Rhizo-lysimetry: facilities for the simultaneous study of root behaviour and          resource use by agricultural crop and pasture systems.
BACKGROUND
Rhizo-lysimeters offer unique advantages for the study of          plants and their interactions with soils. In this paper, an existing facility at Charles          Sturt University in Wagga Wagga Australia is described in detail and its potential to          conduct both ecophysiological and ecohydrological research in the study of root          interactions of agricultural crops and pastures is quantitatively assessed. This is of          significance to future crop research efforts in southern Australia, in light of recent          significant long-term drought events, as well as potential impacts of climate change as          predicted for the region. The rhizo-lysimeter root research facility has recently been          expanded to accommodate larger research projects over multiple years and cropping          rotations.


RESULTS
Lucerne, a widely-grown perennial pasture in southern Australia,          developed an expansive root system to a depth of 0.9 m over a twelve month period. Its          deeper roots particularly at 2.05 m continued to expand for the duration of the          experiment. In succeeding experiments, canola, a commonly grown annual crop, developed a          more extensive (approximately 300%) root system than wheat, but exhibited a slower rate of          root elongation at rates of 7.47 x 10-3 m day-1 for canola and 1.04          x10-2 m day-1 for wheat. A time domain reflectometry (TDR) network was          designed to accurately assess changes in soil water content, and could assess water content          change to within 5% of the amount of water applied.


CONCLUSIONS
The rhizo-lysimetry system          provided robust estimates of root growth and soil water change under conditions          representative of a field setting. This is currently one of a very limited number of global          research facilities able to perform experimentation under field conditions and is the          largest root research experimental laboratory in the southern hemisphere.
EH Graham Centre for Agricultural Innovation, School of Agricultural and                Wine Sciences, Charles Sturt University, Boorooma St, 2678, Wagga Wagga, NSW,                Australia. peberbach@csu.edu.au.
Philip L
PL
Eberbach
Jeffrey
J
Hoffmann
Sergio J
SJ
Moroni
Leonard J
LJ
Wade
Leslie A
LA
Weston