Effects of different drip fertigation regimes on yield, quality and nutrient uptake of cut chrysanthemum

Objectives Excessive fertilization is common in the production of cut chrysanthemum. We studied the possibility of reducing fertilizer application regime in cut chrysanthemum production using automatic drip fertigation system and the traditional fertilizer tank machine.

Methods Microplot experiment was conducted using cut chrysanthemum cultivar ‘Iwanohakusen’ as the test material. The four treatments were topdressing 4 and 7 times using drip fertigation equipment (T1 and S1), and fertilizer tank machine (T2, S2), with the same fertilizer rate per topdressing (75 kg/hm²) in each topdressing. At the 35, 62, and 85 days after transplanting, the agronomic and flower indexes, and plant NPK contents of cut chrysanthemum were determined, and the available NPK contents in soil were analyzed at 85 days.

Results Compared with fertilization tank treatment (S2 and T2), the fertigation equipment treatment (S1 and T1) recorded higher plant height, stem diameter, aboveground fresh weight, aboveground dry weight, underground fresh weight, and underground dry weight of cut chrysanthemum at 62 days, while T1 improved the plant height, aboveground and underground fresh weight of the chrysanthemum than S1. At 85 days, T1 recorded higher plant height than S2 and T2 but similar flower diameter and flowering rate as S1 and S2. T1 also recorded the highest plant K content at 35 days, the highest P and K contents in stems, leaves at 62 days, and the highest root P and K contents at 85 days. Further, T1 significantly increased the contents of available P and readily available K contents in soil at 62 and 85 days.

Conclusions Using fertigation equipment, reducing topdressing from 7 times to 4 times, i.e., reducing fertilizer rate from 525 kg/hm² to 375 kg/hm², improves the agronomic and flower traits of cut chrysanthemum ‘Iwanohakusen’, promotes the absorption and utilization of nutrients by the plant, and increases the available P and readily available K contents in soil, however, using fertilizer tank machine does not have the effect. Therefore, automatic drip fertigation equipment should be promoted to realize the fertilizer reduction and flower production efficiency of cut chrysanthemum.