Nanobubble (NB) technology in agriculture has received increased interest due to its potential to promote soil moisture retention and plant development. Therefore, this review investigates the impact of various types of NBs—such as oxygen, carbon dioxide, and air—on soil and plant systems. Various studies revealed that nanobubble-saturated water (NBSW) increases moisture retention, microbial activity, and nutrient absorption, which contribute to better plant development. However, there are still gaps in understanding the specific roles of different gases regarding their stability, interactions with soil, and long-term agricultural impacts. This review aims to combine previous research by focusing on various types of NBs impact on soil moisture, water quality, and nutrient retention. Challenges include the quick dissolution of particular gases, limited field studies, and scalability. The analysis showed that despite these challenges, NBs have potential for enhancing agriculture by improving soil structure and crop yield. More study is needed to maximize their application, particularly in determining the most effective gas types and concentrations for certain agricultural areas.

Nanobubble-saturated water (NBSW) has received significant attention in water management in recent years. Therefore, three parallel experiments (E1, E2, and E3) were conducted on two silty loam soils (one with 12.11% higher clay) and sandy loam soil, with additional biochar amendments in each soil type, to assess air NBSW’s impact on soil moisture, nutrient retention, and plant growth. The results revealed increased soil moisture retention in the sandy loam and silty loam soils with a lower clay content. It reduced the K⁺ input compared to conventional watering without highly affecting the amount of leached-out substances. Biochar amendment significantly reduced the TDS losses from silty loam with a higher clay content and reduced the leaching of NO₃⁻, Ca²⁺, and K⁺ from sandy loam soil. Air NBSW enhanced the stomatal conductance in California pepper plants in silty loam and sandy loam soils but had no effect on silty loam with a higher clay content. A decrease in chlorophyll concentrations and stomatal conductance was observed when air NBSW was combined with biochar in sandy loam soil. The study highlighted that air NBSW alone does not significantly affect water and nutrient retention or key plant parameters. However, its combination with biochar can enhance agricultural water management and sustainability by increasing soil moisture retention and reducing nutrient leaching.

This study examined the impact of watering with air and oxygen nanobubble-saturated water (NBSW) on soil moisture retention, electrical conductivity (EC), nutrient leaching, and CO₂ emissions in sandy loam (SL) and silty clay loam (SCL) soils amended with composted sludge (CS). The results revealed that air nanobubbles (air NBs) had greater stability, while oxygen nanobubbles (ONBs) showed lower stability but higher oxygen diffusion potential. Soil moisture under NBSW treatment was more sensitive to changes in ambient conditions and tended to decrease due to higher evaporation compared to conventional water. NBSW was more effective in enhancing moisture in SL soil than in SCL soil. Overall, the results revealed that the application of NBSW tended to increase soil compaction due to stimulation of microbial activity; however, air NBs may temporarily reduce compaction and enhance soil–water interactions. Additionally, NBSW increased soil EC due to increased dissolved ion concentration, with effects more apparent in SL soil than in SCL. This may indicate increased nutrient availability for plant uptake. Notably, NBSW, particularly ONB, showed quick but short-lived changes in soil physical and microbial properties, and soil texture played a significant role in treatment results. Furthermore, the leaching of nutrients and heavy metals remained negligible across all treatments. The study confirms that using NB in controlled environments is more practical for boosting short-term plant growth than improving long-term soil water retention to support more sustainable agriculture systems.

This study examined the long-term effects of nanobubble-saturated water (NBSW) on silty clay loam and sandy loam soils, with an emphasis on soil moisture dynamics, water balance, compaction, and electrical conductivity (EC) over a 1.5-year experimental period. NBSW did not induce a significant long-term increase in soil moisture storage compared to conventional watering, though there were short-term changes. In both soils, NBSW caused higher cumulative evaporation and reduced leaching in water partitioning. Compaction increased over time, and this response was stronger under NBSW, with a greater increase in silty clay loam than in sandy loam. EC remained higher in both soils under NBSW treatment, with a greater temporal increase in sandy loam and permanently higher levels in silty clay loam, indicating more dissolved-ion retention in the soil profile and less leaching. Compaction and EC were normalized to the maximum measured soil moisture. This study reveals that NBSW has a greater long-term influence on water-loss partitioning and root-zone solute dynamics than it does on long-term soil water storage.

Nanobubble-saturated water (NBSW) is widely seen as a potential innovation for sustainable agriculture; however, its overall environmental impact still requires clarification. This study examined the sustainability performance of NBSW using laboratory experiments, a life-cycle assessment (LCA), and an expert-based feasibility evaluation. Air and oxygen nanobubble (ONB) watering were applied to silty clay loam and sandy loam soils, and environmental impacts were assessed using ILCD 2011 midpoint indicators. The results revealed that the electricity required for NB generation was the most significant contributor to the impacts across all categories, while material and nutrient inputs had only a minor impact. Air-NB and ONB treatments demonstrated similar life-cycle profiles because of their comparable energy demand. Conventional watering did not involve electricity use but increased nitrate leaching in sandy soil, leading to the possibility of eutrophication. Expert assessments indicated that future adoption of NBSW depends mainly on reducing energy consumption and improving operational reliability and cost efficiency. When combined with low-carbon energy and efficiency improvements, NBSW may contribute to reducing nutrient losses and enhancing resource efficiency in watering. These findings show that NB technology has potential as an eco-innovation, but more study is needed before it can be considered a viable circular-agriculture solution.

Nanobubble-saturated water (NBSW) has gained prominence in agricultural research due to its ability to affect root-zone oxygenation and soil–plant interactions. This review aimed to analyze the available research on the impacts of NBSW on soil moisture storage, percolation, electrical conductivity (EC), microbial activity, and soil structural dynamics across different gas types and soil textures. Therefore, a systematic literature search was carried out, and the retrieved publications were synthesized with keyword co-occurrence and bibliometric analysis. This review fills the gap in the literature by integrating findings on root-zone oxygenation, nutrient dynamics, and soil structural responses into a single framework. Research showed that NBSW may influence water partitioning by increasing evaporation and lowering percolation, leading to different vertical moisture gradients. However, the effects could be impacted by the soil texture, as finer textures retained more moisture, while coarser soils increased oxygen penetration and microbial stimulation. Furthermore, increased oxygen availability under NBSW further changed microbial community activity, which could impact soil CO₂ emissions and nitrogen and phosphorus cycling. While repeated NBSW application may gradually increase soil compaction, particularly in finer-textured soils, overall, NBSW demonstrated versatile watering modifications that might influence soil physical, chemical, and biological processes. However, further research is needed to determine the appropriate gas types and application strategies for different soils under real field-scale agricultural conditions.