Effect of ground water level and steel slag application on soil moisture variability and actual hydrophobicity of peat soil in oil palm plantation

Abstract

The study was carried out to study the effect of ground water level and steel slag application on soil moisture variability and actual peat soil hydrophobicity in oil palm plantation agro-ecosystem. The study plot was designed using split plot design with three treatments of water level management as main plot and four dosages of steel slag (electric furnace slag) application as sub plot. During the study, actual moisture content observation was carried out in the field for six times, representing dry and wet months. Actual hydrophobicity valuation was determined by comparing actual water content with the critical water content of peat hydrophobicity. The result showed that the ground water level apparently affected actual soil moisture content at layer of 0-2.5, 2.5-5 and 5-10 cm, especially during the dry month. The highest moisture content that can be stored at upper layer (0-10 cm) was obtained at the water level management of 40-60 cm from peat soil surface. At dry month, the groundwater level was too deep (>80 cm) will cause soil hydrophobicity of the layer 0-10 cm, at the circle area as well as at interrow area of oil palm tree. Steel slag application on the circle area until 9.86 kg/tree in the all water level management treatment plots did not apparently affected the soil moisture of the upper layer. Ground water level management at ranged of 40-60 cm could retain higher soil moisture and avoid the upper layer from hydrophobicity.