Plant-Soil Interactions at Low pH pp 227-237 | Cite as
Tolerance to acid soil conditions of the velvet beans Mucuna pruriens var. utilis and M. deeringiana
Abstract
Velvet beans, fast growing leguminous cover crops used in the humid tropics, are shallow rooted on acid soils. This might be due to an inherent branching pattern, to an intrinsic toxicity of the acid subsoil or to a relative preference for root development in the topsoil. Such preference could be based on soil chemical factors in the subsoil or on physical factors such as penetration resistance or aeration.
In a field experiment with two species of velvet bean (Mucuna pruriens var. utilis and M. deeringiana) all topsoil was removed and plants were sown directly into the acid subsoil. Root development was neither affected by this treatment nor by P fertilization or liming. In the absence of topsoil good root development in the exposed upper layer of subsoil was possible, so the hypothesis of a toxicity per se of the subsoil could be rejected.
To test whether poor root development in the subsoil in the presence of topsoil is due to an inherent branching pattern of the plant or to a relative preference for topsoil, a modified in-growth core technique was used. Local topsoil and subsoil and an acid soil with a higher exchangeable Al content were placed in mesh bags at different depths and at different bulk densities, with and without lime and/or P fertilizer. A comparison of root development in mesh bags placed in the topsoil or subsoil showed that position and thus inherent branching pattern is not important. Root development in the subsoil was poor when this soil was placed in a mesh bag in the topsoil, but in an acid soil of much higher exchangeable Al content and higher percentage Al saturation more roots developed. In a second experiment in mesh bags, bulk density of the repacked soil in the range 1.0—1.5 g cm−3 had no significant effect on root development. P fertilization and a high rate of liming of the soil placed in the mesh bag had a positive effect on root length density. It is concluded that poor root development in the acid subsoil under field conditions is due to a relative preference for topsoil. Al saturation and bulk density of the soil are not directly involved in this preference, but differences in availability of P and Mg or in Ca/Al ratios might play a role.
Key words
aluminium toxicity in-growth core technique split-root experimentsPreview
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References
- Anderson J M and Ingram J S I (Eds.) 1989 Tropical Soil Biology and Fertility: A Handbook of Methods. C.A.B. International, Wallingford. 171 p.Google Scholar
- Blarney F P C and Edwards D G 1989 Limitations to food crop production in tropical acid soils. In Nutrient Management for Food Crop Production in Tropical Farming Systems. Proc. Symp. Malang, 19–24 Oct. 1987. Ed. J van der Heide. pp 73–94. Institute for Soil Fertility Research, Haren, The Netherlands.Google Scholar
- Bolan N S, Barrow N J and Posner A M 1985 Describing the effect of time on sorption of phosphate by iron and aluminum hydroxides. J. Soil Sci. 36, 187–197.CrossRefGoogle Scholar
- Bruce R C, Warrell L A, Edwards D C and Bell L C 1988 Effects of aluminium and calcium in the soil solution on root elongation of Glycine max cv. Forrest. Aust. J. Agric. Res. 38, 319–338.CrossRefGoogle Scholar
- Cuevas E and Medina E 1988 Nutrient dynamics within Amazonian forests. II. Fine root growth, nutrient availability and leaf litter decomposition. Oecologia76, 222–235.CrossRefGoogle Scholar
- De Jager A 1985 Response of plants to a localized nutrient supply. Doctoral thesis, University of Utrecht. 137 p.Google Scholar
- De Willigen P and Van Noordwijk M 1989 Model calculations on the relative importance of internal longitudinal diffusion for aeration of roots of non-wetland plants. Plant and Soil 113, 111–119.CrossRefGoogle Scholar
- Hairiah K and Van Noordwijk M 1989 Root studies on a tropical ultisol in relation to nitrogen management. Institute for Soil Fertility Research, Haren, The Netherlands. Report 7-86. 121 p.Google Scholar
- Hairiah K and Van Noordwijk M 1989 Root distribution of leguminous cover crops in the humid tropics and effects on a subsequent maize crop. In Nutrient Management for Food Crop Production in Tropical Farming Systems. Proc. Symp. Malang, 19–24 Oct. 1987. Ed. J van der Heide. pp 157–169. Institute for Soil Fertility Research, Haren, The Netherlands.Google Scholar
- Hairiah K, Stulen I and Kuiper P J C 1990 Aluminum tolerance of the velvet beans Mucuna pruriens var utilis and M. deeringiana. I. Effects of aluminum on growth and mineral composition. In Plant Nutrition-Physiology and Applications. Ed. M L van Beusichem. pp 365–374. Kluwer Academic Publishers, Dordrecht.CrossRefGoogle Scholar
- Heide J van der, Setyono S, Syekhfani, Flach B, Hairiah K, Sunarto and Noordwijk M van 1991 Can low external input cropping systems on acid upland soils in the humid tropics be sustainable? AGRIVITA (In press).Google Scholar
- Horst W J, Klotz F and Szulkiewicz P 1990 Mechanical impedance increases Al tolerance of soybean roots. Plant and Soil 124, 227–231.CrossRefGoogle Scholar
- Schuurman J J and Goedewaagen M A J 1971 Methods for the examination of root systems and roots. 2nd ed., PUDOC, Wageningen. 86 p.Google Scholar
- Scott B J and J A Fisher, 1989. Selection of genotypes tolerant of aluminium and manganese. In Soil Acidity and Plant Growth. Ed. A D Robson. pp 167–203. Academic Press, Sydney.Google Scholar
- Tennant D 1975 A test of a modified line intersect method of estimating root length. J. Ecol. 63, 995–1001.CrossRefGoogle Scholar