Preprints
https://doi.org/10.5194/amt-2023-253
https://doi.org/10.5194/amt-2023-253
05 Feb 2024
 | 05 Feb 2024
Status: this preprint is currently under review for the journal AMT.

Role of time-averaging of eddy covariance fluxes on water use efficiency dynamics of Maize crop

Arun Rao Karimindla, Shweta Kumari, Saipriya SR, Syam Chintala, and BVN Phanindra Kambhammettu

Abstract. Direct measurement of carbon and water fluxes at high frequency makes eddy covariance (EC) as the most preferred technique to characterize water use efficiency (WUE). However, reliability of EC fluxes is hinged on energy balance ratio (EBR) and inclusion of low-frequency fluxes. This study is aimed at investigating the role of averaging period to represent EC fluxes and its propagation into WUE dynamics. Carbon and water fluxes were monitored in a drip-irrigated Maize field at 10 Hz frequency and are averaged over 1, 5, 10, 15, 30, 45, 60, and 120 minutes considering daytime unstable conditions. Optimal averaging period to simulate WUE fluxes for each growth stage is obtained by considering cumulative frequency (ogive) curves. A clear departure of EBR from unity was observed during dough stage of the crop due to ignorance of canopy heat storage. Error in representing water (carbon) fluxes relative to the conventional 30 min. average is within ± 3 % (± 10 %) for 10–120 min. averaging and is beyond ± 3 % (± 10 %) for other time-averages. Ogive plots conclude that optimal averaging period to represent carbon and water fluxes is 15–30 min. for 6th leaf and silking stages, and is 45–60 min. for dough and maturity stages. Dynamics of WUE considering optimal averaging periods are in the range of 1.49 ± 0.95, 1.37 ± 0.74, 1.39 ± 0.79, and 3.06 ± 0.69 μmol mmol-1 for the 6th leaf, silking, dough, and maturity stages respectively. Error in representing WUE with conventional 30 min. averaging is marginal (< 1.5 %) except during the dough stage (12.12 %). Our findings can help in developing efficient water management strategies by accurately characterizing WUE fluxes from the EC measurements.

Arun Rao Karimindla, Shweta Kumari, Saipriya SR, Syam Chintala, and BVN Phanindra Kambhammettu

Status: open (until 11 Mar 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2023-253', Anonymous Referee #2, 25 Feb 2024 reply
  • RC2: 'Comment on amt-2023-253', Anonymous Referee #3, 26 Feb 2024 reply
Arun Rao Karimindla, Shweta Kumari, Saipriya SR, Syam Chintala, and BVN Phanindra Kambhammettu
Arun Rao Karimindla, Shweta Kumari, Saipriya SR, Syam Chintala, and BVN Phanindra Kambhammettu

Viewed

Total article views: 142 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
112 21 9 142 3 2
  • HTML: 112
  • PDF: 21
  • XML: 9
  • Total: 142
  • BibTeX: 3
  • EndNote: 2
Views and downloads (calculated since 05 Feb 2024)
Cumulative views and downloads (calculated since 05 Feb 2024)

Viewed (geographical distribution)

Total article views: 149 (including HTML, PDF, and XML) Thereof 149 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 28 Feb 2024
Download
Short summary
This study is aimed at investigating the role of the averaging period of Eddy Covariance (EC) fluxes on EBR and further propagation into WUE dynamics. Application was demonstrated on a Maize field considering EC flux data. We obtained that the time averages of EC fluxes that yield the most effective EBR are at 45 min and 60 min. The 30-min averaging period proves insufficient for capturing low-frequency fluxes. Time-averaging of EC fluxes needs to be performed based on crop growth stage.