This research was conducted to measure subsidence rate of fibric peat, soil physical properties, soil pH, and fluctuation of irrigation water table that affected subsidence rate. A field experiment has been done on fibric peat at Riak Siabun in Bengkulu. The experiment was arranged in Randomized Completely Block Design by five replicates with depth of drainage open channel as first factor and lime dosage as second factor. Results of the experiment showed that the subsidence rate of fibric peat was reached 3.54 cm/year, soil pH as 5,79 – 6,79, soil moisture content as 74,4 % – 132,27 % (based on soil dry weight), bulk density as 0,11 – 0,13 ton m-3
, decomposition level by van Post increased from H2
to H, and irrigation water table level accelerated 55,22 cm–110,29 cm near plot experiment and 39,6 cm–142,05 cm in other side. Not only soil moisture content decreases, but also soil pH and bulk density increase that affeted subsidence rate increasing
