Potential of Sentinel-2 Satellite Images for Monitoring Green Waste Compost and Manure Amendments in Temperate Cropland

Maxence Dodin,Emmanuelle Vaudour,Florent Levavasseur,Dalila Hadjar,Hunter D Smith,Sabine Houot

doi:10.3390/rs13091616

Abstract

Increasing attention has been placed on the agroecological impact of applying exogenous organic matter (EOM) amendments, such as green waste compost (GWC) and livestock manure, to agricultural landscapes. However, monitoring the frequency and locality of this practice poses a major challenge, as these events are typically unreported. The purpose of this study is to evaluate the utility of Sentinel-2 imagery for the detection of EOM amendments. Specifically, we investigated the spectral shift resulting from GWC and manure application at two spatial scales, satellite and proximal. At the satellite scale, multispectral Sentinel-2 image pairs were analyzed before and after EOM application to six cultivated fields in the Versailles Plain, France. At the proximal scale, multi-temporal spectral field measurements were taken of experimental plots consisting of 14 total treatments: EOM variety, amendment quantity (15, 30 and 60 t.ha−1) and tillage. The Sentinel-2 images showed significant spectral differences before and after EOM application. Exogenous Organic Matter Indices (EOMI) were developed and analyzed for separative performance. The best performing index was EOMI2, using the B4 and B12 Sentinel-2 spectral bands. At the proximal scale, simulated Sentinel-2 reflectance spectra, which were created using field measurements, successfully monitored all EOM treatments for three days, except for the buried green waste compost at a rate of 15 t.ha−1.

Highlights

IntroductionThe application of exogenous organic matter (EOM), such as compost and manure, to agricultural fields is a widespread practice with the objective of increasing soil fertility
The application of exogenous organic matter (EOM), such as compost and manure, to agricultural fields is a widespread practice with the objective of increasing soil fertility.Farmers use EOMs primarily to add macronutrients to their fields for crop production and to increase organic carbon content of their soils [1]
The overall approach is described in Figure 1: for farm fields, pairs of Sentinel-2 images were chosen around the very dates of EOM spreading obtained from farmers’ surveys, while the changes of spectral behavior of EOM amendments over time, influence of type, rate and tillage, were studied from field reflectance measurements carried outout in an of type, rate and tillage, were studied from field reflectance measurements carried in experiment over a 38 dayday period

Summary

Introduction

The application of exogenous organic matter (EOM), such as compost and manure, to agricultural fields is a widespread practice with the objective of increasing soil fertility. Farmers use EOMs primarily to add macronutrients (nitrogen, phosphate and potassium) to their fields for crop production (fertilizing EOMs) and to increase organic carbon content of their soils (amending EOMs) [1]. The increase of soil organic carbon (SOC) content favors soil biology and improves soil physical properties, such as aggregate stability [2]. Soil organic carbon storage has been identified as one of the most prominent challenges of soil science in the 2020s [4] and the advancement of agricultural practices that favor SOC storage, e.g., EOM application, have been of particular focus, e.g., the 4‰ initiative [5,6].

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