Abstract
Compacted soils are not uniformly hard; they usually contain structural cracks and biopores, the continuous large pores that are formed by soil fauna and by roots of previous crops. Roots growing in compacted soils can traverse otherwise impenetrable soil by using biopores and cracks and thus gain access to a larger reservoir of water and nutrients. Experiments were conducted in a growth chamber to determine the plant response to a range of uniform soil densities, and the effect of artificial and naturally-formed biopores. Barley plants grew best at an intermediate bulk density, which presumably represented a compromise between soil which was soft enough to allow good root development but sufficiently compact to give good root-soil contact. Artificial 3.2 mm diameter biopores made in hard soil gave roots access to the full depth of the pot and were occupied by roots more frequently than expected by chance alone. This resulted in increased plant growth in experiments where the soil was allowed to dry. Our experiments suggest that large biopores were not a favourable environment for roots in wet soil; barley plants grew better in pots containing a network of narrow biopores made by lucerne and ryegrass roots, responded positively to biopores being filled with peat, and some pea radicles died in biopores. A theoretical analysis of water uptake gave little support to the hypothesis that water supply to the leaves was limiting in either very hard or very soft soil. The net effect of biopores to the plant would be the benefits of securing extra water and nutrients from depth, offset by problems related to poor root-soil contact in the biopore and impeded laterals in the compacted biopore walls.
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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.
Alexander K G and Miller M H 1991 The effect of aggregate size on early growth and shoot-root ratio of maize (Zea mays L.). Plant and Soil 138, 189–194.
Avidsson J and Håkansson I 1991 A model for estimating crop yield losses caused by soil compaction. Soil Tillage Res. 20, 319–332.
Bengough A G and Mullins C E 1990 Mechanical impedance to root growth: a review of experimental techniques and root growth responses. J. Soil Sci. 41, 341–358.
Blaikie S J and Mason W K 1993 Restrictions to root growth limit the yield of shoots of irrigated white clover. Aust. J. Agric. Res. 44, 121–135.
Boone F R 1986 Towards soil compaction limits for crop growth. Neth. J. Agric. Sci. 34, 349–60.
Chan K Y, Mead J A, Roberts W P and Wong P T W 1989 The effect of soil compaction and fumigation on poor early growth of wheat under direct drilling. Aust. J. Agric. Res. 42, 221–228.
Cresswell H P and Kirkegaard J A 1995 Subsoil amelioration by plant roots: the process and the evidence. Aust. J. Soil Res. 32, 221–239.
Cornish P S, So H B and McWilliam J R 1984 Effects of soil bulk density and water regimen on root growth and uptake of phosphorus by ryegrass. Aust. J. Agric. Res. 35, 631–644.
Davies W J and Zhang J 1991 Root signals and the regulation of growth and development of plants in drying soil. Ann. Rev. Plant Physiol. Molec. Biol. 42, 55–76.
Dexter A R 1986 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.
Donald R G, Kay B D and Miller M H 1987 The effect of soil aggregate size on early shoot and root growth of maize (Zea mays L.) Plant and Soil 103, 251–259.
Edwards C A and Lofty J R 1978 The influence of arthropods and earthworms upon root growth of direct drilled crops. J. Appl. Ecol. 15, 789–795.
Ehlers W, Köpke U, Hesse F and Böhm W 1983 Penetration resistance and root growth of of oats in tilled and untilled loess soil. Soil Tillage Res. 3, 261–275.
Evans D G and Miller M H 1988 Vesicular-arbuscular mycorrhizas and the soil-disturbance-induced reduction of nutrient absorption in maize. 1. Causal relations. New Phytol. 110, 67–74.
Herkelrath W N, Miller E E and Gardner W R 1977 Water uptake by plants. The root contact model. Soil Sci. Soc. Am. J. 41, 1039–1043.
Hulugalle N R and Lal R 1986 Root growth of maize in a compacted gravelly tropical alfisol as affected by rotation with a woody perennial. Field Crops Res. 13, 33–44.
Jakobsen B F and Dexter A R 1988 Influence of biopores on root growth, water uptake and grain yield of wheat (Triticum aestivum) based on predictions from a computer model. Biol. Fertil. Soils 6, 315–321.
Körner Ch, Susanna Pelaez Menendez-Riedl and John P C L 1989 Why are Bonsai plants small? A consideration of cell size. Aust. J. Plant Physiol. 16, 443–447.
Krizek D T, Carmi A, Mirecki R M, Snyder F W and Bunce J A 1984 Comparative effects of soil moisture stress and restricted root zone volume on morphogenetic and physiological responses of soybean. J. Exp. Bot. 36, 25–38.
Kooistra M J, Schoonderbeek D, Boone F R, Veen B W and Van Noordwijk M 1992 Root-soil contact of maize, as measured by a thin-section technique. II. Effects of soil compaction. Plant and Soil 139, 119–129.
Lee K E 1985 Earthworms: Their Ecology and Relationships with Soils and Land Use. Academic Press, Sydney, Australia. 411 p.
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
Masle J and Passioura J B 1987 The effect of soil strength on the growth of young wheat plants. Aust. J. Plant Physiol. 14, 643–656.
McKenzie B M and Dexter A R 1988 Radial pressures generated by the earthworm.Aporrectodea rosea. Biol. Fertil. Soils 5, 328–332.
Nambiar E K S and Sands R 1992 Effects of compaction and simulated root channels in the subsoil on root development, water uptake and growth of radiata pine. Tree Physiol. 10, 297–306.
Nye P H 1992 Towards the quantitative control of crop production and quality. III. Some recent developments in research into the root-soil interface. J. Plant Nutr. 15, 1175–1192.
Nye P H 1994 The effect of root shrinkage on soil water inflow. Phil. Trans. R. Soc. Lond. B 345, 395–402.
Passioura J B and Cowan I R 1968 On solving the non-linear diffusion equation for the radial flow of water to roots. Agric. Meteorol. 5, 129–134.
Passioura J B 1980 The transport of water from soil to shoot in wheat seedlings. J. Exp. Bot. 31, 331–345.
Passioura J B 1988 Water transport in and to roots. Annu. Rev. Plant Physiol. Plant Mol. Biol. 39, 245–265.
Passioura J B 1991 Soil structure and plant growth. Aust. J. Soil Res. 29, 717–728.
Passioura J B and Stirzaker R J 1994 Feedforward responses of plants to physically inhospitable soil.In International Crop Science I. Ed. D R Buxton. pp 715–719. Crop Science Society of America, Madison, WI, USA.
Richards D and Rowe R N 1977 Effects of root restriction, root pruning and 6-benzylaminopurine on the growth of peach seedlings. Ann. Bot. 41, 729–740.
Rose D A 1968 Water movement in porous materials. III. Evaporation of water from soil. Br. J. Appl. Phys. 1, 1779–1791.
Stirzaker R J, Passioura J B, Sutton B G and Collis-George N 1993 Soil management for irrigated vegetable production. 2. Possible causes for slow vegetative growth of lettuce associated with zero-tillage. Aust. J. Agric. Res. 44, 831–844.
Stirzaker R J and Passioura J B 1996 The water relations of the root-soil interface. Plant Cell Environ. 19, 201–208.
Stirzaker R J and White I 1995 Amelioration of soil compaction by a cover-crop for no-tillage lettuce production. Aust. J. Agric. Res. 46, 553–568.
Tardieu F, Bruckler L and Lafolie F 1992 Root clumping may affect the root water potential and the resistance to soil-root water transport. Plant and Soil 140, 291–301.
Veen B W, Van Noordwijk M, De Willigen P, Boone F R and Kooistra M J 1992 Root-soil contact of maize, as measured by a thin-section technique. III. Effects on shoot growth, nitrate and water uptake efficiency. Plant and Soil 139, 131–138.
Wang J, Hesketh J D and Woolley J T 1986 Preexisting channels and soybean rooting patterns. Soil Sci. 141, 432–437.
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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Stirzaker, R.J., Passioura, J.B. & Wilms, Y. Soil structure and plant growth: Impact of bulk density and biopores. Plant Soil 185, 151–162 (1996). https://doi.org/10.1007/BF02257571
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DOI: https://doi.org/10.1007/BF02257571