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在德国下萨克森州南部黄土地区的肥料试验中,通过对冬性大麦和小麦茎基部节间硝酸盐含量的测定,来检验是否可作为冬性谷类作物从拔节到抽穗期间的氮肥需要量的适宜指标。从实际应用角度考虑,采用简便的植株汁液测定,进而确定硝酸盐的浓度。测定结果表明:1、用二苯胺-硫酸试剂可以精确地测出鲜样中200—2000ppm的硝酸盐浓度。这种方法简便易行,适于农民应用。2、试验区的冬小麦和冬大麦,在春季氮素供应[土壤矿质态N(Nmin)+氮肥]相同的条件下,从拔节到抽穗期间,茎基都节间的NO_3~-含量在50—4000ppm之间不等,这些差别主要是由于前茬作物和有机肥不同而引起的。3、植株茎基部节间的硝酸盐含量和耕层土壤中的硝酸盐含量密切相关。4、从拔节到抽穗期间测定茎基部节间的硝酸盐含量与氮肥需要量呈显著相关。由此不仅可以对冬小麦及冬大麦后期的氮素追肥提供参考,还可以确定氮肥的需要量和施用时间。
Fertilizer trials in the loess region of southern Lower-Saxony in Germany tested the suitability of nitrogenous fertilizer as a winter cereal crop from jointing to heading, based on the determination of the nitrate content in the basal internode of winter barley and wheat stems index. From a practical point of view, the use of simple plant juice determination, and then determine the nitrate concentration. The results show that: 1, with diphenylamine - sulfuric acid reagent can accurately measure the fresh sample of 200-2000ppm nitrate concentration. This method is simple and convenient and suitable for farmer application. In winter wheat and winter barley, under the same nitrogen supply condition (Nmin and nitrogen fertilizer) in spring, the content of NO_3 ~ in interstitial internode from jointing to heading was in the range of 50- 4000ppm range, these differences are mainly due to the previous crop and organic fertilizer caused by different. Nitrate content in plant stem basal internode is closely related to nitrate content in topsoil. During the period from jointing to heading, the content of nitrate in the basal internode was significantly correlated with the nitrogen requirement. Therefore, it can not only provide a reference for topdressing nitrogen of winter wheat and winter barley, but also determine the requirement of nitrogen fertilizer and the application time.