## 3 Discussion  
### H\({}_{2}\)-Based Irrigation Represents a Sustainable Approach for Strawberry Yield Improvement  
Exploiting the benefits and corresponding mechanisms of H\({}_{2}\)-based irrigation improvement of both yield and quality traits represents a sustainable approach for low-carbon agricultural production [19]. This study integrated metagenomic and biochemical analysis to show that the altered rhizosphere microbial communities by H\({}_{2}\)-based irrigation might positively influence soil C, N, and P cycles, thus increasing plant nutrient uptake capacity and strawberry yield. Similar to the positive results obtained from small-scale field studies of rice in Qingpu, Shanghai [26], and dayliily in Suqian, Jiangsu Province [27], our field trials during 4-year growing seasons (2019-2023) confirmed that H\({}_{2}\)-based irrigation resulted in a remarkable increase in strawberry growth or yield under fertilization or non-fertilization conditions (Figure 1, Supplementary Figures S1 and S5, Table S1). Yield of H\({}_{2}\)-irrigated strawberry in 2022 and 2023 increased by 16.67\(\sim\)33.3% (planting area was extended to \(\sim\)0.82 ha, with the conventional management using fertilizers, the yield was estimated by the growers). Therefore, our findings are significant for both basic and applied hydrogen biology. Plant growth and yield are closely associated with soil nutrient dynamics [28]. Interestingly, our further results showed that H\({}_{2}\)-based irrigation in field trials led to a pronounced reduction in soil nutrients, regardless of whether fertilizers were present or not (Figure 2A). Accordingly, it is reasonable to deduce that above changes might be attributed to altered microbial nutrient metabolism and plant uptake. Promotional Effect of H\({}_{2}\) Might Be Linked with the Alterations in Rhizsphere Microbial Community Composition  
In contrast to the data reported by [PERSON] et al. [29], several laboratories discovered that a high concentration of H\({}_{2}\) infusion can influence soil microbial composition in environmentally controlled conditions [13; 30; 31]. For instance, elevated H\({}_{2}\) directly decreased the abundance of Actinobacteria, while it increased Gammaproteobacteria [5]. Although H\({}_{2}\)-based irrigation failed to influence the diversity of rhizosphere microbial communities (assessed by [PERSON], Shannon, and Simpson indexes; Figure 2B), our field trials also showed that microbial community composition was remarkably altered, especially in the absence of fertilizer (Figure 2C), suggesting a possible functional link between the alteration in microbial community composition and improved strawberry field achieved by H\({}_{2}\). Partially consistent with the results reported by [PERSON] et al. [31], our subsequent experiment revealed that after H\({}_{2}\)-based irrigation, increases in group 2a and 2b [NiFe]-hydrogenases were observed in strawberry rhizospheres under both unfertilized and fertilized conditions (Supplementary Figure S4). These results clearly indicated that bacteria with the ability to sense and oxidize H\({}_{2}\) might be activated in response to H\({}_{2}\) supply and rapidly utilize this energy source for growth. Certainly, we also admitted that under more variable field conditions, H\({}_{2}\) might be not the only driving factor influencing microbial survival, and other factors might include soil moisture, soil type, and plant species [24; 31], which need to be considered in the future field trials using H\({}_{2}\)-based irrigation. Changes in the composition of the rhizosphere microbial communities were observed at the phylum and genus levels in response to H\({}_{2}\)-based irrigation, especially under non-fertilization condition.