The objective of this study was to verify the effect of pig slurry application with acidification and biochar on feed value, nitrogen use efficiency (NUE) of maize forage, and ammonia (NH3) emission. The four treatments were applied: 1) non-pig slurry (only water as a control, C), 2) only pig slurry application (P), 3) acidified pig slurry application (AP), 4) acidified pig slurry application with biochar (APB). The pig slurry and biochar were applied at a rate of 150 kg N ha-1 and 300 kg ha-1, respectively. The AP and APB treatments enhanced all feed values compared to C and P treatments. The NUE for plant N was significantly increased 92.1% by AP and APB treatment, respectively, compared to the P treatment. On the other hand, feed values were not significantly different between AP and APB treatments. The acidification treatment with/without biochar significantly mitigated NH3 emission compared to the P treatment. The cumulative NH3 emission throughout the period of measurement decreased by 71.4% and 74.8% in the AP and APB treatments. Also, APB treatment reduced ammonia emission by 11.9% compared to AP treatment. The present study clearly showed that acidification and biochar can reduce ammonia emission from pig slurry application, and pig slurry application with acidification and biochar exhibited potential effects in feed value, NUE, and reducing N losses from pig slurry application through reduction of NH3 emission.

The objective of this study was to prove the effect of pig slurry application with charcoal on nitrogen use efficiency (NUE), feed value and ammonia (NH3) emission from maize forage. The four treatments were applied: 1) non-pig slurry (only water as a control), 2) only pig slurry application (PS), 3) pig slurry application with large particle charcoal (LC), 4) pig slurry application with small particle charcoal (SC). The pig slurry was applied at a rate of 150 kg N ha-1, and the charcoal was applied at a rate of 300 kg ha-1 regardless of the size. To determine the feed value of maize, crude protein, dry matter intake, digestible dry matter, total digestible nutrient, and relative feed value were investigated. All feed value was increased by charcoal treatment compared to water and PS treatment. Also, the NUE for plant N was significantly higher in charcoal treatments (LC and SC) compared to PS treatment. On the other hand, there is no significant difference for feed value and NUE between LC and SC. The NH3 emission was significantly reduced 15.2% and 27.9% by LC and SC, respectively, compared to PS. Especially, SC significantly decreased NH3 emission by 15% compared to LC. The present study clearly showed that charcoal application exhibited positive potential in nitrogen use efficiency, feed value and reducing N losses through NH3 emission.