Effects of Nitrogen,Phosphorus,and Potassium Fertilizer on the Growth,Blossom,and N,P,K Uptake in Calendula officinalis L.

Fertilizer is one of the most important factors affecting flower growth.A greenhouse pot experiment was conducted with Calendula officinalis L.plants to study the effect of different fertilization regimes on growth,flowering,and absorption of nitrogen,phosphorus,and potassium.Results showed that the recommended fertilization treatment(using N-P₂O₅-K₂O:(0.4-0.2-0.3) g/kg) significantly promoted growth and flowering during the growing period in comparison to the control(no fertilization) and the habitual fertilization practice(using N-P₂O₅-K₂O:(0.3-0.15-0.3) g/kg).Dry weight of the plants under recommended fertilization increased by 16% and 264.3% in comparison to habitual fertilization and no(control) fertilization,respectively.Recommended fertilization also increased flowering,measured by total number of flowers produced,by 25.0% in comparison to habitual fertilization and 323.1% in comparison to the control.The largest amount of dry matter accumulation occurred between 29 and 35 days after transplantation,and reached 0.15 g/d in the control plants,0.43 g/d in the plants with habitual fertilization,and 0.42 g/d with the recommended fertilization treatment.Analysis of N,P,K accumulation for recommended treatment was 0.33 g/plant,0.04 g/plant,and 0.39 g/plant,which was 6.93,3.94,and 3.61 times the control and 1.49,1.35,and 1.24 times the habitual fertilization.The range ratio of N:P:K absorption was 1:(0.13-0.24):(1.20-2.30),with an average ratio of 1:0.17:1.65.