Abstract
A field experiment was conducted to evaluate the influence of root diameter on the ability of roots of eight plant species to penetrate a compacted subsoil below a tilled layer. The soil was a fine sandy loam red-brown earth with a soil strength of about 3.0 MPa (at water content of 0.13 kg kg-1, corresponding to 0.81 plastic limit) at the base of a tilled layer. Relative root diameter (RRD), which was calculated as the ratio of the mean diameters of roots of plants grown in compacted soil to the mean diameters of those from uncompacted soil, was used to compare the sensitivity of roots to thicken under mechanical stress.
Diameters of root tips of plants grown in soil with a compacted layer were consistently larger than those from uncompacted soil. Tap-rooted species generally had bigger diameters and RRDs than fibrous-rooted species. A higher proportion of thicker roots penetrated the strong layer at the interface than thinner roots. There were differences between plant species in the extent to which root diameter increased in response to the compaction. The roots which had larger RRD also tended to have higher penetration percentage.
The results suggest that the size of a root has a significant influence on its ability to penetrate strong soil layers. It is suggested that this could be related to the effects which root diameter may have on root growth pressure and on the mode of soil deformation during penetration.
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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. Engng. Res. 14, 236–248.
Anderson G, Pidgeon J D, Spencer H B and Parks R 1980 A new hand held recording penetrometer for soil studies. J. Soil Sci. 31, 279–296.
Barley K P 1954 Effect of root growth and decay on the permeability of a synthetic sandy loam. Soil Sci. 78, 205–210.
Barley K P 1968 Deformation of the soil by the growth of plants. Trans. 9th Int. Congr. Soil Sci. Adelaide 1, 759–768.
Barley K P and Greacen E L 1967 Mechanical resistance as a factor influencing the growth of roots and underground shoots. Adv. Agron. 19, 1–43.
Blake G R, Nelson W W and Allmaras R R 1976 Persistence of subsoil compaction in a mollisol. Soil Sci. Am. J. 40, 943–948.
Dexter A R 1986a Model experiments on the behaviour of roots at the interface between a tilled seed-bed and a compacted sub-soil. I. Effects of seed-bed aggregate size and sub-soil strength on wheat roots. Plant and Soil 95, 123–133.
Dexter A R 1986b Model experiments on the behaviour of roots at the interface between a tilled seed-bed and a compacted sub-soil. II. Entry of pea and wheat roots into sub-soil cracks. Plant and Soil 95, 135–147.
Dexter A R 1986c Model experiments on the behaviour of roots at the interface between a tilled seed-bed and a compacted sub-soil. III. Entry of pea and wheat roots into cylindrical biopores. Plant and Soil 95, 149–161.
Dexter A R 1991 Amelioration of soil by natural processes. Soil Tillage. Res. 20, 87–100.
Dexter A R and Hewitt J S 1978 The deflection of plant roots. J. Agric. Engng. Res. 23, 17–22.
Elkins C B 1985 Plant roots as tillage tools. In Proc. Int. Conf. on Soil Dynamics. Vol. 3: Tillage Machinery Systems as Related to Cropping Systems. Auburn, A L. 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. In Proc. 34th Southern Pasture and Forage Crop Improvement Conf. Auburn A L. pp 21–26.
Ellis T W 1990 Controlled traffic cropping at Roseworthy College — The first year. In Proc. Conf. Agric. Engng. 1990. pp 25–29. Inst. Engng. Aust. Publ. No. 9/13, Toowoomba, Queensland.
Gaultney L, Krutz G W, Steinhardt G W and Liljedahl J B 1982 Effect of subsoil compaction on corn yield. Trans. Am. Soc. Agric. Eng. 25, 563–569.
Genstat 5 Committee 1987 Reference Manual for Genstat 5. Clarendon Press, Oxford.
Gibbons J D 1974 Nonparametric Statistical Inference. McGraw-Hill, London.
Gill W R and Bolt B G 1955 Pfeffer's studies of the root growth pressures exerted by plants. Agron. J. 47, 166–168.
Goss M J 1987 The specific effects of roots on the regeneration of soil structure. In Soil Compaction and Regeneration. Eds. G Monnier and M J Goss. pp 145–155. A A Balkema, Boston.
Håkansson I 1982 Long-term effects of vehicles with high axle load on subsoil compaction and crop response. In Proc. Int. Soil Till. Res. Org. 9th Int. Conference. Osijek, Yugoslavia, pp 213–218.
Håkansson I, Voorhees W B, Elonea P, Raghavan G S V, Lowery B, vanWijk A L M, Rasmussen K and Riley H 1987 Effect of high axle-load traffic on subsoil compaction and crop yields in humid regions with annual freezing. Soil Tillage. Res. 10, 259–268.
Hettiaratchi D R P 1990 Soil compaction and plant root growth. Phil. Trans. R. Soc. Lond. B 329, 343–355.
Materechera S A, Dexter A R and Alston A M 1991 Penetration of very strong soil by seedling roots of different plant species. Plant and Soil 135, 31–41.
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.
Nelson W W and Allmaras R R 1969 An improved monolith method for excavating and describing roots. Agron. J. 61, 751–754.
Northcote K H 1979 A Factual Key for the Recognition of Australian Soils. 3rd Ed. Rellim Tech. Publs., Adelaide, South Australia.
Oades J M, Lewis D G and Norrish K 1981 Red-brown Earths of Australia. Waite Agric. Res. Instit. and CSIRO Division of Soils, Adelaide.
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.
Schuurman J J and Goedewaagen M A J 1971 Methods for the Examination of Root Systems and Roots. 2nd Ed. Pudoc, Wageningen.
Somapala H and Willatt S T 1979 Effect of plant age on root penetration. In Soil Physical Properties and Crop Production in the Tropics. Eds. R Lal and D J Greenland. pp 349–361. Wiley, London.
Voorhees W B 1983 Relative effectiveness of tillage and natural forces in alleviating wheel-induced compaction. Soil Sci. Soc. Am. J. 47, 129–133.
Voorhees W B, Nelson W W and Randall G W 1986 Extent and persistence of subsoil compaction caused by heavy axle loads. Soil Sci. Soc. Am. J. 50, 428–433.
Whiteley G M and Dexter A R 1981 Elastic response of the roots of field crops. Physiol. Plant. 51, 407–417.
Whiteley G M, Hewitt J S and Dexter A R 1982 The buckling of plant roots. Physiol. Plant. 54, 333–342.
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Materechera, S.A., Alston, A.M., Kirby, J.M. et al. Influence of root diameter on the penetration of seminal roots into a compacted subsoil. Plant Soil 144, 297–303 (1992). https://doi.org/10.1007/BF00012888
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DOI: https://doi.org/10.1007/BF00012888