Combined management of olive mill wastewater and compost in olive grove: Effects on soil chemical properties at different layers depth

Abstract

The effects of combined agronomic application of olive mill wastewater (OMW) with compost were evaluated in an olive field (Tunisia). Four treatments were used. The first plot was spread by 50 m3 ha−1 of OMW, the second treated with 5 T ha−1 of compost, the third amended by both (50 m3 ha−1 + 5 T ha−1), and the fourth, used as a control. After ten days of organic amendment, the soil upper layers presented the highest organic matter (OM), total nitrogen, available phosphorus, exchangeable potassium and sodium contents, with the highest values noted for the mixed treatment. Also, this treatment exhibited the most important soil phenolic concentrations accumulation. All organic fertilizing treatments produced significant increase in the total alkali-extractable humic carbon (HEC), humic acid carbon (HAC) and fulvic acid carbon (FAC) concentrations, especially with OMW and compost applied simultaneously.