Micro-nano bubble water oxygation: Synergistically improving irrigation water use efficiency, crop yield and quality

Coordination of water saving, yield and quality increase remains an attractive problem in agricultural production. Transporting irrigation water rich in micro-nano bubbles and fertilizers to the crop root zone through subsurface drip irrigation is expected to be an effective technique. In present study, cucumber and tomato cultivated in greenhouse were subjected to investigate the effects of three mixing ratios of micro-nano bubble water and groundwater combined with three different oxygation frequencies on irrigation water use efficiency, crop yield and quality. The results indicated that micro-nano bubble water oxygation could significantly increase their yield, irrigation water use efficiency and fruit quality (p < 0.05) without increasing the amounts of irrigation water and fertilizer, which demonstrated a cleaner production being friendly to soil ecological environment and sustainability using water saving technology. In the optimal treatment, the yield, irrigation water use efficiency, vitamin C, and soluble sugar of tomatoes increased by 16.9%, 16.9%, 17.7% and 39.2%, while those for cucumbers were 22.1%, 22.1%, 16.7% and 19.4%, respectively. This was mainly due to the increased soil oxygen content, longer retention time and stronger mass transfer ability of micro-nano bubbles. The recommended micro-nano bubble water oxygation mode for tomato plantation was the mixing ratio of 1:4 combined with the frequency of once every 5d, while that of cucumber being the mixing ratio of 1:0 with the same frequency with tomato. The study aims to provide a novel concept for the synergistic realization of water saving, yield increases and quality improvements in greenhouse crop production using subsurface drip irrigation.