African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6574

Full Length Research Paper

Effects of calcium carbonate, prunings of Gliricidia Sepium and maize variety on an ultisol

S. A. Robert1*, J. S. Robinson2 and E. R. Rhodes1
1Sierra Leone Agricultural Research Institute, PMB 1313, Freetown, Sierra Leone. 2Department of Geography and Environmental Sciences, University of Reading, P. O. Box   233, Whiteknights, Reading, Berkshire RG6 6DW, United Kingdom.
Email: [email protected], [email protected]

  •  Accepted: 12 November 2013
  •  Published: 30 November 2013

Abstract

The potential of the agroforestry species Gliricidia sepium, as a liming material needs to be investigated in the search for alternatives to slash and burn agriculture. Lime (CaCO3) and organic residue in the form of Gliricidia sepium prunings, were incubated with an acid, P deficient ultisol from Sierra Leone at different rates to target pH values 5.0, 5.5, and 6.3 for 70 day. Although in several cases the target pH values were not met, the rates of application of the amendments, based on soil pH buffer capacity and neutralising value of the amendment, decreased the Al saturation from 89% to less than 10%. While CaCO3 often decreased P, Mg and K availability in the soils, Gliricidia prunings increased these essential nutrients.  The Al-sensitive and Al-tolerant maize genotypes subsequently grown for 28 day in the amended soils following incubation decreased the soil pH, but also decreased the Al saturation by markedly increasing the effective cation exchange capacity of the soil.

 

Key words: Aluminium toxicity, soil acidity, maize growth, liming, aluminium tolerance, P availability, Gliricidia sepium, agroforestry.