不同施肥模式对设施生菜产量和氮损失的影响

  目的  探讨液体肥滴灌施肥模式和常规施肥模式对设施生菜产量和氮损失（氨挥发、氧化亚氮排放、硝态氮淋洗）的影响。  方法  采用田间小区试验，以日光温室生菜为对象，共设3个处理，分别为液体肥优化施肥模式（LF，170 kg hm?2 N，基肥不施氮肥 + 3次追肥）、固体水溶肥常规施肥模式（CF，200 kg hm?2 N，基肥 + 2次追肥），以及不施氮对照（CK，0 kg hm?2 N，磷钾做基肥+清水滴灌）。安装水肥一体化设施进行追肥灌水，采用通气法和静态箱法收集并测定生菜生长季内氨挥发和氧化亚氮的排放。  结果  结果表明，与常规施肥处理（CF）相比，液体肥料处理（LF）在生长前期可以延迟氨挥发和氧化亚氮的排放高峰3 ~ 5 d，且在生长季内显著降低土壤氨挥发和氧化亚氮的排放量，减排率分别为24.6%和21.6%；应用液体肥料可以减少0 ~ 100 cm土层硝态氮残留21.0%，降低了氮素淋洗风险；与CF模式相比，LF模式在减氮15.0%的基础上，产量没有下降，氮肥利用率提高了32.4%。  结论  新型液体肥料优化施肥模式（LF）可以显著降低设施菜田氨挥发和氧化亚氮排放量，减轻土壤硝态氮淋洗风险，维持产量不降低并提高肥料利用效率，是一种节氮减排的绿色生产方式。

Effects of Different Fertilization Patterns on Yield and Nitrogen Loss of Lettuce in Greenhouse

The effects of liquid fertilizer drip irrigation and conventional fertilization on lettuce yield and active nitrogen losses (ammonia volatilization, nitrous oxide emission and nitrate leaching) were investigated. A field experiment was conducted in a greenhouse of lettuce, with three treatments of optimized fertilization mode with liquid fertilizer (LF, 170 kg N hm?2, basal fertilizer without nitrogen + 3 topdressing), conventional fertilization mode with solid water-soluble fertilizer (CF, 200 kg N hm?2, basal fertilizer + 2 topdressing) and no nitrogen fertilizer (CK, 0 kg N hm?2, phosphorus and potassium as basal fertilizer + drip irrigation with clear water). Drip fertigation was adopted for topdressing and irrigation, and ammonia volatilization and nitrous oxide emissions were measured by the methods of aeration and static chamber, respectively. Compared with the CF treatment, the LF treatment could delay the emission peak of ammonia volatilization and nitrous oxide for 3-5 days in the early growth stage, and significantly reduced soil ammonia volatilization and nitrous oxide in the growing season by 24.6% and 21.6%, respectively. Also, it reduced soil residual NO₃-N by 21.0% at 0-100 cm soil depth. Additionally, it could not only save nitrogen input by 15.0%, but also achieve a high and steady yield and increase the nitrogen use efficiency by 32.4%. Generally, the LF treatment could significantly reduce ammonia volatilization and nitrous oxide emissions from greenhouse vegetable fields, alleviate the risk of soil nitrate leaching, and maintain the lettuce yield and improve the fertilizer utilization efficiency. Therefore, the application of new liquid fertilizer should be an effective measure to promote the efficient production of greenhouse vegetables.