Effect of different irrigation thresholds on growth and yield of garland chrysanthemum (Chrysanthemum coronarium L.) in greenhouse

An experiment was conducted to study the effect of different irrigation thresholds on yield and growth of garland chrysanthemum under simulated micro-spray irrigation in greenhouse. The experiment included six treatments, which controlled soil water potential (SWP) at 15cm depth with -10 kPa (T1),-15 kPa (T2), -20 kPa (T3), -25 kPa (T4),-30 kPa (T5) and -40 kPa (T6), respectively. The results showed that effect of different irrigation threshold on the crop yield was significant. Treatment T2 had the highest yield and compared with T1, T3, T4, T5 and T6, its yield increased by 0.5%，18.7%，62.6%，73.4%，71.7%，respectively. Irrigation amount of T2 was 195 mm throughout the growth period，saving 56.4% than that of T1. The plant height and growth rate of T2 had no difference from T1. When the irrigation threshold was lower than -25 kPa in SWP, garland chrysanthemum would be under severe water stress, negatively affecting seedling emergence and restraining its growth. The SWP of -15 kPa was recommended as the best irrigation threshold for garland chrysanthemum, because of both high-yield and water-saving.