Post-drought productivity resilience in rubber plantations: Critical thresholds of water supply scheme and effects of water supply timing

Drought is a critical limiting factor for rubber plantations (RB) productivity. While numerous studies have documented drought impacts, scientific findings on post-drought productivity resilience remain scarce, particularly regarding water supplementation strategies to regulate recovery pathways. Therefore, we investigated gross primary productivity (GPP) resilience in RB at the northern tropical margin using a calibrated SEIB-DGVM validated with eddy covariance flux data, through multiple post-drought water supply scenarios designed based on ecological water demand (EWD), with variations in intensity, timing, and duration. The results exhibited that GPP resilience positively correlates with both percentage and gross quantity of post-drought water supply. Extending the distribution duration proves more advantageous when the gross water supply quantity is fixed, particularly ensuring adequate coverage through the first post-drought dry season, which determines whether the RB ecosystem GPP resilience will be compromised again. Drought termination timing influences post-drought GPP resilience. RB ecosystems exhibited superior GPP resilience when drought persisted until the peak-rainy season than when they ended in the early rainy season, despite equivalent drought intensities across conditions. RB ecosystems experiencing drought termination during early rainy season require sustained moisture availability for seven consecutive months post-drought, with water input (precipitation and supplemental irrigation) reaching 40 % of EWD, to achieve optimal post-drought GPP recovery. Conversely, RBs experiencing drought until the peak rainy season require a 9-month moisture support period; however, they have a lower cumulative water threshold of only 20 % of annual EWD. Our study provides a scientific basis for irrigation management strategies to enhance RB resilience under climate change conditions. • Prolonged irrigation outperforms high-intensity pulses for post-drought recovery. • The first post-drought dry season is critical to prevent secondary decline. • Duration-based strategies reduce water use while maintaining recovery efficacy. • Drought timing determines thresholds: 7 months/40 % vs. 9 months/20 % of water demand.