Margarita Ros’s research while affiliated with Link Campus University and other places

Harnessing agro-industrial residues through composting is gaining importance as a means of phosphorus recovery , as is its reutilization as plant available phosphorus. This research seeks to analyze various combinations of agroindustrial waste and observe the microbial communities contributing to the availability of this element for plants. Six composts were used with different proportions of agroindustrial waste. Phosphorus fractionation was carried out, and the available phosphorus was determined. The molecules involved in phosphorus mineralization and solubilization, alkaline phosphatase activity, organic acids, and microbial communities were also determined. Finally, the potential phosphorus genes (Inorganic P solubilization genes (gcd, ppx, ppqC), and Organic P mineralization genes (phoA, phoD, phnL, phnl, phnJ, phnP, phnH, and phnG)) present in the analyzed composts were established. Compost X2B, composed of vineyard and tomato residues, demonstrated superior performance in providing available phosphorus compared to other composts. This was determined by microbial communities harboring genes involved in the phosphorus cycle, facilitating phosphorus availability.

Monocrop of mandarin leading to reduced soil biodiversity and functionality that must be changed to a sustainable agriculture practice such as alley cropping. In this study an attempt has been made to assess how two different alley cropping strategies promote soil bacterial diversity, microbial activities and the abundance of beneficial bacteria. Three treatments were established: (i) mandarin monoculture (MC); (ii) mandarin diversified with barley/vetch (summer) and with fava bean (winter) for 3 consecutive years (DIV1); and (iii) mandarin diversified with fava bean, purslane and cowpea (DIV2). Results reveal that alley cropping did not significantly affect alfa‐diversity indices, but beta‐diversity showed significant differences among the three treatments, indicating changes in the bacterial community. Specific genera such as Haliangium, Microbacterium, Pseudonocardia, Solirubrobacter and Sphingomonas, known as plant growth‐promoting bacteria, showed higher relative abundances in DIV1 and DIV2 than MC. The genus Novosphingobium showed a higher relative abundance in DIV2, while MND1 showed a higher relative abundance in DIV1. Regarding potential gene abundances related to C and N cycling at the end of the experiment, only manB (hemicellulose degradation) showed a higher abundance in DIV2 than MC, while nifH (N fixation), amoA, and hao (nitrification) showed higher values in DIV1 and DIV2. Enzyme activities showed lower values in diversified treatments than in MC. Most significant changes were observed in the diversification of the alley with a sequence of different crops every year (DIV1), rather than repeating the same crops (DIV2). These alley cropping strategies (DIV1 and DIV2) seem an effective strategy to enhance the abundance of beneficial bacteria with increased potential activity related to N fixation and nitrification.

The biodegradation of polyurethane foam (PU foam) using a combination of oxidative pre-treatment (ozonization) and Tenebrio molitor (T. molitor) mealworms was conducted in this study. Different degrees of ozone oxidation (0%, 25%, and 50%) were applied to PU foam, which was subsequently fed to mealworms. The mealworms’ survival and growth were then compared to mealworms receiving a normal diet (bran). Results showed that mealworms fed with non-oxidized PU foam (PUF0) exhibited a higher consumption rate (11.8%) than those fed with 25% (PUF25) and 50% (PUF50) oxidized PU foam (7.7% and 5.7%, respectively). The survival rate was similar across all the PU foam diets and the bran diet. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) analyses revealed minor structural changes in the PU foam. The gut microbiota analysis showed a significant correlation between the PU foam and bran diets. Among the different oxidized PU, distinct microbial community profiles were also observed, with the genus Klebsiella consistently present across the PU foam diets. The ozone pre-treatment altered the palatability and degradation of the PU foam by mealworms, while the mealworm frass and chitin obtained could potentially be used as resources for agricultural and industrial applications that would close the circular bio-economy cycle.

Soil is crucial for the long-term sustainability of agricultural/agrarian systems and the environment. Agricultural systems affect all soil components and can have a deep impact on soil biodiversity. Since soil biodiversity plays a crucial role in providing ecosystem services, supporting soil multifunctionality and bringing value to humanity, it is necessary to monitor, conserve, restore and improve it. Soil biodiversity can be measured through abundance, composition, functionality, interactions, and processes that will allow preserving soil and its functionality for present and future generations. Therefore, the objective of this article is to identify and describe different bioindicators of soil microbial biodiversity to integrate them into sustainable soil management policies. Measurements of different bioindicators such as total organic carbon, microbial carbon biomass, soil respiration, enzymatic activities related to the C, N and P cycles, DNA metabarcoding, microscopy, and network analysis, among others, will help us monitor soil health and make appropriate de cisions for sustainable agricultural management under the current scenario of global change.

Soil supports and maintains all life systems on the planet, but society has used it in a way that depletes and degrades it, affecting soil quality. Based on a systemic review of publications appearing between 2000 and 2020, this article analyses the conceptual evolution of soil quality, addressing aspects such as management, sampling depth, methods and indicators of soil quality, and the challenges soil science faces to achieve comprehensive quality assessments that promote soil conservation and its sustainable use. The analysis reveals the conceptual evolution of soil quality and how, from its new conception, the holistic understanding of this natural resource is promoted by including soil ecosystem services and the social component. New methods and indicators have allowed researchers to increase their knowledge of soil quality, and they are relevant in each of the study contexts analysed. However, the minimum data sets (MDS) do not always comprise physical, chemical, and biological attributes. The priorities for comprehensive soil quality assessment include strengthening the participatory approach, introducing sustainability‐based scenarios, including biochemical indicators, and establishing a legal framework that articulates the results of assessments for decision‐making. In the current global context of land use, soil quality should not only be seen as a concept but as a scientific and social instrument that can contribute to comprehensive land planning and management.

In the beekeeping industry, “slumgum” is generated as a solid organic waste during the beeswax-rendering process from old scraped honeycombs. This bio-waste could be considered as a novel organic fertilizer due to its high content in organic matter and nutrients. As a novelty in this study, we analysed the effect of application of solid and liquid slumgum transformed or not with Penicillium chrysogenum on purslane ( Portulaca oleracea ) yield and its relationship with soil rhizosphere. For this purpose, nutritional composition, enzymatic activities involved in the P, N and C cycles, fungal and bacterial community composition, diversity and potential functionality in the rhizosphere were measured. The application of solid and liquid slumgum transformed with P. chrysogenum (TS and TL, respectively) and slumgum liquid (L) significantly increased purslane shoot biomass and foliar P content, compared to the non-transformed solid slumgum (S). The different types of slumgum tested resulted in changes in the composition of both bacteria and fungi communities, resulting in distinct communities for each treatment. Moreover, changes in the functional fungal guilds were observed, with increased abundances of saprotrophs and reduced number of plant pathogens under the TS, TL, and L treatments. Solid slumgum transformed with P. chrysogenum (TS) was also the most effective in enhancing enzymatic activities related with C, N and P cycles in the rhizosphere. Conversely, the use of solid slumgum (S) led to an increase in the abundance of bacterial genes primarily associated with the denitrification process. Our preliminary results suggest that solid and liquid slumgum transformed with P. chrysogenum , as well as liquid non-transformed slumgum (TS, TL, and L, respectively), could be considered as novel organic fertilizers, amendments or additives within the circular economy context and the sustainable use of natural resources. Nevertheless, further studies are necessary to validate the positive outcomes observed, particularly under field conditions and with a variety of species.

In the beekeeping industry, “slumgum” is generated as a solid organic waste during the beeswax-rendering process from old scraped honeycombs. This bio-waste could be considered as a novel organic fertilizer due to its high content in organic matter and nutrients. As a novelty in this study, we analysed the effect of application of solid and liquid slumgum transformed or not with Penicillium chrysogenum on purslane ( Portulaca oleracea ) yield and its relationship with soil rhizosphere. For this purpose, nutritional composition, enzymatic activities involved in the P, N and C cycles, fungal and bacterial community composition, diversity and potential functionality in the rhizosphere were measured. The application of solid and liquid slumgum transformed with P. chrysogenum (TS and TL, respectively) and slumgum liquid (L) significantly increased purslane shoot biomass and foliar P content, compared to the non-transformed solid slumgum (S). The different types of slumgum tested resulted in changes in the composition of both bacteria and fungi communities, resulting in distinct communities for each treatment. Moreover, changes in the functional fungal guilds were observed, with increased abundances of saprotrophs and reduced number of plant pathogens under the TS, TL, and L treatments. Solid slumgum transformed with P. chrysogenum (TS) was also the most effective in enhancing enzymatic activities related with C, N and P cycles in the rhizosphere. Conversely, the use of solid slumgum (S) led to an increase in the abundance of bacterial genes primarily associated with the denitrification process. Our preliminary results suggest that solid and liquid slumgum transformed with P. chrysogenum , as well as liquid non-transformed slumgum (TS, TL, and L, respectively), could be considered as novel organic fertilizers, amendments or additives within the circular economy context and the sustainable use of natural resources. Nevertheless, further studies are necessary to validate the positive outcomes observed, particularly under field conditions and with a variety of species.