Effects of Irrigation with Vinasse and the Dynamics of its Constituents in the Soil: II – Microbiological Aspects

Abstract

The effects of irrigation with vinasse (distillery effluent) on microbial populations in experimental squares of sugar-cane plantation were studied. The soil was a haplortox, with a sandy clay loam texture. The plantation was at Usina Costa Pinto, São Paulo State. A substantial and temporary increase was observed in the populations of bacteria and fungi. The actinomycetes were inhibited during the initial period. The major chemical compound known to be present in the vinasse is simple carbohydrate, although other complex organic compounds may be present. The behaviour of the cellulolytic micro-organisms was analysed, as a tentative attempt to select a biological indicator. Nitrifying micro-organisms were inhibited during the second stage of the decomposition of the waste. The great microbiological transformations resulting from the irrigation of soil with vinasse did not cause, as expected, a significant elevation in the soil pH.