Atividade Microbiana no Solo em Diferentes Ambientes da Região Semiárida de Alagoas <p> Microbial Activity in the Soil of Different Environments of the Semiarid Region of Alagoas <outra>

Abstract

O objetivo foi avaliar a atividade microbiana em diferentes ambientes (Caatinga nativa, Área com presença de Murici, Área cultivada com Palma forrageira e Área desmatada) utilizando o método da respirometria no campo, na região Semiárida de Olho D’Água do Casado-AL. O trabalho foi realizado em junho de 2012 e em cada área foram selecionados nove pontos de coleta para determinação da atividade microbiana, totalizando 72 amostras, sendo 36 no período diurno (05:00 às17: 00 h) e 36 no noturno (17:00 às 05:00h). O CO2 liberado por uma área de solo foi absorvido pela solução de KOH 0,5 N e titulado com HCl 0,1 N. Foram utilizados os indicadores fenolftaleína e alaranjado de metila a 1%, sendo usado um frasco controle que permaneceu fechado e foi submetido ao processo de titulação. Também foram retiradas amostras de solo na profundidade de 0-10 cm nos diferentes ambientes para determinação do conteúdo de água do solo e realizadas medidas de temperatura do solo na mesma profundidade. A produção de CO2 noturna foi maior do que a diurna, nos quatro agrossistemas estudados; Os diferentes sistemas de manejos influenciam a atividade metabólica dos microrganismos presentes no solo, obedecendo à seguinte sequência: Cultivada &gt; Desmatada &gt; Murici &gt; Caatinga; Dentre as áreas analisadas, a que apresentou menores emissões de CO2 foi à área de Caatinga nativa que funcionou como um receptor de CO2 em contraposição a área cultivada que funcionou como emissor de CO2.The objective was to evaluate the microbial activity in different environments (native Caatinga, area with presence of Murici, cultivated with forage palm area, and deforested area) using the method of respirometry in the field, in the Semiarid region of Olho D’Água do Casado-AL. The research was performed in June 2012 and in each area nine sites were selected for determination of microbial activity, totaling 72 samples, including 36 during the day (05:00 to 17: 00 h) and 36 at night (17:00 to 05:00). The CO2 released by an area of soil was absorbed by KOH solution and titrated with 0.5 N HCl 0.1 N. There were used, the phenolphthalein and methyl orange indicators 1%, using a control flask which remained closed and submitted to the titling process. Soil samples were also collected at a depth of 0-10 cm in different environments to determine the water content of the soil and we measured the temperature of the soil at the same depth. The night CO2 production was higher than the daytime in the four environmental systems; Different managements systems influence the metabolic activity of microorganisms in the soil, in the following sequence: Cultivated &gt; Deforested &gt; Murici &gt; Caatinga; Among the areas examined, the one with lower CO2 emissions was the native Caatinga area that performed as a receiver of CO2 versus cultivated that functioned as CO2 emitter area.

Basal soil respiration in land use and cover systems in a caatinga enclaves moist forest

“…Greater release of soil CO 2 occurred in the systems whose soils showed higher temperature and moistures values. These results corroborate those found by Araujo et al (2016), according to whom more anthropized areas, without ground cover, allow a greater incidence of ultraviolet radiation, increasing microbiological activity and, consequently, the release of soil CO 2 . As stated by the authors, the microbial activity responsible for the production of CO 2 is controlled by the temperature and water content in the soil, and if the temperature is not within the favorable physiological limits of the soil microorganisms, microbial activity can be interrupted.…”

Comparison of Carbon Dioxide Efflux in Different Land Use Typologies

“…According to Torres et al ( 2015), the distribution of CO 2 in soil management systems throughout the day reflects their physical capacity, which is why conservation systems show less CO 2 dispersion throughout the day, thanks to the characteristics that conservation management has, which also provide greater protection against extreme environmental conditions such as erosive rains, water crisis, and high rates of solar radiation. However, cultivated systems with less tree cover contribute to the carbon stored in the soil in organic and microbial form and in the form of plant biomass, being returned to the atmosphere (Araújo et al, 2016).…”

Preliminary evaluation of ASCAT-SWI and SMOS SM soil moisture products against in-situ observations in the Brazilian Caatinga biome

“…Both sites show the presence of xerophytic and deciduous species such as Murici (Byrsonima gardneriana A. Juss). Its climate is semiarid and characterized by a mean annual precipitation of 546 mm yr -1 with a rainy season from November to April (Araujo et al, 2016;Santos et al, 2017). The soil has been classified as Neossolos and shows high content of sand in its upper layer (Souza, 2011).…”