Höglind, Mats

Schapendonk, A. H. M. C.

Thorsen, S. M.

van Oijen, Marcel

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Process‐Based Modelling of Timothy Survival in Winter Marcel van Oijen Centre for Ecology and Hydrology, UK S. M. Thorsen Norwegian Institute for Agricultural and Environmental Research, Norway A. H. M. C. Schapendonk Plant Dynamics, The Netherlands Mats Höglind Norwegian Institute for Agricultural and Environmental Research, Norway Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/8-1/25 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　 瞯 ]893　 瞯Grasslands/Rangelands Resources and Ecology ——— Climate Change and Impact on Grasslands/RangelandsProcess‐based modelling of timothy survival in winterM . V an Oi jen1 , S .M . Thorsen2 , A .H .C .M . Schapendonk3 , M . H迸glind21 CEH‐Edinburgh , Bush Estate , Penicuik EH26 0QB , U .K . , E‐mail : mvano＠ ceh .ac .uk , 2 Bio f orsk , Saerheim , Norway ,3 Plant Dynamics , W ageningen , The NetherlandsKey words : climate change , damage mechanisms , tolerance , physiology , yieldIntroduction Timothy ( Phleum p ratense , L .) is the most widely grown sown grass species for silage and hay production inScandinavia , and is common in many other countries with a cold and maritime climate , like Canada and the Baltic countries .Although timothy is a winter hardy species , every winter some damage is suffered . The two most severe damage mechanismsare frost and ice‐encasement followed by anoxia and build‐up of toxic compounds in and around the plants . The major tolerancemechanism is hardening , which can be quantified as the LT５０ ( Lethal Temperature for ５０％ of the plants in standard testing ) .Climate change is expected to increase both average winter temperature and weather variability . This may impede the hardeningprocess . The international project WINSUR aims to quantify the associated risks for Norwegian grassland , using bothexperimentation and process‐based modelling .Materials and methods Our work builds on previous work with the grassland model LINGRA ( Schapendonk et al . １９９８ ) . Wereviewed the literature on timothy ( H迸glind et al . , ２００１ ) and performed simulations with the model showing that tilleringdynamics and the formation and loss of leaves from tillers were key knowledge gaps for timothy . This was addressed byexperimentation followed by model improvement in these areas ( Van Oijen et al . ２００５ ) . We now have expanded the model toinclude simulation of snow and frost dynamics , and damage and tolerance mechanisms .Results The model was extensively tested for various sites in Southern and Middle Norway . The dynamics of LT５０ and totaltiller density , showing severe tiller loss during February — April ( days ４００‐５００ in the Figure below ) showed reasonablecorrespondence with observations .Figure 1 Simulation o f L T５０ and T iller density in Saerheim , Southern Norway during the grow ing seasons o f ２０００ and２００１ and the w inter in between .Conclusions and outlook The process‐based timothy model seems to capture the essential dynamics of the grassland system inboth summer and winter . Hardening is the key tolerance mechanism , not only against frost but also against ice encasement .Further model development is under way .ReferencesH迸glind , M . , Schapendonk , A .H .C .M . & M . Van Oijen ( ２００１) . Timothy grow th in Scandinavia : a review of quantitativeinformation on underlying processes and an analysis by means of simulation modelling . New Phytologist １５１ : ３５５‐３６７ .Schapendonk A .H .C .M . , Stol , W . , Van Kraalingen , D .W .G . & B .A .M . Bouman (１９９８) . LINGRA , a sink/ source modelto simulate grassland productivity in Europe . European Journal o f A gronomy ９ : ８７‐１００ .Van Oijen , M . , H迸glind , M . , Hanslin , H .M . & N . Caldwell ( ２００５ ) . Process‐based modelling of timothy regrow th .A gronomy Journal ９７ : １２９５‐１３０３ .-6 4000 -7- LT50 3500- Tillers(m') -8-3000 -9-2500 -10 -11 - 2000 -12 1500 -13L 1000 '~ -14 500 100 200 300 400 500 600 700 100 200 300 400 500 600 700 Time (d) Time (d) 

Process‐Based Modelling of Timothy Survival in Winter

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2939&amp;context=igc

Process‐Based Modelling of Timothy Survival in Winter

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