Swine manure application methods effects on ammonia volatilization, forage quality, and yield in the Pre-Amazon Region of Brazil|
Costa, Mayanna; Shigaki, Francirose; Alves, Bruno; Kleinman, Peter & Pereira, Marcos
The use of swine manure (SM) as a nutrient source for pastures is increasingly common in Brazil, due to its low cost.
However, this practice can cause N losses in agricultural soil, where ammonia (NH3) volatilization may be the main
drawback, generating undesirable economic and environmental consequences. The objective of this study was to evaluate
SM application methods that retain N within the system and determine how these methods affect forage yield and quality.
The study was conducted in the municipality of Chapadinha, Maranhão, Brazil, and the following SM application methods
were evaluated: (1) surface application, (2) incorporation at 5-cm soil depth, (3) incorporation at 10-cm soil depth, and
(4) control when SM was not applied. Lower N losses due to NH3 volatilization and higher pasture yield and quality were
found when SM was incorporated at 10-cm soil depth (83 kg N-NH3 ha-1 and 6.3 Mg DM ha-1, respectively, compared to 86
kg N-NH3 ha-1 and 1.5 Mg DM ha-1 for the control), whereas higher N-NH3 losses and lower pasture yield were observed
when SM was applied to the soil surface (143 kg N-NH3 ha-1 and 2.6 Mg ha-1, respectively). Higher quality forage in terms
of chemical composition was also observed when SM was incorporated at greater soil depth. Incorporating SM at 10-cm
depth represents an efficient management to mitigate N-NH3 volatilization, and this application method is associated with
significantly increased in DM yield and improved chemical composition.
Brachiaria brizantha; manure management; nitrogen loss; semi-opened chamber