摘要
【目的】以北方半干旱湿润区潮土为对象,探讨土壤剖面不同层次硝态氮(NO-3-N)的运移及其后效。【方法】采用外源标记微注射法,设置田间微区试验。【结果】在试验水氮管理条件下,15、45、75cm3个标记处理分别向下迁移了65、35、25cm,但均未移出作物根区(1m)。播后至冬前3个标记处理100cm处土壤溶液NO-3-N浓度变动较小,生长后期小麦15、45cm标记处理出现上升,而菠菜则有所降低,两种作物的75cm标记处理在整个生长季持续上升,说明作物对75cm标记硝态氮利用程度较低。夏玉米对前茬标记氮的利用率为2.1%～5.6%,其中以标记45cm土层处理残效最高;15cm和45cm2个标记深度前茬小麦京411显著高于前茬小麦小偃54。【结论】土壤剖面不同层次累积硝态氮在作物生长季内未发生强烈的淋洗,但表现出上层标记硝态氮移动距离长,下层移动距离短的规律;100cm处土壤溶液NO-3-N浓度的动态变化可在一定程度上反映作物根区内氮素利用的状况;后茬作物对标记于土壤剖面不同深度的硝态氮的利用是很有限的,与前茬作物吸收、土壤剖面硝态氮的运移及残留密切相关。
【Objective】The purpose of this study was to investigate the movement and residual effect of labeled NO3^--N in different layers of fluvo-aquic soil of semi-arid and wet land in north China.【Method】Field micro-plot experiment and the external injection technique of labeled NO3^--N were adopted.【Result】The results showed that,NO3^--N for three treatments labeled at the depth of 15,45 and 75 cm was moving downwards 65,45 and 25 cm,respectively,however,no labeled NO3^--N was found outside crop root zone（1m）.The labeled NO3^--N concentration in 100 cm under three treatments showed less fluctuation from after-sowing period to before-winter.It was detected an increasing tendency of labeled NO3^--N at the stage of anaphase under two treatments labeled at the depth of 15 and 45 cm for wheat.A decreasing tendency occurred under the same treatments for spinach.The labeled NO3^--N under the treatment of 75 cm labeled was sustainable,increasing during the growing season of wheat and spinach,which indicated low NO3^--N use in this layer.Afterwards,the labeled NO3^--N utilization ratio in summer maize ranged from 2.1% to 5.6%,and the residual effect under the treatment of labeled 45 cm was the highest among all labeled NO3^--N treatments.Under two treatments of 15 and 45 cm labeled,the residual effect was significantly higher for proceeding wheat Jin411 than that for proceeding wheat Xiaoyan54.【Conclusion】As a conclusion,there was no severe nitrate leaching in different soil layers during the growing season,which represented that long moving distance of labeled NO3^--N in upper labeled soil and short moving distance in subsoil.The dynamics of NO3^--N concentration in soil solution at 100 cm labeled could be reflected N utilization in root zone.The utilization of NO3^--N labeled in different soil layers was limited for the succession crop,which was related to N uptake of proceeding crop,movement and residual of labeled NO3^--N in different soil layers.
出处
《中国农业科学》
CAS
CSCD
北大核心
2007年第9期1964-1972,共9页
Scientia Agricultura Sinica
基金
国家自然科学基金项目(40571072和30571110)
河北省自然基金项目(C2006000491)
