Canopy greenness as a midseason nitrogen management tool in corn production. (22nd October 2020)

• Record Type: Journal Article
• Authors: dos Santos, Caio L.; Roberts, Trenton L.; Purcell, Larry C.
• Is Part Of: Agronomy Journal. Volume 112:Number 6(2020)
• Page Start: 5279
• Page End: 5287
• Publication Date: 2020-10-22
• Subjects: Agronomy -- Periodicals; 630
• DOI: 10.1002/agj2.20443
• Languages: English
• ISSNs: 0002-1962

Abstract

Abstract: An in‐season nitrogen (N) assessment tool would be valuable in improving N management in corn ( Zea mays L.). This study evaluated the intensity of canopy greenness, as determined by the Dark Green Color Index (DGCI) measured from aerial digital images, to serve as a guideline for in‐season N management. Measurements of DGCI from high N (258 kg N ha −1 ) experimental units were used as a reference DGCI (RDGCI) to correct for variable lighting conditions. Ability of DGCI to assess in‐season N status was investigated by predicting leaf N (LN) concentration and relative grain yield (RGY) as functions of DGCI and RDGCI. Eight field studies were conducted on silt loam soils in Arkansas. Digital images and leaf samples were collected at the 10 th collared leaf stage (V10), the 12 th collared leaf stage (V12), and tasseling (VT). Across a wide range of environmental lighting conditions, LN was described by a regression ( P < .0001) as a function of DGCI and RDGCI with a root mean square error of 3.49 g N kg −1 and a bias of −0.03 g N kg −1 . Likewise, RGY was regressed against DGCI and RDGCI ( P < .0001) and predicted RGY with a RMSE of 10.3% and a bias of −0.3%. Measurements of DGCI and RDGCI predicted LN and RGY accurately, demonstrating the potential to assess N status and improve N management in corn. These relationships provide reliable metrics for N status during late vegetative and early reproductive growth using aerial images.