap more effectively. © 2021, The Author(s).

Published
2022

31. Bioconversion of aflatoxin-contaminated agri-food by-products with fly larvae into animal feed

Author

Gold, M., Niermans, K., Heuel, M., Kreuzer, M., Nyirarwego, N., Uwamahoro, F., Jooste, F., Standford, M., Wanja, M., Hoek, E., Wilde, B., Six, J., Mathys, A., Gangnat, I.D.M., Frossard, E., Zurbrügg, C., Egger, J., Dortmans, B., Jaster-Keller, J., Weigel, S., Sandrock, C., Nishimwe, K., Terranova, M., Gold, M., Niermans, K., Heuel, M., Kreuzer, M., Nyirarwego, N., Uwamahoro, F., Jooste, F., Standford, M., Wanja, M., Hoek, E., Wilde, B., Six, J., Mathys, A., Gangnat, I.D.M., Frossard, E., Zurbrügg, C., Egger, J., Dortmans, B., Jaster-Keller, J., Weigel, S., Sandrock, C., Nishimwe, K., and Terranova, M.

Abstract

Bioconversion of aflatoxin-contaminated agri-food by-products with fly larvae into animal feed

Published
2022

48. Soil Phosphorus Exchange as Affected by Drying-Rewetting of Three Soils From a Hawaiian Climatic Gradient

Author

Helfenstein, J., Frossard, E., Pistocchi, Chiara, Chadwick, Oliver A., Vitousek, Peter, Tamburini, Federica, Helfenstein, J., Frossard, E., Pistocchi, Chiara, Chadwick, Oliver A., Vitousek, Peter, and Tamburini, Federica

Abstract

Current understanding of phosphorus (P) dynamics is mostly based on experiments carried out under steady-state conditions. However, drying-rewetting is an inherent feature of soil behavior, and as such also impacts P cycling. While several studies have looked at net changes in P pool sizes with drying-rewetting, few studies have dynamically tracked P exchange using isotopes, which would give insights on P mean residence times in a given pool, and thus P availability. Here, we subjected three soils from a climatic gradient on the Kohala peninsula from Hawaii to 5-month drying-rewetting treatments. The hypotheses were that physico-chemical and biotic processes would be differently affected by repeated drying-rewetting cycles, and that response would depend on climatic history of the soils. Soils were labeled with 33P and 18O enriched water. At select time intervals, we carried out a sequential extraction and measured P concentration, 33P recovery (only first 3 months), and incorporation of 18O from water into phosphate. This allowed tracing P dynamics in sequentially extracted pools as well as O dynamics in phosphate, which are driven by biological processes. Results showed that P concentration and 33P recovery were predominantly driven by soil type. However, across all soils we observed faster dilution of 33P from resin-P into less mobile inorganic pools under drying-rewetting. On the other hand, O dynamics in phosphate were mostly governed by drying-rewetting treatment. Under drying-rewetting, considerably less O was incorporated from water into phosphate of resin-P, microbial-P and HCl-P, suggesting that drying-rewetting reduced biological P cycling. Hence, our results suggest that repeated drying-rewetting increases inorganic P exchange while reducing biological P cycling due to reduced microbial activity, independent of climatic history of the soils. This needs to be considered in P management in ecosystems as well as model representations of the terrestrial P cy

Published
2021

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