Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system
Background and Aims Fine roots play a major role in the global carbon cycle through respiration, exudation and decomposition processes, but their dynamics are poorly understood. Current estimates of root dynamics have principally been observed in shallow soil horizons (<1 m), and mainly in forest systems. We studied walnut (Juglans regia × nigra L.) fine root dynamics in an agroforestry system in a Mediterranean climate, with a focus on deep soils (down to 5 m), and root dynamics throughout the year. Methods Sixteen minirhizotron tubes were installed in a soil pit, at depths of 0.0–0.7, 1.0–1.7, 2.5–3.2 and 4.0–4.7 m and at two distances from the nearest trees (2 and 5 m). Fine root (diameter ≤ 2 mm) dynamics were recorded across three diameter classes every 3 weeks for 1 year to determine their phenology and turnover in relation to soil depth, root diameter and distance from the tree row. Results Deep (>2.5 m) root growth occurred at two distinct periods, at bud break in spring and throughout the winter i.e., after leaf fall. In contrast, shallow roots grew mainly during the spring-summer period. Maximum root elongation rates ranged from 1 to 2 cm day−1 depending on soil depth. Most root mortality occurred in upper soil layers whereas only 10 % of fine roots below 4 m died over the study period. Fine root lifespan was longer in thicker and in deeper roots with the lifespan of the thinnest roots (0.0–0.5 mm) increasing from 129 days in the topsoil to 190 at depths > 2.5 m. Conclusions The unexpected growth of very deep fine roots during the winter months, which is unusual for a deciduous tree species, suggests that deep and shallow roots share different physiological strategies and that current estimates based on the shortest root growth periods (i.e., during spring and summer) may be underestimating root production. Although high fine root turnover rates might partially result from the minirhizotron approach used, our results help gain insight into some of the factors driving soil organic carbon content.
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K10 - Production forestière F08 - Systèmes et modes de culture F62 - Physiologie végétale - Croissance et développement Juglans nigra phénologie agroforesterie plantation forestière enracinement racine cycle du carbone facteur édaphique profil du sol saison froide croissance zone méditerranéenne http://aims.fao.org/aos/agrovoc/c_4059 http://aims.fao.org/aos/agrovoc/c_5774 http://aims.fao.org/aos/agrovoc/c_207 http://aims.fao.org/aos/agrovoc/c_3048 http://aims.fao.org/aos/agrovoc/c_6649 http://aims.fao.org/aos/agrovoc/c_6651 http://aims.fao.org/aos/agrovoc/c_17299 http://aims.fao.org/aos/agrovoc/c_15617 http://aims.fao.org/aos/agrovoc/c_14402 http://aims.fao.org/aos/agrovoc/c_29557 http://aims.fao.org/aos/agrovoc/c_3394 http://aims.fao.org/aos/agrovoc/c_29563 http://aims.fao.org/aos/agrovoc/c_3081 http://aims.fao.org/aos/agrovoc/c_4698 K10 - Production forestière F08 - Systèmes et modes de culture F62 - Physiologie végétale - Croissance et développement Juglans nigra phénologie agroforesterie plantation forestière enracinement racine cycle du carbone facteur édaphique profil du sol saison froide croissance zone méditerranéenne http://aims.fao.org/aos/agrovoc/c_4059 http://aims.fao.org/aos/agrovoc/c_5774 http://aims.fao.org/aos/agrovoc/c_207 http://aims.fao.org/aos/agrovoc/c_3048 http://aims.fao.org/aos/agrovoc/c_6649 http://aims.fao.org/aos/agrovoc/c_6651 http://aims.fao.org/aos/agrovoc/c_17299 http://aims.fao.org/aos/agrovoc/c_15617 http://aims.fao.org/aos/agrovoc/c_14402 http://aims.fao.org/aos/agrovoc/c_29557 http://aims.fao.org/aos/agrovoc/c_3394 http://aims.fao.org/aos/agrovoc/c_29563 http://aims.fao.org/aos/agrovoc/c_3081 http://aims.fao.org/aos/agrovoc/c_4698 |
spellingShingle |
K10 - Production forestière F08 - Systèmes et modes de culture F62 - Physiologie végétale - Croissance et développement Juglans nigra phénologie agroforesterie plantation forestière enracinement racine cycle du carbone facteur édaphique profil du sol saison froide croissance zone méditerranéenne http://aims.fao.org/aos/agrovoc/c_4059 http://aims.fao.org/aos/agrovoc/c_5774 http://aims.fao.org/aos/agrovoc/c_207 http://aims.fao.org/aos/agrovoc/c_3048 http://aims.fao.org/aos/agrovoc/c_6649 http://aims.fao.org/aos/agrovoc/c_6651 http://aims.fao.org/aos/agrovoc/c_17299 http://aims.fao.org/aos/agrovoc/c_15617 http://aims.fao.org/aos/agrovoc/c_14402 http://aims.fao.org/aos/agrovoc/c_29557 http://aims.fao.org/aos/agrovoc/c_3394 http://aims.fao.org/aos/agrovoc/c_29563 http://aims.fao.org/aos/agrovoc/c_3081 http://aims.fao.org/aos/agrovoc/c_4698 K10 - Production forestière F08 - Systèmes et modes de culture F62 - Physiologie végétale - Croissance et développement Juglans nigra phénologie agroforesterie plantation forestière enracinement racine cycle du carbone facteur édaphique profil du sol saison froide croissance zone méditerranéenne http://aims.fao.org/aos/agrovoc/c_4059 http://aims.fao.org/aos/agrovoc/c_5774 http://aims.fao.org/aos/agrovoc/c_207 http://aims.fao.org/aos/agrovoc/c_3048 http://aims.fao.org/aos/agrovoc/c_6649 http://aims.fao.org/aos/agrovoc/c_6651 http://aims.fao.org/aos/agrovoc/c_17299 http://aims.fao.org/aos/agrovoc/c_15617 http://aims.fao.org/aos/agrovoc/c_14402 http://aims.fao.org/aos/agrovoc/c_29557 http://aims.fao.org/aos/agrovoc/c_3394 http://aims.fao.org/aos/agrovoc/c_29563 http://aims.fao.org/aos/agrovoc/c_3081 http://aims.fao.org/aos/agrovoc/c_4698 Germon, Amandine Cardinael, Rémi Prieto, Iván Mao, Zhun Kim, John H. Stokes, Alexia Dupraz, Christian Laclau, Jean-Paul Jourdan, Christophe Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system |
description |
Background and Aims Fine roots play a major role in the global carbon cycle through respiration, exudation and decomposition processes, but their dynamics are poorly understood. Current estimates of root dynamics have principally been observed in shallow soil horizons (<1 m), and mainly in forest systems. We studied walnut (Juglans regia × nigra L.) fine root dynamics in an agroforestry system in a Mediterranean climate, with a focus on deep soils (down to 5 m), and root dynamics throughout the year. Methods Sixteen minirhizotron tubes were installed in a soil pit, at depths of 0.0–0.7, 1.0–1.7, 2.5–3.2 and 4.0–4.7 m and at two distances from the nearest trees (2 and 5 m). Fine root (diameter ≤ 2 mm) dynamics were recorded across three diameter classes every 3 weeks for 1 year to determine their phenology and turnover in relation to soil depth, root diameter and distance from the tree row. Results Deep (>2.5 m) root growth occurred at two distinct periods, at bud break in spring and throughout the winter i.e., after leaf fall. In contrast, shallow roots grew mainly during the spring-summer period. Maximum root elongation rates ranged from 1 to 2 cm day−1 depending on soil depth. Most root mortality occurred in upper soil layers whereas only 10 % of fine roots below 4 m died over the study period. Fine root lifespan was longer in thicker and in deeper roots with the lifespan of the thinnest roots (0.0–0.5 mm) increasing from 129 days in the topsoil to 190 at depths > 2.5 m. Conclusions The unexpected growth of very deep fine roots during the winter months, which is unusual for a deciduous tree species, suggests that deep and shallow roots share different physiological strategies and that current estimates based on the shortest root growth periods (i.e., during spring and summer) may be underestimating root production. Although high fine root turnover rates might partially result from the minirhizotron approach used, our results help gain insight into some of the factors driving soil organic carbon content. |
format |
article |
topic_facet |
K10 - Production forestière F08 - Systèmes et modes de culture F62 - Physiologie végétale - Croissance et développement Juglans nigra phénologie agroforesterie plantation forestière enracinement racine cycle du carbone facteur édaphique profil du sol saison froide croissance zone méditerranéenne http://aims.fao.org/aos/agrovoc/c_4059 http://aims.fao.org/aos/agrovoc/c_5774 http://aims.fao.org/aos/agrovoc/c_207 http://aims.fao.org/aos/agrovoc/c_3048 http://aims.fao.org/aos/agrovoc/c_6649 http://aims.fao.org/aos/agrovoc/c_6651 http://aims.fao.org/aos/agrovoc/c_17299 http://aims.fao.org/aos/agrovoc/c_15617 http://aims.fao.org/aos/agrovoc/c_14402 http://aims.fao.org/aos/agrovoc/c_29557 http://aims.fao.org/aos/agrovoc/c_3394 http://aims.fao.org/aos/agrovoc/c_29563 http://aims.fao.org/aos/agrovoc/c_3081 http://aims.fao.org/aos/agrovoc/c_4698 |
author |
Germon, Amandine Cardinael, Rémi Prieto, Iván Mao, Zhun Kim, John H. Stokes, Alexia Dupraz, Christian Laclau, Jean-Paul Jourdan, Christophe |
author_facet |
Germon, Amandine Cardinael, Rémi Prieto, Iván Mao, Zhun Kim, John H. Stokes, Alexia Dupraz, Christian Laclau, Jean-Paul Jourdan, Christophe |
author_sort |
Germon, Amandine |
title |
Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system |
title_short |
Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system |
title_full |
Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system |
title_fullStr |
Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system |
title_full_unstemmed |
Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system |
title_sort |
unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable mediterranean agroforestry system |
url |
http://agritrop.cirad.fr/580241/ http://agritrop.cirad.fr/580241/1/580241.pdf |
work_keys_str_mv |
AT germonamandine unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT cardinaelremi unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT prietoivan unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT maozhun unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT kimjohnh unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT stokesalexia unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT duprazchristian unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT laclaujeanpaul unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem AT jourdanchristophe unexpectedphenologyandlifespanofshallowanddeepfinerootsofwalnuttreesgrowninasilvoarablemediterraneanagroforestrysystem |
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1792499036039675904 |
spelling |
dig-cirad-fr-5802412024-01-28T23:26:01Z http://agritrop.cirad.fr/580241/ http://agritrop.cirad.fr/580241/ Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system. Germon Amandine, Cardinael Rémi, Prieto Iván, Mao Zhun, Kim John H., Stokes Alexia, Dupraz Christian, Laclau Jean-Paul, Jourdan Christophe. 2016. Plant and Soil, 401 (1-2) : 409-426.https://doi.org/10.1007/s11104-015-2753-5 <https://doi.org/10.1007/s11104-015-2753-5> Unexpected phenology and lifespan of shallow and deep fine roots of walnut trees grown in a silvoarable Mediterranean agroforestry system Germon, Amandine Cardinael, Rémi Prieto, Iván Mao, Zhun Kim, John H. Stokes, Alexia Dupraz, Christian Laclau, Jean-Paul Jourdan, Christophe eng 2016 Plant and Soil K10 - Production forestière F08 - Systèmes et modes de culture F62 - Physiologie végétale - Croissance et développement Juglans nigra phénologie agroforesterie plantation forestière enracinement racine cycle du carbone facteur édaphique profil du sol saison froide croissance zone méditerranéenne http://aims.fao.org/aos/agrovoc/c_4059 http://aims.fao.org/aos/agrovoc/c_5774 http://aims.fao.org/aos/agrovoc/c_207 http://aims.fao.org/aos/agrovoc/c_3048 http://aims.fao.org/aos/agrovoc/c_6649 http://aims.fao.org/aos/agrovoc/c_6651 http://aims.fao.org/aos/agrovoc/c_17299 http://aims.fao.org/aos/agrovoc/c_15617 http://aims.fao.org/aos/agrovoc/c_14402 http://aims.fao.org/aos/agrovoc/c_29557 http://aims.fao.org/aos/agrovoc/c_3394 http://aims.fao.org/aos/agrovoc/c_29563 France région méditerranéenne http://aims.fao.org/aos/agrovoc/c_3081 http://aims.fao.org/aos/agrovoc/c_4698 Background and Aims Fine roots play a major role in the global carbon cycle through respiration, exudation and decomposition processes, but their dynamics are poorly understood. Current estimates of root dynamics have principally been observed in shallow soil horizons (<1 m), and mainly in forest systems. We studied walnut (Juglans regia × nigra L.) fine root dynamics in an agroforestry system in a Mediterranean climate, with a focus on deep soils (down to 5 m), and root dynamics throughout the year. Methods Sixteen minirhizotron tubes were installed in a soil pit, at depths of 0.0–0.7, 1.0–1.7, 2.5–3.2 and 4.0–4.7 m and at two distances from the nearest trees (2 and 5 m). Fine root (diameter ≤ 2 mm) dynamics were recorded across three diameter classes every 3 weeks for 1 year to determine their phenology and turnover in relation to soil depth, root diameter and distance from the tree row. Results Deep (>2.5 m) root growth occurred at two distinct periods, at bud break in spring and throughout the winter i.e., after leaf fall. In contrast, shallow roots grew mainly during the spring-summer period. Maximum root elongation rates ranged from 1 to 2 cm day−1 depending on soil depth. Most root mortality occurred in upper soil layers whereas only 10 % of fine roots below 4 m died over the study period. Fine root lifespan was longer in thicker and in deeper roots with the lifespan of the thinnest roots (0.0–0.5 mm) increasing from 129 days in the topsoil to 190 at depths > 2.5 m. Conclusions The unexpected growth of very deep fine roots during the winter months, which is unusual for a deciduous tree species, suggests that deep and shallow roots share different physiological strategies and that current estimates based on the shortest root growth periods (i.e., during spring and summer) may be underestimating root production. Although high fine root turnover rates might partially result from the minirhizotron approach used, our results help gain insight into some of the factors driving soil organic carbon content. article info:eu-repo/semantics/article Journal Article info:eu-repo/semantics/publishedVersion http://agritrop.cirad.fr/580241/1/580241.pdf text Cirad license info:eu-repo/semantics/restrictedAccess https://agritrop.cirad.fr/mention_legale.html https://doi.org/10.1007/s11104-015-2753-5 10.1007/s11104-015-2753-5 info:eu-repo/semantics/altIdentifier/doi/10.1007/s11104-015-2753-5 info:eu-repo/semantics/altIdentifier/purl/https://doi.org/10.1007/s11104-015-2753-5 |