Database n°1 (DB1) – Measurements under controlled laboratory conditions: exploring the leaf biochemical – optical trait relationship for phytosanitary assessment
2023: focus on leaf and shoot scale, vertical crown variability, varietal and fertilization trials
From 5 monthly measurement campaigns between June and October 2023, a total of 156 leaves were sampled from the collection of 31 tree shoots at ECOPECHE S1 & S3 and CORE COLLECTION INRAE orchards. For apricot trees, a single variety was systematically monitored (Early Blush) while a second variety changed from month to month (Poizat, Greta, Goldrich, Mei Hwang). For peach trees from one variety (Nectar Love), two very contrasted fertilization trials were monitored (0N vs. 180N). Shoot samplings were performed on the bottom and top of trees. The laboratory measurements at ONERA were performed within 48 hours after collections. From 4 leaves on each shoot, leaf dimensions were recorded, leaf optical properties over the spectral range 0.4 – 15 µm were measured as well as leaf water/dry matter content, and SPAD leafclip measures were performed. The samples were transported to PSH and GAFL laboratories for further and more precise biochemistry data measurements at shoot scale: pigments (chlorophylls, carotenoids, phenolics compounds), nitrogen, sugars and starches, acids and vitamins. In addition, the phytosanitary status was scored based on chlorosis, leafhopper attack, presence of shot holes and rust, from visual assessment at leaf and shoot scale.
2024: focus on leaf scale, top of canopy, varietal and phytosanitary trials
From 5 monthly measurement campaigns between May and September 2024, a total of 160 leaves were sampled from the collection of 40 treetop shoots at DIVAE and CORE COLLECTION INRAE orchards. 2 peach species (Zaibop Early Top, Monivo-Ivoire) were sampled on DIVAE while 3 apricot species (Farbaly, Stark Early Orange, Rouge du Roussillon) were sampled on both orchards. The same laboratory measurements at ONERA, PSH and GAFL were performed, with the addition of DUALEX leafclip measures. Also, multi-angular polarized spectroscopic data over 0.4 – 1 µm were acquired for a few leaves.
Database n°2 (DB2) – Measurements under field conditions: upscaling to UAV observations
In June and September 2024, two field campaigns occurred at DIVAE and CORE COLLECTION INRAE orchards. Several workshops were carried out:
- Drone acquisitions with a visible to short-wave infrared range hyperspectral camera (June/September), a visible to near-infrared range multispectral polarized camera (September) and a LiDAR instrument (September),
- Terrestrial LiDAR acquisitions,
- Spectroscopic and SPAD/DUALEX leafclip measurements for leaves,
- Spectroscopic measurements for fruits and trunks,
- Biochemical, morphological and ecophysiological trait measurements,
- Disease and pest visual ratings,
- Plant canopy analyzer acquisitions to retrieve the plant area index.
Database n°3 (DB3) – Investigating the intra-crown variability of tree health/nutritional status
In June and September 2024, and in parallel of the DB2 acquisition, 24 trees were selected over the two orchards from which 10 or 20 leaves were tagged, and the following in situ measurements were performed:
- SPAD/DUALEX leafclip measurements,
- Biochemical and morphological trait measurements,
- Disease and pest visual ratings.
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