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| Dalgaard, Tommy; Hutchings, Nicholas J.; Dragosits, U.; Olesen, J.E.; Kjeldsen, Chris; Drouet, J.L.; Cellier, P.. |
| The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with... |
| Tipo: Journal paper |
Palavras-chave: Air and water emissions; Landscape and recreation; Farm nutrient management. |
| Ano: 2011 |
URL: http://orgprints.org/19043/4/19043.pdf |
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| Fournier, C.; Andrieu, B.; Buck-Sorlin, G.; Evers, J.B.; Drouet, J.L.; Escobar-Gutiérrez, A.J.; Vos, J.. |
| The Gramineae have been a pioneer group among non-woody plants to be modelled with the approach of functional-structural plant modelling (FSPM). During the past decade, models have focussed on morphological aspects of plant development. They now provide crop scientists with general guidelines for building new cereal models. We present some of them here, considering the different aspects of cereal architectural modelling: plant development, pattern formation and plant geometry. We also review some significant examples that illustrate the different types of uses of these models for agronomic research. We conclude that the next generation of cereal models should be based on a less empirical modelling of the processes that control morphogenesis. |
| Tipo: Conference proceedings |
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| Ano: 2007 |
URL: http://library.wur.nl/ojs/index.php/frontis/article/view/1381 |
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| Drouet, J.L.; Pagès, L.. |
| An integrated functional-structural model, called GRAAL, has been developed to simulate and analyse the interactions between morphogenetic processes and assimilate partitioning during the vegetative development of individual plants. GRAAL associates models of plant morphogenesis and models simulating the growth of plant compartments as related to assimilate availability. Using objectoriented methods, knowledge is formalized at the organ level (i.e., local rules of development and functioning). The behaviour of the plant arises from interactions between the organs and the integration of the processes within the whole plant. Shoot and root organs are initiated as a function of temperature. Using the source–sink concept, organ growth is calculated from its... |
| Tipo: Conference proceedings |
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| Ano: 2007 |
URL: http://library.wur.nl/ojs/index.php/frontis/article/view/1380 |
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