Biomassa microbiana e acúmulo de liteira em sistemas agroflorestais composto por meliáceas, utilizadas como indicadores biológicos de qualidade do solo.

Abstract

The objective ofthis research was to evaluate different agioforestiy arrangements, composites for species of the Meliacea family, and its use as biological indicator of soil quality; through lhe dynamics of carbon, nitrogen and the activity of the microbial biomass; and its interdependence on chemical soil property, beyond the influence exerted for the accumulation of liHer in the djTiamics of soil nutrients. To determinate the biological and chemical soil properties were collected some samples in areas with plant cover cultivation shifting, SAF1 (mahogany), SAF2 {neem}, SAF3 {cedar}, SAF4 {mahogany x neem}7 SAF5 {mahogany x cedar} and pasture], by the collection ofsamples in two layers ofthe ground (Õ-5 and 5-20cm). and during drought season (october/2004) and rainy season (may/2005), repeating the process Ürree times. To the collect of ütter. the same parameters had been observed, which are, the plant cover and the collection season, used in the collection of the samples of soil In analysis of soil biological properties, organic carbon contents had been determined (Walkle3'-Black Method), total N (Kjeldahl Method), CBM and NBM (íumigation-extraction method), the relation betvveen organic carbon and microbial carbon, microbial N / total N, relation C/N, basal breath (Co2 Evolution Method) and metabolics quotient (qC02). To lhe chemical properties analysis was obtained organic substance contents, N, P, K, Ca, Mg, Al, pFí. The litter was weighed, dried, triturated and afterwards extracted nutrients N, P, K, Ca, and Mg, through the methodology proposal for the EMBRAPA (1997), The gotten results to the biological and chemical soil properties, had been submitted to analysis of variance and comparison of average for the Duncan Test with 5% of probability, using statistical program SAEG 8.1. Also it was proceeded a correlation canonic analysis between lhe chemical and biological soil attributes, to verify the signifícance of canonic correlation in canonic pairs, the reason test of maximum probability was used, which statistics symbol is Lambda (1) of Wilks, that is analyzed through lhe statistical program SAS, version 9.0. The chemical properties ofthe ground had been iníluenced by the vegetal coverings, with biggesl texts of P, Here, Mg, organic substance and pH had been found in lhe agroflorestais systems . The chemical characteristics of the ground had been influenced by lhe time of collection and depth of sampling, with bigger accumulation in the dry station of here. Mg, Al and H+Al, and of P, K and pH in the rainy station. In general the nutrients had been found in bigger amounts in the layer of 0-5cm, with rise of pH following the increase of the depth of the ground. The texts of carbon of the microbian biomass and nitrogen of the microbian biomass had not been efficient in demonstrating to the occured alterations in ground in the different systems of use, the two times of collection and the depths of sampling ofthe ground. Microbian activity, through the basal breath and of the metabolic quotient, when associates to carbon and nitrogen of the microbian biomass, are considered as good pointers ofthe potential of functionality ofthe different arrangements and the different systems of use, at the two times of collection and the depths of sampling of the ground. The biological and chemical properties ofthe ground are not considered independem. The associations between these groups had been established, with bigger relative importance. for the influence of the basal breath and nitrogen of the microbian biomass with carbon and nitrogen of the ground. The nitrogen was the nutrienl with bigger participalion in the liteira of the analyzed vegetal coverings. In the cover cultivation shifting the biggest participalion was of the K with 40%, It had effect of the interaction time of collection in the nutrients of the liteira. greaters supplies in the rainy station.