IMPACT OF HUMIC SUBSTANCES ON SOIL FERTILITY, GROWTH AND PRODUC- TIVITY OF PLANT GROWN ON NEWLY RECLAIMED SOILS

Abstract

This investigation was conducted to evaluate stability and maturity of composted rice straw (RS) and olive pomace (OP) to extract humic substances and determine their characteristics. As well as, to assess the impact of humification degree of these composted materials on metal loading capacity of extracted humic acids with Fe, Mn and Zn. In addition, the humic acids loaded with micronutrients were applied in two pot experiments and two field experiments to assess the impact of the concerned humic acids on soil fertility, growth, and productivity of plant grown on newly reclaimed soils. For this purpose, a composting experiment was carried out to evaluate the stability and maturity of three compost piles i.e. pile A (60% RS+10% OP+10% tomato hallum+10% banana residues+10% farmyard manure), pile B (50% RS+20% OP+10% tomato hallum+10% banana residues+10% farmyard manure) and pile C (40% RS+30% OP+10% tomato hallum+10% banana residues+10% farmyard manure). The mature piles i.e. A, B and C as well as compost D (cotton stalks and rice straw, farmyard manure) as comparative sample were used for extraction and purification of humic substances to determine characteristics of humic and fulvic acids (total acidity, carboxylic groups and phenolic groups, elemental analysis and IR absorption). Laboratory study was performed to determine loading capacity of