Assessing relationships of cover crop biomass and nitrogen content to multispectral imagery
Date
2024-02-29
Journal Title
Journal ISSN
Volume Title
Publisher
Agronomy Journal
Abstract
Cover crops provide valuable roles in sustainable agriculture, provided they produce enough biomass. To accurately measure their services to field management, spatial estimates would be useful to producers. This study used multispectral drone imagery to produce maps of normalized difference vegetation index (NDVI), normalized difference red edge index (NDRE), and a digital surface model (DSM) of cover crop plots on sandy, Mid-Atlantic soils. Cover crops included cereal rye (Secale cereale), mixtures of rye and crimson clover (Trifolium incarnatum), and mixtures of rye and hairy vetch (Vicia villosa). Their biomass was sampled in the spring of 2019, 2020, and 2021, dried, weighed, and analyzed for total nitrogen (N) content. Measurements of NDVI became saturated (i.e., reached a linear plateau) at 3.86 Mg biomass ha−1, NDRE at 5.72 Mg biomass ha−1, and the DSM at 5.11 Mg biomass ha−1. The measured N content became saturated at 80.9, 139.1, and 75 kg N ha−1 for NDVI, NDRE, and the DSM, respectively. Based on log transformations, NDVI was a stronger predictor of biomass and N, but not C:N. The NDRE was important for biomass, N, and C:N, while the DSM interactions with cover crop species helped predict both the N content and C:N of cover crop tissues. Accumulated growing degree days was important as an individual variable for biomass and N and as an interaction with cover crop species.
Abbreviations
DSM
digital surface model
GDD
growing degree days
NDRE
normalized difference red edge index
NDVI
normalized difference vegetation index
Description
This article was originally published in Agronomy Journal. The version of record is available at: https://doi.org/10.1002/agj2.21554. © 2024 The Authors. Agronomy Journal published by Wiley Periodicals LLC on behalf of American Society of Agronomy. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Keywords
zero hunger, climate action, life on land
Citation
Miller, J. O., Shober, A. L., & Taraila, J. (2024). Assessing relationships of cover crop biomass and nitrogen content to multispectral imagery. Agronomy Journal, 00, 1–11. https://doi.org/10.1002/agj2.21554