African Journal of Biotechnology Vol. 10(34), pp. 6510-6515, 11 July, 2011 Available online at http://www.academicjournals.org/AJB DOI: 10.5897/AJB11.277 ISSN 1684–5315 © 2011 Academic Journals Full Length Research Paper Effects of olive oil solid waste on growth and nutrient uptake of faba bean, onion, and radish plants Saime Seferoglu Department of Soil Science, Faculty of Agriculture, Adnan Menderes University, Aydin, Turkey. E-mail: sseferoglu@adu.edu.tr. Tel: +90256 7727024 Ext: 1901. Fax: +90256 772 7233 Accepted 10 May, 2011 Although, olive oil industry is crucial for Turkey, olive oil solid waste or olive vegetation water, a by- product of the industry, leads to environmental pollution during olive oil production. This study investigated the fields where olive oil solid waste was used as an organic substance. Olive oil solid waste in different concentrations (0, 10, 20, 30 and 40 t ha -1 ) were applied to faba bean, onion and radish plants grown (in 1 m 2 plots) in the field conditions. Germination rates and growth of the plants were monitored. The application at the rates of 10 to 30 t ha -1 were determined as the most appropriate rates for both faba bean and onion. The higher rates of application negatively affected germination and growth of plants. The application at 20 t ha -1 concentration of olive oil solid waste provided the best results for faba bean and onion plants. However, none of the application rates were found suitable for radish. Keywords: Olive oil solid waste; germination; plant growth; plant analysis INTRODUCTION In recent years, environmental pollution caused by indus- trial waste materials has been one of the most substantial public issues in the world. Olive oil solid waste (OSW), a biomass material disposed by olive oil processing factories, is considered an important pollutant for the environment in olive producing countries; therefore, many olive oil processing companies directed themselves to find a recycling method to overcome this pollution problem. Turkey is the fourth leading olive producing country in the world and the fifth one for olive oil production (FAO, 2009; IOC, 2009). Although, olive oil production through olive makes a great profit; significant amount of waste materials are released improperly, resulting in a signifi- cant environmental pollution problem. In order to reduce or prevent improper releasing of olive wastes, due precautions have to be taken urgently. In that point, OSW utilization in different ways must be considered. Oil and various by-products are derived from olive during oil extraction process. One of these by-products, OSW is an acidic liquid substance and very rich in terms of organic Abbreviation: OSW, Olive oil solid waste. compounds and minerals. Although, OSW may be utilized as a plant nutrient, it contains a high level of waste materials that are potential pollutants for the environment. In spite of its adverse effects to environment, OSW has some benefits as previously reported from different countries. Indications that OSW consists of organic contents and several mineral nutrition materials such as N, P, K and Mg, Ursinos (1986) described several alter- native utilization methods for OSW commonly used in the olive producing countries such as fertilizer, irrigation water, animal feeding product additive, bio-fuel, and heating material. Puskulcu et al. (1995) stated that approximately 500000 tones of OSW are released to the environment every year in Turkey, which means that 3500-11000 tones of K 2 O, 650-2000 tones of P 2 O 5 and 150-500 tones of MgO are wasted. In addition, the rise in mineral fertilizers prices in recent years cause inadequate crop fertilization. When the cost of mineral fertilizers is taken into account, utilization of OSW having high organic and mineral nutrient contents is almost free. In order to obtain high quality crop in satisfactory quantity, optimization of nutrient contents and inducing living organism popu- lations in soil need to be achieved by adding organic matters. On the other hand, since animal manure, a well