Effect of Adding Different Levels of Potassium Humate and Olive Mill Wastewater on The Physical and Hydro-Dynamic Properties of Subsurface Soil Layers and Potato Plant Production

The research was conducted in fall 2019 on silty clay soil at the Center of Scientific Agricultural Research in Latakia. It involved nine treatments comprising additions of olive mill wastewater at 0, 2, 4 L.m-2 and potassium humate at 0, 10, 20 kg.ha-1. The results showed a significant decrease in bulk density at 0.26 g.cm-3 from the highest rates of each treatment compared to the control at 1.4 g.cm-3. Increasing the treatment levels improved soil porosity compared to the control, while the a and b values of the constants also increased. This is considered a good indicator of better water availability to the plant for the olive mill wastewater treatments. Potassium humate was added at the same moisture tension value. The average production of potato tubers at the highest treatment levels was significantly above that for other treatments, increasing by 80%. This was followed by the 64.45% and 63.43% production increase from the olive mill wastewater and potassium humate treatments of 4 L.m-2 and 10 kg. ha-1 and 2 L.m-2 and 20 kg.ha-1, respectively