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Water Relations of Winter Wheat: the Root System, Petiolar Resistance and Development of a Root Abstraction Equation

Published online by Cambridge University Press:  03 October 2008

M. McGowan
Affiliation:
Nottingham University, School of Agriculture, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, England
E. Tzimas
Affiliation:
Nottingham University, School of Agriculture, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, England

Summary

The vertical distribution of water potentials within the leaf canopy, along the stem and within the soil profile of a winter wheat crop was analysed and it is concluded the failure by previous workers to recognize the significance of petiolar resistance has probably resulted in over-estimates of the resistance of the soil to water uptake by root systems of field crops.

From an analysis of the water relations of several winter wheat crops an equation is developed to describe the extraction of soil water reserves by crop root systems, based upon values of soil water potential, root xylem potential and ‘effective’ resistance to water uptake which can be obtained from field experiments. The equation provides an empirical basis to specify the minimum desirable root system for efficient capture of soil water reserves, to analyse the effects of differing root distributions and thus to help identify situations where it would be profitable to modify rooting either by tillage or by plant breeding.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1985

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