施肥对连作蔬菜地蔬菜产量和土壤氮素含量的影响

为了研究施肥对连作蔬菜地蔬菜产量、肥料效应以及土壤养分铵态氮与硝态氮含量的影响，笔者等人进行了连续四茬蔬菜的田间试验。结果表明，在试验设计范围内，随着施氮量的增加，四茬蔬菜鲜样可食部分产量随着施氮量的增加而增加，芹菜的最佳施氮量为537.4kg/hm2，白菜的最佳施氮量为473.88kg/hm2。同时，与对照相比，用于每茬蔬菜生长所施用的肥料明显增加了土壤中铵态氮含量，且随着施用量的增加而显著增加。土壤硝态氮含量随施肥量的增加而增加，随蔬菜种植时间的延长而上升。试验同时表明，经过了四茬蔬菜收获后，土壤剖面硝态氮含量已经发生了变化，除了未施肥对照区的土壤剖面硝态氮含量下降外，其余施肥处理土壤剖面硝态氮含量均呈上升趋势。研究结果给连作蔬菜地的合理施肥提供了参考依据。

Effect of Fertilization on the Yield of Vegetable and Nitrogen Content in Continuous Cropping Vegetable Soil

Field experiment was carried out by planting four continuous stubbles of vegetable, in order to research the effects of fertilization on the yield of vegetable, fertilizer effect, the contents of NO3-N and NH4-N in soil. Experimental result shows that, the fresh yield of eatable part of vegetable increased along with adding the dosage of nitrogenous fertilizer in the four continuous stubbles of the designed field experiment. It also shows that the optimal dosages are 537.4 and 473.88 kg/hm2 for celery planting and cabbage planting, respectively. By contrast with the non-fertilization counterpart region, the contents of NH4-N increase along with adding the dosages of nitrogenous fertilizer, and the contents of NO3-N also increase with prolonging the planting time of vegetable. On the other hand, fertilization has changed the contents of NO3-N in soil profiles of counterpart regions after harvesting of four continuous stubbles. In the different treatments of fertilization，the contents of NO3-N have increasingly raised in the soil profiles of the fertilized regions. But the content of NO3-N decreased in soil profile of counterpart region without nitrogen fertilization. The experimental result can be used as a reference to guide proper fertilization in the continuous cropping vegetable soil.