Coffee seedling growth as affected by mycorrhizal inoculation and organic amendment

Abstract

An experiment was carried out to evaluate the effects of mycorrhizal inoculation and an organic amendment on coffee (Coffea arabica L.) seedling growth. A soil (fine, mixed, isothermic Typic Dystrudept) was either amended or unamended with composted coffee pulp (2:1 ratio, V:V), sterilized or not sterilized with Basamid™, and either inoculated or uninoculated with three mycorrhizal inocula: (i) Entrophospora colombiana, (ii) native Glomus spp., or (iii) a mix containing G. manihotis, G. fasciculatum, and E. colombiana. Plant growth and mycorrhizal activity were severely constrained in the unamended soil, which had low organic matter content, low pH, very high extractable aluminum (Al), and low availability of phosphorus (P), boron (B), calcium (Ca), magnesium (Mg), and potassium (K). Plants grew significantly better in the amended soil and further increases in coffee seedling height resulted with mycorrhizal inoculation. No significant differences were found among mycorrhizal inocula. In addition, sterilization significantly reduced plant growth in both amended and unamended soils.

Acknowledgments

This work was done with the financial support of the Regional Committee of Coffee Growers of Antioquia. We especially thank J. Almánzar and P.N. Maya of this committee, F.H. Orozco of the National University of Colombia for his cooperation, and also L. Delisle, D. Fallon, and D.R. Hurchanik of the University of Hawaii for valuable suggestions on this manuscript.