Estimating oil palm water usage in peat soils using sap flow technique

Abstract

Massive issues on significant water used by oil palm trees suggest further estimation of water exploited by oil palm trees. This research employed sap flow technique using thermal dissipation probes (TDP), compared to Penman-Monteith equation as the benchmark. Water utilization by plants was studied through evapotranspiration, to investigate their water footprint and water productivity. Field study was carried out in a 17 year old oil palm plantation in Siak, Riau, Indonesia. Sap flow measurement was carried out on the 17th frond over sapric peat soil during 7th January - 18th March 2019. Water used from 19th oil palm was 40.97±6.63 L day−1 equals to 0.51±0.083 mm day−1 (mean ±SD). While, estimation based on Penman-Monteith equation was 286.3 ± 64.078 L day−1 equals to 3.58±0.80 mm day−1 (mean ±SD). Total accumulated water from Penman-Monteith equation (286.3 L day−1) was considerably higher than the one from sap flow measurement (41 L day−1). The result showed that water footprint from 17 year old oil palm tree based on sap flow and Penman-Monteith equation was 0.204 and 1.43 m3 kg−1 fresh fruit bunches respectively. While water productivity estimated from sap flow was 0.70 kg m−3 while Penman-Monteith equation achieved 4.89 kg m−3.