1. Potassium fertilization increases hydraulic redistribution and water use efficiency for stemwood production in Eucalyptus grandis plantations
- Author
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Jean-Christophe Domec, Cassio Hamilton Abreu-Junior, Verónica Asensio, José Lavres, Jean-Pierre Bouillet, Jean-Paul Laclau, Yann Nouvellon, Juan Sinforiano Delgado Rojas, Lionel Jordan-Meille, Joannès Guillemot, Escola Superior de Agricultura 'Luiz de Queiroz', Centro de Energia Nuclear na Agricultura, University of São Paulo, Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Interactions Sol Plante Atmosphère (UMR ISPA), Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Département Performances des systèmes de production et de transformation tropicaux (Cirad-PERSYST), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), CENA, Plant Nutrition Laboratory, University of São Paulo (USP), Agro Ambiência Serviços Agrícolas, and Universidade de São Paulo (USP)
- Subjects
0106 biological sciences ,0301 basic medicine ,Eucalyptus grandis ,Soil biology ,Engrais potassique ,F62 - Physiologie végétale - Croissance et développement ,Plant Science ,01 natural sciences ,Fertilisation ,Relation plante eau ,03 medical and health sciences ,Efficience d'utilisation de l'eau ,Hydraulic redistribution ,Water-use efficiency ,Ecology, Evolution, Behavior and Systematics ,ComputingMilieux_MISCELLANEOUS ,TRANSPIRAÇÃO VEGETAL ,Réponse de la plante ,Bois de fût ,15. Life on land ,Throughfall ,Photosynthetic capacity ,030104 developmental biology ,Agronomy ,13. Climate action ,Soil water ,[SDE]Environmental Sciences ,Soil horizon ,Environmental science ,Agronomy and Crop Science ,Water use ,010606 plant biology & botany ,F04 - Fertilisation - Abstract
Climate change is expected to increase the frequency of droughts in most tropical regions in the coming decades. A passive phenomenon called hydraulic redistribution (HR) allows some plant species to take up water from deep and wet soil layers and redistribute it in the upper dry layers where other plants and soil biota can benefit from it. In addition, soil fertilization, particularly potassium (K), may also affect drought-adaptive mechanisms and increase water use efficiency (WUE) on poor and acidic tropical soils. The present study aimed at quantifying the role of HR and K fertilization on both wood productivity and WUE for stemwood production (WUEp) of Eucalyptus grandis plantations in Brazil under ambient and reduced (−37%) throughfall conditions. Tree transpiration was measured using trunk sap flow sensors over 21 months, and HR was estimated from the reverse sap flow (RF) observed in shallow roots over 18 months. Tree biomass, hydraulic conductance, soil water storage from surface to the water table (down to 17 m), and leaf photosynthetic capacity were also assessed. Significant HR was detected over the whole year, even during the rainy seasons. Neither potassium fertilization nor throughfall exclusion affected the velocity of water transported by HR, probably because most trees reached water table. Nonetheless, some photosynthetic capacity parameters, including the maximum photosynthetic rate (Amax), increased in treatments with K addition. This higher Amax combined with an increased sapwood area index, was associated with an increase in water uptake by 30 %–50 % and WUEp by 300 % relative to K-deficient trees. We postulate that the increase in WUEp promoted by potassium fertilization was partly driven by an increase in biomass allocation to wood, at the expense of foraging organs (leaves and roots), because K addition alleviated constraints on light and water use. Our results indicate that fertilizing E. grandis plantations with K is beneficial to both wood biomass production and WUEp.
- Published
- 2020