Marcos Paradelo

Viticulture in England has expanded rapidly over the last two decades, driven by climate change and the adoption of commercially viable grape varieties suited to sparkling wine production.This study examined, over two years, the establishment and performance of cover crops and under-vine weed management strategies in two commercial vineyards and one experimental vineyard in the South East of England, representing contrasting soil types. A range of cover crops were established between March 2022 and October 2024, including phacelia, common vetch, faba bean, a perennial mix of berseem, crimson and white clovers with creeping red fescue, and an annual mix of rye and common vetch. In parallel, under-vine weed management practices were evaluated, including herbicide application, mechanical control, and strimming.Soil assessments included nutrient content, microbial biomass, soil organic matter, bulk density, hydraulic conductivity, soil moisture, soil respiration, and soil microbial community composition (16S rRNA and ITS sequencing). Vine performance was evaluated through measurements of leaf nutrient content, chlorophyll index, canopy area index, grape yield, and juice quality.Soil organic matter did not differ between cover crop treatments and the control (grass cover). Microbial biomass increased under faba bean at the clayey site in 2023; however, no significant differences among treatments or sites were observed in 2024. As expected, available nitrogen levels were consistently higher in the faba bean treatment across all three sites in both years, although these differences were only statistically significant in 2023.Regarding soil physical properties, bulk density tended to be higher under faba bean compared with the control, whereas no significant differences were observed in hydraulic conductivity. Soil moisture content was generally lower in the cover crop treatments than in the grass-covered control.In 2023, grapes from vines adjacent to faba bean cover crops at the clayey site showed significantly higher yeast-assimilable nitrogen (YAN), malic acid, and ammonium-N compared with the grass control. However, these differences were not observed in the following season.Weeding management influenced soil physical properties and vine performance, with higher soil bulk density and greater vine vigour under herbicide control.Overall, groundcover management has the potential to influence soil health and vine responses, but the effects observed in this study were not conclusive over the short term. Soil type, seasonal conditions, and the longevity of both treatments and vines are likely key factors regulating the impacts of groundcover management in vineyards.

The decomposition of organic material (OM _t ) in agricultural ecosystems impacts soil fertility and is influenced by land management. This study aimed to unravel the biophysical drivers contributing to the decomposition of OM _t in long‐term cropping systems (crop rotation with and without ley, bare fallow and perennial grassland) on sandy and silty soils. First, we considered physical properties, such as water‐stable aggregates, gas transport and pore size distribution, as well as microbiological properties, including the biomass of arbuscular mycorrhizal fungi, saprophytic fungi and bacteria and fluorescein diacetate enzyme activity. Soil organic carbon (SOC) content, total nitrogen, water‐extractable phosphorus, plant‐available potassium and magnesium, pH and electrical conductivity were also determined. Finally, we elucidated the relationships between OM _t decomposition and the examined soil properties. The OM _t decomposition was assessed using the tea bag protocol with two types of tea representing OM _t with a high C:N ratio (low quality) and a low C:N ratio (high quality). Results showed that the difference in the soil properties between arable and ley‐arable rotation was more pronounced in the sandy soil than in the silty soil. The OM _t decomposition showed no clear difference in the silty soil among different cropping systems, while there was a greater decomposition of both types of OM _t in the arable rotation than in the other systems in the sandy soil. For both sites, the greater decomposition of low‐quality OM _t was associated with soil biochemical properties, while the decomposition of high‐quality OM _t was associated with gas diffusion; for the sandy soil, the former was also associated with nutrient contents, and the latter was associated with SOC, soil structural properties and enzyme activity. In summary, the biophysical drivers for OM _t decomposition varied with the OM _t quality and soil texture, and there was no consistent effect of crop rotation on OM _t decomposition depending on the soil texture.

Whilst the potential of fish effluents as nutrient sources for crop production has been demonstrated, their use in the European Union remains prohibited in organic farming. In this study, we investigate the efficacy in greenhouse basil cultivation of two types of fish effluents (filtered ‘fish water’ and unfiltered ‘fish sludge’) from an aquaponic system, and assess their role in maintaining and enhancing soil fertility as well as their potential to create a ’living soil’, which are two of the prerequisites for organic certification in the EU. To evaluate the contribution of fish effluents to plant growth in comparison with soil nutrients, basil plants were grown in pots containing two types of substrate: compost-free (without organic matter) and with compost (with organic matter). The results indicate that fish water and fish sludge demonstrate significant potential as fertilisers and outperform compost in certain parameters, such as plant biomass. The results also align with existing literature by demonstrating the positive impact of compost on soil microbial diversity, underscoring its role in fostering plant health. Although the treatments did not show differences in microbial composition at the genus level, the higher microbial diversity observed following fish effluent application highlights its potential for promoting ’living soil’. This research underscores the need for continued exploration of the implications of compost application in conjunction with fish effluent fertilisation on soil microbial communities and the production of specialty crops such as herbs.

The Feeding Mars study was devised as a small, pilot proof of concept study to research the potential for using aquaponic effluents as an additive to regoliths which on Mars and the Moon are devoid of organic material and thus lacking microbes which assist in the delivery of water and nutrients to the plants via their roots. This research investigates aquaponics as a way to potentially produce fish and vegetal products in regoliths on Mars and the Moon as well as in extreme environments on Earth. In order to settle on Mars, settlers will have to grow their own food in systems that are self-perpetuating, with little or no inputs being brought from Earth once these systems have been established. This means that nutrients from the fish water can be used to grow plants in the hydroponic parts of the aquaponic system but also potentially in the Martian regoliths which are treated with effluents taken from aquaponic systems. Once production is established additional nutrients can be sourced from the arisings and waste, both from the fish (that are processed and eaten) and the plants, which can be used as compost to turn the regoliths into soil. In order to have fish in space, there is also the need for the systems to be self-sustaining in the production of fish feed. The key outcomes of the project were that all the species grown (potatoes, tomatoes, dwarf beans, carrots, lettuce, spring onions, chives and basil) indicate the potential to be grown in regoliths with the addition of aquaponic effluents. A significant result was that on the whole the plants that were grown with the addition of aquaponic effluents were greener than those grown in the horticultural soil, indicating that the nutrient supply was adequate. However, a key lesson learned is that germination and thus development of the plants grown in the Mars simulant and analogue was slower than those grown in the horticultural soil. Thus, developing nutrients in the soil before planting is necessary as it is with agriculture and horticulture practices on Earth, where manuring/fertilization occurs before planting. The consequence of this research, and the envisaged research to follow is not only for extra-terrestrial environments. The Earth has its own hostile environments, characterised with regoliths and other unproductive soils, and aquaponic water and aquaponic wastes can readily be envisaged as providing solutions to growing nutritious food in areas where agriculture is not currently viable. The research was undertaken in an exhibition gallery setting at the University of Greenwich in order to encourage public interest and dialogue, which it did.

This study investigated the efficacy of fermented seaweed (Eucheuma cottonii) on the remediation of fluoride-contaminated soil. The soil was amended with either 1.25, 3.0, or 5.0% (w/w) fermented seaweed (FSW), parallel with the controls (0%). The amendment improved the physicochemical properties of the soil particularly pH regulated from strong alkaline (9.3) to neutral (7.0) which is essential for germination, crop growth, and yield. The amount of water soluble-fluoride (Ws-F) dropped from 81.7 +/- 3.1 mg/kg to 42.7 +/- 2.4, 33.7 +/- 1.2, 19.6 +/- 0.9, and 12 +/- 1.3 mg/kg following 0, 1.25, 3, and 5% amendment dosage, respectively. Most of the Ws-F was converted into exchangeable fluoride (Ex-F) and to fluoride-bound to iron and manganese (Fe/Mn-F). Furthermore, the amendment also enhanced microbial mass and diversity in the soil. The FSW contains organic acids which participate in ionic bonding with the multivalent cations in the soil. The formed compound participates in ion exchange with clay or with anionic adsorption to positively charged clay sites at the edges. This interaction is further essential for enhancing the fluoride holding capacity of the soil. The use of seaweed reduced the bioavailability of fluoride in the agricultural soils and had positive effects on promoting soil fertility. However, further studies to observe its effects on crop performance is of significance.

Soil organic matter is associated with important biological and physical functions. There are many theories to interpret this association, as yet there is not a fully developed understanding linking soil properties to nutritional management in arable systems.We used X-ray computed tomography to analyse soil structure at the core and aggregate scale on the Broadbalk long term experiment (Hertfordshire, England). Here we present results of the treatments that have been under continuous wheat for 175 years. Corresponding to treatments that the only difference between the treatments is the nutrient management regime, with the exception of the baseline, or ‘wilderness’ treatment in which the plot was left unmanaged and has returned to mature woodland since 1882. The other nutrient treatments correspond to inorganic fertiliser addition with and without phosphorus, farmyard manure, and no added nutrient.At core scale (40 µm resolution) we capture macro pore structures that are responsible for convective flow, while the aggregate scale images (1.5 µm resolution) include structures responsible for retention of water by capillary forces.  Therefore, a comparison of images taken at the two resolutions 1.5 µm and 40 µm provides information on how soil partitions between drainage and storage of water, and therefore on the air water balance under different environmental contexts.The results are presented as a state-space plot of simulated permeability vs. porosity for each treatment. We find that nutrient management resulted in two distinct states at aggregate scale corresponding to water storage potential. Inorganic nutrient management resulted in structures of lower porosity and lower simulated permeability. There was no significant difference between each treatment, or between these treatments and the treatment with no nutrient addition. By comparison, the wilderness and manure treatments had higher porosity and higher permeability, with no significant difference between them.At core scale, the results are slightly different. Again, the inorganic nutrient management treatments had lower porosity and simulated permeability, with no significant difference between them, and between them and the treatment with no nutrient addition. However, the manure treatment had a significantly lower porosity and permeability than the wilderness treatment. We conclude that long-term cultivation with organic nutrient management results in a similar capacity for water storage and transport to roots than a wilderness control, but that long-term management using a purely inorganic nutrient regime results in a smaller capacity for water storage and a lower transport rate to roots. Organic inputs, roots and plant detritus ploughed into the soil after harvest had no significant impact. Infiltration potential is highest in the wilderness control, lower for the manure treatment, and lowest for the inorganic nutrient management treatment. Again, inputs of organic nutrients from plants had no significant impact. We interpret these findings in terms of a previously hypothesised self-organising feedback loop between microbial activity and soil structure.