Carbon and nitrogen mineralization in a vineyard soil amended with grape marc vermicompost

Vermicomposting technology as a dynamic strategy to mitigate environmental crisis: a bibliometric study of last three decades

Efficient recycling of resources forms the cornerstone of sustainable development. Among multiple options in stock for waste recycling, vermicomposting technology is regarded as a futuristic strategy, being tested in every part of the globe due to easy accessibility. Hence, a bibliometric study was planned to set a sight on global scientific trends encompassing vermicomposting research in last three decades. The data were retrieved from Google Scholar, Scopus and PubMed. Publications from different search engines were filtered out and 2064 unique documents were collected and illustrated in MS Excel and Vos-viewer. Inferences were drawn on significant aspects, such as publication growth trend, journal analysis and co-occurrence of keywords. The study revealed that the number of publications increased from 3 in 1992 to 166 in 2021. The number of citations also increased and peaked at 4314 in 2015. Following this, we clustered keywords using principle component analysis and worked out links between domains of vermicomposting. Vermicomposting conjoined to words substrate manipulation, quality improvement, heavy metal adsorption, and yield parameters. This implies that vermicompost is being explored for many alternate uses in addition to its use as a fertiliser. We concluded that vermicomposting is one of the promising technologies for waste recycling. It modulates plant growth and subdues stress in plants. Additionally, being an efficient adsorbent, it serves bioremediation of contaminated sites. Therefore, the future of this technology lies in synthesising nano-formulations, integrating into biosensor technology, simulating for predicting timelines under different conditions and making efforts to improve their adsorption.

Soil response to root-knot nematode management with wine vinasse in a solarised horticultural soil under glasshouse conditions

The increasing interest in agroecological practices and the current consideration of agrarian soils as a sustainable resource are driving the development of new strategies to manage soil parasites and diseases. The application of organic matter from different sources to reduce plant parasites contributes to circular economy by applying by-products as soil organic amendments that reduce wastes. Wine vinasse (WV) is a by-product generated to obtain alcohol from wine by physical methods in distilleries. The aim of this study was to determine the potential of WV and its combination with animal manure (WV+M) as soil biodisinfestation products. For this, it was compared with a plastic-covered control to distinguish the biodisinfestation from solarisation effect. The crops tested consisted of a tomato-Swiss chard rotation under glasshouse conditions. Their effects on Meloidogyne incognita, soil fertility, nematode community and crop yield were assessed. The results obtained after two seasons showed a reduction of M. incognita galling in the root system of both crops. The immediate effect after the treatment application was a reduction in the abundance of nematodes and changes in the nematode-based indices that affected all plots, including the control, most likely related to the tillage effect for the treatments application and the plastic cover. Soil fertility was improved by the application of WV (NO3−, Bioav. P) and WV+M (C, Ntotal, K), which reduced herbivore nematode metabolic footprints and enhanced bacterivore footprints. Our results indicate that the combination WV+M was effective reducing M. incognita infection, and improved crop yield. Use of by-products such as WV is a helpful tool for managing horticultural soils.

Nitrogen mineralization from organic fertilizers and composts: Literature survey and model fitting

Organic fertilizers and composts are valuable sources of nutrients. However, their nutrient availability is often not known and can be variable. The objective of the present study was to collect net nitrogen (N) turnover data from peer-reviewed articles and fit a model that simulates gross N mineralization and gross N immobilization to determine pool sizes and their rate constants of different common organic amendments. A total of 113 datasets were included in the study. The model predicted that 61 and 72.5% of total N in feather meal and guano, respectively, would be in the mineral form after 100 d under optimal conditions. Nitrogen availability from poultry manure and poultry manure compost was lower. On average, 16-17% of total N was present as mineral N in the materials, whereas at the end of the 100-d simulation, 39.6 and 32.7% of total N from an average poultry manure and its compost, respectively, were in the mineral form. Yard waste compost and vermicompost are stable materials, with <10% of the total N in an average material being in the mineral form at the end of the 100-d simulation. Model simulations revealed that changes in the assumed temperature sensitivity of N mineralization have a strong effect on N availability of readily available organic amendments during the first weeks after incorporation. The model performed well for guano and feather meal but was unsatisfactory for the other amendment groups. Model performance may have been hampered by different incubation protocols used in the studies included and variability in amendment properties not considered by the model. The results of this study allow estimating the release of N from a variety of organic fertilizers and composts and can be a valuable tool to improve N management of organic amendments in crop production.

Carbon Storage Distribution Characteristics of Vineyard Ecosystems in Hongsibu, Ningxia

Given that the global winegrape planting area is 7.2 × 10⁶ hm², the potential for winegrape crop-mediated carbon capture and storage as an approach to reducing greenhouse gas emissions warranted further research. Herein, we employed an allometric model of various winegrape organs to assess biomass distributions, and we evaluated the carbon storage distribution characteristics associated with vineyard ecosystems in the Hongsibu District of Ningxia. We found that the total carbon storage of the Vitis vinifera 'Cabernet Sauvignon' vineyard ecosystem was 55.35 t·hm^-2, of which 43.12 t·hm^-2 came from the soil, while the remaining 12.23 t·hm^-2 was attributable to various vine components including leaves (1.85 t·hm^-2), fruit (2.16 t·hm^-2), canes (1.83 t·hm^-2), perennial branches (2.62 t·hm^-2), and roots (3.78 t·hm^-2). Together, these results suggested that vineyards can serve as an effective carbon sink, with the majority of carbon being sequestered at the soil surface. Within the grapevines themselves, most carbon was stored in perennial organs including perennial branches and roots. Allometric equations based on simple and practical biomass and biometric measurements offer a means whereby grape-growers and government entities responsible for ecological management can better understand carbon distribution patterns associated with vineyards.

Bacterial community composition of vermicompost-treated tomato rhizospheres

Vermicompost application has been shown to promote plant growth, alter the rhizosphere microbiome, and suppress plant pathogens. These beneficial properties are often attributed to the activity of vermicompost-associated microorganisms. However, little is known about the microbial shifts that occur in the rhizosphere after vermicompost application. To better understand the impact of vermicompost treatments on the assembly of rhizosphere bacterial communities, 16S rDNA communities of vermicompost and rhizospheres of each peat- and soil-grown tomatoes were profiled after conventional fertigation, irrigation without additional nutrients, and addition of three different vermicompost-extracts. The full dataset consisted of 412 identified genera, of which 317 remained following stringent quality filtration. Tomato rhizosphere microbiome responses to treatments were complex and unique between peat and soil growth substrates. Direct colonization of vermicompost-origin taxa into rhizospheres was limited, with genera Photobacterium and Luteimonas colonizing peat rhizospheres, genera Truepera, Phenylobacterium, and Lysinibacillus colonizing soil rhizospheres, and genus Pelagibius appearing in both soil and peat rhizospheres. Further patterns of differential abundance and presence/absence between treatments highlight vermicompost-mediated effects on rhizosphere microbiome assembly as an interplay of rhizosphere medium, direct colonization of vermicompost-origin taxa and vermicompost-induced shifts in the rhizosphere microbial community. This exploratory analysis is intended to provide an initial look at 16S community composition of vermicompost and the effects of vermicompost treatment on the rhizosphere microbiome assembly to highlight interactions of potential merit for subsequent investigations.

Composting as a strategy to recycle aquatic animal waste: Case study of a research centre in São Paulo State, Brazil

Aquaculture is a fast-growing activity in Brazil and around the world, which generates large amounts of waste from fingerling production to the final consumer. Among several possibilities for the management of these wastes, windrow composting stands out as a simple and low-cost method. In this study, 16 composting piles were assembled with wood shavings and peanut shells and managed according to two methods; one with carcasses recharges and another without. A description of the daily occurrences and management details were made. Temperature and moisture content were monitored and at the end of the decomposition process, and after 60 and 100 days of curing, physic-chemical analysis was performed to assess composts quality. A germination index test was performed to assess composts phytotoxicity. All piles exceeded 55 °C for more than 15 days (with the aid of turnings) and germination indices were above 50% for both lettuce and cress seeds. Total nitrogen concentration among composts varied from 22.1 to 33.2 g kg^-1 and carbon:nitrogen ratios were below 20, while pH values were above 6.0 in all composts. Curing composts for 60 and 100 days did not influence any of the physic-chemical characteristics of all composts, so this practice can be dodged, thus avoiding unnecessary land use and increasing production costs. The type of management adopted for carcasses of aquatic animals influenced total and inorganic nitrogen, C/N ratio, organic matter and pH values of the composts, being recommended the recharge of carcasses to improve composts stability and quality.

Bacterial succession and functional diversity during vermicomposting of the white grape marc Vitis vinifera v. Albariño

Winemaking produces millions of tons of grape marc, a byproduct of grape pressing, each year. Grape marc is made up of the skins, stalks, and seeds remaining after pressing. Raw grape marc can be hazardous to the environment due to its low pH and high polyphenol content, but previous work has shown that grape marc can be stabilized via vermicomposting to produce organic fertilizer. Here, we utilize 16S rRNA high-throughput sequencing to characterize the bacterial community composition, diversity and metabolic function during vermicomposting of the white grape marc Vitis vinifera v. Albariño for 91 days. Large, significant changes in the bacterial community composition of grape marc vermicompost were observed by day 7 of vermicomposting and throughout the duration of the experiment until day 91. Similarly, taxonomic and phylogenetic α-diversity increased throughout the experiment and estimates of β-diversity differed significantly between time points. Functional diversity also changed during vermicomposting, including increases in cellulose metabolism, plant hormone synthesis, and antibiotic synthesis. Thus, vermicomposting of white grape marc resulted in a rich, stable bacterial community with functional properties that may aid plant growth. These results support the use of grape marc vermicompost for sustainable agricultural practices in the wine industry.

Strategies for recycling and valorization of grape marc

Grapes are one of the most cultivated fruit crops worldwide. Either for wine or juice production, grape processing generates a large amount of residues that must be treated, disposed of or reused properly to reduce their pollution load before being applied to the soil. In this review, a special focus is given to the treatment and valorization of the winemaking by-product like grape marc via anaerobic digestion, composting and vermicomposting at laboratory, pilot, and industrial scales. The impact of the final products (digestates, composts, and vermicomposts) on soil properties is briefly addressed. Moreover, the role of grape marc and seeds as a valuable source of natural phytochemicals that include polyphenols and other bioactive compounds of interest for pharmaceutical, cosmetic, and food industries is also discussed. This is of paramount importance given the fact that sustainability requires the use of management and valorization strategies that allow the recovery of valuable compounds (e.g. antioxidants) with minimum disposal of waste streams.

Evolution of organic matter during the mesophilic composting of lignocellulosic winery wastes

Winery wastes were composted in the laboratory during five months in order to study the composting process of lignocellulosic wastes. In a first experiment, spent grape marc was composted alone, and in a second one, hydrolyzed grape marc, which is the residue generated after the acid hydrolysis of spent grape marc for biotechnological purposes, was composted together with vinification lees. During the composting of spent grape marc, total organic matter did not change, and as total N increased only slightly (from 1.7% to 1.9%), the reduction in the C/N ratio was very low (from 31 to 28). The mixture of hydrolyzed grape marc and lees showed bigger changes, reaching a C/N ratio around 20 from the third month on. Water-soluble organic matter followed the usual trend during composting, showing a progressive decrease in both experiments. Although the mixture of hydrolyzed grape marc and lees presented the highest initial water-soluble carbon concentrations, the final values for both experiments were similar (8.1 g kg(-1) for the spent grape marc, and 9.1 g kg(-1) for the mixture). The analysis of the humification parameters did not allow an adequate description of the composting process, maybe as a consequence of the inherent problems existing with alkaline extractions. The total humic substances, which usually increase during composting as a consequence of the humification process, followed no trend, and they were even reduced with respect to the initial values. Notwithstanding, the fractionation of organic matter into cellulose, hemicellulose and lignin enabled a better monitoring of the waste decomposition. Cellulose and hemicellulose were degraded mainly during the first three months of composting, and the progressive reduction of the cellulose/lignin ratio proved that the main evolution of these wastes took place during the first three months of composting.

Plant tests for determining the suitability of grape marc composts as components of plant growth media

Five grape marc composts prepared by different procedures (composting and vermicompost at several scales) were tested as potential components of plant growth media. The five composts had high organic matter content (>90%), low electric conductivity (<1 dS m(-1)) and a pH between 7 and 8. Different chemical and biochemical analyses performed indicated the higher stability of those composts submitted to a longer composting process or to a vermicomposting process (lower water soluble organic matter, respiration and dehydrogenase activity). In order to determine the suitability of the composts as substrate components, plant growth tests were performed by blending the composts with peat or commercial substrate at two compost rates (25% and 50%). The mixtures were sown with barley (Hordeum vulgare L.) and grown under controlled conditions in an incubation chamber. No prejudicial effects derived from the use of composted grape marc were observed, whatever the procedure of composting used. The results showed that four out of the five composts would be suitable for use in plant growth substrates elaboration, as they did not reduce productivity with respect to the control substrates.