| Acoording to the current status of winter potato nutritionalcharacteristic and appropriate NPK fertilizer amount and proportion research, this thesis use potato cultivar Favorita, set three different N levels: 195 kg·hm-2(N1), 240 kg·hm-2(N2), 285 kg·hm-2(N3); and three different NPK ratio: N:P2O5:K2O =1:0.56:1.95(P1), N:P2O5:K2O =1:0.3:1.95(P2), N:P2O5:K2O =1:0.2:1.95(P3). Furthermore, the basal fertilizer and top dressing ratio of NPK werefixed. NPK basal fertilizer rates were 40 %, 100 %, and 50 %, nitrogen topdressing of 20 %, 20 % and 20 %, and potash topdressing of 10 %, 15 % and 25 %. In order to determine appropriate NPK fertilizer amount and ratio for high yield winter potato production in Guangdong province, we explored the effects of different NPK fertilizer amounts and ratios on potato NPK accumulation and distribution, apparent NPK fertilizer utilization rate, yield, economic efficiency and quality through our fertilizer program. This study will provide an important evidence for rational application of fertilizeron Guangdong winter potato, and give a reference for related research. The main findings are as follows:(1) N, P, K accumulation and distribution rules indifferent potato organsduring different growth and development stage. N, P, K accumulation in potato leaves and stems reached the peak at 32 d, 18 d, 46 d, respectively, after the even emergence of seedlings, gradually decreased following the fertility process. However, in potato tuber, N, P, K accumulation showed an increase trend followed the whole growth process until harvest. In potato leaves and stems, the highest distribution ratio of N and P appeared in 4 d after the even emergence of seedlings, then decreased gradually followed the growth period. Caused by larger amounts of N, P, K were transferred to the tuber for its formation, the distribution ratio of N, P, K in potato tuber showed an upward trend accompany with the growth and development process.(2) In different dosage and ratio of N, P, K fertilizer, dry matter accumulation in potato tuber at each growth stageshowed the slow-fast-slow accumulation regularity. Results showed that dry matter accumulation was incrementedin all the treated tubersduringwhole growth period. All the treatments at 60 d after the even emergence of seedlings, dry matter accumulation changed with a relatively larger variationin tubers. Especially in 18~60 d after the even emergence of seedlings, dry matter accumulation in tuber increased sharply, treatment N1P2K1 got the most, followed by N2P2K2 and N3P2K3. These results showed that in test conditions, N level of 195 kg·hm-2 and NPK ratio of N:P2O5:K2O =1:0.3:1.95 was the bestfordry matter accumulation in potato tubers.(3) When N level was 195 kg·hm-2and NPK ratio was N:P2O5:K2O =1:0.3:1.95, potato NPK fertilizer utilization rate was significantly higher than other treatments.(4) Different NPK fertilizeramounts and ratioshad certain impacts on total potato production, marketable tuber yield, total output value and economic benefits. Generally, under application conditions of NPK, potato output, marketable tuber yield, output value and economic benefits of each treatment were significantly higher than those treated by pure organic fertilizer CK. And among them, treatment N1P2K1 was the most appropriate, its total tubers, marketable tuber yield, output value and economic benefits was significantly higher than the control of farmers.(5) Under test conditions, when N level was 195 kg·hm-2, and NPK ratio was N:P2O5:K2O =1:0.3:1.95, potato tuber’s starch and Vc contentsin treatment N1P2K1 reached up to 14.10 % and 156.43 mg·kg-1, respectively, which was significantly higher than farmers treated with TF.(6) Through the comparison of total potato output, marketable tuber yield, economic benefits, apparent NPK fertilizer utilization and the quality, we concluded that under test conditions, the suitable fertilization program was N1P2K1, with N level of 195 kg·hm-2 and NPK ratio of N:P2O5:K2O =1:0.3:1.95. |
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