Submitted to: Proceedings of the International Cocoa Producer's Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 9, 2006
Publication Date: October 9, 2006
Citation: Baligar, V.C., Fageria, N.K., Machado, R.C., Meinhardt, L.W. 2006. Concentration and uptake of p,zn and fe as influenced by soil acidity, and levels and forms of n,p and fe in cacao. Proceedings of the International Cocoa Producer's Conference. 10.09.06 Technical Abstract: Many cacao plantation soils have become infertile and acidic as a result of long term cultivation, lack of fertilizer additions and leaching of nutrients. Deficiency of P, Zn and Fe in cacao has been reported. Greenhouse and growth room experiments were conducted with cacao to assess the effects of soil Al saturation, levels and forms of N (NO3-N, NH4N), P and Fe on concentrations and uptake of P, Zn, and Fe by cacao. Increasing soil Al saturation from 0.2 to 26% increased the concentrations of P, Zn and Fe in shoots. However increasing Al saturation to 26% reduced the uptake of these elements. Different source of N had significant effects on the concentrations and uptake of P, Zn and Fe. With the exception of P uptake, levels of N had no significant effects on Zn and Fe concentrations and uptake. Phosphorus levels in the growth medium had significant effects on the concentration and uptake of P, but had no effects on the concentration and uptake of Zn and Fe. Furthermore, with the exception of Zn uptake, the forms of Fe had significant effects on the concentration and uptake of P and Fe. Reduction of soil acidity constraints and the addition of N, Fe and Zn fertlizers to soils appears to be a key factor for improving P, Zn and Fe nutrition in cacao.