Efeito da reutilização da cama de frango no conforto térmico das aves e seu uso como fertilizante para a cultura do milho

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Universidade Federal de Goiás
A large generation of poultry litter (PL), arising from the increased production of broiler chicken, has become an environmental problem with indiscriminate use. The best forms of reuse are needed to minimize this impact on the environment and to be used by agriculture as a fertilizer to improve physical and chemical soil characteristics and to reduce fertilizer expenditure. Understanding some variables that include the reuse of PL in the livestock environment is also necessary. The enthalpy comfort index (ECI) can be used to understand the environmental conditions in relation to the condition of thermal stress suffered by the animal under conditions of reuse of the PL. The aim of this research was to evaluate the microclimate of sheds of broiler with different types of PL using the ECI, and to evaluate the addition of two chemical soil conditioners in different PL produced as fertilizer in corn crop. The experiments were conducted at Santa Terezinha Farm and GRANJA 54 (Goiás-Brazil), which carries out commercial broiler and grain production. Two broiler sheds (negative pressure tunnel type) measuring 1,680m2 and 20,000 birds/shed were used in this experiment (population density of 11.9 birds/m²). The treatments consist of the amount of reuse of poultry litter (R3 - PL with 3 flocks of reuse and R6 - PL with 6 flocks of reuse). The absorbent material used was a rice husk. No experiment I, of welfare, the design used was completely randomized, with time subdivided plots and the data were analyzed in a factorial scheme 2x4 (poultry litter reuses x schedules), totaling 8 treatments with 12 replicates. Were collected the instantaneous temperature, maximum and minimum of sheds and PL, the relative humidity, ammonia levels and ECI, from 7 to 42 days of age of birds. We used three digital thermo hygrometer at equidistant points in the sheds and as measurements were taken at the following schedules: 07: 00h, 10: 00h, 14: 00h and 19: 00h. ECI equation considers 3 environmental variables: temperature, relative humidity and local barometric pressure (Brasília average = 890mmHG). The results were statistically analyzed using the R software and comparing as media by the Tukey test (5% significance). A difference (P≤0.05) was observed in the relative humidity between sheds, R6 with 47.32% and R3 with 44.31%, and between the measurement hours (P≤0.05), with average humidity higher than 07am with 54.02%, against 44.01% at 10am, 41.09% at 14pm and 44.14% at 19pm. No interaction (P>0.05) was observed for the ECI, being classified as a “comfort zone” for both sheds. The ECI did not differ between the different poultry litter reuse values. This result means that either reuse for six flocks consecutive in relation to three reuse is safe with respect to broiler comfort. In experiment II, the adopted statistical design was the completely randomized, with three blocks and nine treatments, composing a 2x4 factorial scheme (reuse of PL x additive or not), each experimental unit media 27m². The conditioners used for the preparation of the treatments were calcitic limestone (40% of the PL weight) and mineralizer (20lts/ton.PL). The treatments were piled up with 55% moisture, fermented aerobically for 10 days and revolved on the 5th day. The treatments applicabled to the soil were: SC: negative control, without PL; R3: PL with 3 reuses; R3: R3 + Calcitic limestone (C); R3M: R3 + Mineralizer (M); R3CM: R3 + C + M; R6: PL with 6 reuses; R6C: R6 + C; R6M: R6 + M; R6CM: R6 + C + M. All treatments received mineral fertilization with 220kg/ha NPK 05.25.15. 4ton./ha of PL treatments were applied in the soil. The corn planted was the high yield hybrid 30F53VYH (PIONEER®). The results were statistically analyzed using the R software and comparing as media by the Scott-Knott test (5% significance). The treatments with PL presented significant (P≤0,05) values for the variables humidity (R6CM and R3CM), pH (R3CM, R3M and R6M), CTC (R3M, R6, R3 and R6M), calcium (R3C, R3CM, R6C and R6CM), manganese (R3CM, R3C, R6C, R6CM and R3CM), boron (R3M and R6M) and iron (R6CM, R3M, R6M and R3CM). The results of corn yield index showed difference for plant height (2.92m) and first ear insertion (1.62m) in R3M. The PL proved to be favorable in several variables for use in agriculture when compared to the treatment without PL, improving soil variables and morphological characteristics of corn.
Conforto térmico, Dejetos avícolas, Índice de entalpia de conforto, Sustentabilidade agrícola, Enthalpy index of comfort, Agricultural sustainability, Poultry manure, Thermal comfort
MIGOTTO, D. L. Efeito da reutilização da cama de frango no conforto térmico das aves e seu uso como fertilizante para a cultura do milho. 2020. 120 f. Tese (Doutorado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2020.