Assessing the Role of Air Nanobubble-Saturated Water in Enhancing Soil Moisture, Nutrient Retention, and Plant Growth

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.