Improvement of thermal comfort indices in agroforestry systems in the southern Brazilian Amazon

Ciro A S Magalhães; Cornélio A Zolin; Jorge Lulu; Luciano B Lopes; Isabela V Furtini; Laurimar G Vendrusculo; Ana P S R Zaiatz; Bruno C Pedreira; José Ricardo Macedo Pezzopane

doi:10.1016/j.jtherbio.2020.102636

Improvement of thermal comfort indices in agroforestry systems in the southern Brazilian Amazon

J Therm Biol. 2020 Jul:91:102636. doi: 10.1016/j.jtherbio.2020.102636. Epub 2020 Jun 5.

Authors

Ciro A S Magalhães¹, Cornélio A Zolin², Jorge Lulu², Luciano B Lopes², Isabela V Furtini³, Laurimar G Vendrusculo⁴, Ana P S R Zaiatz⁵, Bruno C Pedreira², José Ricardo Macedo Pezzopane⁶

Affiliations

¹ Empresa Brasileira de Pesquisa Agropecuária, Embrapa Agrossilvipastoril, P.O. Box 343, 78550-970, Sinop, MT, Brazil. Electronic address: ciro.magalhaes@embrapa.br.
² Empresa Brasileira de Pesquisa Agropecuária, Embrapa Agrossilvipastoril, P.O. Box 343, 78550-970, Sinop, MT, Brazil.
³ Empresa Brasileira de Pesquisa Agropecuária, Embrapa Arroz e Feijão, P.O. Box 179, 75375-000, Santo Antônio de Goiás, GO, Brazil.
⁴ Empresa Brasileira de Pesquisa Agropecuária, Embrapa Informática Agropecuária, P.O. Box 6041, 13083-886, Campinas, SP, Brazil.
⁵ Universidade Federal de Mato Grosso, Programa de Pós-Graduação em Agronomia, campus Sinop, 78557-267, Sinop, MT, Brazil.
⁶ Empresa Brasileira de Pesquisa Agropecuária, Embrapa Pecuária Sudeste, P.O. Box 339, 13560-970, São Carlos, SP, Brazil.

PMID: 32716878
DOI: 10.1016/j.jtherbio.2020.102636

Abstract

Agroforestry systems can minimize heat stress and improve cattle welfare, but the influence of the forest component in microclimatic changes in the southern Amazon remains unclear. This study aimed to compare the thermal comfort indices in grass monoculture and integrated systems. The three systems were pasture under full sunlight (PFS), integrated (triple-row) livestock-forestry (ILF_T), and integrated (single-row) livestock-forestry (ILFs), across four seasons, for two years, from June 2017 to June 2019. We assessed photosynthetically active radiation (PAR), air temperature, relative humidity, black globe temperature, and wind speed. Thermal comfort indices such as temperature-humidity index (THI), black globe temperature-humidity index (BGHI), and radiant thermal load (RTL) were calculated based on microclimate data daily-collected from 8:00 to 16:00. The ILF_T mean THI (76.8) was slightly lower than ILF_S and PFS. The BGHI and RTL values decreased as shading increased (PFS > ILFs > ILF_T). The most challenging heat stress conditions for grazing animals occurred predominately during winter and autumn. In conclusion, the presence of trees in pastures of the southern Amazon improved the microclimate and, consequently, the thermal comfort indices. Agroforestry systems can foster an environment with a more suitable thermal comfort or less restrictive to animal performance, which contribute to mitigating global climate change for forage-livestock systems in Brazilian Amazon.

Keywords: Animal husbandry; Black globe temperature; Heat stress; Microclimate; Tropical farming systems.

MeSH terms

Agriculture / methods*
Agriculture / standards
Animals
Body Temperature Regulation*
Brazil
Cattle / physiology*
Forests*
Global Warming
Humidity
Seasons
Temperature
Tropical Climate