PIROLENHOSO EXTRACT AND NITROGEN VOLATILIZATION IN MOMBAÇA GRASS

Abstract

Ammonia volatilization is one of the main forms in which nitrogen applied to the soil surface is lost to the atmosphere. This fact represents a loss of capital invested both for the fertilizer and for its expected effects on the production of forage. Thus, the application of pyrolenhosextracts, here called black pirolenhosextract (EEP) and yellow extract (EPA) as a volatilization reducer, was evaluated, at 0.1% dilution (v v-1) in water and applied after nitrogen fertilization (300 kg ha-1 N-urea) in plots of Mombasa grass. Plastic bottles (2L) were used for the estimates simulating bell sands in which containers containing boric acid with indicator were placed. Two collections spaced in 32 days were evaluated in a period of 144 hours. The experimental design was randomized in complete blocks in three replications. The expected effects of an efficient reduction in volatilized ammonia levels were not observed and even contradictory results were found. For the first evaluation, the black pirolenhosextract reduced volatilization in relation to the control treatment by 13%. For yellow pirolenhoso extract the reduction was 32%. However, for the second evaluation, the use of pirolenhosextract promoted an increase in volatilization in 200% (EPA) or even 294% (PpS), which may represent more than 50% of nitrogen added as fertilizer to the soil after 144 hours.