## 1 Introduction  
Microorganisms, algae, and plants have capabilities to synthesize or metabolize molecular hydrogen (H\({}_{2}\)) [1, 2]. Among these, microbial H\({}_{2}\) cycling in agricultural soils is beneficial for plant growth [1]. For example, H\({}_{2}\) production/leakage during N\({}_{2}\)-fixation by rhizobia stimulated the proliferation of H\({}_{2}\)-oxidizing bacteria (HOB), carbon (C) fixation, and soil enzyme activities in rhizosphere soil [3, 4, 5, 6]. These findings were used to partially explain legume-associated benefits in crop rotation and plant growth promotion [3, 5, 6]. Further studies about rhizosphere bacteria and the surrounding soil revealed that numerous taxonomic groups, with Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria dominating, harbor specific sequence-encoding high-affinity group 1h [NiFe]-hydrogenases, therefore scavenging a trace concentration of H\({}_{2}\)[7, 8, 9]. Some Proteobacteria, including _Bradylhizobium japonicum_ and _Cuprizvidus reactor_, can use their low-affinity group 1d and 3d [NiFe]-hydrogenases to survive and grow on high levels of H\({}_{2}\)[10]. Surprisingly, various taxa can grow efficiently on a wide range of concentrations of H\({}_{2}\) using group 2a [NiFe]-hydrogenases [11, 12]. Ample evidence further revealed that H\({}_{2}\) exposure could influence soil biogeochemical processes and microbial communities [13]. Although the synthetic pathway of H\({}_{2}\) in higher plants is not elucidated, several lines of evidence clearly discovered increased H\({}_{2}\) production upon abiotic stress, such as drought [14], salinity [15], cold [16], and herbicide [17], as well as disease attack [18]. The involvement in plant responses was mostly validated when H\({}_{2}\) was supplied with H\({}_{2}\)-enriched solution or its fumigation [14; 15; 16; 17; 18; 19]. The physiological function of H\({}_{2}\) in plant responses against salinity [20] and drought [21] was further confirmed using transgenic plants overexpressing hydrogenase 1 gene (_CrHYDI_) from _Chlamydomonas reinhardtii_. This genetic approach further confirmed that plant-based H\({}_{2}\) can improve nitrogen uptake in Arabidopsis, particularly under low N supply conditions by targeting nitrate reductase, thus increasing seed size and yield [22]. Strawberry (_Fragaria \(\times\) ananssa_ Duch.) is cultivated globally and has a high commercial value. To cope with environmental and health concerns caused by excessive chemical fertilizer and pesticide application, seeking a more sustainable and low-carbon cultivation approach becomes an important issue. Compared to the above positive results obtained in the environmentally controlled laboratory conditions, the application of H\({}_{2}\) might have potential in agricultural benefits. However, the H\({}_{2}\) supplementation in field trials is a challenge for both researchers and farmers [23]. H\({}_{2}\) gas infusion was usually used for investigation of the H\({}_{2}\) effect on soil microbes, and the H\({}_{2}\)-pretreated soils were used for planting [3; 5; 6]. [PERSON] et al. [24] had buried pipes in soils for field H\({}_{2}\) infusion (1% H\({}_{2}\)). Therefore, this method for H\({}_{2}\) supplementation is unpractical in agricultural production. Besides, H\({}_{2}\) is used in a high concentration, where the inflammability of H\({}_{2}\) has to be considered. Due to the sensitivity of plants to H\({}_{2}\) (0.0004-0.0016%), a high concentration of H\({}_{2}\) infusion might have a negative effect on plant growth [19]. Comparatively, H\({}_{2}\) dissolved water is the better method for its easy operation and high safety (H\({}_{2}\) concentration \(<\) 0.0016%). Our previous field results show that the preharvest irrigation of hydrogen nanobubble water (HNW) can efficiently alleviate the negative effects of fertilizers on strawberry fruit aroma, thus improving consumer preferences [25].