SOME CHARACTERISTICS OF A NEW ORGANIC SOIL CONDITIONER FROM THE CO-COMPOSTING OF OLIVE OIL PROCESSING WASTE-WATER AND SOLID RESIDUE

The effectiveness of a new organic soil conditioner from the co-composting of olive oil processing wastewater and solid residue was examined through the evaluation of some of its physical and chemical characteristics. The concentration of 25% w/w of this material into the conditioner-soil mixtures appears to be the maximum level for the cultivation of tomato plants. The plants grown on this conditioner-soil mixture were 1.52+/-8.5% times larger than those grown on a sandy loam soil. The pure conditioner cannot be used as a substrate for the growth of tomato plants. The water-holding capacity of the conditioner was almost two times higher than that of the pure soil and remained almost Stable for temperatures between 8-40 degrees C. The apparent density of the conditioner was 0.5 times smaller than that of the pure soil. With increased application rate of the conditioner to the soil, there was a decrease in the pH, an increase in the specific conductivity, and an increase in the ammonium-nitrogen (NH4-N) and phosphorus (P) concentration of the mixture.