Intensive land use enhances soil ammonia-oxidising archaea at a continental scale

Archaea are an important group of soil organisms that play key roles in carbon and nitrogen cycling, particularly in nitrification (ammonia oxidation) and methanogenesis. However, there are knowledge gaps regarding their importance in ecosystem processes relative to other microbial groups and how they may be impacted by land-use and environmental changes. Here, by carrying out a continental-scale sample collection and utilising archaea-specific primers for metabarcoding and shotgun metagenomics, we aimed to decipher the structure and function of archaeal communities across various land-use types in Europe. Metagenomic data reveal that land-use intensification increases the relative abundance of archaea, whereas bacteria and eukaryotes show no increase. Alongside this, ammonia oxidising archaea (AOA) increase as a proportion of the total metabarcoding reads, from 1 % of archaea in coniferous woodland to >90 % in croplands. Functional gene profiles reveal that land-use intensification shifts archaeal communities from adaptive metabolic pathways in forests to specialised, ammonia-oxidising microbes in fertiliser-enriched cropland soils. Our data suggest that land-use intensification may shift archaeal communities toward greater dependence on external nitrogen inputs, with potential consequences for soil fertility and greenhouse gas emissions

The state of soils in Europe

This report delves into the intricate interplay between drivers, pressures and impacts on soil in the 32 Member States of the European Environment Agency (EEA), along with six cooperating countries from the West Balkans, Ukraine and UK, shedding light on the multifaceted challenges facing soil conservation efforts. Our analysis shows the complex interactions among various factors, both anthropogenic and natural, shaping soil degradation processes and their subsequent consequences. We highlight key findings, including the significant impacts of soil degradation on agriculture, ecosystem resilience, water quality, biodiversity, and human health, underscoring the urgent need for comprehensive soil management strategies. Moreover, our examination of citizen science initiatives underlines the importance of engaging the public in soil monitoring and conservation efforts. This work emphasises the policy relevance of promoting sustainable soil governance frameworks, supported by research, innovation, and robust soil monitoring schemes, to safeguard soil health and ensure the long-term resilience of ecosystems.JRC.D.3 - Land Resources and Supply Chain Assessment

Soil bulk density assessment in Europe

The topsoil Land Use and Cover Area frame Statistical survey (LUCAS) aims at collecting harmonised data about the state of soil health over the extent of European Union (EU). In the LUCAS 2018 survey, bulk density has been analysed for three depths, i.e., 0-10 cm = 6140 sites; 10-20 cm = 5684 sites and 20-30 cm =139 sites. The laboratory analysis and the assessment of the results conclude that the bulk density at 10-20 cm is 5-10% higher compared to 0-10 cm for all land uses except woodlands (20%). In the 0-20 cm depth, croplands have 1.5 times higher bulk density (mean: 1.26 g cm -3) compared to woodlands (mean: 0.83 g cm -3). The main driver for bulk density variation is the land use which implies that many existing pedotransfer rules have to be developed based on land use. This study applied a methodological framework using an advanced Cubist rule-based regression model to optimize the spatial prediction of bulk density in Europe. We spatialised the circa 6000 LUCAS samples and developed the high -resolution map (100 m) of bulk density for the 0-20 cm depth and the maps at 0-10 and 10-20 cm depth. The modelling results showed a very good prediction (R2: 0.66) of bulk density for the 0-20 cm depth which outperforms previous assessments. The bulk density maps can be used to estimate packing density which is a proxy to estimate soil compaction. Therefore, this work contributes to monitoring soil health and refine estimates on carbon and nutrients stocks in the EU topsoil

Evaluation of the ecological risk of pesticide residues from the European LUCAS Soil monitoring 2018 survey.

The 2018 LUCAS (Land Use and Coverage Area frame Survey) Soil Pesticides survey provides a European Union (EU)-scale assessment of 118 pesticide residues in more than 3473 soil sites. This study responds to the policy need to develop risk-based indicators for pesticides in the environment. Two mixture risk indicators are presented for soil based, respectively, on the lowest and the median of available No Observed Effect Concentration (NOEC and NOEC) from publicly available toxicity datasets. Two further indicators were developed based on the corresponding equilibrium concentration in the aqueous phase and aquatic toxicity data, which are available as species sensitivity distributions. Pesticides were quantified in 74.5% of the sites. The mixture risk indicator based on the NOEC exceeds 1 in 14% of the sites and 0.1 in 23%. The insecticides imidacloprid and chlorpyrifos and the fungicide epoxiconazole are the largest contributors to the overall risk. At each site, one or a few substances drive mixture risk. Modes of actions most likely associated with mixture effects include modulation of acetylcholine metabolism (neonicotinoids and organophosphate substances) and sterol biosynthesis inhibition (triazole fungicides). Several pesticides driving the risk have been phased out since 2018. Following LUCAS surveys will determine the effectiveness of substance-specific risk management and the overall progress toward risk reduction targets established by EU and UN policies. Newly generated data and knowledge will stimulate needed future research on pesticides, soil health, and biodiversity protection. Integr Environ Assess Manag 2024;20:1639-1653. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)