The abilities of seedling roots of twenty-two plant species to penetrate a strong growth medium were compared under controlled conditions. Seedlings were grown for 10 days in compression chambers filled with siliceous sandy soil at 0.2 kg kg−1 water content and mean penetrometer resistance of 4.2 MPa. Root elongation and thickening were measured after growth. The results show that soil strength reduced the elongation of roots of all plant species by over 90% and caused the diameters of the roots to increase compared with control plants grown in vermiculite (0 MPa resistance).
Differences in both root elongation and root diameter were observed among plant species. Generally, the roots of dicotyledons (with large diameters) penetrated the strong medium more than graminaceous monocotyledons (with smaller diameters). There was a significant positive correlation (r=0.78, p<0.05) between root diameter and elongation over all the species in the stressed plants. The species were ranked according to the relative root elongation and relative root thickening. Based on this ranking, lupin (Lupinus angustifolius), medic (Medicago scutelata) and faba bean (Vicia faba) were the species with the greatest thickening and elongation while wheat (Triticum aestivum), rhodesgrass (Chloris gayana) and barley (Hordeum vulgare) had the least. The weight of the seeds did not seem to influence either the thickening or elongation of the roots.
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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, 236–248.
Atwell B J 1988 Physiological responses of lupin roots to soil compaction. Plant and Soil 111, 277–281.
Atwell B J and Newsome J C 1990 Turgor pressure in mechanically impeded lupin roots. Aust. J. Plant Physiol. 17, 49–56.
Aubertin G M and Kardos L T 1965 Root growth through porous media under controlled conditions. 1. Effect of pore size and rigidity. Soil Sci. Soc. Am. Proc. 29, 290–293.
Barley K P 1962 The effects of mechanical stress on the growth of roots. J. Expt. Bot. 13, 95–110.
Barley K P 1963 Influence of soil strength on growth of roots. Soil Sci. 96, 175–180.
Barley K P, Farrell D A and Greacen E L 1965 The influence of soil strength on the penetration of a loam by plant roots. Aust. J. Soil Res. 3, 69–79.
Bennie A T P and Burger R 1981 Root characteristics of different crops as affected by mechanical resistance in fine sandy soils. Proc. 10th Congr. Soil Sci. Soc. South. Africa, East London, pp 29–32.
Cahn M D, Zobel R W and Bouldin D R 1989 Relationship between root elongation rate and duration of growth of lateral roots of maize. Plant and Soil 119, 271–279.
Collis-George N and Yoganathan P 1985 The effect of soil strength on germination and emergence of wheat (Triticum aestivum L.) 1. Low shear strength Conditions. Aust. J. Soil Res. 23, 577–578.
Dexter A R 1987 Mechanics of root growth. Plant and Soil 98, 303–312.
Dexter A R 1990 Amelioration of soil by natural processes: Soil and Tillage Research. (In press).
Elkins C B 1985 Plant roots as tillage tools. Proceedings of an international conference on soil dynamics. Volume 3: Tillage machinery systems as related to cropping systems. Auburn, AL. pp 519–523.
Elkins C B, Haaland R L and Hoveland C S 1977 Grass roots as a tool for penetrating soil hardpans and increasing crop yields. Proc. 34th Southern Pasture and Forage Improvement Conference, Auburn, AL. pp 21–26.
Gibbons J D 1971 Nonparametric Statistical Inference. McGraw Hill, London.
Gill W R and Bolt G H 1955 Pfeffer's studies of the root growth pressures exerted by plants. Agron. J. 47, 166–168.
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.
Gooderham P T 1973 Soil Physical Conditions and Plant Growth. Ph.D. Thesis, University of Reading.
Goss M J and Drew M C 1972 Effect of mechanical impedance on growth of seedlings. Agric. Res. Council, Letcombe Laboratory Annual Report 1977, 35–42.
Greacen E L and Oh J S 1972 Physics of root growth. Nature New Biology 235, 24–25.
Greacen E L, Barley K P and Farrell D A 1969 Mechanics of root growth in soils with particular reference to the implications for root distribution. In Root Growth. Ed. W JWhittington. pp 256–269. Butterworths, London.
Greacen E L 1986 Root response to soil mechanical properties. Trans. 13th Congr. Int. Soc. Soil Sci., Hamburg 5, 20–47.
Heinonen R 1986 Alleviation of soil compaction by natural forces and cultural practices. In Land Clearing and Development in the Tropics. Eds. R.Lal, P ASanchez and R WCummings. pp 285–297. A A Balkema, Boston.
Henderson C W L 1989 Lupin as a biological plough: Evidence for and effects on wheat growth and yield. Aust. J. Expt. Agric. 29, 99–102.
Johnson C M, Stout P R, Broyer T C and Carlton A B 1957 Comparative chlorine requirements of different plant species. Plant and Soil 8, 337–353.
Lar R, Wilson G F and Okigbo B N 1979 Changes in properties of an Alfisol produced by various crop covers. Soil Sci. 27, 377–382.
Misra R K, Dexter A R and Alston A M 1986 Maximum axial and radial growth pressures of plant roots. Plant and Soil 95, 315–326.
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.
Rosenberg N J 1964 Responses of plants to the physical effects of soil compaction. Adv. Agron. 16, 181–196.
Russell R S and Goss M J 1974 Physical aspects of soil fertility: The response of roots to mechanical impedance. Neth. J. Agric. Sci. 22, 305–318.
Taylor H M 1971 Effects of soil strength on seedling emergence, root growth and crop yields. In Compaction of Agricultural Soils. Eds. K KBarnes et al. pp 292–304. ASAE, St. Joseph, MI.
Taylor H M 1980 Mechanical impedance to root growth. In Priorities for Alleviating Soil-related Constraints to Food Production in the Tropics. pp 389–404. IRRI, Los Baños, Phillipines.
Taylor H M and Burnett E 1964 Influence of soil strength on the root growth habit of plants. Soil Sci. 98, 174–181.
Taylor H M and Gardner H R 1960 Relative penetrating ability of different plant roots. Agron. J. 52, 579–581.
Taylor H M and Ratliff L F 1969 Root elongation rates of cotton and peanuts as a function of soil strength and soil water content. Soil Sci. 108, 113–119.
Wilson A J, Robards A W and Goss M J 1977 Effects of mechanical impedance on root growth in barley. Hordeum vulgare L. II. Effects on the development in seminal roots. J. Expt. Bot. 28, 1216–1227.
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Materechera, S.A., Dexter, A.R. & Alston, A.M. Penetration of very strong soils by seedling roots of different plant species. Plant Soil 135, 31–41 (1991). https://doi.org/10.1007/BF00014776
- penetrometer resistance
- plant species
- root diameter
- root elongation
- seedling roots
- soil strength