Spatial variability of methane and carbon dioxide gases in a Compost-Bedded Pack Barn system

The dairy sector significantly contributes to global food production, however, it is closely associated with environmental concerns, specifically the emission of greenhouse gases such as methane (CH4) and carbon dioxide (CO2). The research problem focuses on the environmental impact of livestock farming, particularly in relation to the emission of greenhouse gases (GHG) such as methane (CH4) and carbon dioxide (CO2). Therefore, the objective of this paper was to assess the spatial variability of CH4 and CO2, as well as the thermal environment through the Temperature and Humidity Index (THI) and of air velocity (V, m s-1) in a Compost Bedded Pack (CBP). The experiment was carried out in October 2023, in a commercial dairy cattle facility measuring 54×22×4.5 m (length×width×height) that housed 80 lactating cows. Measurements were collected at 75 points, 0.25 m above the bedding, for one minute at each point. To characterize the distribution of gases and the thermal environment, the data underwent geostatistical techniques and kriging maps. THI values ranged from 72.4 to 78.4, categorizing the animals into two environments within the facility, comfort and alert to thermal conditions. The maximum recorded for CO2 was 713.60 ppm in the region with a low ventilation incidence. CH4 reached a range from 103.38 to 196.73 ppm in areas with low ventilation and higher temperatures. The use of geostatistics enabled the characterization of spatial variability of greenhouse gases CH4 and CO2, as well as THI and V. Analyzing these variables is crucial for implementing mitigation actions and developing an increasingly sustainable production system.