Call for Proposals: Grant-Supported Analysis of over 1,000 Greenhouse EW Experiment Soil & Biomass Samples

Written By Dirk Paessler

We need your support in unearthing enhanced weathering (EW) insights from a true scientific treasure! 

Since 2023, we are running the world’s largest greenhouse experiment for EW research near Fürth, Germany. Our first 2023/2024 wave of experiments consisted of 400 pot experiments combining 16 soils and 12 feedstocks in which we grew lolium perenne grass. Throughout the experiments’ lifetime, we collected the grass whenever it needed to be cut and we continuously monitored soil water leachate chemistry (monthly) and soil CO₂ efflux. We furthermore took multiple soil samples during the disassembly of these pots in early 2025.

Together, there are  more than 1,000 individual soil and biomass samples currently in our storage (see sample inventory list below). These samples potentially hold an enormous amount of insights on what happened in the soil columns during two years of enhanced weathering - but they are largely not yet analysed.

We have shared the data and insights from the leachate water analyses and CO2 efflux measurements in various blog posts and articles (see links below). While analysing these data and writing up the reports, it became clear that to truly understand the carbon transport and storage in our experiments we also need to study the soil and biomass samples. In depth analyses of these over 1,000 samples requires effort, expertise and time. We are looking for research collaborators to help us carry out such analyses.

Our current research results (foremost data from monthly leachate water analysis and CO₂ efflux measurements) do not allow us to fully track the whereabouts of the weathering products, mainly the cations, or any changes in soil carbon pools. We are interested in closing these knowledge gaps and believe that the soil samples (collected during dismantling of the experiment after 1 to 2 years of weathering) and biomass samples (collected over the whole two years) should contain most of the answers. You are hereby invited to submit research proposals for biomass and/or soil analyses that will shed light on processes relevant for carbon dioxide removal (CDR) through EW. This could include, for example, looking into the different soil (in)organic carbon pools, measuring cation contents in different soil phases, assessing plant nutrient and/or heavy metal contents in biomass samples.

Please see below for the link to an overview of the experiment setup. We offer soil samples (we have retained a few hundred grams, of which you could receive up to 100 g from an upper and lower part of roughly 20 cm of soil column of each replicate pot) and biomass samples (several tens to hundreds of grams, accumulated for each pot) from EW experiments that were running for up to 2 years. These will come with the info on experimental setup and starting materials, as well as financial support for the analyses, if necessary. We are open to consider both established and novel analytical approaches, but please do keep in mind that we do not have unlimited funds, or sample volumes, when writing up your research proposal. Per proposal/applicant the upper limits are 50.000 Euro and 100 g of soil per sample. Please make sure we are legally allowed to send you such samples (moving soils across borders is not without issues, as we found out recently).

There is one important requirement that we attach to our grants: You agree to have carried out most of the analyses and share at least preliminary data with us and the larger EW community at a virtual/hybrid conference that we will set up together with all other collaborators in May/June 2026. You also agree to open-access publish your results later in some appropriate form to the public (please include such costs in the justification of resources). Please note that we choose this somewhat tight timeline because of the urgency of the climate crisis which can’t wait forever for our understanding of enhanced weathering! 

The deadline for your proposal is October 24th, 2025. We are providing an Online Form where you can submit your application. We need your name, your institution, the amounts of soil/biomass samples you would need, the type of analyses you propose to carry out, a description of what insights you expect to get and a justification of the resources you might need (max. € 50.000 per proposal, max. 15% overhead) and what the analyses are. After careful review of the received proposals our scientific team aims to decide by Nov 15th which projects we want to go ahead with. From then onwards we will arrange delivery of the samples and financial support as soon as possible.

Here is the form for your submission:

https://prettyform.addxt.com/a/form/vf/1FAIpQLSempaycXokHDWmz_jrBU8r5gkgXd3uRYYEHUTpKK7zIEz39qw 

For any further questions you might have about our EW research project or to apply, please contact info@carbon-drawdown.de 

Links

Sample inventory (compact version)

SOIL SAMPLES

Each soil with its measured properties and the added treatments.  Each experiment was built with 4–7 replicates.

Standardised soils (agricultural soils from an agricultural research institute (LUFA)):

  • LUFA 2.1 — TIC Below Detection Limit (BDL), TOC 1.28 %, CEC 2.9, pH 4.60
    Treatments: Mafic 20/40/100 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • LUFA 2.2 (Batch 1) — TIC BDL, TOC 1.94 %, CEC 6.9, pH 5.50
    Treatments: Mafic 20/40/100 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • LUFA 2.2 (Batch 2) — TIC 0.01 %, TOC 1.97 %, CEC 7.4, pH 5.61
    Treatments: Limestone 10 t/ha; Mafic 40 t/ha; Ultramafic 40 t/ha;
            Industrial 40 t/ha; Glacial sediment 40 t/ha.

  • LUFA 6S (Batch 1)— TIC 0.26 %, TOC 1.46 %, CEC 21.9 meq/100 g, pH 7.30
    Treatments: Mafic 20/40/100 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • LUFA 6S (Batch 2) — TIC 0.37 %, TOC 2.05 %, CEC 24.2, pH 7.31
    Treatments: Limestone 10 t/ha; Mafic 40 t/ha; Ultramafic 40 t/ha;
            Industrial 40 t/ha.

Fürth soils:

  • Fürth 1 (Batch 1) — TIC 0.15 %, TOC 1.08 %, CEC 6.4, pH 7.45
    Treatments: Mafic 20/40/100/200/400 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • Fürth 2 (Batch 2) — TIC 0.14 %, TOC 0.97 %, CEC 7.3, pH 7.69
    Treatments: Divers Mafic 40/100/200/400 t/ha; Divers Ultramafic 40 t/ha; Industrial 40 t/ha.

Farmer soils (8 distinct) — each tested as Control and Mafic 40 t/ha:

  • Farmer 1 — TIC BDL, TOC 1.64 %, CEC 6.8, pH 6.10

  • Farmer 2 — TIC BDL, TOC 1.05 %, CEC 7.6, pH 6.10

  • Farmer 3 — TIC 2.94 %, TOC 1.63 %, CEC 12.7, pH 7.30

  • Farmer 4— TIC 0.30 %, TOC 2.75 %, CEC 26.3, pH 7.30

  • Farmer 5 — TIC 0.11 %, TOC 1.14 %, CEC 6.6, pH 5.80

  • Farmer 8 — TIC BDL, TOC 1.43 %, CEC 9.5, pH 6.70

  • Farmer 9 — TIC BDL, TOC 0.88 %, CEC 10.8, pH 6.50

  • Farmer 10 — TIC BDL, TOC 1.04 %, CEC 4.1, pH 6.10

Short version of all experiments (feedstocks) across the trials:

  • Controls for every soil.

  • Mafic rocks widely tested (20–400 t/ha, most commonly 40 t/ha; high-rate sets at 100/200/400 t/ha in Fürth and LUFA columns).

  • Ultramafic rock 40 t/ha on LUFA 6S/2.1/2.2 and Fürth.

  • Industrial material 40 t/ha on LUFA 6S/2.1/2.2 and Fürth.

  • Calcite 10 t/ha on LUFA 6S (batch 2) and LUFA 2.2 (batch 2).

  • Glacial sediment 40 t/ha on LUFA 2.2 (batch 2).

Biomass samples

Biomass (Lolium perenne) was cut, dried at 40 °C, and stored in paper bags. We only have a total bulk sample of all cutting events over the entire time. Grass samples are available for the following experiments:

Standardised soils (agricultural soils from an Agricultural Research Institute (LUFA)):

  • LUFA 2.1 — TIC Below Detection Limit (BDL), TOC 1.28 %, CEC 2.9, pH 4.60
    Experiments: Control; Mafic 20/40/100 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • LUFA 2.2 (Batch 1) — TIC BDL, TOC 1.94 %, CEC 6.9, pH 5.50
    Experiments: Control; Mafic 20/40/100 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • LUFA 2.2 (Batch 2) — TIC 0.01 %, TOC 1.97 %, CEC 7.4, pH 5.61
    Experiments: Control; Limestone 10 t/ha; Mafic 40 t/ha; Ultramafic 40 t/ha;
            Industrial 40 t/ha; Glacial sediment 40 t/ha.

  • LUFA 6S (Batch 1)— TIC 0.26 %, TOC 1.46 %, CEC 21.9 meq/100 g, pH 7.30
    Experiments: Control; Mafic 20/40/100 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

  • LUFA 6S (Batch 2) — TIC 0.37 %, TOC 2.05 %, CEC 24.2, pH 7.31
    Experiments: Control; Limestone 10 t/ha; Mafic 40 t/ha; Ultramafic 40 t/ha;
            Industrial 40 t/ha.

Fürth soil:

  • Fürth 1 (Batch 1) — TIC 0.15 %, TOC 1.08 %, CEC 6.4, pH 7.45
    Experiments: Control; Mafic 20/40/100/200/400 t/ha; Metabasalt (with
            27% calcite) 40 t/ha ; Ultramafic 40 t/ha; Industrial 40 t/ha.

Dirk Paessler
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