Abstract
Information on the response of root growth and morphology to soil strength is useful for testing suitability of existing and new tillage methods and/or for selecting plants suitable for a specific site with or without tillage. Although there is extensive published information on the root growth-soil strength relationships for annual agricultural plants, such information is scarce for woody, perennial tree species. The purpose of this study is to examine growth and morphology of the root systems of 17-day-old eucalypt seedlings with respect to variation in soil strength. Soil strength in this study was varied by compaction of a well-aggregated clay soil to bulk densities of 0.7–1.0 Mg m-3 whilst maintaining adequate water availability and aeration for plant growth. Lengths and tip-diameters of primary and lateral roots were measured on the excavated root systems of seedlings.
With increase in bulk density and also soil strength (expressed as penetrometer resistance), total length of primary and lateral roots decreased. There were 71 and 31% reduction in the lengths of primary and lateral roots respectively with an increase in penetrometer resistance from 0.4 to 4.2 MPa. This indicated primary roots to be more sensitive to high soil strength than the lateral roots. Average length of lateral roots and diameters of both primary and lateral root tips increased with an increase in soil strength as well. There was greater abundance of lateral roots (no. of lateral roots per unit length of primary root) and root hairs with increased soil strength. The observed root behaviour to variable soil strength is discussed in the context of compensatory growth of roots and overall growth of plants.
Similar content being viewed by others
References
Andrus C W and Froehlich H A 1983 An evaluation of four implements used to till compacted forest soils in the Pacific North West. Oregon State University Forest Research Lab Research Bulletin 45. 12 p.
Attiwill M, Turvey N D and Adams M A 1985 Effects of mound-cultivation (bedding) on concentration and conservation of nutrients in a sandy podzol. For. Ecol. Manage. 11, 91–110.
Atwell B J 1988 Physiological responses of lupin roots to soil compaction. Plant and Soil 111, 277–281.
Barley K P 1968 Deformation of the soil by the growth of plants. Trans. 9th Int. Congr. Soil Sci. Adelaide, Australia. pp 759–768.
Barley K P and Greacen E L 1967 Mechanical resistance as a soil factor influencing the growth of roots and underground shoots. Adv. Agron. 19, 1–43.
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.
Barraclough P B and Weir A H 1988 Effects of a compacted subsoil layer on root and shoot growth, water use and nutrient uptake of winter wheat. J. Agric. Sci., Camb. 110, 207–216.
Bengough A G and Mullins C E 1991 Penetrometer resistance, root penetration resistance and root elongation rate in two sandy loam soils. Plant and Soil 131, 59–66.
Bengough A G and Young I M 1993 Root elongation of seedling peas through layered soil of different penetration resistance. Plant and Soil 149, 129–139.
Bennie A T P 1991 Growth and mechanical impedance. In Plant Roots: The Hidden Half. Eds. YWaisel, AEshel and UKafkafi. pp 393–414. Marcel Dekker Inc., New York, USA.
Bennie A T P and Burger R Du T 1981 The effect of soil compaction on root growth and nutrient uptake by maize. Proc. 9th. Nat. Congr. Soil Sci. Soc. S. Africa Tech. Comm., Dept. of Agric. and Fish, Republic of South Africa. No. 174, pp 2–9.
Boland D J, Brooker M I H and Turnbull J W 1980 Eucalyptus Seed. CSIRO, Canberra, Australia. 191 p.
Boone F R and Veen B W 1982 The influence of mechanical resistance and phosphate supply on morphology and function of maize roots. Neth. J. Agric. Sci. 30, 179–192.
Cromer R, Smethurst P, Turnbull C, Misra R, LaSala A, Herbert A and Dimsey L 1995 Early growth of eucalypts in Tasmania in relation to nutrition. In Eucalypt Plantations: Improving Fibre Yield and Quality. Eds. B MPotts, N M GBorralho, J BReid, R NCromer, W NTibbits and C ARaymond. pp 331–335. CRC for Temperate Hardwood Forestry, Hobart, Australia.
Davis G R 1984 Effect of soil compaction on root growth of Pinus radiata D. Don. In Proc. IUFRO Symp. on Site and Productivity of Fast growing Plantations. Vol 2, pp 871–879. South African Forest Research Institute, Pretoria, South Africa.
Dexter A R 1987 Mechanics of root growth. Plant and Soil 98, 303–312.
Genstat 5 Committee 1987 Genstat 5 Reference Manual. Clarendon Press, Oxford, UK. 749 p.
Glinski J and Lipiec J 1990 Soil Physical Conditions and Plant Roots. CRC Press, Inc., Boca Raton, FL, USA. 250 p.
Goss M J 1977 Effects of mechanical impedance on root growth in barley (Hordeum vulgare L.). I. Effects on the elongation and branching of seminal root axes. 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 and Sands R 1980 Compaction of forest soils. A Review. Aust. J. Soil Res. 18, 163–189.
Materechera S A, Dexter A R and Alston A M 1991 Penetration of very strong soils by seedling roots of different plant species. Plant and Soil 135, 31–41.
Materechera S A, Alston A M, Kirby J M and Dexter A R 1992 Influence of root diameter on the penetration of seminal roots into a compacted subsoil. Plant and Soil 144, 297–303.
Mirreh H F and Ketcheson J W 1973 Influence of soil water matric potential and resistance to penetration on corn root elongation. Can. J. Soil Sci. 53, 383–388.
Misra R K, Dexter A R and Alston A M 1986a Penetration of soil aggregates of finite size. II. Plant roots. Plant and Soil 94, 59–85.
Misra R K, Dexter A R and Alston A M 1986b Maximum axial and radial growth pressures of plant roots. Plant and Soil 95, 315–326.
Misra R K, Alston A M and Dexter A R 1988 Root growth and phosphorus uptake in relation to the size and strength of soil aggregates. I. Experimental studies. Soil Tillage Res. 11, 103–116.
Schultz R P and Wilhite L P 1974 Changes in a flatwoods site following intensive preparation. For. Sci. 20, 230–237.
Snedecor G W and Cochran W G 1989 Statistical Methods. Iowa State University Press, Ames, Iowa, USA. 503 p.
Soil Survey Staff 1975 Soil Taxonomy. A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Govt Printer, Washington D.C., USA. 754 p.
Stace H T C, Hubble G D, Brewer R, Northcote K H, Sleeman J R, Mulcahy M J and Hallsworth E G 1968 A Handbook of Australian Soils. Rellim Technical Publications, Adelaide, Australia. 435 p.
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.
Tsegaye T and Mullins C E 1994 Effect of mechanical impedance on root growth and morphology of two varieties of pea (Pisum sativum L.). New Phytol. 126, 707–713.
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.
Williamson J R 1990 The Effects of Mechanised Forest Harvesting Operations on Soil Properties and Site Productivity. Tasmanian Forest Research Council Research Report No 5, Hobart, Tasmania. 193 p.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Misra, R.K., Gibbons, A.K. Growth and morphology of eucalypt seedling-roots, in relation to soil strength arising from compaction. Plant Soil 182, 1–11 (1996). https://doi.org/10.1007/BF00010990
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00010990