LINKING THE BIOLOGY AND PHYSICS OF TEMPERATE MULTIFUNCTIONAL GRASSES AND
SOIL HYDROLOGICAL FUNCTION
C.J.A. Macleod1, A. Binley2, A. Gregory3, P.M. Haygarth2, M.W. Humphreys3, A. Joynes1, A.
Papadopoulos2, L. Skot3, L.B. Turner3, C Watts4, and W.R. Whalley4
1North
Wyke Research, Okehampton, UK (kit.macleod@bbsrc.ac.uk),
University, Bailrigg, Lancaster, UK, LA1 4YW, UK,
3Rothamsted Research, Harpenden, Hertfordshire, AL52JQ, UK,
4Institute for Biological, Environmental and Rural Sciences, Aberystwyth, Ceredigion SY23 3EB, UK.
2Lancaster
Temperate grassland systems need to provide multiple functions: these include production and
regulatory services. Here we report on research that aims to develop new temperate forage grass
varieties to provide benefit under periods of water excess in areas that are at risk of flooding and
associated diffuse pollution from the field to catchment scale. Our results are centered on replicated
rainfall-runoff plots that are 10 m long and hydrologically isolated from surrounding areas. We have
established ryegrasses, fescues and hybrids between ryegrasses and fescue parents. In addition to
aggregated plot scale rainfall-runoff response, observations of above and below ground plant growth
have been made along with measurements of soil physical structure using X-ray computed
tomography and tension-infiltration measurements of soil hydrological function. During 2008 fourty
four individual rainfall-runoff events were identified from a high temporal resolution time series and
simple hydrological indices extracted for these events. Anova results show significant (P <0.001)
differences between treatments. We seek to explain these plot scale responses using information
from within plot observations and with supporting microcosm experiments examining the physiology of
the plant material, changes in soil structure and hydrological function. The combination of
observations from the plant to plot scale will improve our understanding of the potential for
modification of soil hydrological functioning through the development and growth of multifunctional
forage grasses.
Key words: grass; genetics; processes; runoff; plot scale; tension-infiltration