Groundwater altered water balance and plant water use efficiency in desert ecosystems - based on large-scale weighing lysimeters

Groundwater is an important water source in water-limited desert ecosystem. Less attention has been paid to how the water balance and plant performance in such ecosystems vary with the presence or absence of groundwater. Appropriate replanting strategies play a pivotal role in preventing desertification. In this study, we used twelve large-scale weighing lysimeters with different replanting configurations, ranging from bare soil to various monocultures and mixtures of shrubs and semi-shrubs, to quantify water balance components and plant growth dynamics in contrasting desert ecosystems (groundwater-dependent vs. groundwater-independent) during 2019-2023. The results indicated that actual evapotranspiration in groundwater-dependent desert ecosystems was greater than in groundwater-independent ones. Linear mixed-effects models showed that groundwater had a significant effect on the water balance components and enhanced plant growth performance. Boosted regression tree models indicated that groundwater alleviated the influence of drought and sparse rainfall on the water balance components in deserts. The water use efficiency (WUE) of the semi-shrub A. ordosica (Ao) in monoculture was 6.74 and 3.10 kg m^-3 in desert ecosystems with and without groundwater, respectively. The WUE of the C. korshinskii shrub (Ck) in monoculture and in a mixture with the semi-shrub A. ordosica (Ao & Ck) in groundwater-dependent desert ecosystems was 3.05 and 2.64 kg m^-3, respectively. Vegetation restoration in arid areas serves as an effective nature-based solution for desertification control, where tailored replanting strategies are key to ensuring long-term sustainability.

Nan, Y. C., Huo, J. Q., Han, G. L., et al. (2025), Groundwater altered water balance and plant water use efficiency in desert ecosystems. Water Resources Research, 61(11), 1-15. doi: 10.1029/2025WR040545