Jorge Medina

• Doctor in Science of Natural Resources
• Professor (Assistant) at Universidad de O’Higgins

This study evaluated the effects of biochar and metallic oxide nanoparticles (iron oxide and halloysite nanoclays) used as compost additives on the decomposition and mean residence time (MRT) of soil organic matter (SOM) in tropical grassland soils. The objective was to explore their impact on decomposition rates and the chemical structure of compo...

This study aimed to evaluate the potential of two carbon (C)-rich carrier materials derived from agricultural residues, spent mushroom substrate (SMS) and composted wheat straw (CWS) for enhancing soil carbon stabilization in an Andisol, with a view towards their future application in smart fertilizer design. We investigated how their contrasting n...

The main organic input for the elaboration of growing media is peat (Sphagnum spp.), due to its physical and chemical characteristics. However, the mining of this material creates a considerable impact in the local ecosystems from which this is obtained, along with a global impact because of the emission of greenhouse gasses. Thus, sustainable mate...

There is a need to develop new strategies to maintain and increase food production on degraded agricultural soils while decreasing the environmental impact of agricultural production. These strategies can be based on the concept of soil as a ‘natural bioreactor”, including modulation of Al/Fe complexes and the microbial carbon pump. Utilization of...

This study was conducted to evaluate the effect of compost produced with agricultural residues and oat-based biochar, iron oxide and halloysite nanoparticles as additives of the process of composting on soil chemical properties, nutrient status and growth of ryegrass Lolium perenne L. For this, a 90-day mesocosm experiment was carried out under gre...

Biochar (BC) is a porous, carbonaceous material produced by slow pyrolysis of biomass under oxygen-limited conditions. BC production has been attracting research interest because it modifies soil physicochemical characteristics and improves the growth of plants in problem soils. These benefits may be best actualized for soils contaminated by metals...

Soil degradation by metal and metalloid (metal[loid]) contamination represents a widespread environmental threat. Most studies investigating soil metal(loid) contamination have disregarded the soil quality concept. Enzyme activities (EAs) are good soil quality indicators due to their direct connection to functions related to C, N, P, and S cycles a...

Metallic oxides and clay minerals have gained increasing interest as additives of composting due to their influence in greenhouse gas emissions reduction and their effectivity in the stabilization of carbon both in compost and soils, leading to a cleaner compost production and potentially C sequestrant amendments. In this study, wheat straw (WS) wa...

Cellulose and lignin as main components of crop residues have a significant influence on composting operations and composition of the final products. Both are strongly associated, and lignin can be considered an important barrier during the biodegradation process of lignocellulosic materials. Saprophytic fungi are efficient lignin de-graders due to...

In modern agriculture large amounts of harvesting residues are produced each year due to the increase of agricultural activities in order to maintain food production for the growing population. The development of innovative fertilizers, able to satisfy nutrient needs without adverse effects on the environment. In order to allow for effective produc...

In the coming decades there will be increasing pressure on global food systems, and agriculture will have the challenge to provide food security for a growing world population without impacting environmental security. Accordingly, it will be necessary to use modern technologies in agroecosystems in order to supply sufficient food and decrease the n...

We characterized humic substances (HS) extracted from a Cu-contaminated soil without compost addition (C) or amended with a wheat straw-based compost (WSC) (H1), co-composted with Fe2O3 (H2), or co-composted with an allophane-rich soil (H3). Extracted HS were characterized under electron microscopy (SEM/TEM), energy-dispersive X-ray (X-EDS), and Fo...

The aim of this study was to characterize a compost blend prepared from sheep manure and oat straw in a co-composting process enriched with oat husk biochar (BC). For this, a co-composting trial was carried out in rota-tories bins of 200 L capacity. Three mixtures (piles) were assayed: BC0: sheep manure (SM) 65% w/w with 35% w/w oat straw (OS) and...

Agricultural activities produce vast amounts of organic residues including straw, unmarketable or culled fruit and vegetables, post-harvest or post-processing wastes, clippings and residuals from forestry or pruning operations, and animal manure. Improper disposal of these materials may produce undesirable environmental (e.g. odors or insect refuge...

Biochar constitutes a promising support material for the formulation of controlled-release fertilizers (CRFs). In this study we evaluated the effect of different polymeric materials as encapsulating agents to control nitrogen (N) leaching from biochar based CRFs. Nitrogen impregnation onto biochar was performed in a batch reactor using urea as N so...

The interactive effect of sugar beet (SB) agrowaste and arbuscular mycorrhizal (AM) fungi inoculation in response to increasing Cu levels was evaluated in the metallophyte Oenothera picensis. Plants were grown in a Cu-added soil (0, 100, or 500 mg Cu kg−1), in presence or absence of SB, and inoculated with: (1) indigenous Cu adapted mycorrhiza (IM)...

High concentrations of metals in soils cause negative effects on microorganisms and plants. However, some microorganisms can adapt to metal stress, and some are able to assist plants in metal polluted soils. Among them arbuscular mycorrhizal fungi (AMF) are the only ones, which provide a direct link between soil and roots. They are widely recognize...

Arbuscular mycorrhizal fungi (AMF) have an important role on the ecosystem stability promoting water and nutrient acquisition by plants and allowing their growth under stress conditions including drought and salinity. This study aimed at describing the colonization of native AMF associated to pioneer plant species growing at the mouth of lake Budi,...

A new species of the Glomeromycetes is diagnosed by bright yellow to dark yellow bi-walled spores (85–131 μm diam.) that form terminally on cylindrical subtending hyphae. The yellow outer spore wall is continuous with the hyphal wall, while the germ tubes emerge during germination from the hyaline inner wall to penetrate the outer wall. Phylogeneti...

Aluminum phytotoxicity in acid soils is an important environmental stress that negatively affects crop production, but arbuscular mycorrhizal (AM) fungi performance would allow plants to better withstand this environmental condition. This study aimed to analyze the effect of soil Al on early AM colonization of wheat (Triticum aestivum L.) and barle...