Edaphic fauna and physico-chemical atributes of soil in different phytophysionomies of Cerrado

ABSTRACT The edaphic community comprises several organisms that perform ecological functions in the environment, such as litter fragmentation, nutrient cycling, and modifications of soil structure, in addition to acting as food chain regulators. Thus, the objective of this study was to evaluate the composition of the edaphic fauna and the physical and chemical attributes of soil in different physiognomies of Cerrado in the Parque Estadual do Mirador (PEM). The study was carried out in two Cerrado formations (Sparse Cerrado and Typical Cerrado) in PEM, where 100 pitfall traps were installed. The edaphic organisms were screened and identified in terms of orders, suborders, subfamilies, families, abundance, richness, Shannon diversity, and Pielou’s equitability. A total of 4,149 individuals were collected from two experimental plots. The plot in the Typical Cerrado showed greater taxonomic richness (25 groups) and greater Shannon diversity (H’ = 1.65), while the plot in Sparse Cerrado presented 19 edaphic groups and Shannon diversity equal to H’ = 1.51. The factorial exploration explained 84.43% of the original data from the Sparse Cerrado and 90.84% from the Typical Cerrado. It is concluded that the plot in the Typical Cerrado showed greater differences in terms of richness and abundance due to the more favorable conditions for soil fauna, such as a high content of organic material and greater vegetation cover.

Effects of soil fauna on litter decomposition in Chinese forests: a meta-analysis

Litter quality and climate have been presumed to be the dominant factors regulating litter decomposition rates on broad spatial scales. However, the role of soil fauna on litter decomposition is poorly understood, despite the fact that it could strongly influence decomposition by fragmentation and subsequent modification of the activities of microorganisms.In this study, we carried out a meta-analysis on the effects of soil fauna on litter decomposition rates in Chinese forests, ranging from boreal to tropical forests, based on data from 20 studies. The effects of climatic factors on decomposition rate were assessed by comparing the contribution of soil fauna to litter decomposition from studies carried out at different latitudes.The degree of influence of the soil fauna was in the order tropical (200%) > subtropical (47%) > temperate forest (28%). Comparing the effect size of soil fauna, it was found that when soil fauna was excluded, the decomposition rate, calculated using Olson’s equation, was most affected in tropical forest (−0.77), while the litter decomposition rate both subtropical (−0.36) and temperate forest (−0.19) were also suppressed to varying degrees (P < 0.001). These results highlight that soil fauna could promote litter decomposition to different extents. Using stepwise multiple linear regression, the effect size of the soil fauna was negatively correlated with the cellulose and nitrogen concentrations of the initial litter material. In Chinese forests, litter decomposition rates were reduced, on average, by 65% when soil fauna was excluded. The impact of soil fauna on decomposition was shown to be closely related to climate and litter quality.

The use of soil biostructures created by soil fauna ecosystem engineers fed with different organic matterials as inoculum source of arbuscular mycorrhiza fungi on cocoa seedling

<p><span lang="IN">Soil fauna as ecosystem engineers </span><span>have the ability to </span><span lang="IN">creat</span><span>e </span><span lang="IN">soil biostructure</span><span>s, with the capacity to </span><span lang="IN">sav</span><span>e</span><span lang="IN"> arbuscular mycorrhizal fungi (AMF) spores. </span><span>This study therefore aims to </span><span lang="IN">investigate the </span><span>AMF </span><span lang="IN">spore density in the biostructures created by cooperation between earthworms and ants with a different organic matter composition</span><span>,</span><span lang="IN"> and to analyze the </span><span>biostructures’ </span><span lang="IN">potential as a source of </span><span>AMF </span><span lang="IN">inoculum on cocoa seedlings. </span><span>In the first experiment, a </span><span lang="IN">combination of earthworms and ants composition</span><span>, as well as a </span><span lang="IN">mixture of <em>G. sepium</em> leaf (GLP), cocoa shell bean (CSB), and sago dregs (SD)</span><span>,</span><span lang="IN"> was tested</span><span>. Meanwhile, </span><span lang="IN">in the </span><span>second</span><span lang="IN"> experiment</span><span>, t</span><span lang="IN">he</span><span> effect of</span><span lang="IN"> biostructures on cocoa seedlings grown </span><span>i</span><span lang="IN">n unsterile soil</span><span>,was </span><span lang="IN">examined</span><span>. According to the results, the highest</span><span lang="IN"> AMF spore </span><span>density was obtained using </span><span lang="IN">20 earthworms+10 ants with 50%GLP+50%CSB + 0%SD treatment</span><span>. Furthermore, the t</span><span lang="IN">otal AMF spores </span><span>were </span><span lang="IN">positively correlated</span><span> with the total P value, but negatively correlated </span><span lang="IN">with </span><span>the </span><span lang="IN">C/N ratio</span><span>. Therefore, bi</span><span lang="IN">ostructure application increased AMF spores number in rhizosphere and </span><span>the cocoa seedling’s </span><span lang="IN">root infection</span><span>. Furthermore, </span><span lang="IN">biostructure</span><span>s</span><span lang="IN"> resulting from the collaborative activity </span><span>between</span><span lang="IN"> different soil fauna ecosystem engineers </span><span>were able to transmit </span><span lang="IN">AMF spore</span><span>s </span><span lang="IN">to </span><span>infected </span><span lang="IN">plant root</span><span>s</span><span lang="IN"> growing </span><span>i</span><span lang="IN">n non-sterile soil.</span></p>