日光温室蔬菜的氮素平衡及施肥调控潜力分析

Nitrogen balance and optimized potential of integrated nitrogen management in greenhouse vegetable system

以寿光日光温室番茄为研究对象,通过2年4个生长季的试验,分析整个生产体系中氮素的平衡及0—180cm土层硝态氮动态,并对氮素优化管理条件下日光温室番茄的生产力、氮素盈余与损失特征进行了研究。结果表明,与传统施氮管理相比,综合利用灌溉水带入氮素和根层土壤无机氮的优化氮素管理技术能够保证番茄产量,同时减少73%的氮肥施用,但节肥主要集中在春茬作物生长后期及秋茬作物生长前期。自休闲至番茄第一次追肥前土壤硝态氮的大量积累与频繁灌溉导致了整个生产体系氮素大量损失,建议通过种植填闲作物或者施用高C/N比作物秸秆等可能的方法来控制土壤氮素转化,减少该时期的氮素损失。

Greenhouse tomato experiments, including four growing seasons, were conducted in Shouguang from 2004 to 2006, in order to investigate effects of integrated N management （INM） on crop productivity, N surplus and apparent N loss based on the analysis of N balance and soil Nmin in the soil profile of 180 cm. The results showed that considering nitrate-N from irrigated water and soil initial nitrate-N content （0-30cm）, INM treatment could maintain tomato yield as conventional N treatment, however, the 73% of fertilizer N was reduced through maintaining critical rootzone N level. Fertilizer N saving with INM treatment was in the late growing stage of Spring tomato season, and in the early growing stage of Autumn tomato season. High risk of N loss should not be ignored in the period from summer fallowing to the first event of N sidedressing because of high nitrate-N content accumulated in soil profile and high irrigated water in greenhouse system. Catch crop planting or crop straw with high C/N incorporation are expected to regulate N transformation, which is beneficial for reducing N loss in this system.