Can Moistube irrigation (MTI) self-regulate to ambient temperature and soil-atmosphere interface conditions? MTI performances under simulated temperature, wind, radiation, transpiration, and precipitation

Moistube irrigation (MTI) delivers water into soils through a semi-permeable membrane, driven by the potential gradient between the internal working pressure and external soil matric suction. This mechanism makes Moistube sensitive to atmospheric conditions. MTI’s dynamic interactivity with the soil-plant-atmosphere continuum renders MTI particularly suitable for optimising environmentally responsive irrigation performance and water use efficiency. In this study, treatments including changed temperature (TP), artificial wind (WD), simulated solar radiation (SR), alfalfa transpiration (TR) and rainfall (RF) were applied to investigate the soil water dynamics under MTI. Statistical analysis and numerical simulation of the experimental data were performed. Results revealed that elevated temperature significantly enhanced Moistube steady discharge, likely due to a warming-induced reduction in water surface tension and viscosity, which facilitated water transport through the nanopores. Regarding water fluxes, the WD, SR, and TR treatments accelerated MTI infiltration by enhancing moisture removal from the wetting front. Interestingly, despite inducing a slight surface cooling, the WD treatment still markedly increased infiltration rates, indicating that the stimulatory effect of soil evaporation prevailed over the cooling-induced suppression. Contrarily, the RF treatment intermittently suppressed infiltration rates due to soil moisture replenishment. This phenomenon, alongside the responses to the WD, SR and TR treatments, stemmed from the moisture-induced alterations in external water potential gradients that governed Moistube's hydraulic driving forces. The mechanisms of MTI's environmental interactions offer a principled framework for parameter optimisation in regions susceptible to diurnal and seasonal thermal variations, dynamic vegetation cover, or recurring rainfall, supporting informed management decisions in precise irrigation.