Organic carbon, biomass and microbial activity in an Oxisol under different management systems

Abstract

Soil management can negatively affect soil quality impairing its functionality. One of the possible ways to assess soils is through the use of biochemical indicators. In this study, the aim of this study was to determine how soil management and use interfere with organic carbon, carbon in biomass and microbial activity, as well as with the acid phosphatase activity of an Oxisol in the Brazilian Cerrado. Five soil uses and management systems were used as treatments: no-tillage, coffee plantation, banana plantation, pasture, and native vegetation. Soil samples were collected at four different times: August, September, October, and November. Reductions in the concentrations of total organic carbon, microbial biomass carbon, and acid phosphatase activity were observed with management and use of soil under no-tillage, pasture, coffee plantation, and banana plantation in relation to native vegetation. The soil under pasture showed lower reductions in biochemical characteristics compared to the other land uses and managements studied. The practice of fallow in the no-tillage area promoted reductions in microbial biomass carbon, acid phosphatase activity and soil organic carbon, but increased the metabolic quotient, demonstrating that this management is not appropriate for this type of soil. RESUMO: O manejo do solo pode afetar negativamente a sua qualidade, prejudicando a sua funcionalidade. Uma das formas de se avaliarem suas características é por meio do uso de indicadores bioquímicos do solo. O objetivo deste trabalho foi determinar a interferência do uso e do manejo do solo sobre o teor de carbono orgânico e do carbono na biomassa, e na atividade microbiana, bem como na atividade da fosfatase ácida de Latossolo Vermelho Distroférrico no Cerrado. Cinco usos e sistemas de manejo do solo foram utilizados como tratamento: lavoura em plantio direto; cafezal; bananal; pastagem, e cerrado nativo. O solo foi amostrado em quatro épocas diferentes: agosto, setembro, outubro e novembro. Reduções nas concentrações de carbono orgânico total e de carbono da biomassa microbiana, e na atividade da fosfatase ácida foram verificadas com o manejo e o uso do solo sob lavoura, pastagem, café e banana, em relação ao cerrado nativo. O solo sob pastagem apresentou menores reduções nos atributos bioquímicos em relação às demais áreas cultivadas. A adoção de pousio na área de lavoura promoveu reduções no carbono da biomassa microbiana, na atividade da fosfatase ácida e no carbono orgânico do solo, e aumento de quociente metabólico, demonstrando não ser o manejo adequado para este solo. Organic carbon, biomass and microbial activity in an Oxisol under different management systems Carbono orgânico, biomassa e atividade microbiana em Latossolo Vermelho de cerrado sob diferentes usos e manejo

Reclamation status of a degraded pasture based on soil health indicators

“…The acid phosphatase had a similar trend, with increased activity in the pasture under reclamation. Consequently, the soil capacity for P supply was enhanced, notably from organic sources (Lacerda et al, 2013). Conversely, the alkaline phosphatase had the inverse behavior, as a consequence of a higher pH in the degraded pasture soil.…”

“…However, an indirect effect could be attributed to the greater forage biomass produced in the sites under reclamation, in addition to greater root biomass (data not shown), resulting in more organic material in the soil and the degraded pasture with U. brizantha, with the lowest, indicated a best condition for the soil microbial community with the improvement of the pasture. The recovered pasture had more inputs of organic C, including rhizodeposition and maintenance of soil moisture, which are favorable to the soil microbial community (Frazão et al, 2010;Lacerda et al, 2013). The microbial biomass contributes to improved soil fertility because the cells constitute a living reservoir of C and nutrients, avoiding their fixation in the mineral fraction, like P, or from leaching through the soil profile, like nitrate (Cardoso et al, 2013;Fagotti et al, 2012).…”

“…As a result, the highest qCO 2 in the degraded pasture, as compared to the pastures recovered with Mombaça and Massai forages, suggests stress-inducing conditions for the microbial community. Higher qCO 2 means less metabolically efficient microbial activity, because this community requires more intense respiration to keep the same unit of microbial biomass as compared to a non-stressed microbial community (Anderson and Domsch, 1993;Lacerda et al, 2013), since microorganisms have to invest more energy for self-maintenance under conditions of stress. Thus, qCO 2 can be used as a sensitive indicator of the soil microbial community stress.…”

Biochemical and Biological Properties of Soil from Murundus Wetlands Converted into Agricultural Systems

“…Microorganisms are the main mediators of biological and biochemical processes in the soil, which are very sensitive to changes in the ecosystem and excellent indicators of agricultural sustainability (Doran and Parkin, 1994). In previous studies, some of these biochemical properties and processes, such as total organic carbon, microbial biomass carbon, metabolic quotient, and enzymatic activities of the soil, have shown sensitivity to the management adopted, being potential to indicate impacts suffered by the conversion of natural environments to agriculture (Pragana et al, 2012;Lacerda et al, 2013;Souza et al, 2016).…”

Occurrence of Weeds in Areas Submitted to Tillage Managements for Soybean Cultivation in the Cerrado of Roraima

“…In the limed area, the highest relative frequencies (Frr) were observed for the species C. flavus (26.09%), Sesamum indicum (21.74%), and Borreria verticillata (17.39%) ( Table 3). The differentiated practice of soil management changes the frequency and species of weeds in cultivated areas (Lacerda et al, 2013;Lima et al, 2014).…”