Atributos químicos e microbiológicos de um Nitossolo sob aplicação de lodo de indústria de gelatina

Abstract

The sludge from gelatin industry (LIG) has nutrients in its composition, allowing its use in agricultural areas as an alternative to disposal and recycling of this waste. However, few studies have examined the impacts of application of LIG can cause in soil chemical and microbiological attributes, justifying the need for knowledge of the dynamics of these residues to the soil, in order to avoid possible environment injury. The present study evaluated the effects of application rates up to 600 m3 ha-1 of LIG on soil chemical attributes, water percolation quality, maize (Zea mays L.) plants and on soil microbiological attributes. For this, two experiments were conducted in a greenhouse: one in soil columns, where the chemical properties of the soil, the quality of drainage water and maize plants were evaluated, and another in pots, where the soil microbiological attributes were evaluated. In both experiments, the treatments consisted of increasing doses of sludge gelatin industry, equivalent to 0, 150, 300, 450 and 600 m3 ha-1 LIG, applied only once, superficially and without incorporation, into dystrophic Red Nitosol, very clayey texture. Maize was sown seven days after the application of the treatments. The collections of plants, soil and leachate were performed 60 days after treatment application. Based on these experiments, it was concluded that the application of up to 600 m3 ha-1 LIG in soil under the conditions of this study, did not lead to negative effects for soil, the quality of drainage water and maize plants. With respect to the soil microbiological attributes, the observed reduction in soil microbial biomass carbon in rates higher than 300 m3 ha-1 of LIG, accompanied by an increase in the metabolic quotient in rate of 600 m3 ha-1 indicated reduced metabolic efficiency of soil microbiota in these conditions, as a consequence of microbial stress.