Combined environmental stresses induced by drip irrigation positively affect most solar greenhouse grown tomato fruit quality

Abstract

To evaluate the potential for improvement of greenhouse grown tomato fruit quality under drip irrigation, this experiment was conducted in arid Northwest China for two consecutive growth cycles from 2017 to 2018 (summer and winter). Drip and furrow irrigation with different designed soil wetting proportions were employed in this study, and irrigation amounts were less in the drip than furrow irrigation. Results showed that the organoleptic quality, nutritional quality and antioxidant activity of tomato fruits generally improved under drip irrigation. However, compared with furrow irrigation, fruit fresh weight and size were significantly lower under drip irrigation in summer cycle, and the improvements in fruit quality attributes were relatively small in winter cycle. The combined environmental stresses, characterized by lower soil water content, higher air temperature, soil temperature and day and night temperature difference, were responsible for the improvements in fruit quality under drip irrigation. According to the correlation network analysis, firmness, b*, lycopene, β-carotene and total phenol were amongst the fruit quality parameters that essentially differed between drip and furrow irrigation. Furthermore, total phenol was important for the responses of tomato fruits to the combined environmental stresses under drip irrigation. In conclusion, drip irrigation in a naturally ventilated solar greenhouse could improve tomato fruit quality while achieving water-saving simultaneously.