Efecto de la exposición y la toposecuencia sobre actividades biológicas del suelo en bosque relicto del centro-sur de Chile

Abstract

SUMMARYCatastrophic disturbances of forest ecosystems are natural and anthropogenic phenomena that promote the natural dynamics of biocenosis and biogeochemical processes, and are the main causes of landscape fragmentation. The aim of this study was to evaluate the effect of orientation and toposequential positions on some biological activities in a relict forest community of LapagerioAextoxiconetum during two seasons. Soil samples were collected from an Andisol (0-15 cm), for each toposequential position (high, medium and low slope) of a forest with orientation northeast and southwest in summer and winter. The parameters evaluated were: fluorescein diacetate hydrolysis, carbon and nitrogen biomass and activity of six enzymes related to microbiological activity: carboximethylcellulase, β-glucosidase, manganese peroxidase, urease, acid phosphatase and arylsulfatase. The results indicate that the high slope with northeast orientation showed most favourable conditions on biological activities. In turn, orientation had direct effects on the evaluated biological activities, mostly significant, due to variation in soil moisture, temperature, pH, organic matter content and nutrient availability. Urease was the only enzyme with higher activity levels in summer, because of increase in soil temperature. Biological activities were affected by seasonality, being significantly higher in winter; the differences observed for different biological parameters are attributed to microclimates that were generated under the tree canopy and mulch.Key words: temperate forests, toposequence, microbial biomass, soil enzyme activities. RESUMENLas alteraciones catastróficas en ecosistemas boscosos son fenómenos naturales o antropogénicos que promueven la dinámica natural de la biocenosis y los procesos biogeoquímicos, y constituyen la principal causa de fragmentación del paisaje. El objetivo de este estudio fue evaluar el efecto de la exposición y la toposecuencia sobre algunas actividades biológicas del suelo de un bosque relicto de la comunidad Lapagerio-Aextoxiconetum, en dos estaciones del año. Se recolectaron muestras de suelo (0-15 cm), con características de Andisol por cada uno de los niveles toposecuenciales (laderas alta, media y baja) con exposición noreste y suroeste, en verano e invierno. Los parámetros evaluados fueron: hidrólisis de la fluoresceína diacetato, carbono y nitrógeno en la biomasa microbiana y la actividad de seis enzimas relacionadas con la actividad microbiológica: carboximetilcelulasa, β-glucosidasa, manganeso peroxidasa, ureasa, fosfatasa ácida y arilsulfatasa. Los resultados obtenidos indican que la ladera alta con exposición noreste presentó condiciones más favorables para las actividades biológicas. La exposición tuvo efectos directos sobre las actividades biológicas, mayoritariamente significativos, debido a la variación del suelo en humedad, temperatura, pH, contenido de materia orgánica y disponibilidad de nutrientes. La ureasa fue la única enzima con mayor actividad en verano, debido al aumento de la t...

Evaluación de las actividades de enzimas del suelo en un bosque de Araucaria–Nothofagus después de un incendio forestal

“…This activity diminished with depth (20-40 cm) to values of 86.3-198.1 mg N-NH 4 g -1 h -1 . The observed decrease of UR activity with increasing soil depth may be related to a minor temperature (Reyes et al, 2011). The UR activity values for PC 0-20 cm depth, were higher during the whole sampling period, as compared with P1 and P2 (Figure 3).…”

“…The soil enzymes activities are an integrating indicator of the biological activity and the physical and chemical conditions, which permits the evaluation of the microbial capacity in the catalytic processes, as well as the availability of nutrients by means of enzymatic processes (Reyes et al, 2011;Cardoso et al, 2013). The importance of certain soil enzymes has been described, such as catalase, cellulase and urease, serving as indicators of the biological activity of the soil in the event of alterations (García and Hernández, 1997;Smethurst et al, 1998;Saviozzi et al, 2001;Levi-Minzi et al, 2002).…”

Comparative Study between Silvopastoral and Agroforest Systems on Soil Quality in a Disturbed Native Forest of South-Central Chile

“…In the case of U RS , the higher C and N biomass in the SPS (M SOC M N ) may stimulate the FDA activity [72], which may explain the differences that were observed mainly at the 5-20 depth between systems. In Andisols (0-15 cm), from a relict-native forest consisting of the plant associations: Aextoxicon punctatum, Nothofagus obliqua,Eucryphia cordifolia, Laurelia sempervirens and Persea lingue in Temuco, Chile, Reyes et al [74] observed similar trends to our findings in M SOC (1245 µg C g dw −1 ), M N (99.5 µg N g dw −1 ), and FDA (51.5 µg F g dw −1 ), although there were remarkable differences for β-GLU and P HOSP activities, with means of 7.3 and 68.2 µmol g dw −1 h −1 PNF, respectively, virtually tripling and exceeding by a 10 order of magnitude our measurements. This may be related to the maturity stage of the forest, compared with our study sites.…”

Impacto del manejo de agroecosistemas cafetaleros en la calidad del suelo en las cuatro estaciones del año en Tlapacoyan, Veracruz

“…Los cafetales producidos como monocultivo y a pleno sol pueden incrementar sus rendimientos por la incorporación de los fertilizantes, pero a costa de la sustentabilidad del suelo que poco a poco se merma y la actividad de la biota también (Guerrero et al, 2012). Las modificaciones edafológicas son un factor que puede aumentar o disminuir la actividad microbiana y la respiración (Reyes et al, 2011). Debido a que la calidad del suelo ya no puede estudiarse con un componente aislado, es necesario entender el recurso suelo como un sistema vivo dinámico que tiende a estar en equilibrio bajo la interacción de factores físicos, químicos y biológicos (Paz-Ferreiro y Fu, 2013).…”