Sammani Ramanayaka

In the move to decarbonise energy supplies to meet Net Zero targets, ground-mounted solar farms have proliferated around the world, with uncertain implications for hosting ecosystems. We provide some of the first evidence on the effects of ground-mounted solar panels on plant and soil properties in temperate agricultural systems. We sampled 32 solar farms in England and Wales in summer 2021. Plant cover and aboveground biomass, as well as soil nutrients and physiochemical properties, were quantified on land underneath solar panels, in the gaps between rows of solar arrays, and in control land (pasture) adjacent to three solar farms. Plant cover and aboveground biomass were significantly lower under solar panels than in the gaps between solar arrays and in pastures. Soil compaction was 14.4% and 15.5% higher underneath solar panels than in gaps and pastures, respectively. Soil organic carbon was 9% lower under solar panels than in gaps, while particulate organic matter was 29.1% and 23.6% lower under solar panels than in gaps and pastures, respectively. Soil mineral nitrogen was 30.5% higher under solar panels than in gaps, while soil (plant-available) phosphorus was approximately 60% higher in solar farm soils than in pasture soils. Reductions in solar radiation and changes to microclimate caused by solar panels may be driving lower plant productivity and growth, with consequences for nutrient cycling and soil properties. However, impacts must be considered in light of the previous land use and the total land area under solar panels, in the gaps between solar arrays, and around the margins of the solar farm. Our findings can inform solar farm design and management options (e.g. increase the proportion of land unaffected by solar panels, enhance plant cover under solar panels) to ensure the long-term provision of ecosystem services (e.g. soil carbon storage) within this fast-growing land use.

The review highlights advanced removal strategies and their impacts on soil algae and nematodes, addressing plasticizer pollution comprehensively.

Soil serves as both a ‘source’ and ‘sink’ for contaminants. As a source, contaminants are derived from both ‘geogenic’ and ‘anthropogenic’ origins. Typically, while some of the inorganic contaminants including potentially toxic elements are derived from geogenic origin (e.g. arsenic and selenium) through weathering of parent materials, the majority of organic (e.g. pesticides and microplastics) as well as inorganic (e.g. lead, cadmium) contaminants are derived from anthropogenic origin. As a sink, soil plays a critical role in the transformation of these contaminants and their subsequent transfer to environmental compartments, including groundwater (e.g. pesticides), surface water (phosphate and nitrate), ocean (e.g. microplastics) and atmosphere (e.g. nitrous oxide emission). A complex transformation process of contaminants in soil involving adsorption, precipitation, redox reactions and biodegradation control the mobility, bioavailability and environmental toxicity of these contaminants. Soil also plays a major role in the decontamination of contaminants, and the ‘cleaning’ action of soil is controlled primarily by the physico-chemical interactions of contaminants with various soil components, and the biochemical transformations facilitated by soil microorganisms. In this article, we examine the geogenic and anthropogenic sources of contaminants reaching the soil, and discuss the role of soil in the sequestration and decontamination of contaminants in relation to various physico-chemical and microbial transformation reactions of contaminants with various soil components. Finally, we propose future actions that would help to maintain the role of soils in protecting the environment from contaminants and delivering sustainable development goals. This article is part of the theme issue ‘The role of soils in delivering Nature's Contributions to People’.

Biochar conversion into nanobiochar induced multiple potential applications as an adsorbent, sensor, capacitor, and photocatalytic and plant nanobionic material.