The Effect of Sugar Beet Molasses and Olive Mill Wastewater (OMWW) on some Soil Physical and Hydrodynamic Properties and on Potato Productivity

Agro-industrial residues are a good alternative to reduce the dependence on large quantity of chemical fertilizers, leading to lower production costs and higher soil productivity.  The research evaluated the effect of sugar beet molasses and OMWW by-products of sugar and olive oil production, on potato productivity as well as some physical and hydrodynamic characteristics of a silty clay soil in the Syrian Coastal Area.  A randomized complete block design field trial was conducted using four rates of OMWW (M0=0, M1=5.4, M2=10.8, M3=16.2 L m-2) and four levels of sugar beet molasses (B0=0, B1=75, B2=150, B3=225 L ha-1). The results showed that soil bulk density (BD) and pores containing unavailable water (PUW) followed a declining trend with rising levels of OMWW and molasses towards gaining the maximum decrement at the treatment B3M3 (16.2 L m-2 of OMWW and 225 L ha-1 of molasses) versus the control (B0M0). Soil water retention curves showed that using OMWW and molasses together at the treatment B3M3 increased water content. The total porosity (TP), macropores >10 μm, pores containing plant-available water (0.2-10 μm) (PAW), and potato productivity experienced the same upward trend with increasing amendment levels separately or together (molasses and OMWW), reaching 63.17, 25.97, 18.87%v and 4551 kg dunum-1, respectively, at the treatment B3M3.