Corn nitrogen uptake and use efficiency under varying irrigation regimes

Authors: ADOTEY, REGINA - University Of Tennessee; SHEKOOFA, AVAT - University Of Tennessee; YIN, XINHUA - University Of Tennessee; SHELDON, KENDALL - University Of Tennessee; POURBRAHIMI, MOHIL - University Of Tennessee; ADOTEY, NUTIFAFA - University Of Tennessee; He, Zhongqi

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Cereal crops are indispensable food source across the globe, especially corn (Zea mays L.), which currently ranks first in global cereal annual production followed by wheat and rice. Apart from serving as major food source for man and livestock feed, corn is utilized for ethanol production, syrup and starch. On the other hand, corn is identified as the chief consumer of N fertilizer globally (16.2%), accounting for 40% increase in N input over the last four decades with yield increment of 140%. Water is also needed for so many critical functions in plants and together with N are considered to be the two most limiting major factors for corn productivity. This work determined how supplemental irrigation regimes affect N-uptake and N-utilization efficiencies of corn, and evaluated the effects of varying levels of irrigation intensity on the N concentration, chlorophyll index, and vegetation index of corn at different growth stages. Data collected from this work are helpful in better corn cropping management to ascertain suitable irrigation levels during the critical growth stages of corn that ensures the optimal N use efficiency.

Technical Abstract: Corn currently ranks first in global cereal annual production with a total production of 1.22 billion MT globally. However, corn is identified as the chief consumer of nitrogen (N) fertilizer globally, accounting for 40% increase in N input over the last four decades. Nitrogen uptake and utilization by plant essentially constitute N use efficiency (NUE) and any constraint such as water deficit stress during the critical growth periods in corn poses threats to yield and NUE. To ensure efficient use of agricultural resources, an experiment was conducted to assess the two most limiting factors for corn productivity: water (irrigation) and N. Field experiments were conducted in 2020 and 2021 in a randomized complete block design with four irrigation treatments (I-1, I-2, I-3, I-RF) that functioned on predetermined application frequency based on three critical growth stages of corn. There was no significant (p > 0.05) difference in the effect of irrigation regimes on most of the NUE indices except Partial Factor Productivity. The response of corn to the different levels of irrigation intensity varied more with year. Higher N uptake efficiency in 2021 appeared attributable to a high post-anthesis N uptake, associated with lower N utilization efficiency and higher grain N concentration. Effects of I-2 irrigation regime resulted in a significantly (p = 0.05) low R4 stage leaf N concentration in 2021. There were significant (p = 0.05) regression relationships found between grain yield (GY) and chlorophyll index, N concentration, and normalized difference vegetation index which corroborated some findings from correlation analysis.