Olive mill wastewaters fractioned soil-application for safe agronomic reuse in date palm (Phoenix dactylifera L.) fertilization

Abstract

This study was conducted to evaluate the valorisation of soil and OMW-intrinsic natural degradation potencies as an alternative for safe agronomic management of raw OMW. The method adopted in this study consists in OMW storage and progressive supply in weekly small doses. In field experiment, results of three years application of crude OMW at relatively high dose (150 m3 ha-1 year-1) reveal no important perturbations as regard to edaphic parameters notably salinity, pH and phenolic content, thus asserting OMW biodegradation in the studied calcareous soil. Besides, plants growth was efficiently raised by OMW inputs. Significant amelioration was obtained notably in term of shoots weight, trunk height and crown circumference (145, 40 and 32%, respectively). In addition, date palm cellular detoxifying capacities were also evidenced by pots trials. Quantitative and qualitative accumulation of phenolics and their oxidation provide evidence of their protective role against the physiological stress induced by OMW. These results highlight the importance of OMW storage and amendment fractioning for toxicity mitigation. Along with the correct choice of convenient soils notably calcareous ones and tolerant crops such as date palm (Phoenix dactylifera L.), this method could constitute an efficient approach for avoiding problems attributed to the uncontrolled disposal of these effluents and efficiently recover their fertilizing value. © 2008 Asian Network for Scientific Information.