我国北方地区几种主要作物氮营养诊断及追肥推荐研究 Ⅳ.冬小麦─夏玉米轮作制度下氮素诊断及追肥推荐的研究

研究了冬小麦夏玉米轮作制度下二苯胺法和反射仪法在两种作物氮营养诊断中的应用。提出冬小麦的最佳氮营养诊断时期和诊断部位为拔节前茎基部节间组织，夏玉米为拔节前功能叶叶脉。确定了两种作物采用两种方法进行氮素营养诊断的临界值，冬小麦为2.00（NO3-N色阶，二苯胺法）、1500mgkg-1（NO3-，反射仪法）;夏玉米为2.40（NO3--N色阶，二苯胺法）和1240mgkg-1（NO3-，反射仪法）。同时建立了两种作物基于氮素营养诊断的作物追肥推荐模型:冬小麦:Nd＝220.2-95.8Td（二苯胺法）Nd＝220.2-0.147Tr（反射仪法）夏玉米:Nd＝185.9-72.5Td（运城，二苯胺法）Nd＝185.9-0.13Tr（运城，反射仪法）Nd＝176.2-80.5Td（永济，二苯胺法）

NITROGEN NUTRITIONAL DIAGNOSIS AND RECOMMENDATION AS TOPDRESSING FERTILIZER N FOR SEVERAL CROPS IN NORTH CHINA Ⅳ. Nitrogen nutritional diagnosis and recommedation as topdressing fertilizer N in wheat-corn rotation

Two quick test methods (diphenylamine method and nitrate test strip) for diagnosising nitrogen nutritional status under condition of rotatiori cropping with winter wheat-summer corn were studied in field expriment. The results suggested that the optimum diagnosis parts of plants was the stem base for wheat arid the midrib of near matured leaf for corn, both just prior to jointing stage, arid the critical values of nitrate was considered to be 2.00(diphenylamine method) and 1500mgkg^-1No₃^- (nitrate test stripe) for wheat and 2. 40(diphenylamine method) and 1240mgkg^-1NO₃^-(nitrate test stripe) for corn. Based upon the results from nitrogen nutritional diagnosis, series fertilizer N topdressing recommendation model was set up as following:wheat:N_d=220. 2-95. 8T_d(diphenylamirie method) N_d=220. 2-0. 147T_r(nitrate test strip) corn:N_d=185. 9-72. 5T_d(Yuncheng, diphenylamine method) N_d=185. 9-0. 13T_r(Yuncheng, nitrate test strip) N_d=176. 2-80. 5T_d(Yongji, diphenylamine method)