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RESEARCH PRODUCT

The role of light in the emergence of weeds: using Camelina microcarpa as an example

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When modelling the emergence of weeds, two main factors are considered that condition this process: temperature and soil moisture. Optimum temperature is necessary for metabolic processes that generate energy for growth, while turgor pressure is necessary for root and shoot elongation which eventually leads to seedling emergence from the soil. Most emergence models do not usually consider light as a residual factor, but it could have an important role as it can alter directly or indirectly the dormancy and germination of seeds. In this paper, inclusion of light as an additional factor to photoperiod and radiation in emergence models is explored and compared with the classical hydrothermal time (HTT) model using Camelina microcarpa as an example. HTT based on hourly estimates is also compared with that based on daily estimates. Results suggest that, although HTT based models are accurate enough for local applications, the precision of these models is improved when HTT is estimated hourly and solar radiation is included as a factor. This work was supported by the Ministerio de Educación y Ciencia de España (AGL2010- 22084-C02-01). We thank the Botanical Garden of the University of Latvia for letting us set the experiment in their court. We thank Núria Moix, Ana Isábal, Jordi Rey, Ana Baños and Eva Edo for their help in the field. We also thank Joe Boots for his expert field assistance at the Morris, Minnesota field site.