Organismos da mesofauna e manejo da adubação verde

Abstract

The use of legumes associated with symbionts has been a great success for the recovery of degraded areas not only for reducing the need for mineral fertilizer, but also to increase biological activity. However, there is a need for more studies on the structure and composition of mesofauna under natural and / or modified conditions. The main objective of the thesis was to evaluate the qualitative and quantitative effects of two green manure of management systems on the population of organisms in the soil mesofauna in a strongly altered soil by using the Berlese-Tullgren method. It has been determined indexes for dominance, evenness and diversity of this population. The study was conducted at the Department of Soil Science Agronomy Institute of Rural Federal University of Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, in highly altered soil. Experimental plots were installed with the treatments: Canavalia ensiformis, Mucuna aterrima, Canavalia brasiliensis, Cajanus cajan and spontaneous vegetation in a Latin square design in two periods. In each of the plots were samples formed by litter and soil material (five-centimeter layer) were collected: a day before the planting of legumes (October), during the cutting of the shoots (March), fifteen days before new planting (October), ten days after planting (December) and the next day after cutting the shoots (April). Samples from the first and second sample were subjected to a several types of time extractions with Berlese-Tüllgren along a period of 15 days, performing the daily count of organisms. Other samples remained in the Berlese-Tüllgren for a period of twelve days. The amount and identification of organisms were determined (Order / family), and used for calculating Margalef index, Simpson, Shannon and Pielou indexes. The experimental plots were divided in March in two subplots: conventional tillage (mechanical incorporation of the shoot) and minimum tillage (mulch). Data were subjected to statistical analysis with the use of correlation of Kendall order (samples 1 and 2) and variance analysis at multiple levels (Multi Level Anova) applied to data from other samples. The results showed that the minimum residence time in the Berlese-Tullgren funnel that allows appropriate inferences about the ecological diversity of soil mesofauna is four days to less heterogeneous environments and six days to more heterogeneous environments. The variance analysis at multiple levels proved the superiority of minimum tillage compared to conventional, but there was no significant effect of green manures on mesofauna. Seasonal effects on the population of the mesofauna organisms were significant, reflecting on the values of indices characterizing the community.