Sentinel-2 satellite images for monitoring cattle slurry and digestate spreading on emerging wheat crop: a field spectroscopy experiment

Abstract

This study is aimed to evaluate the utility of Sentinel-2 imagery for monitoring exogenous organic matter (EOM) applied on winter wheat crop, using two spatial scales: proximal and satellite. From proximal sensing, multi-temporal spectral field measurements were taken on experimental fields consisting of three treatments (cattle slurry, liquid and raw digestates) and a control throughout 46 days. From Sentinel-2 satellites, images were analysed before and after EOM application. For both sensing scales, EOM and vegetation indices were used. On any scale of observation, the digestates spread on emerging wheat were easily detectable in late winter, in contrast to spring spreading events which were hindered by the developed vegetation. The agglomerative hierarchical clustering from the EOM indices divided by EVI achieved to discriminate digestates at early and medium stages of vegetation growth. Our findings did not apply for cattle slurry, presumably because of both lower organic and dry matter contents.

HIGHLIGHTS

• Digestates spread on emerging wheat are detectable in late winter.

• Developed vegetation constrains the detection of spring spreading events.

• Spectral measurements did not separate the field with cattle slurry and the control.

• The visible to near infrared bands are the most impacted after digestate spreading.

Keywords:

• Remote sensing
• exogenous organic matter
• spectral measurement
• organic fertilizer
• winter wheat

Acknowledgments

We wish to thank Jean-Marc Gilliot for making his recent update of the read.asd tool available, thus enabling us to simulate the MSI spectral bands. Special thanks to the PAO experimental unit team who participated in this experimentation.

Authors’ contributions

Conceptualization, M.D., F.L., A.S., E.V.; data curation, M.D., E.V.; methodology, M.D., F.L., A.S., E.V.; validation, M.D., F.L., E.V.; resources, L.M., J.F.; writing original draft, M.D.; writing-review & editing, M.D., F.L., A.S., L.M., J.F., E.V.; supervision, F.L., E.V.; project administration, E.V.; funding acquisition, E.V.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Data availability statement

The data that support the findings of this study are available from the corresponding author, M.D., upon reasonable request.

Additional information

Funding

This work was supported by the European Union’s Horizon H2020 research and innovation European Joint Programme Cofund on Agricultural Soil Management (EJP-SOIL Grant Number 862695) and was carried out in the framework of the STEROPES of EJP-SOIL. This work was also supported by CNES, France, in the framework of the POLYPHEME project through the TOSCA program of the CNES (Grant Number 200769/id5126) and the MELICERTES project (ANR-22-PEAE-0010) of the French National Research Agency (France2030 and national PEPR ‘agroécologie et numérique’ programmes). Maxence Dodin has received the support of a PhD scholarship from the French Ministry of Agriculture.