Francis Rayns

Agroecology has traditionally been implemented using conventional methods. However, the integration of precision equipment, advanced methodologies, and digital technologies (DT) is now essential for transitioning to a more modern and efficient approach. While agroecological principles remain fundamental for planning and managing sustainable food systems by optimizing natural resources, technological tools can significantly support their implementation and adoption by farmers. This transition, however, must also consider socioeconomic factors and policy frameworks to ensure that technological advancements lead to meaningful improvements in farms and agroecosystems. Across both industrialized and emerging economies, various initiatives, such as precision agriculture, digital platforms, and e-commerce, are driving the digitalization of agroecology. These innovations offer clear benefits, including enhanced knowledge generation and direct improvements to the food supply chain; however, several barriers remain, including limited understanding of digital tools, high-energy demands, insufficient financial resources, economical constrains, weak policy support, lack of infrastructure, low digital learning by framers, etc. to facilitate the transition. This review looks for the understanding of how digitalization can align or conflict with local agroecological dynamics across distinct political frameworks and reality contexts because the information about DT adoption in agroecological practices is limited and it remains unclear if digital agriculture for scaling agroecology can considerably change power dynamics within the productive systems in regions of Europe and Latin America. In South America, among countries like Ecuador, with strong potential for agroecological development, where 60% of farms are less than 1 ha, and where farmers have expressed interest in agroecological practices, 80% have reported lacking sufficient information to make the transition to digitalization, making slow the adoption progress of these DT. While agroecology is gaining global recognition, its modernization through DT requires further research in technical, social, economic, cultural, and political dimensions to more guide the adoption of DT in agroecology with more certainty.

With the immediate actions required to address environmental issues posed by waste generation and the growing interest in the circular economy, anaerobic digestion (AD) offers a promising solution. As a major component of waste‐to‐energy, AD plays a dual role by processing waste and generating renewable energy at the same time, thus contributing to the success of closed‐loop systems. However, the success of AD as a business remains uncertain due to the high costs of material handling. Through a systematic literature review (SLR), this study reveals AD‐specific key barriers in feedstock exchanges and typical strategies applied to address them. The dual role of AD and the involvement of different stakeholders in the upstream processes further complicate these challenges, thus necessitating a more holistic approach to strategy formulation—an aspect not fully covered in the current literature. These gaps present opportunities to theorise the unique operations of AD businesses and the dynamics of multi‐stakeholders in complex feedstock supply processes. This study integrates resource management theories and duality theory, proposing a theoretical framework to enhance the sustainability and circularity of AD ventures. The proposed framework views AD from a resource‐oriented perspective and thus reinforces its pivotal role in fostering a truly closed‐loop system within the circular economy.

Soil microbes are essential for soil nutrient cycling. However, frequent tillage and the use of synthetic agrochemicals can reduce soil microbial diversity and enzyme activity. In this study, the effects of four tillage treatments (mouldboard plough, shallow tine‐tillage, no‐tillage, and tillage rotation) and two rates of synthetic agrochemicals (standard and reduced, with biostimulants) on soil microbial diversity and enzyme activity were investigated between 2018 and 2020 in a Mediterranean climate zone in South Africa. It was hypothesized that a reduction in tillage frequency and quantity of synthetic agrochemical application would lead to greater microbial diversity and enzyme activity. Soil samples were collected from the 0‐ to 150‐mm layer of a field trial under a dryland crop rotation system. Soil microbial species richness and abundance were assessed using the Shannon–Wiener diversity and evenness indices. The activities of four microbial enzymes—β‐glucosidase, acid phosphatase, alkaline phosphatase, and urease—were used to evaluate ecosystem functioning. The combined effects of tillage rotation with a shallow tine implement and the application of biostimulants failed to significantly improve soil microbial diversity, enzyme activity, and crop productivity relative to other treatments. However, the combination did not reduce the wheat (Triticum aestivum) grain yield and quality, and soil biological parameters. Furthermore, the less intensive tillage treatments, ST, NT, and ST‐NT‐NT‐NT, resulted in higher enzyme activity than the mouldboard treatment. Therefore, we suggest that combining non‐intensive tillage with reduced synthetic agrochemical use can be a safer, more environmentally friendly alternative to intensive tillage and high agrochemical application in dryland cropping systems.

Global urbanisation is leading to the degradation of living soils, with substantial and direct impacts on climate, biodiversity, food security, and human health. Urban land use policies are beginning to address soil protection. However, they rarely address the depollution and remediation of urban soils and the revitalisation of the agricultural socio-economic fabric, both essential to recover and maintain healthy soils. Instead polluted soils are often managed through further soil sealing (i.e. covering with a plastic ‘geotextile’ layer to isolate it and adding new soil on top). As alternatives, emerging urban communities of practice are currently experimenting with integrated and holistic practices of soil care, such as sourcing urban organic waste streams (food waste, leaves, grass clippings, waste from breweries, ecological paperboard packaging, etc.) for topsoil regeneration or using nature-based approaches (e.g. bioremediation) for the depollution of topsoils. Such practices urgently need enabling and adequate policy frameworks to be mainstreamed and aligned with related policies regarding climate action, green/blue infrastructure and urban food policy plans.

For the last 30 years, interest has focused on biochar and its potential to store carbon in soil to mitigate climate change whilst improving soil properties for increased crop production and, therefore, could play a critical role in both agricultural sustainability and broader environmental aims. Biochar, a carbonaceous product, is formed from organic feedstock pyrolysised in the absence of air and, therefore, is a potential means of recycling organic waste. However, different feedstock and pyrolysis conditions result in a biochar with a range of altered characteristics. These characteristics influence nitrogen transformation processes in soil and result in the metabolism of different substrates and the formation of different products, which have different effects on agricultural yield. This paper reviews how the production of biochar, from varying feedstock and pyrolysis conditions, results in different biochar characteristics that influence each stage of the nitrogen cycle, namely processes involved in fixation, assimilation, mineralisation and denitrification. The nitrogen cycle is briefly outlined, providing a structure for the following discussion on influential biochar characteristics including carbon composition (whether recalcitrant or rapidly metabolisable), mineral composition, surface area, porosity, cation exchange capacity, inhibitory substances and pH and so on. Hence, after the addition of biochar to soil, microbial biomass and diversity, soil porosity, bulk density, water-holding capacity, cation exchange capacity, pH and other parameters change, but that change is subject to the type and amount of biochar. Hence, products from soil-based nitrogen transformation processes, which may be beneficial for plant growth, are highly dependent on biochar characteristics. The paper concludes with a diagrammatic summation of the influence of biochar on each phase of the nitrogen cycle, which, it is hoped, will serve as a reference for both students and biochar practitioners.

The efficacy of soil conditioner (vermicompost tea), fertiliser (potassium silicate), and biological control agents (BCAs) as practical agroecological copper alternatives against olive leaf spot (Spilocaea oleaginea (Cast.) Hughe.) disease was investigated between 2018 and 2021 under organic management in a Mediterranean climate. In total, 9 agroecological alternatives to copper oxychloride (vermicompost tea, potassium silicate, Bacillus subtilis EU 007 WP, Platanus orientalis leaf extract, Mycorrhiza mix, seaweed commercial product, Trichoderma citrinoviride TR1, vermicompost tea+Platanus orientalis mix, Penicillium (Mouldy bread pieces)) were applied to olive trees in a randomised block design with 4 replicationsTotal water soluble phenol compounds (TWSP) were found to be the main bioindicator to assess the alternatives and their potential to phase-out copper application. Results related to TWSP indicated that copper oxychloride (control), potassium silicate and vermicompost tea showed significantly higher content of TWSP as we compared zero application of copper and other treatments. These stimulate the antioxidant capacity in olive fruits and reduce the olive leaf spot disease incidence. The pollution effect of copper was monitored during the trial to identify soil pollution in the organic in-conversion experimental land. The total annual ‘active copper’ application was 4.7 kg.ha⁻¹.year⁻¹ and this is in accordance with the legal organic legislation of Turkey. During the conversion period from conventional to organic management, we determined approximately 50% reduced copper content in the soil 0–30 cm depth samples in 2020 (3.70 mg.kg⁻¹) as it is compared to those initial samples (6.43 mg.kg⁻¹) in 2018. We conclude that alternatives to copper that are easily accessible, e.g., vermicompost tea, have a potential for use in organic olive production to replace copper in mitigating olive leaf spots. Furthermore, we find that reduced copper application in organic management with the aim to decrease copper accumulation in soil, fruits and leaves was not yet enough to reduce copper to satisfactory levels. We conclude that further research with the aim of a total replacement of copper fungicide treatments in organic and non-organic systems is needed.

Micronutrient malnutrition is widespread and is linked with diets low in fruit and vegetables. However, during the twentieth century, declines in essential minerals in fruits and vegetables were reported in the UK and elsewhere. A new analysis of long-term trends of the mineral content of fruits and vegetables from three editions of the UK’s Composition of Foods Tables (1940, 1991 and 2019) was undertaken. All elements except P declined in concentrations between 1940 and 2019 – the greatest overall reductions during this 80-year period were Na (52%), Fe (50%), Cu (49%) and Mg (10%); water content increased (1%). There could be many reasons for these reductions, including changes in crop varieties and agronomic factors associated with the industrialisation of agriculture. Increases in carbon dioxide could also play a role. We call for a thorough investigation of these reductions and steps to be taken to address the causes that could contribute to global malnutrition.

Peat is a highly contentious input in agriculture. Replacing or reducing peat by substitution with lignocellulosic biomass processed into fibre by twin-screw-extrusion could contribute to more sustainable agriculture with regard to horticultural production. Therefore, plant wastes including pruning from Olea europaea L. and Vitis spp. L., residues from perennial herbs like Salvia spp. L., Populus spp. L. and forest biomass were processed to fibre for peat replacement with a biomass extruder. The water-holding-capacity (WHC), particle-size-distribution and other physical fibre characteristics were determined and compared to peat. The specific energy demand during extrusion was measured for aperture settings from 6–40 mm. No fibre reached the 82% WHC of peat. At the setting of 20 mm of all materials investigated, Salvia performed best with a WHC of 53% and moderate specific energy demand (167 kWh t_DM⁻¹) followed by Olea europaea with a WHC of 43% and a low energy demand (93 kWh t_DM⁻¹). For Populus, opening the aperture from 20–40 mm decreased energy demand by 41% and WHC by 27%. The drying of biomass for storage and remoistening during extrusion increased the specific energy demand. Despite a lower WHC than peat, all investigated materials are suitable to replace peat in growing media regarding their physical properties.