Komponen Neraca Air Tanaman Kelapa Sawit di PTPN VIII, Cimulang, Bogor

Abstract

Rainfall interception is a process of keeping temporarily of the rain water on vegetation before evaporated back into the atmosphere. The loss of water through interception is an important part of the hydrologic cycle. Besides the interception, the water loss can be caused by evapotranspiration. Evapotranspiration is the loss of water through the soil and plant surfaces. This research was aimed to determine interception, stemflow, throughfall, and evapotranspiration. The results showed that there were 16 rainy days in 3 months period of observation which variation of daily rain from 4.83 mm/day to 95.53 mm/day. Stemflow and throughfall were increasing as the increase of rainfall. The value of stemflow obtained in field observation was very low i.e. fewer than 1%, therefore the value used for measuring interception was adapted from research conducted by Purba (2007) i.e. 7.8%. The stemflow values of each rainy day were obtained varied from 0.38 mm to 7.45 mm. The throughfall were obtained varied from 5.00 mm to 87.47 mm or from 73.00% to 127.84%. Generally, the interception values increase with the increase of rainfall, yet the percent of intercepted rainfall decreased, also the interception decreased stemflow and throughfall. The average value of interception varied between 0.51 mm and 4.32 mm or from 0.64% to 19.20%. Decreasing soil moisture in 30 cm root depth were 2.40 mm/day. Decreasing soil moisture in 60 cm root depth were 4.28 mm/day. Those values were equal to evapotranspiration.