Nitrogen deficiency and corn yield with delayed N application. (6th July 2021)

• Record Type: Journal Article
• Authors: Nafziger, Emerson D.; Yoder, Brian; Mathesius, Jeff; Carter, Paul
• Is Part Of: Agronomy Journal. Volume 113:Number 4(2021)
• Page Start: 3665
• Page End: 3674
• Publication Date: 2021-07-06
• Subjects: Agronomy -- Periodicals; 630
• DOI: 10.1002/agj2.20760
• Languages: English
• ISSNs: 0002-1962

Abstract

Abstract: Delaying the application of N to corn ( Zea mays L.) may help to match N supply to N uptake, but may also increase the risk of yield loss if N is applied too late or N uptake is delayed. In a 3‐yr study with corn following soybean [ Glycine max (L.) Merr.] (SC) and corn following corn (CC), N application was either split, with half (112 kg N ha –1 ) at planting and the rest at stages ranging from V3 to R3; or with the entire increment (224 kg N ha –1 ) applied at these stages. In SC, there was no yield loss from delaying application of the second increment of N to as late as R3, but yields declined as the full increment of N was delayed, by 5% at V9 to 34% at R3. In CC, delaying the second N increment to stage R2 or R3 lowered yield by 5% compared to application at V3, and delaying the full increment of N increasingly lowered yield, by 8% at V6 to 40% at R3. Corn able to recover leaf chlorophyll content (SPAD) following delayed N application produced full yields, and cumulative N deficiency (CND, ΔSPAD × delay expressed as modified growing degree days over periods with ΔSPAD>0, SPAD‐MGGD) was linearly correlated with yield loss. With half of the N at planting, the remainder could be delayed to R1 or later without yield loss, but without N at planting, N needed to be applied before stage V9 in SC and before stage V6 in CC in order to assure maximum yield. Core Ideas: How late N can be applied to corn without loss of yield is a pressing question. With half of the N applied early, delaying the rest to R3 in SC or R1 in CC maximized yield. Delaying the full increment of N past V6 in SC or past V3 in CC brought risk of yield loss. Plants able to recover leaf chlorophyll after delayed N application produced full yields. Yield loss with delayed N was correlated with cumulative N deficiency based on SPAD.