Root length density and water uptake in cereals and grain legumes: How well are they correlated? [spring wheat; barley; Lupinus angustifolius; Pisum sativum; morphology]
1987
Hamblin, A. (Commonwealth Scientific and Industrial Research Organization, Wembley (Australia). Dryland Crops and Soils Research Program) | Tennant, D. (Western Australian Dept. of Agriculture, Perth. Crop Science Branch)
The water use of spring wheat, barley, lupin (Lupinus angustifolius) and field pea (Pisum sativum) on 4 differing soil types in drought-stressed conditions was determined. The total root length per unit ground area (L) values of cereals were consistently 5-10 times as large as those of grain legumes, whereas the above-ground biomass was similar and never greater than twice that of the grain legumes. Growing-season water loss (WL) from the soil profile was very similar for wheat and lupins. When crop water uptake was compared for the period when leaf areas was greatest, rates of change in soil water content within the root zone were still similar and were not well correlated with L. Specific root water uptake was consistently greater for lupin than wheat. Maximum rooting depth was better correlated with WL than was L in all cases. These results provide strong evidence for genotypic variation in root morphology, density and root extension between dicotyledenous and monocotyledenous species. They also indicate that L is not necessarily the root morphological characteristic most responsible for efficiency of water uptake in drought-stressed environments.
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