Effect of Olive Mill Wastes on Soil Physicochemical Properties and Maize Yield Under Saline Soil Conditions

Abstract

 The addition of olive mill wastes (OMW) to agricultural soils has becoming a common disposal strategy to improve the soil’s physical and chemical properties. There is a dearth of information concerning the impact of OMW on soil properties in Egypt's saline soil conditions. Consequently, the aim of this study was to investigate the effects of various types of OMW on soil properties and maize yield in saline soil conditions. This study conducted field experiments in the North Sinai Governorate of Egypt on salt-affected sandy clay loam soil. Different types of OMW were applied at rates of 5 and 10 tons per hectare, either in fresh or compost form, individually or in combination with effective microorganisms (EM-1). The results revealed that the compost from EM-Bokashi and OMW treatment (T₇) at a rate of 10 tons per hectare significantly decreased pH, EC, and ESP values. For instance, application of T₇ significantly decreased EC by 30.6 and 34.8% compared to the fresh OMW treatment (T₃) at a rate of 10 tons per hectare in the soil depths of 0-10 and 10-20 cm, respectively. Moreover, the T₇ treatment significantly decreased soil bulk density by 18.7 and 20% compared to the control treatment (T₁) in the soil depths of 0-10 and 10-20 cm, respectively. However, the differences between T₇ and other treatments were not significant. Furthermore, the application of T₇ significantly increased maize yield by 38.5% compared to T₁. Overall, the best treatment for reducing salinity and bulk density as well as enhancing soil fertility and maize yields was the application of T₇ at a rate of 10 tons per hectare. Therefore, it is desirable to encourage farmers to use the compost of EM-Bokashi and OMW at the rate of 10 tons per hectare as soil amendment in order to enhance soil physicochemical properties and fertility status and to obtain high yields under saline conditions. This practice allows farmers to produce high yields even in saline conditions by improving soil physicochemical properties and fertility status.