Atividade microbiana em solo do semi-árido sob cultivo de Atriplex nummularia

Abstract

Resumo -Métodos para avaliar a atividade microbiana no solo são fundamentais no monitoramento ambiental de áreas degradadas. O objetivo deste trabalho foi investigar a atividade microbiana de solo do semi-árido cultivado com Atriplex nummularia Lindl. em áreas que receberam rejeito salino durante um e três anos, em comparação com um solo nativo, sem cultivo e não irrigada. O solo cultivado por três anos e que recebeu rejeito salino apresentou, no período seco, valores de pH, CE e atividade de hidrólise do diacetato de fluoresceína (FDA) superiores aos das demais áreas. No entanto, foi observada correlação negativa entre o carbono microbiano e os valores do quociente metabólico (qCO 2 ). A biomassa microbiana e a fosfatase alcalina também foram superiores no solo cultivado por três anos e que recebeu rejeito salino em relação ao solo nativo sem irrigação, confirmando o desempenho de plantas halófitas na melhoria da qualidade do solo sob condições de estresse salino. O cultivo de A. nummularia constitui uma das alternativas para utilização de rejeito salino proveniente da dessalinização por osmose reversa.Termos para indexação: emissão de CO 2 , biomassa microbiana, diacetato de fluoresceína, fosfatase alcalina. Microbial activity in a semiarid soil cultivated with Atriplex nummulariaAbstract -Methods used to estimate the soil microbial activity are important to environmental monitoring of degraded areas. The objective of this research was to investigate the microbial activity of a semiarid soil cultivated with Atriplex nummularia Lindl. in a field receiving saline waste during one and three years, in comparison with an area without crop and irrigation. Soil cultivated during three years presented, during the dry season, values of pH, CE, and activity of FDA hydrolyses higher than those registered in other areas. However, a negative correlation between the microbial carbon and values of qCO 2 was observed. The microbial biomass and the alkaline phosphates were also higher in the three years cultivated soil, in comparison with the native soil, non irrigated, confirming the role of halophytes for enhancing quality of soils under saline stress. Thus, the cultivation of A. nummularia is an alternative for using saline waste from the desalinization process.

Effect of Salinity on Soil Microorganisms

“…The authors found that although the irrigation with saline waste affected the physical and chemical properties of the soil, cultivation of the halophyte favored microbial activity. Similar results were obtained by Pereira et al (2004) studying soil cultivated for three years with Atriplex nummularia Lindl., and irrigated with saline waste. In the dry periods, the values for pH, electrical conductivity, fluorescein diacetate hydrolytic activity and alkaline phosphatase activity were higher than in other areas.…”

Glomalin Production and Microbial Activity in Soils Impacted by Gypsum Mining in a Brazilian Semiarid Area

“…The values for this variable (microbial biomass C) are within the range mentioned for savannas, gallery forest and eucalyptus forest (Behera and Sahani, 2003;Melloni et al, 2001); but lower values were observed in other native semiarid area in Northeast Brazil (Pereira et al, 2004). Probably the gypsum mining activity contribute for increasing the levels of pH in the studied areas (almost neutral), reducing the metabolic activity of the microbial community.…”

“…Confirming other studies, in some of the areas total soil enzyme was affected by the season, being higher during the wet than in the dry period. Conversely, greater enzyme activity (FDA) was found during the dry period in a semiarid soil cultivated with Atriplex nummularia (Pereira et al 2004). Swisher and Carroll (1980) demonstrated that this variable (hydrolysis of FDA) is directly proportional to the microbial population.…”

“…Methods to estimate the microbial activity in semiarid soils are important for environmental monitoring and recovery of degraded areas (Pereira et al, 2004). Studies on the impact of environmental changes to microbial populations and their activity have used, among others: microbial biomass carbon, enzyme activity (fluorescein diacetate hydrolysis-FDA) and microbial respiration (Sarig and Steinberg, 1994;Garcia et al, 2004).…”

Reforestation of a Degraded Area with Eucalyptus and Sesbania: Microbial Activity and Chemical Soil Properties

“…Microbial respiration and the hydrolysis of fluorescein diacetate (FDA) are some of the parameters most commonly used to evaluate microbial activity in soils; they define the total enzymatic activity in a soil where microorganisms are the main source of enzymes (Pereira et al, 2004;Green et al, 2006;Batista et al, 2008;Carvalho et al, 2008;Carneiro et al, 2009;Evangelista et al, 2012). Research has shown that these factors are significantly influenced by soil use and management methods (Pell et al, 1998;Stenström et al, 1998;Arshad and Martin, 2002;Schloter et al, 2003;Gil-Sotres et al, 2005;Batista et al, 2008).…”