Recent advances in understanding the impact of extreme drought on belowground productivity in China's grasslands have been made by the team of Soil Fertility Improvement and Amelioration at the Institute of Agricultural Resources and Regional Planning (IARRP), CAAS. The research, conducted using the Extreme Drought in Grasslands Experiment (EDGE) platform, has revealed key mechanisms by which plant root systems regulate the effects of extreme drought through vertical redistribution. The findings have been published in National Science Review under the title "Vertical root distribution underpins belowground resistance to extreme drought". 

The impact of extreme drought on the productivity of grassland ecosystems is receiving increasing attention. Previous studies have primarily focused on aboveground productivity, with insufficient understanding of belowground productivity and how root systems in different soil layers respond to extreme drought. In particular, there is a lack of long-term, multi-site field validation based on a unified experimental method to determine whether root systems in different grassland ecosystems maintain belowground functions by adjusting their vertical distribution. The study selected six grassland ecosystems across China, spanning a distinct precipitation gradient, and conducted a continuous four-year extreme drought experiment. The results showed that extreme drought had a minimal impact on overall belowground net primary productivity and root biomass, but there was significant compensatory redistribution among different soil layers. The direction of the adjustment was found to be varied with rainfall and was closely related to soil moisture responses in different layers. The study elucidated the vertical distribution patterns of grassland plant roots under extreme drought and revealed the mechanism by which soil moisture changes regulate root redistribution among different soil layers, maintaining the stability of belowground net primary productivity and root biomass. It emphasized the crucial role of vertical root redistribution in drought resistance in grasslands, providing a new perspective for understanding and predicting belowground carbon cycling and ecosystem stability under future extreme drought conditions.

A relationship is shown between vertical root redistribution under extreme drought and soil moisture changes in different grasslands. 

Dr. Xu Chong, a postdoctoral researcher at the IARRP, is the first author. Associate Professor Zhang Yunlong from the College of Grassland Science and Technology at China Agricultural University is a co-first author. Research Professor Wu Honghui from the IARRP is the corresponding author, and Professor Melinda D. Smith from Colorado State University is a co-corresponding author. Academician Yu Guirui from the Institute of Geographic Sciences and Natural Resources Research at the Chinese Academy of Sciences, Academician Xu Minggang from Shanxi Agricultural University, and research Professors Zhang Wenju, Xin Xiaoping, and Yang Yadong from the IARRP are co-authors. This research was funded by the National Key Laboratory of Efficient Utilization of Arid and Semi-arid Farmland in Northern China, the National Natural Science Foundation of China (W2511021, 32171651), the Fundamental Research Funds for the Central Universities (QNTD202505), the Scientific and Technological Innovation Project of the China Academy of Chinese Medical Sciences (CI2024C003YN), and the Fundamental Research Funds for Central Public Welfare Research Institutes (G2026-01-58).

Link: https://doi.org/10.1093/nsr/nwag592