Mitteilungen der Gesellschaft für Pflanzenbauwissenschaften Band 23

Mitt. Ges. Pflanzenbauwiss. 23: 182 (2011)
Spatio-temporal patterns of phenological development in Germany
in relation to temperature and day length
Stefan Siebert and Frank Ewert
Institute of Crop Science and Resource Conservation, University of Bonn. E-Mail: s.siebert@unibonn.de
Introduction
Phenological development of crops has been extensively studied in field experiments
but less at larger scales for which data availability is often limited. To which extent
the spatio-temporal variability of crop development can be explained by relationships
derived from field studies as the temperature sum concept (e.g. McMaster et al.,
2008; Ewert et al., 1999), used in many crop models is unclear but would support the
large scale application of these models. The aim of this study was to analyze the
spatio-temporal patterns of crop phenological development in response to
temperature and day length.
Material and Methods
We used a comprehensive data set (656234 phenological observations at 6019
observation sites) about the phenology of oat (Avena sativa L.) and related climate
data from Germany for the period 1959 to 2009.
Results and Discussion
Our results show that the statistically significant warming trend since 1959 resulted in
an earlier onset of all phenological stages and a shortening of most phenological
phases with a 17 days earlier onset of yellow ripeness and a shortening of the phase
sowing to yellow ripeness by 14 days. There was also a distinct spatial pattern in
phenological development with differences among eco-regions in the occurrence of
development stages of 15-26 days depending on the stage and the length of the
phases between stages of 6-21 days depending on the phase. Most of this spatiotemporal
variability could be explained through the effect of temperature and day
length. However, temperature sums (thermal times) and day length corrected
temperature sums (photothermal times) also varied in time and space pointing to the
use of different varieties over time and across eco-regions. The good agreement of
the thermal and photothermal requirements of oat computed in this study with
relationships known from field experiments supports the use of the temperature sum
concept for large scale application to simulate crop phenology in response to
temperature and day length.
References
Ewert, F., van Oijen, M., Porter J.R 1999: Simulation of growth and development processes of spring
wheat in response to CO2 and ozone for different sites and years in Europe using mechanistic crop
simulation models. European Journal of Agronomy 10:231-247.
McMaster, G.S., White, J.W., Hunt, L.A., Jamieson, P.D., Dhillon, S.S., Ortiz-Monasterio, J.I. 2008:
Simulating the influence of vernalization, photoperiod and optimum temperature on wheat
developmental rates. Annals of Botany 102:561-569.