Soil Mineralogy on Ecosystem Functioning

Dear Colleagues,

In our Special Edition, "Soil Mineralogy on Ecosystem Functioning", the journal Minerals will exhibit articles on the mineral content of soil rather than rocks or stones. We are inviting mineralogists, geochemists, and other specialists to make contributions in order to achieve a broader understanding of the characterization, origin, and evolution of minerals in soils, as well as the role that those minerals play within their functioning ecosystem.

The composition of soil minerals depends on several factors, and forms following a long process. Rocks and their constituent minerals are extremely hard, compact, insufficiently porous, and do not have enough surface reactivity in their early state. These rocks were not propitious to life on the surface of our planet Earth. Many of these rocks and their minerals were formed underground in very different conditions of pressure, temperature, humidity, and oxygen content to those on the surface. When exposed to the surface, these rock minerals suffered several transformations.

The formation of soils was triggered by these changes in environmental conditions. The rhombic network of olivine minerals—for instance, forsterite Mg₂SiO₄, which is formed at 1900 °C—crumbled on the Earth's surface. This triggered the release of all of its atoms into their new medium. Other minerals, such as those of the phyllosilicate group—muscovite (Si₃Al)Al₂O₁₀(OH)₂K and the monoclinic network—are able to readapt their structure and composition. This process causes the loss of their mineral identity as they transform into other minerals according to their new environment. Other minerals, such as quartz (SiO₂; trigonal network) are more resistant to alteration and can survive for millions of years under soil conditions. Additionally, even the formation of new minerals (or the regrowth of existing minerals) in the soil from released atoms and ions, and even neoformation, induced by soil microorganisms is possible. 

Soils make life on Earth possible and are essential to our survival. We could say that in the soil, also known as the pedosphere, the lithosphere converges with hydrosphere and atmosphere, and this is what makes our biosphere viable. In the soil medium, the solid fraction is made up of 95% inorganic matter: essentially minerals. Their particles have different sizes and organizations, which generate aggregates that sponge the original compact material of the rocks. The pores that were subsequently formed permit the exchange of gases (atmosphere) and liquids (hydrosphere). This way, their surface area increases and various different reactions are facilitated. This is the primal connection between soil and life.

Life still has a very long way to go. At this stage, some minerals are toxic in their morphology and composition. Although certain microorganisms and plants evolved to coexist with their toxins, these seriously affect, directly or indirectly, the health of living organisms, such as animals and human beings.

Therefore, the study of soil minerals is relevant to our understanding of how ecosystems work. Their identification techniques are often specific. The geochemistry of soil minerals is part of the cycles of nutrients and toxic elements. Their crystallochemistry (lattice parameters, crystalline defects, polytypism, amongst others) is their adaptive response to the conditions of their environment. Their surface reactivity plays a crucial role in physical fertility by regulating the processes of flocculation/dispersion that control the formation of soil aggregates as well as water retention on their surface. Surface reactivity is also pivotal in analyzing chemical fertility, which controls the natural reserve of nutrients, retaining and exchanging ions with the environment. It is also pivotal for biological fertility through mineral–microorganism interactions. Additionally, even their superficial morphology (idiomorph/xenomorph) or their scars (superficial features) are the result of the action of supergenic processes that use the surface of the mineral grain as a parchment to write their history.

All of the above renders the study of soil minerals through different analytical techniques (XRD; HRTEM; VPSEM; SEM-CL; SEM-EDX; EMPA; LA-ICPms) essential for our greater understanding of soil characteristics, origins and development over time and under diverse environmental conditions in different locations on Earth. These techniques open up to areas of research that constitute an exciting prospect for this particular field.

We are looking forward to receiving the partial or final results of your papers submitted to this Special Issue for consideration. If published, your important research will reach out to a wider audience and earn greater exposure to many relevant stakeholders.

Prof. Dr. Juan Manuel Martín-García
Dr. Rafael Delgado
Dr. Julio Calero
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.