采用田间试验研究福建主要蔬菜氮磷钾施肥效应,建立菜田速效氮磷钾丰缺指标.根据148个试验的空白区产量水平,将土壤肥力分为“高”、“中”和“低”3个等级.结果表明,土壤肥力对蔬菜产量贡献率为(50.9士12.8)％,随土壤肥力等级的降低而明显下降;空白区产量与平衡施肥产量之间存在显著的线性关系.肥效试验结果表明,叶菜类、根茎类、瓜果类和葱类等蔬菜施用氮磷钾肥有显著的增长效果,随着土壤肥力水平的下降,氮磷钾肥效明显提高；增产幅度和净增收数均为氮肥明显高于钾肥,钾肥明显高于磷肥；叶菜类和葱类的氮肥产投比明显高于磷钾肥,而根茎类和瓜果类则为磷肥产投比明显高于氮钾肥.叶菜类蔬菜的土壤养分高产临界指标分别为碱解氮243mg·kg-1、Olsen-P 52 mg·kg-1和速效钾150mg·kg-1,根茎类和瓜果类等蔬菜则分别为碱解氮276 mg· kg-1、Olsen-P 47mg· kg-1和速效钾132mg·kg-1.%Based on the results of field experiments on the vegetables' response to N, P and K, soil fertilization indices of available N, P and K in vegetable gardens in Fujian were established. Soil fertility of the croplands was classified as high, medium and low grades according to the vegetable yield from 148 field experiments conducted in a test area. The results showed that the average contribution rate of soil nutrients to the growth of vegetables was (50. 9±12. 8)%. It decreased significantly when the soil fertility declined. A significant linear relationship existed between the yield on the control and fertilized areas. Leafy vegetables, melon, fruits, root-stock and onion-type vegetables were used in this study. Their yields increased significantly in response to the NPK fertilization. The effect of the NPK application increased significantly as the soil fertility declined. The extent and net gain from N fertilization were significantly greater than those from K, and those from K significantly greater than those from P. The value/cost ratios (VCRs) of N fertilization for leafy and onion-type vegetables were significantly higher than those of P or K. The VCRs of P for the root-stock vegetables, melon and fruits were significantly higher than those of N and P. The critical application levels of alkali-hydrolyzable N, Olsen-P and available K to achieve high yield for leafy vegetables were found to be 243 mg · Kg-1, 52 mg · Kg-1 and 150 mg · Kg-1, respectively. And those for other vegetables were 276 mg · Kg"1, 47 mg · Kg"1 and 132 mg · Kg"1, respectively. These recommended application levels were all significantly higher than for grains and oil crops. The results provided a scientific basis for soil evaluation and fertilization optimization for vegetable gardens in Fujian.
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