Soil chemical properties and forest floor nutrients under repeated prescribed-burning in Eucalypt forests of south-east Queensland, Australia

An Unassigned Group, An Unassigned DepartmentNo Full Tex

Understanding the ineffectiveness of Cu and Zn in reducing urea hydrolysis losses from grazed dairy pasture soils

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Influence of long-term repeated prescribed burning on mycelial communities of ectomycorrhizal fungi

To demonstrate the efficacy of direct DNA extraction from hyphal ingrowth bags for community profiling of ectomycorrhizal (ECM) mycelia in soil, we applied the method to investigate the influence of long-term repeated prescribed burning on an ECM fungal community. DNA was extracted from hyphal ingrowth bags buried in forest plots that received different prescribed burning treatments for 30 yr, and denaturing gradient gel electrophoresis (DGGE) profiles of partial fungal rDNA internal transcribed spacer (ITS) regions were compared. Restriction fragment length polymorphism (RFLP) and sequence analyses were also used to compare clone assemblages between the treatments. The majority of sequences derived from the ingrowth bags were apparently those of ECM fungi. DGGE profiles for biennially burned plots were significantly different from those of quadrennially burned and unburned control plots. Analysis of clone assemblages indicated that this reflected altered ECM fungal community composition. The results indicate that hyphal ingrowth bags represent a useful method for investigation of ECM mycelial communities, and that frequent long-term prescribed burning can influence below-ground ECM fungal communities.No Full Tex

Dominant species' resprout biomass dynamics after cutting in the Sudanian savanna-woodlands of West Africa: long term effects of annual early fire and grazing

The potential of forest to regenerate after harvesting is a key element for sustainability of the ecosystem. For semi-arid tropical savanna environments, managing resprouts after tree cutting is ideally suited because of the natural ability of many indigenous species to regenerate vegetatively. Regeneration in this ecosystem is, however, prone to many disturbance factors such as fire and grazing by livestock. In this paper, we used a factorial experiment to examine the long-term effects of annual early burning and grazing on dominant species' resprout biomass dynamics after selective cutting in the Sudanian savanna-woodlands of Burkina Faso, West Africa Burning decreased shoot mortality of Crossopteryx febrifuga while grazing increased that of Detarium microcarpum. Burning, in later measurement years, reduced resprouts' size of Acacia macrostachya, C. febrifuga and D. microcarpum while an increased basal area was observed for Combretum glutinosum. There was no significant evidence of grazing hampering growth. Moderate livestock grazing could be integrated in the forest management prescriptions in Burkina Faso for the sake of multi-purpose uses, while more attention should be paid to burning practices to lower fire severity, as complete fire exclusion is utopian in this savanna ecosystem

Short-term effects of prescribed burning on phosphorus availability in a suburban native forest of subtropical Australia

Purpose Prescribed burning can alter nutrient availability to plants. Plant growth in tropical and subtropical forests is frequently phosphorus (P) limited. Soil P availability is influenced by a combination of multiple factors including soil chemical and biological properties. The aims of this study were to investigate the short-term effects of prescribed burning on soil P status and to evaluate the key drivers responsible for the variation in soil P fractions. Materials and methods Soil samples were collected at a depth of 0-10 cm at two sites in a suburban native forest. One site (the burnt site) was burned on 11 August 2011. The other site (the control site) was not burned but served as a reference. Sampling was conducted at four times: before burning, 12 days after burning (T1), 1 week after T1 (T2), and 1 month after T2 (T3). Soil pH, P fractions, microbial biomass carbon (C) and P, and activities of acid and alkaline phosphatase were measured. Results and discussion Total P was relatively low at both sites compared with other subtropical forests. Microbial biomass P accounted for approximately 10 % of soil total P at the two sites, suggesting that the turnover of microbial biomass is critical for soil P availability. Soil properties at the control site remained unchanged over the time. Soil organic forms of P at the burnt site were decreased by the prescribed burning, and the greatest reduction was found in moderately labile organic P (e.g., NaOH-extractable fractions). Soil inorganic forms of P, however, were not correspondingly increased by the prescribed burning. Microbial biomass P was closely related to the shifts in P fractions. These effects were only detected immediately after the fire. Conclusions Microbial biomass could serve as a sink of P in P-impoverished soils and play an important role in soil P transformation. Our results indicate that microbial biomass is an important factor that governs P status after prescribed burning. The rapid recovery of microbial biomass P could be beneficial to the P requirement for plant regrowth after prescribed burning.No Full Tex