The objective of this work was to evaluate the losses of N by ammonia volatilization with the use of pig slurry in no-till system. In the fall, the application of pig slurry (0, 40 and 80 m³ ha-1) was on the residues of spontaneous vegetation and on the residues of black oat from the last cultivation. In the summer, the pig slurry was applied on the same residues, recently handled with roller knife blade. On the residues of spontaneous vegetation, the loss of N by ammonia volatilization reached 16.1% of the total ammoniacal N applied with the pig slurry at fall, and 11.0% at summer time. On the black oat residues these values were 12.7% in the fall and 6.5% in the summer. The first 20 hours after the pig slurry application were responsible for the approximately 50% of total N loss. The results of this work show that in no-till system the use of pig slurry on the black oat residues reduce the ammonia emission compared to the residues of winter spontaneous vegetation. This reduction was in average 18.4% in the fall and 34.5% in the summer.
environmental pollution; crop residues; slurry
