Jens Leifeld

• Head Climate and Agriculture Group at Agroscope Zurich

Pyroligneous acid (PA) or wood vinegar, a co-product of biomass pyrolysis, is thought to be beneficial for plant productivity and soils, with the potential to reduce otherwise harmful agrochemicals. Here, we review the evidence for the use of PA on plant growth and soil health parameters. The analysis includes 65 peer-reviewed studies with 171 (yie...

The potential for soil carbon (C) sequestration strongly depends on the availability of plant biomass inputs, making its efficient use critical for designing net zero strategies. Here, we compared different biomass processing pathways and quantified the long-term effect of the resulting exogenous organic materials (EOMs) to that of direct plant res...

Peatland drainage is worldwide a major human-induced greenhouse (GHG) source and rewetting increasingly considered a silver bullet to not only reverse the climate burden of peatland management, but also recover other ecosystem functions. Peatland rewetting is therefore one key measure in the evolving frameworks for carbon farming projects and an im...

Simple humus balance calculators were developed for farmers and consultants to determine the best crop rotation and amount of organic fertilizer required to improve soil quality and prevent nutrient leaching in croplands. Although the potential of these tools to infer the impact of different agricultural practices on soil organic carbon (SOC) dynam...

The agricultural use of organic soils usually requires drainage, resulting in soil subsidence and high greenhouse gas (GHG) emissions, mainly CO2. One proposed strategy to maintain the productivity of these soils is adding a mineral soil cover. However, its impact on the GHG budget has yet to be discovered. Herein, we determined the net ecosystem c...

Carbon-rich peat soils have been drained and used extensively for agriculture throughout human history, leading to significant losses of their soil carbon. One solution for rewetting degraded peat is wet crop cultivation. Crops such as rice, which can grow in water-saturated conditions, could enable agricultural production to be maintained whilst r...

Organic-rich agricultural soils, including drained peatlands, are hotspots for biogenic CO2 emissions. Due to microbial mineralisation, the organic carbon (OC) content of these soils transitions to that of mineral soils, but it remains unclear how the residual OC content controls the rate of CO2 emission. Here we show that area-scaled CO2 emissions...

Pyrogenic carbon capture and storage (PyCCS), which comprises the production of biomass, its pyrolysis, and the non-oxidative use of the biochar to create carbon sinks, has been identified as a promising negative emission technology with co-benefits by improving soil properties. Using biochar as a soil additive becomes increasingly common as farmer...

Munoz et al. (2024) raised concerns regarding our recent contribution and the definition of the term C sequestration in soils (Don et al., 2024). We performed a review and therefore based our analysis on existing definitions of C sequestrations, mainly by the IPCC. We recommend sticking with terminologies around C sequestration and climate mitigati...

The draining and fertilization of peatlands for agriculture is globally an important source of the greenhouse gas nitrous oxide (N 2 O). Hitherto, the contribution of major sources to the N 2 O emission—that is, fertilization and nitrogen (N) release from peat decomposition—has not yet been deciphered. This hampers the development of smart mitigati...

Soil organic carbon (C) is a key component of the global C budget. As soil organic C turnover rates decrease with depth, agricultural practices favoring deep organic C storage will gain importance as long-term climate change mitigation strategies. In addition, amendment of pyrogenic organic matter (biochar) is considered a promising practice for se...

Organic soils are important carbon stocks. The conventional (dry) cultivation of these soils turns them into strong sources of greenhouse gas (GHG) emissions. For situations where restoration of natural land cover is not possible, solutions to this problem include the wet cultivation of these soils, reducing CO 2 and N 2 O emissions. One option, pa...

The term carbon (C) sequestration has not just become a buzzword but is something of a siren's call to scientific communicators and media outlets. Carbon sequestration is the removal of C from the atmosphere and the storage, for example, in soil. It has the potential to partially compensate for anthropogenic greenhouse gas emissions and is, therefo...

Improving soil management to enhance soil carbon sequestration (SCS)—a cost-efficient carbon dioxide (CO2) removal approach—can result in co-benefits or trade-offs. Here we address this issue by setting up a modeling framework for Switzerland that combines soil carbon (C) storage, food production and agricultural greenhouse gas (GHG) emissions. The...

Animal manure has been used to manage soil fertility since the dawn of agriculture. It provides plant nutrients and improves soil fertility. In the last decades, animal husbandry has been significantly expanded globally. Its economics were optimized via the (international) trade of feed, resulting in a surplus of animal manure in areas with intensi...

Biochar is a carbon (C)‐rich material produced from biomass by anoxic or oxygen‐limited thermal treatment known as pyrolysis. Despite substantial gaseous losses of C during pyrolysis, incorporating biochar in soil has been suggested as an effective long‐term option to sequester CO 2 for climate change mitigation, due to the intrinsic stability of b...

Soil organic matter (SOM) plays a vital role for soil quality, sustainable food production and climate change mitigation. It is common knowledge that SOM consists of different pools with varying qualities, quantities, and turnover times. However, it is still poorly understood how mineral and organic fertilization affects the formation and stabiliza...

The role of carbon farming in agriculture or forestry to mitigate climate change is currently under intensive scientific discussion along with the gradual but progressing evolution of the voluntary carbon market and its certification. An overarching issue is the question of the permanence of terrestrial carbon sinks. In this comment, I discuss the...

Draining peatlands for agriculture induces peat decomposition, subsidence, and carbon (C) and nitrogen (N) losses, thereby contributing to soil degradation and climate change. To sustain the agricultural productivity of these organic soils, coverage with mineral soil material has increasingly been used. To evaluate the effect of this practice on th...

Supporting Information on "Organo-chemical characterisation of peat reveals decomposition of specific hemicellulose structures as main cause of organic matter loss in the acrotelm".

Peatlands store carbon in the form of dead organic residues. Climate change and human impact impose risks on the sustainability of the peatlands carbon balance due to increased peat decomposition. Here, we investigated molecular changes in the upper peat layers (0-40 cm), inferred from high-resolution vertical depth profiles, from a boreal peatland...

Zusammenfassung Rund 30 % der Fruchtfolgeflächen der Schweiz (137 000 ha) sind drainiert. Zunehmend stellt sich für die älteren Drainagen die Frage der Erneuerung und der entsprechenden Kostenfolgen. Gleichzeitig sind Feuchtlebensräume in der Agrarlandschaft durch die grossflächige Entwässerung selten geworden. Die Entwässerung beeinflusst verschie...

Terre assolée humide, périodiquement saturée d'eau jusqu'à la surface. (Photo: Thomas Walter, Agroscope) Résumé En Suisse, environ 30 % des surfaces d'assolement (137 000 ha) sont drainées. De plus en plus, la question de la rénovation des anciens drainages se pose et avec elle, celle des conséquences financières qui en découlent. Parallèlement, le...

Organic soils of intact peatlands store 1/4 of the global soil organic carbon (SOC). Despite being an important source of methane (CH4), they are climate coolers because they continuously accumulate new organic carbon. However, when these organic soils are drained for agriculture, the resulting aerobic conditions lead to fast decomposition of the p...

Reversibility of soil carbon sinks is a major obstacle in assigning soil carbon sequestration as negative emission technology and it is still unclear how a non-permanent CO2 removal shall be accounted for. In this study, we combine various scenarios of reversible and non-reversible soil carbon sinks with atmospheric CO2 impulse response functions a...

Atmospheric C sequestration in agricultural soils is viewed as one of the most promising negative emission technologies currently available. Nonetheless, it remains unclear how strongly soil organic carbon (SOC) stocks respond to agricultural practices, especially for subsoil. Here, we assess the SOC storage potential in croplands and how the prese...

Black carbon (BC) plays an important role in terrestrial carbon storage and can sustainably improve soil fertility. However, the accurate quantification of BC remains critical to fully unravelling the functions and dynamics of BC in soil. In this study, we explored the potential of differential scanning calorimetry (DSC) to identify, characterize a...

Peatland degradation is tightly connected to hydrological changes and microbial metabolism. To better understand these metabolism processes, more information is needed on how microbial communities and substrate cycling are affected by changing hydrological regimes. These activities should be imprinted in stable isotope bulk values (δ ¹⁵N, δ ¹³C) du...

Peatlands drained for agriculture emit large amounts of nitrous oxide (N2O) and thereby contribute to global warming. In order to counteract soil subsidence and sustain agricultural productivity, mineral soil coverage of drained organic soil is an increasingly used practice. This management option may also influence soil-borne N2O emissions. Unders...

Black carbon (BC) plays an important role in terrestrial carbon storage and can improve sustainably soil fertility. Nevertheless, the accurate quantification of BC remains a critical issue to fully unravel the functions and dynamics of BC in soil. In this work, we explored the potential of differential scanning calorimetry (DSC) to identify, charac...

The use of wood ash as an additive in biochar production was shown to increase biochar yields and was suggested to improve the recycling of ash-derived nutrients. However, there is limited knowledge on the interaction of ash addition with pyrolysis conditions and their effects on biochar yield and properties. Here, we performed experimental pyrolys...

The rapidly collapsing glacial systems of the Alps produced a large number of melt-water lakes and mires after the Last Glacial Maximum (LGM) in the Late Glacial period. The Rhone-Aare-glacier system gave rise to large moorlands and lakes in the region of the Three Lakes Region of Western Switzerland. When moorlands are formed, they are efficient s...

Aerobic decomposition increases in drained peatlands; releasing stored organic matter (OM) and shifting greenhouse gas fluxes from sink to source. This study explored how drainage influenced peat OM chemical composition by investigating paired sites from a Sphagnum-dominated ombrotrophic Finnish bog undergoing contrasting hydrological management (n...

Biochar is obtained by pyrolyzing biomass and is, by definition, applied in a way that avoids its rapid oxidation to CO2. Its use in agriculture includes animal feeding, manure treatment (e.g. as additive for bedding, composting, storage or anaerobic digestion), fertilizer component or direct soil application. Because the feedstock carbon is photos...

Peatland degradation impairs soil functions such as carbon storage and the existence of biodiversity hotspots. Therefore, and in view of the ongoing climate change, an efficient method of evaluating peatland hydrology and the success of restoration efforts is needed. To understand the role of microbial groups in biogeochemical cycling, gaseous loss...

The role of soils in the global carbon cycle and in reducing GHG emissions from agriculture has been increasingly acknowledged. The “4 per 1000” initiative (4p1000) has become a prominent action plan for climate change mitigation and achieve food security through an annual increase in soil organic carbon (SOC) stocks by 0.4 %, ( i.e. 4‰ per year)....

Drainage for agriculture has turned peatlands from a net sink to a net source of carbon (C). In order to reduce the environmental footprint of agricultural peatland drainage, and to counteract soil subsidence, mineral soil coverage is becoming an increasingly used practice in Switzerland. To explore the effect of mineral soil coverage on soil C los...

Water-table drawdown across peatlands increases carbon dioxide (CO2) and reduces methane (CH4) emissions. The net climatic effect remains unclear. Based on global observations from 130 sites, we found a positive (warming) net climate effect of water-table drawdown. Using a machine-learning-based upscaling approach, we predict that peatland water-ta...

To evaluate the sustainability of biomass plantations, effects on soil organic carbon (SOC) need to be quantified. Miscanthus × giganteus is increasingly used as a bioenergy plant, and it has been hypothesized that, after conversion from cropland, Miscanthus cropping increases SOC storage whereas conversion from grassland to Miscanthus provides, on...

A Correction to this paper has been published: https://doi.org/10.1038/s41558-021-00991-1.

The agricultural use of peatlands usually requires drainage, thereby transforming these organic soils from a net carbon sink into a net source. The Seeland region of Switzerland is characterised by fens that have been intensively used for agriculture for 150 years. Our site is a degraded fen with a remaining peat layer of 60 cm that had been used a...

All reports are available on the EJP SOIL homepage: https://ejpsoil.eu/knowledge-sharing-platform/reports-publications/roadmap-reports-publications/ This synthesis identifies the available knowledge of achievable carbon sequestration in mineral soils and GHGs mitigation in organic soils in agricultural land, including pasture/grassland across Euro...

The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidenc...

Understanding the processes underlying carbon (C) stability in soils is of utmost importance in the context of climate change. In this setting, biochar is often studied for its persistence in soils and reported to have positive impacts on soil fertility. Whilst recent research has mostly focused on the short-term effects of biochar amendments to so...

Intact peatlands serve as a globally important carbon sink. However, impacts from climate change, extraction, and drainage increase aerobic decomposition in these ecosystems—shifting their carbon flux from sink to source. A variety of projects are ongoing to restore peatlands to their natural or near-natural states; however, for carbon sequestratio...

Peatlands cover only about 3% the global land area, but store about twice as much carbon as global forest biomass. If intact peatlands are drained for agriculture or other human uses, peat oxidation can result in considerable CO2 emissions and other greenhouse gases (GHG) for decades or even centuries. Despite their importance, emissions from degra...

Sustainable soil carbon sequestration practices need to be rapidly scaled up and implemented to contribute to climate change mitigation. We highlight that the major potential for carbon sequestration is in cropland soils, especially those with large yield gaps and/or large historic soil organic carbon losses. The implementation of soil carbon seque...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

For centuries European peatlands have been degrading along with drainage, land use and climate changes. Increasing pressure on peatland ecosystems calls for a more cost-efficient method to indicate the current state of peatlands and the success of restoration efforts. Metabolic pathways in peatland soils are imprinted in stable isotope compositions...

To track changes in organic matter (OM) in peat soils, analytical techniques are needed that effectively characterize their chemical components. Pyrolysis-gas chromatography/mass spectrometry is a useful method for obtaining a chemical “fingerprint” of OM. To obtain representative fingerprints, the pyrolysis process should be highly reproducible an...

Peatlands accumulate organic matter (OM) under anaerobic conditions. After drainage for forestry or agriculture, microbial respiration and peat oxidation induce OM losses and change the stoichiometry of the remaining organic material. Here, we (i) evaluate whether land use (cropland CL, grassland GL, forest FL, natural peatland NL) is associated wi...

While many studies have measured the CO2 and N2O exchange of grassland ecosystems and analysed the influence of relevant drivers, only few reported the entire carbon budget over multiple years, which is most relevant for the net greenhouse gas (GHG) source or sink effect. When analysing eddy-covariance-based flux measurements for management and wea...

Abstract. During the last centuries major parts of European peatlands were degraded along with drainage and land use changes. Peatland biodiversity and essential ecosystem functions (e.g. flood prevention, groundwater purification and CO₂ sink) were dramatically impaired. Moreover, climate change threatens peatlands in the near future. I...

Context Globally, the intensive use of peatlands contributes substantially to greenhouse gas emissions. The intensification of peatland use has led to increasing carbon (C) losses over the last centuries, but without historical emissions data, these increases and cumulative emissions are difficult to quantify. Objectives To understand the magnitud...

Land-use change disturbs the function of peatland as a natural carbon sink and triggers high GHG emissions1. Nevertheless, historical trends and future trajectories of GHG budgets from soil do not explicitly include peatlands2,3. Here, we provide an estimate of the past and future role of global peatlands as either a source or sink of GHGs based on...

This report is the result of a stakeholder risk dialogue on atmospheric greenhouse gas removal. Participants were invited from a broad range of institutions and include CO2 removal (CDR) practitioners, NGOs, federal offices and industry. The neutral and independent Risk Dialogue Foundation carried out the project between March 2018 and July 2019. T...

Major common production activities on organic soils require drainage, which results in the loss of important ecosystem services such as carbon storage. This paper provides an overview of the farming situation on organic soils in a western region of Switzerland characterized by intensive vegetable farming and therefore by high opportunity costs of a...

The effect of biochar application on nitrous oxide (N2O) and carbon dioxide (CO2) emissions from an arable soil amended with maize leaves was studied in a laboratory experiment using soil samples collected from plots with three different fertiliser treatments: no fertilisation (CONT), mineral fertiliser (NPKMg) and farmyard manure (FYM), of a well...

Reducing greenhouse gas emissions from arable soil while maintaining productivity is a major challenge for agriculture. Biochar is known to reduce N2O emissions from soil, but the underlying mechanisms are unclear. This study examined the impact of green waste biochar (20 Mg ha−1) and lime (CaCO3; 2 Mg ha−1) application on soil gas transport proper...

Environmental changes significantly affect biodiversity, nutrient uptake and nutrient sources in peatlands. In formerstudies, we identified significant relationships of stable isotope signatures, particularly of nitrogen, and peatlandconditions (natural, disturbed, rewetted). We hypothesized that these changes were related to different micro bi-oti...

Rice Paddys on drainend soils might have the potential to be a sink for green house gases, when cultivated in disconituous flood irrigation, but elevated water level (palaudicultur) on peat soils, restoring partially the characteristics of wetlands.

Below ground carbon (BGC) inputs to soil, i.e. root biomass and rhizodeposition carbon (C), are among the most important variables driving soil C dynamics in agroecosystems. Hence, increasing BGC inputs to deep soil is a proposed strategy to sequester C in the long term. As BGC inputs are inherently difficult to measure in the field, they are usual...

Metal-blending of biomass prior to pyrolysis is investigated in this work as a tool to modify physico-chemical biochar properties and its behavior as adsorbent. Six different compounds were used for metal-blending: AlCl3, Cu(OH)2, FeSO4, KCl, MgCl2 and Mg(OH)2. Pyrolysis experiments were performed at 400 and 700 �C and the characterization of bioch...

The static chamber approach is often used for greenhouse gas (GHG) flux measurements, whereby the flux is deduced from the increase of species concentration after closing the chamber. Since this increase changes diffusion gradients between chamber air and soil air, a nonlinear increase is expected. Lateral gas flow and leakages also contribute to n...

N2O is a major greenhouse gas and the majority of anthropogenic N2O emissions originate from agriculturally managed soils. Therefore, developing N2O mitigation strategies is a key challenge for the agricultural sector and biochar soil treatment is one reported option. Biochar's capacity to increase soil pH and to foster activity of specialized N2O...

Soil carbon sequestration and avoidable emissions through peatland restoration are both strategies to tackle climate change. Here we compare their potential and environmental costs regarding nitrogen and land demand. In the event that no further areas are exploited, drained peatlands will cumulatively release 80.8 Gt carbon and 2.3 Gt nitrogen. Thi...

Nitrous oxide (N2O) contributes substantially to greenhouse gas (GHG) emissions in the agricultural and land-use sectors. Owing to the high effort needed for measuring N2O emissions and the resulting lack of sufficient field measurements to apply at country-wide scale, soil-borne N2O emissions are often estimated by applying published IPCC default...

Organic soils comprise a large yet fragile carbon (C) store in the global C cycle. Drainage, necessary for agriculture and forestry, triggers rapid decomposition of soil organic matter (SOM), typically increasing in the order forest < grassland < cropland. However, there is also large variation in decomposition due to differences in hydrological co...

Root biomass is the most commonly studied root parameter to investigate below ground crop response to environmental conditions and carbon cycling in agroecosystems. Root growth is strongly regulated by site-specific growth conditions and resource availability, but only little is known about the extent to which root biomass, vertical distribution, a...

Drainage and land-use are key factors that trigger CO2 emissions from cultivated organic soils. Drainage enhances aeration, and land-use might affect peat decomposition due to the input of fresh organic matter (FOM). The effect of FOM addition on peat decomposition of agriculturally used organic soils has seldom been quantified experimentally. In t...

Der Artikel enthält folgende Kapitel: Zusammenfassung Einleitung Menge und Eintragspfade der Streu in den Boden Qualität und Eigenschaften landwirtschaftlicher Streu Zusammensetzung und Abbaubarkeit der Streu Rhizodeposition Funktion der Streu landwirtschaftlicher Nutzflächen Nährstoffquelle für Kulturpflanzen und Bodenorganismen Streu als...

Pyrogenic carbon (PyC) derives from incomplete combustion of organic matter and is ubiquitous in terrestrial and aquatic systems. Most PyC is inherently more stable against decomposition than plant residues, and PyC therefore forms an important component of the global carbon (C) cycle. During the Holocene, about 436 Pg organic C accumulated in nort...

Quick Fire presentation

The application of dynamic models to report changes in soil organic carbon ( SOC ) stocks, for example as part of greenhouse gas inventories, is becoming increasingly important. Most of these models rely on input data from harvest residues or decaying plant parts and also organic fertilizer, together referred to as soil carbon inputs (C). The soil...

The close link between carbon (C) inputs to the soil and soil organic carbon (SOC) stocks is well documented for agroecosystems (Buyanovsky & Wagner 1998). Hence, correctly calculated and unbiased C inputs are critical for the study and interpretation of soil C dynamics. In a recent paper, Luo et al. (2017) demonstrate that SOC dynamics in agricult...

Palsas develop as permafrost aggradation uplifts peat out of the zone influenced by groundwater. Here we relate δ15N values to C/N ratios along depth profiles through palsas in two peatlands near Abisko, northern Sweden, to identify perturbation of the peat. The perturbation by uplift as well as the potential nutrient input from the adjacent hollow...

Peatlands store large amounts of soil organic carbon (SOC). Drainage, required for agriculture, aerates these organic soils and triggers rapid peat decomposition. In turn, cultivation of organic soils is also accompanied by input of young organic carbon (YOC) from plant residues. The extent to which YOC inputs compensate for oxidative peat loss is...

Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous cro...

Black carbon (BC) plays an important role in terrestrial carbon storage. Nevertheless, the effect of cultivation on long term dynamics of BC in soil has been poorly addressed. To fill this gap, we studied the chemical properties of charcoal particles extracted from preindustrial kilns in Wallonia, Belgium, along a chronosequence of land use change...