Thermal environment characterization in a compost bedded pack barn with photovoltaic plates and ammonia volatilization under the application of remineralizers in different bedding materials

Abstract

The advancement of intensive dairy farming is subject to the search for new techniques and strategies that aim to improve the productivity, efficiency and sustainability of this sector by identifying and correcting gaps and bottlenecks, especially in relation to animal ambience. This work aimed to characterize the spatial variability of the thermal environment inside a Compost Barn (CB) shed, which in one of the roof waters has, throughout its extension, the arrangement of photovoltaic panels. In addition, the objective was also to verify if the addition of remineralizers in compost beds are able to minimize the volatilization of ammonia (NH3) from the compost and, still, be a potential source of nutrients such as potassium. The characterization of the thermal environment was carried out in a CB shed located in the municipality of Rio Paranaíba, Minas Gerais, in the spring, summer, autumn and winter seasons of 2021. They were determined at heights of 1,0, 2,0, 3,0 and 4,0 meters the global temperature and humidity indixes (BGHI) were collected from 60 points uniformly distributed longitudinally over the shed area. Radiant thermal load (RTL) was also determined at heights of 1,0, 2,0, 3,0 and 4,0 meters in the cross section of the shed in three different internal positions. The BGHI and RTL data were submitted to geostatistical analysis to verify the spatial variability of the data through semivariograms and kriging maps. The modeling proved to be efficient to represent the microclimate of the shed. The BGHI and RTL maps estimated by ordinary kriging allowed the visualization of specific points of thermal discomfort inside the installation. It could not be noticed any changes in the thermal environment inside the shed due to the arrangement of photovoltaic panels on the roof, notably at the level of the cows. Research on the addition of remineralizers to compost beds was carried out in the laboratory in a completely randomized design with 10 treatments structured in a factorial scheme (2 x 4 +2), with two types of organic material used as bedding (coffee husks and fine wood shavings). pinus), four remineralizers (glauconite, phonolite, gypsum and control) and two additional treatments with microbial inoculants from native vegetation, with four replications, totaling 40 experimental units. The composting process yield, compost moisture, C/N ratio, NH3 volatilization and nitrogen (N), organic carbon, total potassium (Ktotal) and available potassium (Kdisp) contents were evaluated. Data were subjected to analysis of variance and means were compared by SNK and Holm-Bonferroni tests at 5% probability of error α. A high N conservation capacity was evidenced after the addition of gypsum, phonolite and glauconite in the material to be composted, especially gypsum, which, in relation to the control compounds, was able to maintain N content of 1,5 and 1,7 times higher in coffee husks and wood shavings, respectively. Furthermore, it was possible to observe an increase in Ktotal and Kdisp contents in both substrates added with glauconite and phonolite (except shavings) and greater decomposition and availability of Ktotal in coffee husks in the presence of microbial inoculants.