PENGUKURAN RETENSI AIR TANAH GAMBUT MENGGUNAKAN KOMBINASI THREE PHASE METER DAN CERAMIC PLATE
Water retention and particle density (PD) measurement on tropical peat are rarely. Appropriate measurement method for both are obviously required because these values are very important in peatlands management. This study was aimed to measure water retention of peat soil, to understand the water retention, to draw the pF curves and also to study the effect of changes in soil moisture content on peat volume. Peat soil samples were taken from three locations with different reclamation age. Peat water retention were measured using Ceramic Plate, peat volume were measured using Three Phase Meter, and pF curve equation was made using Genucthen (1980) model. The results showed that the pattern of soil water retention in peat at three locations with different land uses were similar. Water in peat soil was easily lost at low pressure ( pF 0-2 ) and strongly bound by peat soil material at a higher pressure (pF 2-4,2 ). Peat pore was dominated by fine pore ( ± 40 % v/v ) and very fast drainage pore ( ± 30 % v/v ). Interval of available water was very small ( < 10 % v/v ). The changes of water content would affect the volume of peat. Peat soils swell and shrink significantly. The intensity of the swell and sringkage are estimated to depend on the origin and degree of decomposition of peat materials. Particle density of peats were found to vary, so direct measurement must be performed.
Keywords: Genucthen, peat, pF curves, water retention