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 materials that can replace, or reduce the use of peat, while maintaining or improving attributes in the growing media and plant growth, are greatly needed. Therefore, this work aims to evaluate the effects of the use of different proportions of compost and biochar on the biological characteristics of growing media and (Lactuca sativa L.) seedling growth prior to transplanting. Out of the biological variables evaluated, the β-glucosidase activity showed the greatest results in growing media based on 80% peat and based on 70% peat, 5% compost and 5% biochar. Moreover, growing media based on the combination of compost, biochar and peat maintained most of the Lactuca sativa L. (Oak Leaf variety) seedling traits obtained in the growing media based on only peat. These findings emphasize the need to further investigate further biological conditions for alternative materials to peat, and the need to pay attention to feedstock initial characteristics and processing in order to obtain high quality organic inputs for optimum growing media.

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 greenhouse conditions. Bare soil and a basal fertilization treatment were compared to soils amended with nonadditive compost (NA compost), compost supplied with oat-based biochar (Bioch compost), iron oxide nanoparticles (Fe compost), and halloysite nanoparticles (Ha compost). Compost supplied with nanoparticles and biochar combined were also considered. The incorporation of compost with or without additives increased the content of total C and N in soil, with N diminishing (total and mineral forms) and C/N modifications after 90 days. The addition of compost and co-composted treatments also increased the total contents of main nutrients such as Ca, K, P and S. Furthermore, the supply of additives into composting did not increase the concentration of trace toxic elements. At the end of the experiment, plant biomass increased by the addition of the different organic amendments, with the highest shoot biomass in soils amended with compost supplied with nanoparticles. These results suggest that the addition of compost based on agricultural residues with additives such as halloysite or biochar improves chemical properties and nutritional status of soil that favor and increase plant growth of Lollium perenne stablished in soils from the Mediterranean Region.

Urban wetland soil provides ecosystem services (ES) through their functions. Changes in soil properties due to anthropogenic disturbances lead to a loss of soil quality. The aim of this research was to evaluate the effect of nearby anthropic disturbance on the chemical, physical and biological properties of the urban wetland soil. Soil samples were collected from four sites (P1, P2, P3 and P4) located in the Angachilla urban wetland, Chile, according to the magnitude of anthropogenic disturbance. An assessment of the physical and chemical properties of the soil profile was carried out in two sites, P1 and P4. Additionally, chemical and biological properties of the soil were evaluated in the four sites selected. Results from the soil profiles showed that Hz1 of P4 had a higher levels of soil fertility as a result of low anthropogenic disturbance in contrast to Hz1 of P1 (p < 0.05). Relevant differences among sites were observed for P-Olsen, pH NaF, nosZ gene, Nitrate and Na (PC1: 50.5%). Composition of the soil bacterial community in P1 and P4 showed higher richness and diversity. Anthropogenic disturbance on the urban wetland soil leads to a loss of the soil’s organic horizon, as well as its soil quality and, subsequently, its capacity to provide ES through its functions.

The growing demand for sustainable alternatives to non-renewable growing media components, such as sphagnum peat, has driven interest in compost–biochar combinations as high-quality horticultural substrates. Nevertheless, the effects of incorporating biochar at the onset of co-composting on process dynamics and the quality of the resulting end-products remain poorly understood and insufficiently characterized. This study evaluated the influence of hardwood residue-derived biochar as an additive on the co-composting of corn stover and swine manure under greenhouse conditions over 94 days. Three treatments were established: a Control (C; without biochar), CB1 (10% v/v biochar), and CB2 (20% v/v biochar), each with three replicates. Physicochemical properties (pH, electrical conductivity, water holding capacity, bulk density, particle size distribution, total organic carbon), enzyme activities (FDA hydrolysis, dehydrogenase, urease, arginine ammonification, acid phosphatase, arylsulfatase), compost stability (Solvita^® test), and phytotoxicity (germination index) were monitored throughout the process and at process completion. Results showed that biochar addition significantly influenced physicochemical and biological parameters in a dose-dependent manner. The CB2 treatment reduced electrical conductivity by 46% relative to the Control (1.87 vs. 3.45 mS/cm) and increased water-holding capacity by 32% (479 vs. 364%), while all treatments met the Chilean composting standard NCh 2880. Enzyme activities were generally higher in the Control and CB1 treatments, indicating that high biochar rates may limit microbial activity due to recalcitrant carbon inputs, yet a 20% biochar addition improved compost maturity and reduced phytotoxicity. These findings indicate that, within the tested range (10–20% v/v), biochar incorporation appears to enhance the quality, supporting its potential as a sustainable component in growing media formulations as an alternative to peat.