Increased hydraulic constraints in Eucalyptus plantations fertilized with potassium

Guillemot Joannès, Asensio Verónica, Bordron Bruno, Nouvellon Yann, Le Maire Guerric, Bouillet Jean-Pierre, Domec Jean-Christophe, Delgado Rojas Juan Sinforiano, Abreu-Junior Cassio Hamilton, Battie Laclau Patricia, Cornut Ivan, Germon Amandine, De Moraes Gonçalves Jose Leonardo, Robin Agnès, Laclau Jean-Paul. 2021. Increased hydraulic constraints in Eucalyptus plantations fertilized with potassium. Plant, Cell and Environment, 44 (9), dossier Hydraulics of Woody Plants : 2938-2950.

Quartile : Outlier, Sujet : PLANT SCIENCES

Résumé : Fertilization is commonly used to increase growth in forest plantations, but it may also affect tree water relations and responses to drought. Here, we measured changes in biomass, transpiration, sapwood-to-leaf area ratio (As:Al) and sap flow driving force (ΔΨ) during the 6-year rotation of tropical plantations of Eucalyptus grandis under controlled conditions for throughfall and potassium (K) fertilization. K fertilization increased final tree height by 8 m. Throughfall exclusion scarcely affected tree functioning because of deep soil water uptake. Tree growth increased in K-supplied plots and remained stable in K-depleted plots as tree height increased, while growth per unit leaf area increased in all plots. Stand transpiration and hydraulic conductance standardized per leaf area increased with height in K-depleted plots, but remained stable or decreased in K-supplied plots. Greater Al in K-supplied plots increased the hydraulic constraints on water use. This involved a direct mechanism through halved As:Al in K-supplied plots relative to K-depleted plots, and an indirect mechanism through deteriorated water status in K-supplied plots, which prevented the increase in ΔΨ with tree height. K fertilization in tropical plantations reduces the hydraulic compensation to growth, which could increase the risk of drought-induced dieback under climate change.

Mots-clés Agrovoc : Eucalyptus grandis, fertilisation, évapotranspiration, stress dû à la sécheresse, bilan hydrique, absorption d'eau, surface foliaire, sève

Mots-clés géographiques Agrovoc : Brésil

Mots-clés libres : Eucalyptus grandis, Allometry, Huber value, Hydraulic conductance, Potassium fertilization, Transpiration, Tree height, Tropical forest plantations, Water potential, Water stress

Classification Agris : F04 - Fertilisation
F60 - Physiologie et biochimie végétale
F01 - Culture des plantes

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Auteurs et affiliations

• Guillemot Joannès, CIRAD-PERSYST-UMR Eco&Sols (BRA) ORCID: 0000-0003-4385-7656 - auteur correspondant
• Asensio Verónica, USP (BRA)
• Bordron Bruno, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0002-6290-1010
• Nouvellon Yann, CIRAD-PERSYST-UMR Eco&Sols (THA) ORCID: 0000-0003-1920-3847
• Le Maire Guerric, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0002-5227-958X
• Bouillet Jean-Pierre, CIRAD-PERSYST-UMR Eco&Sols (MDG)
• Domec Jean-Christophe, Bordeaux Sciences Agro (FRA)
• Delgado Rojas Juan Sinforiano, USP (BRA)
• Abreu-Junior Cassio Hamilton, USP (BRA)
• Battie Laclau Patricia, USP (BRA)
• Cornut Ivan, CIRAD-PERSYST-UMR Eco&Sols (FRA)
• Germon Amandine, INRAE (FRA)
• De Moraes Gonçalves Jose Leonardo, USP (BRA)
• Robin Agnès, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0003-3044-2304
• Laclau Jean-Paul, CIRAD-DG-Direction générale (FRA) ORCID: 0000-0002-2506-214X

Source : Cirad-Agritrop (https://agritrop.cirad.fr/598509/)

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