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在设施栽培条件下,采用田间多点位微区试验,研究莴苣、芹菜和生菜3种蔬菜氮肥的当季利用与损失。结果表明:3种蔬菜氮肥施用量在习惯施氮量的基础上减少25%,氮肥当季利用率增加,植株总吸氮量中来自于氮肥的比例降低。经过莴苣、芹菜和生菜一季的吸收,0～20 cm土层氮肥残留显著高于20 cm以下各土层当季氮肥残留。在莴苣种植系统中氮肥有23.90%～31.15%损失,在芹菜种植系统中氮肥有18.69%～27.71%损失,生菜种植系统中氮肥损失低于15%。
Under the condition of cultivation, the field multi-site micro-plot test was used to study seasonal utilization and loss of nitrogen fertilizer of lettuce, celery and lettuce. The results showed that the nitrogen application rate of three kinds of vegetables decreased by 25% on the basis of the conventional nitrogen application, the utilization rate of nitrogen fertilizer in the season increased, and the proportion of nitrogen from the total nitrogen uptake decreased. After lettuce, celery and lettuce were absorbed in the first season, the residual nitrogen in 0 ~ 20 cm soil layer was significantly higher than that in the soil layer below 20 cm. In the system of lettuce planting, nitrogen loss was 23.90% ~ 31.15%, loss of nitrogen fertilizer was 18.69% ~ 27.71% in celery planting system, and loss of nitrogen fertilizer was less than 15% in lettuce planting system.