Microrganismos indicadores da qualidade do solo sob sistemas de uso no perímetro irrigado de Sousa - PB.

Abstract

Agricultural practices can cause changes in soil quality, and among the quality indicators, microorganisms are the most sensitive. The objective was to evaluate the occurrence and density of soil microorganisms, as quality bioindicators of the systems used in the Irrigated Perimeter of Várzeas de Sousa - PB. The design used in the experiment was completely randomized, with a 9x3 factorial scheme, with soil sampled from 0 to 20 cm, from nine areas of land use systems in areas of the Savana farm - Grupo Santana Sementes, Perimeter Irrigated of Sousa, PB, namely: Cotton in Dry Land 1 (ASM1), Cotton in Dry Land 2 (ASM2), Irrigated Cotton (AI), Sorghum in Dry Land (SS), Fallow (P), Crop rotation Cotton / Corn Stain 1 (RAMM1), Crop rotation Cotton / Maize Spot 2 (RAMM2), Permanent Preservation Area Spot 1 (APPM1) (Reference 1), Permanent Preservation Area Spot 2 (APPM2) (Reference 2); and three specific culture media, BDA (potato dextrose agar) plus starch for the growth of actinomycetes, NA (agar nutrient) for total bacteria and BDA for total fungi, and three dilutions (10-4, 10-5 and 10-6), with three repetitions. The biological attributes evaluated were the analysis of the total density of actinomycetes, bacteria and fungi. In all samples of the studied areas, the presence of bacteria, fungi and actinomycetes were detected. The density of microorganisms, indicators of soil quality in all areas of the use systems of the Savana Farm - Santana Sementes Group, in the Irrigated Perimeter of Várzeas de Sousa - PB were altered by the management adopted. The density of bacteria, an indicator of soil quality, in all the use systems of the nine areas studied were higher. The densities of bacteria, fungi and actinomycetes, indicators of soil quality, were used to group the use systems, keeping the Permanent Preservation Area Mancha 1 (APPM1) separate from the other managements.