三种氮素营养快速诊断方法在油菜上的适宜性分析

Applicability of three rapid methods of nitrogen nutrition diagnosis on rapeseed

通过大田试验研究SPAD仪(叶绿素仪)法、硝酸盐反射仪法和光谱仪法在油菜氮素营养快速诊断上的适宜性。试验设施氮0、60、120、180、240、300和400kg/hm2处理,在八叶期、十叶期和蕾薹期对各处理SPAD值、冠层归一化植被指数(NDVI值)和硝酸盐含量进行检测,并测定各时期油菜生物量和收获期籽粒产量。对不同施氮量下的油菜产量进行显著性检验及方程拟合,并对三种诊断方法各测定指标与氮肥用量、籽粒产量进行相关分析。结果表明,油菜施氮量与籽粒产量具有较好的相关关系,满足进行氮素营养快速诊断要求。三种诊断方法中,硝酸盐反射仪法能在一定程度上反映油菜氮素营养状况,但受油菜生理特性(苗期生物量小、蕾薹期氮素奢侈性吸收等)影响,诊断结果的可信度和稳定性不高。光谱仪法比较适宜于油菜蕾薹期氮素营养诊断,但存在追肥时期过晚、操作不方便等缺点。综合分析认为,SPAD仪法诊断结果稳定,并且具有快速、简便、低耗等优点,适合于油菜氮素营养快速诊断。

SPAD meter,nitrate reflectrometer and spectrometer were used in field experiments to rapidly diagnose nitrogen（N） nutrition of rapeseed.Seven treatments as N 0,90,180,240,300 and 400kg/hm2 were applied.SPAD（soil and plant analyzer development） index,NDVI（normalized difference vegetation index）,nitrate content and dry matter weight were determined at eight-leaf stage,ten-leaf stage and bolting stage of rapeseed respectively,while the yield was measured at maturity stage.Results indicated a preferable interrelation between N application rates and yield.The relation met the demand of nitrogen nutrition diagnosis for rapeseed.Among the three diagnostic methods,nitrate reflectrometer could reflect rapeseed N nutrition status,but for the influences of physiological characteristics（such as plant growth and development,nitrogen nutrition status,etc.）,the result lacked reliability and stability.Spectrometer was suitable for rapid N nutrition diagnosis at bolting stage,but difficult to operate and could delay fertilizer top dressing.SPAD meter could reflect rapeseed nitrogen nutrition better,and had advantages of fast,stable results,easy to apply,and low cost.So SPAD meter was the most suitable method of rapid N diagnosis in rapeseed.