|Costa, Mayanna - Federal University - Brazil|
|Shigaki, Francirose - Federal University - Brazil|
|Alves, Bruno - Embprapa|
|Pereira, Marcos - Universidade Federal Do Rio De Janeiro|
Submitted to: Chilean Journal of Agricultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2014
Publication Date: 10/30/2014
Citation: Costa, M., Shigaki, F., Alves, B., Kleinman, P.J., Pereira, M. 2014. Swine manure application effects on ammonia volatilization, forage quality, and yield in the Pre-Amazon Region of Brazil. Chilean Journal of Agricultural Research. 74:311-318.
Interpretive Summary: Conservation of nitrogen to improve crop production and minimize adverse environmental consequences is particularly difficult with manure and has not been widely pursued in emerging agricultural economies such as Brazil. This study quantifies the benefits of using subsurface manure application practices on forage production in Brazil. Results show that technologies, such as manure injectors, that directly incorporate manure with minimal surface disturbance can reduce the loss of nitrogen as ammonia by more than 40%, resulting in higher yields and nutritional quality of the animal forages. These findings underscore efforts to bring new manure incorporation technologies to Brazilian agriculture.
Technical Abstract: The use of swine manure as a nutrient source for pastures is increasingly common in Brazil, due to its low cost. However, this practice can cause nitrogen (N) losses in agricultural soil, where ammonia volatilization may be the main drawback, generating undesirable economic and environmental consequences. The objective of this study was to evaluate swine manure 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. The following swine manure 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 swine manure was not applied. Lower N losses due to ammonia volatilization and higher pasture yield and quality were found when swine manure was incorporated at 10-cm soil depth (83 kg ammonia-N ha-1 and 6.3 Mg dry matter ha-1, respectively, compared to 86 kg ammonia-N ha-1 and 1.5 Mg dry matter ha-1 for the control), whereas higher ammonia-N losses and lower pasture yield were observed when swine manure was applied to the soil surface (143 kg ammonia-N ha-1 and 2.6 Mg ha-1, respectively). Higher nutritional quality of forage was also observed when swine manure was incorporated at greater soil depth. Incorporating swine manure at 10-cm depth represents an efficient management to mitigate ammonia volatilization, and this application method is associated with significantly increased in dry matter yield and improved chemical composition.