Abstract:

To optimize the water-saving irrigation technology of melon/sunflower intercropping mode, and improve irrigation water use efficiency in the oasis area, a field experiment comprising monoculture and intercropping of two crops (melon and sunflower) was conducted under nine irrigation systems to study the leaf water status and water use efficiency. The results showed that the water efficiency of the intercropping system was significantly higher than that of the melon and sunflower monoculture, increasing by 30.3% and 107.8%, respectively. Intercropping significantly increased the water saturation deficit of melon leaves at maturity stage and had no significant effect on relative water content, but reduced the relative water content and water saturation deficit of sunflower leaves at flowering and maturity stages. Under different irrigation times of intercropping, 8 times of irrigation and 9 times of irrigation were beneficial to improving the water use efficiency of the intercropping system. Under different irrigation quotas, the water use efficiency of the irrigation quota of 225 m³/hm² was significantly higher than that of 450 m³/hm² and 300 m³/hm² under the 8-time and 9-time treatments with an increase of 47.8 % and 21.4% and 37.6% and 31.0%, respectively. Under different intercropping irrigation times, 7 times irrigation was helpful to increasing the relative water content of melon leaves at maturity stage, and 8 times irrigation was helpful to increasing the water saturation deficit of both melon leaves and sunflower leaves at maturity stage, while the intercropping irrigation times had no significant effect on relative water content. Under different irrigation quotas for intercropping, the irrigation quota of 225 m³/hm² was beneficial to increasing the relative water content and water saturation deficit of melon leaves and relative water content of sunflower leaves, but the irrigation quota had no significant effect on sunflower leaf water saturation deficit. Under the melon/sunflower intercropping system in the Hexi oasis region, the more suitable irrigation system is to irrigate 8 times during the whole growth period with the water quota of 225 m³/hm².

Key words: irrigation system, melon/sunflower intercropping, relative water content of leaf, water use efficiency