The effect of olive oil solid waste application on soil properties and growth of sunflower (Helianthus annuus L.) and bean (Phaseolus vulgaris L.)

Research on the reuse and recycling of agricultural by-products and industrial wastes are becoming increasingly important due to storage and environmental problems associated with these wastes. This study investigated the effect of olive oil solid waste (OSW) application rates on the macro- and micro-elemental contents and plant growth of bean (Phaseolus vulgaris L.) and sunflower (Helianthus annuus L.) and soil properties. OSW was mixed with soil at rates of 0, 3, 5 and 7% w/w. Sunflower was grown for 45 days and bean for 30 days in pots. Relative phosphorus (P), calcium (Ca), zinc (Zn) and boron (B) contents by mass of sunflower plants increased while nitrogen (N) and carbon (C) content decreased. In contrast in bean, P, B and Zn contents were increased but C, N, Ca, and manganese (Mn) contents decreased. Total carbon (TC), total nitrogen (TN) and electrical conductivity (EC) increased while pH decreased pot soils after harvesting. Direct application of OSW to clay loam soil has significant negative impacts on growth of sunflower and bean. However, soil properties were enhanced and organic matter content increased.