| Eggplant(Solanum melongena L.) is one of the most important vegetables for sale in domestic and export markets, and the cultivation area expands year by year in our country. Applying fertilizer blindly and excessively to eggplant production, influenced yield and quality, increased production costs and reduced the economic benefits of eggplant. But there is rare research on fertilization and mineral nutrition absorption and distribution in eggplant. Compared with the formula of Yamazaki Eggplants(1978), the influences of combined application of nitrogen(N), phosphorus(P) and potassium(K) on growth, yields and qualities, and the uptake and distribution of N, P and K of eggplants were studied used vermiculite as culture substrate and nutrient solution, based on an optimized fertilization scheme of eggplant by computer analyzing. The results will provide a theoretical basis of water and fertilizer integrated management in production of eggplant. The main results were as follows:1. According to the data obtained, a mathematical model was established, in which N, P and K were independent variables and eggplant yields and qualities were dependent variables. The model analysis showed that N, P and K significantly influenced eggplant yields and qualities. K affected yields the most, then followed by N and P. K affected qualities the most and P is better than N. The interactions of NP, NK and NK for eggplant yields were significant, with the biggest interaction area being N at 13.75~22.00 mmol·L-1, P at 1.90~2.78 mmol·L-1 and K at 5.25~14.00 mmol·L-1. The interactions of NK for eggplant quality were significant, with the biggest interaction area being N 16.50~22.00 mmol·L-1, K 9.63~14.00 mmol·L-1.2. In this experiment, the scheme of fertilizers that the yields of eggplants per plant reached 3600 g, could use N 15.994~19.986 mmol·L-1, P 2.202~2.619 mmol·L-1, K9.893~12.857 mmol·L-1. The scheme that comprehensive score reached 90 could use N 18.028~19.986 mmol·L-1, P 2.202~2.587 mmol·L-1, K 10.645~12.857 mmol·L-1. In summary, scheme of high yield and quality of eggplants could use N 18.028~19.986mmol·L-1, P 2.202~2.587 mmol·L-1, K 10.645~12.857 mmol·L-1. The approptiate proportion of N, P and K was 7.9:1:4.9.3. The plant physiological indexs under the treatment of the optimum fertilization scheme(T) were better than CK. The plant height and stem diameter under T treatment were 11.0% and 12.9% higher than CK, respectively. The dry matter weight of roots, stems and leaves were 10.9%, 8.4%, 1.5% heavier than CK, respectively. The dry matter of fruits were 29.5% heavier. Chlorophyll a, chlorophyll a+b and carotenoid were higher than these under CK treatment significantly, which were 14.7%, 11.5% and 133.3% higher respectively. However, there was no significant difference in chlorophyll b and chlorophyll a/b between CK and T. The net photosynthetic rate was 33.4% higher than CK; ?PSII and Fv/Fm were 39.4% and 4.7% higher than CK. Root length, surface area, volume and number of root tips were 85.9%, 85.9%, 91.3% and 72.8% higher than CK, repectively.4. The qualities and yield of eggplants were improved significantly by the optimum fertilization scheme. Under the treatment of T, the contents of Vc, FAA, soluble protein in pulps and the contents of anthocyanins, total phenols, flavonoid in peels were much higher than CK, except there was no significant difference in the content of soluble sugar in pulps between two treatments. Yield under Ttreatment was 22.9% higher than CK.5. During seedling stage of eggplants, the plant absorbed 12~14% of total absorptions of N, P, K in whole growth stage. Under CK treatment, the absorption of K was as high as 10%, yet the absorption of N, P were less than 10%. In fruit-bearing stage, under T treatment absorptions of N, P, K were 85%~88% in whole growth stage, while those were 89%~96% under CK. The proportion of K absorption in different periods was highestt, then fllowed by N and P. 1.72 g N, 0.97 g P and 4.90 g K were absorbed by plant in order to product 1000 g eggplant fruits under T treatment, 1.81 g, 1.00 g, and 5.11 g were absorbed under CK. |
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