Effects of irrigation on oil palm transpiration during ENSO-induced drought in the Brazilian Eastern Amazon

Oil palm plantations are rapidly expanding in the Brazilian eastern Amazon. Further expansion of irrigated oil may occur because they improve productivity during drought events compared to rainfed-only plantations. To investigate importance irrigation alleviate drought-induced stress on trees, and its potential as a management alternative, we monitored transpiration (T, mm day–1) five-year-old plantation an extreme caused by El-Niño Southern Oscillation (ENSO) event Amazon basin. Our study spanned over dry season (DS) wet (WS), using ongoing experiment (control with no irrigation, drip sprinkler irrigation), identify how differences water supply affect T period reduced precipitation induced ENSO. results indicate that independently system, was higher DS, WS. Higher soil moisture both treatments, relative control plot, allowed for 23% average plot. The vapor pressure deficit (VPD) variation presented effect than photosynthetic active radiation. In systems, rate increases VPD observed plot ENSO drought. Additionally, within individual fronds, also tolerance (higher lower older leaves) avoidance upper newer leaves). Results increased fruit production 35% 26% respectively. Overall, these demonstrate role maintain periods stress, while highlighting possible feedback increasing balance hydrologic regulation.