Fertilizing effect of the application of sugarcane ash and mycorrhizae to different soils in Cuba

Abstract

In Cuba, sugarcane ash is produced in enormous quantities as a residue of the sugar industry. On the other hand, the lack of sufficient research limits its use as a fertilizer. In order to determine the effect of sugarcane residue ash, alone and together with mycorrhiza, on the plant compared to NPK chemical fertilizers, a field study and a pot experiment were carried out with two different Cuban soils: Brown fluffy carbonated and Ferrallitic red agrogenic (Mollic eutrudept and Rhodic eutrustox) and corn as an indicator plant. Soil phosphorus and potassium concentrations were suboptimal/insufficient. The ash content was 1.03 % P2O5 and 2.54 % K2O. The mycorrhizal strains (Rhizoglomus irregulare and Glomus cubense) were applied with the commercial product EcoMic®. The results showed that sugarcane ash can be an adequate substitute for chemical fertilizers, due to its promoting effect on plant growth in both soils. Also, it was remarkable that only 5 t ha-1 of ash, if accompanied by mycorrhizal substrate, produced almost similar effect as 10 t ha-1 of ash in Rhodic eutrustox soil. On the contrary, when mycorrhiza was applied with 10 t ha-1 of ash in the Mollic eutrudept soil, the mycorrhiza far from increasing the effectiveness of the applied ash, showed a clear tendency to decrease its effect, probably due to a high nutrient supply with respect to the mycorrhiza requirements.

Keywords

• mycorrhizal fungi
• fertilization of tropical soils
• sustainable agriculture