Dynamics of Physicochemical Parameters During Composting of Olive Pomace andCattle Manure

摘要

The aim of this study is to evaluate the maturity of the compost product. This was performed by measuring some of the main physico-chemical parameters of the mixture of olive pomace and cattle manure that were composted in different proportions. It must be noted that the composting was conducted at a medium experimental scale. The proportions of olive pomace to cattle manure were as the following: 1/1, 2/1, 3/1, 4/1, with a control for each of the used raw materials. Several parameters of the piles such as temperature, density, pH, electrical conductivity, total nitrogen, organic matter, ammoniumitrate ratio, available phosphorus and extractable potassium were periodically monitored. It was noticed a difference in the temperature for the treatments that were rich in carbon compared to the manure control. In addition, the results showed significant differences (P<0.05) between the different applied treatments during the composting process as follows: the pH tends, in all treatments, to shift to neutral (~7-8), while the electrical conductivity decreased but remained high in the manure control. The value of the ammoniumitrate ratio was lower than one unit especially in the mixture (1/1). The Carbon/Nitrogen ratio (C/N) decreased in all treatments. The lowest C/N ratio and the highest phosphorus and potassium contents were noticed in the mixtures (1/1 and 2/1). This study shows that the mixture of olive pomace and cattle manure with the proportions 1/1, 2/1 were probably adequate to be used in the composting process of the used raw materials. However, the duration of composting must be over five months in order to obtain an adequate C/N ratio that may indicate a real state of the maturity of the compost.