@article{fdi:010046328,
  title = {{A}ssessing the protective effect of vertically heterogeneous canopies against radiative frost : {T}he case of quinoa on the {A}ndean {A}ltiplano},
  author = {{W}inkel, {T}hierry and {L}homme, {J}ean-{P}aul and {L}aura, {J}. {P}. {N}. and {A}lcon, {C}. {M}. and del {C}astillo, {C}. and {R}ocheteau, {A}lain},
  editor = {},
  language = {{ENG}},
  abstract = {{N}ight radiative frost is a highly limiting factor for agriculture in {A}ndean highlands. {N}evertheless, a diversity of crop species have been domesticated there, commonly showing high heterogeneity in plant growth at the field level. {T}he possible protective effect of crop canopy heterogeneity against nocturnal radiative frost is examined using a dual approach, combining a field experiment and a simplified energy balance model at the leaf level. {L}eaf and air temperatures were registered over an entire quinoa crop cycle in the {A}ndean highlands of {B}olivia, comparing two cultivars: {B}lanca de {Y}anamuyu, a traditional landrace with high plant height heterogeneity, and {S}urumi, a more homogeneous selected variety. {I}n both cultivars, inverted air density profiles during calm and clear nights result in air temperature changes up to 3 degrees {C} over 0.5 m height, with minimum air temperature concentrated at the upper part of the canopy. {I}n these conditions, leaf temperature gradients of up to 2.6 degrees {C} m(-1) develop within the canopy of the traditional landrace, with minimum leaf temperature significantly higher ({P} < 0.001) in shaded plants of the landrace than in the selected cultivar. {A} dynamic model of leaf temperature based on canopy parameters and climatic records at screen level adequately simulates leaf temperature differences in the case of a vertically heterogeneous quinoa canopy. {A} sensitivity analysis of the model reveals that canopy height, leaf area index, and sky cloudiness have the most important influences on the development of the sheltering effect, while air temperature and air humidity play a minor role under typical radiative frost conditions. {A}s for wind speed, its actual influence remains unclear due to experimental and modelling limitations at low wind speeds. {T}he significance of these results is discussed in terms of the trade-off between stress adaptation and biomass productivity.},
  keywords = {{C}henopodium quinoa ; {C}anopy thermal stratification ; {L}eaf temperature ; {N}ight conditions ; {R}adiation view factor},
  booktitle = {},
  journal = {{A}gricultural and {F}orest {M}eteorology},
  volume = {149},
  numero = {10},
  pages = {1759--1768},
  ISSN = {0168-1923},
  year = {2009},
  DOI = {10.1016/j.agrformet.2009.06.005},
  URL = {https://www.documentation.ird.fr/hor/fdi:010046328},
}