نوع مقاله : مقاله پژوهشی
1 دانشآموخته دکتری، گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران، تهران، ایران
2 استاد، گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران ، تهران، ایران
3 دانشیار، گروه مهندسی آبیاری و آبادانی، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران
4 دانشیار، گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران، تهران، ایران
عنوان مقاله [English]
The nitrogen (N) consumption management during the plant growth season plays an important role in achieving maximum crop yield and reducing environmental hazards. Determination of N nutrition index (NNI) is one of the methods for diagnosing plant N status. The main objective of this study was to investigate the role of monitoring NNI in improving nitrogen consumption management. The field experiment was carried out during the growth period of summer maize in Pakdasht region, southeast of Tehran, in 2015 and 2016. Grain yield, dry matter and nitrogen concentration of crop samples from seven treatments including: 0 (N0), 50 (N1), 100 (N2), 150 (N3), 200 (N4), 250 (N5) and 300 kg N. ha-1 (N6) were measured during the growing season. The results showed that NNI monitoring during the growing season could show the variation of N status in different treatments. In addition, NNI was closer to one in the optimal treatment (N4), which produced maximum dry matter with less N application, as compared with other treatments. Moreover, the relative grain yield decreased with a constant rate whenever the NNI was less than one. Agronomy and recycling efficiencies for the N4 treatment were higher than the ones in the other treatments. Water use efficiency of N4, N5 and N6 treatments in both cultivation years was almost equal and more than the ones of other treatments. These results indicated that the water and nitrogen use efficiencies were higher in treatment with NNI closer to 1 (optimal treatment) as compared to other treatments.