Stable soil moisture promotes shoot performance and shapes the root-rhizosphere microbiome

Authors: LIU, DICHUAN - Chinese Academy Of Agricultural Sciences; WANG, ZHUAN - Chinese Academy Of Agricultural Sciences; ZHU, GUOLONG - Chinese Academy Of Agricultural Sciences; XU, AIQUO - Chinese Academy Of Agricultural Sciences; ZHANG, RENLIAN - Chinese Academy Of Agricultural Sciences; Bryant, Ray; DROHAN, PATRICK - Pennsylvania State University; LONGA, HUAIYU - Chinese Academy Of Agricultural Sciences; WILLEMSEN, VIOLA - Wageningen University And Research Center

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2025
Publication Date: 2/11/2025
Citation: Liu, D., Wang, Z., Zhu, G., Xu, A., Zhang, R., Bryant, R.B., Drohan, P.J., Longa, H., Willemsen, V. 2025. Stable soil moisture promotes shoot performance and shapes the root-rhizosphere microbiome. Agricultural Water Management. 310(2025)109354. https://doi.org/10.1016/j.agwat.2025.109354.
DOI: https://doi.org/10.1016/j.agwat.2025.109354

Interpretive Summary: Negative pressure irrigation is a recent technology for irrigating crops that can maintain a stable soil moisture. Current research suggests than plants grow better with stable soil moisture than under manual irrigation methods in which soil moisture fluctuates. Rhizosphere microbes grow on some plant roots and are very important in moving water and nutrients from the soil into the roots. However, little is known about how these rhizosphere microbes function when they are in stable soil moisture conditions where the soil does not dry out or get flushed with excess water during the growing season. We assessed, via a pot experiment, the effect of soil moisture dynamics on plant growth, yield, water use efficiency, and rhizosphere bacterial and fungal community structures. We found that lettuce grew more and used water more efficiently under stable soil moisture conditions than under fluctuating moisture conditions, even when total amounts of water were the same. The microbial community composition of the lettuce rhizosphere was different in the two cases also. When soil moisture was steady, three microbes -- Bacillus, Aspergillus, Chaetomium and Talaromyces -- did better in the lettuce rhizosphere, and three -- Proteobacteria, Patescibacteria and Alternaria – did worse. Our results suggest that higher lettuce yield may be due to these differences in rhizosphere microbial communities of lettuce, instead of being directly affected by soil moisture regimes. This is an important step toward a better understanding of plant response to this negative pressure irrigation technology.

Technical Abstract: Soil moisture change process can be divided into fluctuating soil moisture (FSM) and stable soil moisture (SSM). Most existing research on the response of rhizosphere microbes to soil moisture is based on FSM, and little is known about the response pattern of rhizosphere microbes under SSM. We assessed, via a pot experiment, the effect of soil moisture change process on plant growth, yield, water use efficiency (WUE) and rhizosphere bacterial and fungal community structures. The FSM was created via manual irrigation and the SSM via negative pressure irrigation (NPI). Results indicate that lettuce grown under SSM has a higher yield and WUE. The microbial community composition of the lettuce rhizosphere was found to be different under SSM and FSM. Under SSM, Bacillus, Aspergillus, Chaetomium and Talaromyces was enriched at Lettuce rhizosphere, while some microbes were reduced such as Proteobacteria, Patescibacteria and Alternaria; this result could be a biomarker responding to soil moisture change process. PLS-PM results reveal that rhizosphere microbial communities were indirectly affected by soil moisture change process as evidenced by improving plant growth. Our results suggest that rhizosphere microbial communities of lettuce responded to changes in soil moisture change process primarily through the interaction of plant and microbes, instead of being directly affected by soil moisture regimes.