Infrared Thermal Profiles in Silvopastoral and Full-Sun Pastures in the Eastern Amazon, Brazil

Abstract

There is a great need to identify interactions among silvopastoral systems and microclimatic indicators that describe the effect of trees compared to conventional pasture systems without trees. The objective of this study was to evaluate thermal conditions in a silvopastoral system and a pasture area exposed to full sunlight in the eastern Amazon, Brazil. The silvopastoral system was composed of the forest tree species Bertholletia excelsa H.B.K., Dipteryx odorata (Aubl.) Willd, and Khaya grandifoliola C.DC.. During the monitoring period, a forest inventory was carried out that included 30 trees from each species for which thermal profiles were created using a high-precision thermographic camera. Near-infrared thermography showed a positive and direct correlation with dendrometric variables. Silvopastoral systems with K. grandifoliola reduced the heat profile the most compared to conditions in a pasture fully exposed to sunlight, which demonstrates the ecosystem service provided by trees for thermal regulation in these systems. The microclimatic conditions explain the greater presence of bovines in the silvopastoral system as they were most likely in search of the thermal comfort provided by the trees during the period of the highest daytime temperatures. The silvopastoral system benefits the caloric balance and thermal comfort of pasture animals.

Thermographic Profiles in Livestock Systems under Full Sun and Shaded Pastures during an Extreme Climate Event in the Eastern Amazon, Brazil: El Niño of 2023

“…Numerous studies have highlighted the relationships between microclimate variables and canopy thermal characteristics in pasture environments [ 35 , 53 , 54 , 55 , 56 , 57 , 58 ]. Do not consider these interactions to influence substantial errors in climate measurements, due to temperature variation between the ground surface and the air masses above the canopy [ 59 ].…”

“…This difference can be explained by the shading phenomenon provided by the treetops. The presence of trees in the Amazon region creates a cooler environment and attenuates direct exposure to the sun, limiting the amount of solar radiation that reaches the ground [ 35 ]. In addition, the transpiration from the trees helps to cool the environment, maintaining milder temperatures in the surroundings.…”

“…It is worth noting that even in the wettest regions of the state of Pará, in El Niño years, from August onwards, estimates using the water balance considering the dominant root zone in pastures already indicate water deficits in the soil [ 46 , 47 ]. The months of October to November are considered the months with the highest heat index in different regions, including the north of the country [ 35 ].…”

“…The Amazon faces intense climatic challenges, such as high temperatures and humidity, which can have a significant impact on animal welfare and performance. By evaluating the thermal variations of the environment in which the animals live, thermography allows for a more in-depth understanding of the thermal conditions of production systems, which makes it possible to adopt management strategies to improve the productive efficiency and health of the herds in each system [ 28 , 31 , 32 , 33 , 34 , 35 ].…”

Understanding the impacts of intensity and harvest frequency on Tithonia diversifolia for use in tropical silvopastoral systems

“…Several advantages have been documented concerning the adoption of SPS in comparison to extensive grazing systems based on forage monocultures, emerging as a promising strategy to mitigate the environmental impact of livestock farming and enhance the resilience of tropical pasture systems towards climate uctuations. These bene ts include improvements in soil physical, chemical, and biological properties (Santos et al 2022), soil organic carbon storage (Resende et al 2020; Filho et al 2024), as well as similar total forage accumulation and greater nutritive value (Gomes et al 2022;Brunetti et al 2022), protein supply during the dry season (Ovani et al 2023), weed reduction (Munaro et al 2023), shaded pasture for animals (Reis et al 2021), promotion of animal welfare (Cândido et al 2023), improved animal performance (Oliveira et al 2022), greenhouse gas emission mitigation (Monteiro et al 2024) and, consequently, provision of ecosystem services (Schmitt Filho et al 2023). These bene ts depend on the characteristics or application of each chosen tree or shrub resource.…”