Reduction of synthetic fertilizer application and heavy metal absorption on oil palm nursery related to the application of humic substances

Abstract

Abstract Humic acid with amorphous and colloidal characteristics can improve soil chemical properties, especially tropical soil with lower fertility. To contribute to an environmentally friendly farming system, the capacity of humic acid to reduce the consumption of synthetic fertilizer on nursery oil palm was tested in this experiment. The experiment’s purpose was to confirm the minimizing fertilizer application and reduce the heavy metal absorption in oil palm nurseries without any deterioration effects on the growth performance. Varied composition types of humic substance products were applied, i.e., in combination with fish meal, seaweed, and chicken manure.The concentration of heavy metals Ba, Cd, Ba and the absorption of macroelements N, P, K, Ca, and Mg in the growing plants was also observed. It showed that humic acid in the dosage of 40 g/plant in the main nursery was capable of reducing the application of mineral fertilizer by 25% base on recommended standard application and at the same time reducing heavy metal Ba and Cd absorption by the plant.