摘要
【目的】设施蔬菜习惯"大水大肥"的传统管理模式,不仅影响蔬菜的品质和产量,造成严重的资源浪费,而且引起的环境污染问题日益受到人们的关注。本研究针对设施蔬菜生产中过量施用氮肥以及不合理的灌溉所导致的氮肥利用率低、氮素损失等资源浪费和环境的负效应问题,重点研究双氰胺(DCD)在设施蔬菜生产体系中的硝化抑制效果及其影响机制,并筛选出了适用于设施黄瓜生产的最优水氮管理方案。【方法】采用田间原位跟踪法,对温室黄瓜追肥期间土壤N2O排放量、氨挥发损失量、无机氮含量等指标进行了测定。N2O气体样品用密闭式静态箱法采集,用Agilent GC6820气相色谱仪进行测定。氨挥发样品用密闭室法采集,硼酸溶液吸收,标准硫酸滴定法测定。新鲜土样用1.0 mol/L KCl浸提,滤液用TRACCS 2000型流动分析仪测定土壤的NH+4-N和NO-3-N含量。【结果】在不同水氮条件下[传统水氮(T)的施氮量为N 988.6 kg/hm2、灌溉量为758.8 t/hm2;推荐水氮Ⅰ(R1)的施氮量为N 709.4 kg/hm2,推荐水氮Ⅱ(R2)的施氮量为N 746.9 kg/hm2,灌溉量均为531.2 t/hm2]。加施DCD后,推荐水氮Ⅰ、推荐水氮Ⅱ处理N2O的排放通量分别显著减少了42.1%和64.1%,但氨挥发损失分别显著增加了34.3%和40.4%;0—10 cm土层土壤硝态氮与N2O排放通量呈极显著的正相关,铵态氮与氨挥发损失呈极显著正相关。传统水氮处理在0—60 cm土壤剖面均检测到大量的硝态氮,前两次追肥后尤为明显。在减氮基础上加施DCD有助于减少硝态氮的累积,对0—30 cm根区硝酸盐淋洗的抑制作用较为明显。在0—30 cm土壤-蔬菜体系中,传统水氮处理的氮素表观损失显著高于其他施氮处理。加施DCD后,推荐水氮Ⅰ、推荐水氮Ⅱ处理的氮素盈余和氮素损失率均有所降低。与传统水氮处理相比,推荐水氮Ⅱ+DCD的处理增产23.3%,经济效益增加25560yuan/hm2。【结论】在本试验条件下,适度减氮控水措施是切实可行的,不仅满足了作物生长所需要的氮素,而且减少了氮素的盈余,提高了氮素的利用率,且不影响作物产量。在控水灌溉条件下,推荐施氮Ⅱ+DCD(氮素用量的15%)不仅能减少土壤氮素的盈余量,而且可有效地增加经济效益和环境效益。
【Objectives】The traditional management mode of greenhouse vegetables is under 'a large number of irrigation and fertilization'. This mode not only affects quality and yield of vegetables,but also causes serious wasteof resources and environmental pollution. Aiming at excessive application of nitrogen fertilizer and low nitrogen fertilizer utilization rate caused by unreasonable irrigation,nitrogen loss and other waste of resources and negative effects of environmental problems in greenhouse vegetable production were studied with focusing on nitrification inhibition effect and its mechanism of dicyandiamide( DCD) to select the best water and nitrogen management program for greenhouse cucumber production. 【Methods】A field in-situ tracking experiment was carried out to determine N2 O emission,ammonia volatilization loss,inorganic nitrogen in soil and other indicators during the greenhouse cucumber dressing. N2 O gas samples were collected by enclosed static box method,and gas samples was analyzed by gas chromatography with Agilent GC6820. Ammonia volatilization samples were collected by closed chamber method,added 20 m L 2% boric acid solution into evaporating dish of 50 m L,and after 24 hours,absorption of ammonia in boric acid was titrated with standard sulfuric acid. Fresh soil samples were extracted with1. 0 mol / L KCl,and analyzed for NH+4-N and NO-3-N using continuous flow analysis( TRAACS 2000) in laboratory. 【Results】Compared with the recommended water and nitrogen treatments ofⅠandⅡ,the applications of DCD with the recommended water and nitrogen treatments ofⅠandⅡcould reduce N2 O emission by 42. 1% and64. 1%,while the applications increase ammonia volatilization loss by 34. 3% and 40. 4% respectively. Soil NO-3-N and N2 O flux,NH+4-N and ammonia volatilization loss in 0-10 cm soil layer are positively correlated. The traditional water and nitrogen treatment has large amounts of NO-3-N in 0-60 cm soil profiles,especially after the first two dressing. Based on the reduction of nitrogen,applying DCD helps reduce the NO-3-N accumulation,and nitrate leaching inhibitory effect is more obvious in 0-30 cm root zone. The N apparent loss in 0-30 cm soil layer and vegetables system of the traditional water nitrogen treatment is significantly higher than those of the other nitrogen treatments. Compared with the recommended water and nitrogen treatments ofⅠandⅡ,the applications of DCD with the recommended water and nitrogen treatments ofⅠandⅡcould reduce nitrogen surplus and loss rate of nitrogen. Compared with the traditional water and nitrogen management,cucumber yield and economic benefit are increased by 23. 3% and 25560 yuan / ha respectively under the addition of DCD with the recommended water and nitrogen treatment Ⅱ( traditional water and nitrogen,N application rate was N 988. 6 kg / ha and irrigation volume was 758. 8 t / ha,the recommended water and nitrogen treatments of Ⅰ and Ⅱ,N application were N 709. 4 and746. 9 kg / ha,and irrigation volume was 531. 2 t / ha). 【Conclusions】Under this experimental condition,moderate reduction of nitrogen and water is feasible to satisfy the need of nitrogen for crop,reduce the surplus of nitrogen and increase the efficiency of nitrogen,and does not affect the output of crops. The DCD application( 15% of the nitrogen rate) with recommended nitrogen Ⅱ under the controlled irrigation condition could not only reduce soil nitrogen surplus capacity,but also increase the economic benefit and environmental benefit effectively.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2015年第1期128-137,共10页
Journal of Plant Nutrition and Fertilizers
基金
农业部"948"项目(2012-Z36)
河北省教育厅项目(Q2012130)资助
关键词
减氮控水
N2O排放
氨挥发
无机氮
产量
经济效益
reduction of nitrogen and water control
N2O emission
ammonia volatilization
inorganic nitrogen
yield
economic profit
