Management model for assessment of nitrogen flow from feed to pig manure after storage in Vietnam.

Nitrogen (N) losses from pig production and the recycling of N from manure to crops can harm the atmosphere, soil and ground water quality. This study intended to build a dynamic management model, adapted to the Vietnamese context, that links the N flow at all stages along the manure management chain from the N in the diets fed to grower-finisher pigs to the application of the manure in the field. The model assesses N contents and losses at each stage of manure management so that application of manure N can be adjusted to ensure optimal fertilizer value, while at the same time minimizing environmental damage.