Abstract
Root penetration resistance and elongation of maize seedling roots were measured directly in undisturbed cores of two sandy loam soils. Root elongation rate was negatively correlated with root penetration resistance, and was reduced to about 50 to 60% of that of unimpeded controls by a resistance of between 0.26 and 0.47 MPa. Resistance to a 30° semiangle, 1 mm diameter penetrometer was between about 4.5 and 7.5 times greater than the measured root penetration resistance. However, resistance to a 5° semiangle, 1 mm diameter probe was approximately the same as the resistnace to root penetration after subtracting the frictional component of resistance. The diameter of roots grown in the undisturbed cores was greater than that of roots grown in loose soil, probably as a direct result of the larger mechanical impedance in the cores.
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References
Abdalla, A M, Hettiaratchi, D R P and Reece, A R 1969 The mechanics of root growth in granular media. J. Agric. Eng. Res. 14, 263–248.
Bengough A G 1988 The Use of Penetrometers for Estimating Mechanical Impedance to Root Growth. Ph.D. thesis, University of Aberdeen, Aberdeen.
Bengough, A G and Mullins, C E 1990a The resistance experienced by roots growing in a pressurised cell. A reappraisal. Plant and Soil 123, 73–82.
Bengough, A G and Mullins, C E 1990b Mechanical impedance to root growth: A review of experimental techniques and root growth responses. J. Soil Sci. 41, 341–358.
Eavis B W 1967 Mechanical impedance to root growth. Agricultural Engineering Symposium, Silsoe, Paper 4/F/39, 1–11.
Eavis, B W and Payne, D 1969 Soil physical conditions and root growth. In Root Growth. Ed. W JWhittington. pp 315–336. Butterworths, London.
Gill, W R and Miller, R D 1956 A method for study of the influence of mechanical impedance and aeration on the growth of seedling roots. Soil Sci. Soc. Am. Proc. 20, 154–157.
Goss, M J 1977 Effects of mechanical impedance on root growth in barley (Hordeum vulgare L.). I. Effects on elongation and branching of seminal roots. J. Exp. Bot. 28, 96–111.
Greacen, E L and Oh J S 1972 Physics of root growth. Nature (New Biol.) 235, 24–25.
Greacen, E L, Farrell, D A and Cockroft, B 1968 Soil resistance to metal probes and plant roots. Trans. 9th Congr. Int. Soil Sci. Soc. 1, 769–779.
Misra, R K, Dexter, A R and Alston, A M 1986 Penetration of soil aggregates of finite size. II. Plant roots. Plant and Soil 94, 59–85.
Richards, B G and Greacen, E L 1986 Mechanical stresses on an expanding cylindrical root analogue in granular media. Aust. J. Soil Res. 24, 393–404.
Stolzy, L H and Barley, K P 1968 Mechanical resistance encountered by roots entering compact soils. Soil Sci. 105, 297–301.
Taylor, H M and Ratliff, L F 1969 Root elongation rates of cotton and peanuts as a function of soil strength and water content. Soil Sci. 108, 113–119.
Voorhees, W B, Farrell, D A and Larson, W E 1975 Soil strength and aeration effects on root elongation. Soil Sci. Soc. Am. Proc. 39, 948–953.
Whiteley, G M, Utomo, W H and Dexter, A R 1981 A comparison of penetrometer pressures and the pressures exerted by roots. Plant and Soil 61, 351–364.
Young I M 1987 Soil Strength and Hard-Setting Behaviour of Some Structurally Unstable British Soils. Ph.D. thesis, University of Aberdeen, Aberdeen.
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Bengough, A.G., Mullins, C.E. Penetrometer resistance, root penetration resistance and root elongation rate in two sandy loam soils. Plant Soil 131, 59–66 (1991). https://doi.org/10.1007/BF00010420
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DOI: https://doi.org/10.1007/BF00010420