Time-Series of Vegetation Indices (VNIR/SWIR) Derived from Sentinel-2 (A/B) to Assess Turgor Pressure in Kiwifruit

Abstract

For more than ten years, Central Chile has faced drought conditions, which impact crop production and quality, increasing food security risk. Under this scenario, implementing management practices that allow increasing water use efficiency is urgent. The study was carried out on kiwifruit trees, located in the O’Higgins region, Chile for season 2018–2019 and 2019–2020. We evaluate the time-series of nine vegetation indices in the VNIR and SWIR regions derived from Sentinel-2 (A/B) satellites to establish how much variability in the canopy water status there was. Over the study’s site, eleven sensors were installed in five trees, which continuously measured the leaf’s turgor pressure (Yara Water-Sensor). A strong Spearman’s (ρ) correlation between turgor pressure and vegetation indices was obtained, having −0.88 with EVI and −0.81 with GVMI for season 2018–2019, and lower correlation for season 2019–2020, reaching −0.65 with Rededge1 and −0.66 with EVI. However, the NIR range’s indices were influenced by the vegetative development of the crop rather than its water status. The red-edge showed better performance as the vegetative growth did not affect it. It is necessary to expand the study to consider higher variability in kiwifruit’s water conditions and incorporate the sensitivity of different wavelengths.

Non-destructive measurement of total phenolic compounds in Arabidopsis under various stress conditions

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Potential of N-CovSel for Variable Selection: A Case Study on Time-Series of Multispectral Images

“…The 945 nm wavelength region had the highest covariance, i.e., the highest overall reflectance intensity, and this is the reason why the algorithm selected and sorted it in the first round. Regarding the spectral slices selected in the second and third rounds, with the range between 1,600 and 2,500 nm, i.e., in the shortwave infrared (SWIR) domain, it is well-known that the reflectance in this region of the spectrum is strongly correlated with vegetation water content (Jopia et al, 2020;Holzman et al, 2021). However, the second round (2,190 nm) showed a baseline additive-type trend profile that reveals, as the first round, possible effects derived from the remote sensing spectral measurement.…”

Effect of acetylsalicylic acid and ammonium sulphate on productive and physiological parameters in Stipa caudata under water shortage conditions

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