| In this paper, the nutritional characteristics and fertilizer management of Cymbidium hybridum were studied adopting the means of potted experiments and indoors analyzes combined with production. The results can be summarized as follows:1. Orthogonal experiment indicated the optimal nitrogen (N) concentrations were different, but the optimal phosphorus (P) and potassium (K) concentrations were the same for two cultivars. For Cymbidium 'Nancy', the growth performance was the best with 100mg·L-1N and various growth indexes were significantly better than that of N2 (200 mg·L-1) ,N3 (300 mg·L-1) . The dry weight (DW) of total plant increased by 38.32% and 74.67% than that of N2, N3; The growth performance was the best with 200mg·L-1N for C. lunagrad 'Eternal Green', compared with N1, N3, the DW of total plant increased by 54.74% and 51.92% respectively. With 62 mg·L-1P and 274 mg-L"'K, the growth performance was the best and the biomass of plant was the biggest of the two cultivars.In the condition of this experiment, The optimum fertilization concentration of NPK for C. 'Nancy' and C. lunagrad 'Eternal Green' was N100 mg-L"1, P62 mg·L-1, K274 mg·L-1 and N200 mg·L-1, P62 mg·L-1, K274 mg·L-1, namely N : P2O5 : K2O was 1 : 1.24 : 3.3 and 1.41 : 1 : 2.33respectively.2. The experiment of different N forms proportions indicated the plant growth performance was better when NO3- —N : NH4+—N were 1 : 1 and 3 : 1 for C. Lucky Flower 'Anmitsu Hime'. For C. lunagrad 'Eternal Green', the plant growth performance was better when NO3-—N : NH4+—N was 1:1, but there were no significant differences among different treatments.The pour-through test results indicated NH4+—N treatment resulted in the decrease of pH value and the increase of EC value of media, NO3-—N treatment was reverse.SPAD results showed the leaves chlorophyll value of the treatment with sole NH4+— N was significantly less than that of other treatments for C. lunagrad 'Eternal Green'.3. The experiment of different strength with the same prescription showed vegetative growth and flowering were affected significantly by nutrient solution strength. The vegetative growth was better with EC of nutrient solution of 1.603.45mS·cm-1, while flower production was the highest and flower quality was the best at EC of 2.292.77mS-cm ' for C. 'Nancy', the number of flower bud and inflorescence per plant was 6.33 and 6.08, which was as much as 1.41, 3.17, 5.86 times and 1.52, 3.17, 5.63 times that of two control treatment (Tl, T7) and 3.60-3.96 mS-cnT1 (T6), the length of inflorescence was more than 60cm, which increased by 21.94%, 37.70% and 35.47% compared with Tl, T7 and T6, the number of florets per inflorescence was more than 13. EC value of nutrient solution 0.90 2.00 mS-cm"1 was suitable for vegetative growth of C. 'Walu Idol'. The number of flower bud and inflorescence per plant was 4.83 and 3.58 , which was as much as 1.18, 2.11 times and 1.13, 1.34 times that of Tl, T7 respectively with EC value of 0.901.25 mS-cm"1, and flower quality was best. In this experiment, the optimum EC value which can promote vegetative growth and flowering of C. 'Nancy' and C. 'Walu Idol' was 2.29—2.77 mS-cm"1 and 0.90—1.25 mS-cm"1 respectively.4. Analysis of leaf nutrients at different stages showed leaf total N content and ratio increased with development of plant at vegetative growth stage, and decreased significantly from middle stage to flower bud appearance, then increased during flower bud development period. Total P, K and Ca content varied differently because of cultivars. Leaf total Mg content was higher at vegetative growth stage, and there was a trend to decrease gradually after middle stage. |
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