不同施肥模式对蔬菜生长、氮肥利用及菜地氮流失的影响

在天然降雨条件下，通过一年三茬蔬菜(小白菜、空心菜和苋菜)田间试验，研究了7种不同施肥模式（不施肥、化肥基施、化肥基追肥各半、化肥和双氰胺基施、化肥和双氰胺基追肥各半、化肥和有机肥基追肥各半、有机肥基施）对蔬菜株高、单株质量、产量、氮累积量、氮肥利用率及菜地硝态氮和铵态氮随地表径流流失的影响.结果表明：与不施肥对照相比，化肥和有机肥基追肥各半、化肥和双氰胺基施2种施肥模式可改善蔬菜农艺性状，分别使蔬菜产量提高103%～219%和93%～226%、植株氮累积量增加153%～216%和231%～320%、氮肥利用率较高，与化肥基施处理相比，还可减少蔬菜种植期间菜地土壤硝态氮和铵态氮随地表径流的流失量，减少幅度分别为48.1%和46.5%，从而减少了菜地土壤造成的农业面源污染.这两种施肥模式应在今后蔬菜生产中推广应用.

Effects of different fertilization modes on vegetable growth, fertilizer nitrogen utilization, and nitrogen loss from vegetable field.

A field experiment with Chinese cabbage, water spinach, and three-colored amaranth cropped three times in one year was conducted to study the effects of seven fertilization modes, i.e., none fertilization, basal application of chemical fertilizers, 1/2 basal application and 1/2 top-dressing of chemical fertilizers, basal application of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure, and basal application of organic manure, on the plant height, yield, nitrogen accumulation, and fertilizer nitrogen utilization of the vegetables, and the loss of NO3--N and NH4+-N from vegetable field under natural rainfall condition. The results showed that comparing with none fertilization, the fertilization modes ‘1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure’ and ‘basal application of chemical fertilizers and dicyandiamide’ improved the agronomic properties of test vegetables, increased their yields by 103%〖KG-*2〗-〖KG-*7〗219% and 93%〖KG-*2〗-〖KG-*7〗226%, and nitrogen accumulation by 153%〖KG-*2〗-〖KG-*7〗216% and 231%〖KG-*2〗-〖KG-*7〗320%, respectively, and enhanced fertilizer nitrogen utilization rate. They also decreased the surface runoff loss of NO3--N and NH4+-N by 481% and 465%, respectively, compared with the mode ‘basal application of chemical fertilizers’, and hence, reduced the risk of agricultural non-point pollution. Therefore, these two fertilization modes could be popularized in vegetable production.