Abstract:
To improve the yield and quality of Chinese cabbage and increase the utilization rate of nitrogen fertilizer in production, this study used Jinding Chinese cabbage variety as the experimental material to explore the optimal nitrogen fertilizer application rate for Chinese cabbage through field experiments. Four treatments were set up in the experiment, namely no nitrogen zone(control, N
0PK), 70% optimized nitrogen zone(N
1PK), optimized nitrogen zone(N
2PK)and 130% optimized nitrogen zone(N
3PK), and the amount of nitrogen applied to the optimized nitrogen zone was 210.0 kg·hm
−2, and the application of phosphorus and potassium fertilizers to all treatments was the same, which were phosphorus fertilizers(P
2O
5)90 kg·hm
−2, potassium fertilizers(K
2O)180 kg·hm
−2, all applied according to the recommended values for local production conditions. The results showed that the moderate increase of nitrogen fertilizer significantly increased the plant height, girth and fresh weight of Chinese cabbage with the 130% optimized nitrogen zone achieved maximum plant height(25.73 cm)and fresh weight(2.12 kg per plant). Each nitrogen application treatment significantly increased yield by 40.92% to 64.36% over the unapplied nitrogen treatment. Nitrogen application treatments differentially increased the soluble sugar content of Chinese cabbage and highly significantly increased nitrate content, while highly significantly decreasing vitamin C content.. The economic benefit analysis showed that, the net yield of Chinese cabbage in the optimized nitrogen zone was
61419.43 yuan·hm
−2, which was not significant difference from the maximum net yield(130% optimized nitrogen zone)of
65558.17 yuan·hm
−2(
P >0.05). Meanwhile, the output-input ratio of the treatment in the optimized nitrogen zone (4.25)showed higher economic efficiency, which was 0.14 lower than the maximum output-input ratio(4.39), but the difference between them was also not significant. In conclusion, under the condition of fixed phosphorus and potassium fertilizer dosage(P
2O
5 90 kg·hm
−2, K
2O 180 kg·hm
−2), the optimized nitrogen zone, i.e., nitrogen fertilizer(pure N)210 kg·hm
−2, is recommended for the production of Chinese cabbage in Changle District to optimize the balance among yield, quality, economic benefits, and environmental sustainability.