Institut für Bodenkunde und Standortslehre

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Soil phosphorus status and P nutrition strategies of European beech forests on carbonate compared to silicate parent material
(2022) Prietzel, Jörg; Krüger, Jaane; Kaiser, Klaus; Amelung, Wulf; Bauke, Sara L.; Dippold, Michaela A.; Kandeler, Ellen; Klysubun, Wantana; Lewandowski, Hans; Löppmann, Sebastian; Luster, Jörg; Marhan, Sven; Puhlmann, Heike; Schmitt, Marius; Siegenthaler, Maja B.; Siemens, Jan; Spielvogel, Sandra; Willbold, Sabine; Wolff, Jan; Lang, Friederike
Sustainable forest management requires understanding of ecosystem phosphorus (P) cycling. Lang et al. (2017) [Biogeochemistry,https://doi.org/10.1007/s10533-017-0375-0] introduced the concept of P-acquiring vs. P-recycling nutrition strategies for European beech (Fagus sylvatica L.) forests on silicate parent material, and demonstrated a change from P-acquiring to P-recycling nutrition from P-rich to P-poor sites. The present study extends this silicate rock-based assessment to forest sites with soils formed from carbonate bedrock. For all sites, it presents a large set of general soil and bedrock chemistry data. It thoroughly describes the soil P status and generates a comprehensive concept on forest ecosystem P nutrition covering the majority of Central European forest soils. For this purpose, an Ecosystem P Nutrition Index (ENIP) was developed, which enabled the comparison of forest P nutrition strategies at the carbonate sites in our study among each other and also with those of the silicate sites investigated by Lang et al. (2017). The P status of forest soils on carbonate substrates was characterized by low soil P stocks and a large fraction of organic Ca-bound P (probably largely Ca phytate) during early stages of pedogenesis. Soil P stocks, particularly those in the mineral soil and of inorganic P forms, including Al- and Fe-bound P, became more abundant with progressing pedogenesis and accumulation of carbonate rock dissolution residue. Phosphorus-rich impure, silicate-enriched carbonate bedrock promoted the accumulation of dissolution residue and supported larger soil P stocks, mainly bound to Fe and Al minerals. In carbonate-derived soils, only low P amounts were bioavailable during early stages of pedogenesis, and, similar to P-poor silicate sites, P nutrition of beech forests depended on tight (re)cycling of P bound in forest floor soil organic matter (SOM). In contrast to P-poor silicate sites, where the ecosystem P nutrition strategy is direct biotic recycling of SOM-bound organic P, recycling during early stages of pedogenesis on carbonate substrates also involves the dissolution of stable Ca-Porg precipitates formed from phosphate released during SOM decomposition. In contrast to silicate sites, progressing pedogenesis and accumulation of P-enriched carbonate bedrock dissolution residue at the carbonate sites promote again P-acquiring mechanisms for ecosystem P nutrition.
Correction to “The stonesphere in agricultural soils: a microhabitat associated with rock fragments bridging rock and soil”
(2025) Dittrich, Felix; Klaes, Björn; Brandt, Luise; Groschopf, Nora; Thiele‐Bruhn, Sören
The stonesphere in agricultural soils: a microhabitat associated with rock fragments bridging rock and soil
(2024) Dittrich, Felix; Klaes, Björn; Brandt, Luise; Groschopf, Nora; Thiele‐Bruhn, Sören
Rock fragments (RFs) are abundant soil constituents, but are routinely excluded from soil analyses. Hence, their contribution to soil properties, and in particular to the microbiome, is incompletely understood. Therefore, shifts in microbial colonisation along the rock‐to‐soil continuum of topsoils from three agricultural sites with different sedimentary parent rock materials were investigated with particular attention to RFs. Microbial biomass and community composition were quantified using phospholipid fatty acid (PLFA) analysis for unweathered and weathered parent rock materials, two RF fractions (8–16 mm and 2–8 mm) and the fine earth (FE; <2 mm). Trends in biogeochemical weathering, nutrient availability and soil organic matter (OM) development were assessed using mineralogical, geochemical and physical analyses. Actinobacterial PLFA was particularly abundant in parent rocks, where Actinobacteria likely contribute to rock weathering and the initiation of OM accumulation. Conversely, bacterial PLFAs were most abundant in the FE under nutrient‐ and OM‐rich conditions. The integral role of RFs as a microbial habitat is demonstrated by a distinct fungal colonisation, which is enabled by the specific physical features of RFs in combination with the provision of inorganic nutrients. Our findings indicate that RFs are colonised by microbes and that differences in the community structure depend on mineralogical properties and chemical weathering status. We document that RFs are microhabitats with a significant potential to host microbial life in cultivated soils, and thus, could play an important role in biogeochemical cycling and the provision of soil functions in agroecosystems.
Bias correction and trend analysis of temperature and rainfall in Eastern India
(2024) Srivastava, Rajiv Kumar; Sadhukhan, Biplab; Chakraborty, Arun; Panda, Rabindra Kumar
In this study trend analysis and bias correction have been done for dry (January–May) and wet (June–September) seasons under two future climate period 2021–2050 and 2051–2080 with respect to the current climate period 1980–2012 in Eastern India. The different representative concentration pathways (RCPs) of 2.6, 4.5, 6.0, and 8.5 were used to assess the future trend of the study area. Results indicate that the increasing RCP increases temperature (maximum and minimum) in all regions due to higher radiative forces (4–8.5 W/m 2 ) with respect to the baseline temperature during the period 2051–2080. Further, the bias-corrected rainfall has a declined trend with respect to baseline, and RCP’s values for both the time slices (2021–2050 and 2051–2080) showed less scattering in the amount of rainfall for the wet season in comparison to the dry season.
Correction to: An overall review on influence of root architecture on soil carbon sequestration potential
(2025) Srivastava, R. K.; Yetgin, Ali
An overall review on influence of root architecture on soil carbon sequestration potential
(2024) Srivastava, R. K.; Yetgin, Ali
Soil carbon sequestration is a vital ecosystem function that mitigates climate change by absorbing atmospheric carbon dioxide (CO2). Root characteristics such as depth, diameter, length, and branching pattern affect soil carbon dynamics through root-soil interactions and organic matter breakdown. Here we review field surveys, laboratory analysis, and mathematical modeling to understand how root structures affect soil carbon storage. Further, certain root features increase soil carbon sequestration, suggesting that selective breeding and genetic engineering of plants could maximize this ecological benefit. However, more research is needed to understand the complex interactions between roots, soil biota, and soil organic matter under changing environmental conditions. In addition, the benefit of climate change mitigation methods and soil carbon models from the inclusion of root architecture was reviewed. Studies in the realm of root-soil interactions encompass a variety of academic fields, including agronomy, ecology, soil science, and plant physiology. Insights into how roots interact with their soil environment and the effects of these interactions on plant health, agricultural productivity, and environmental sustainability have been gained through this research.
A slow-fast trait continuum at the whole community level in relation to land-use intensification
(2024) Neyret, Margot; Le Provost, Gaëtane; Boesing, Andrea Larissa; Schneider, Florian D.; Baulechner, Dennis; Bergmann, Joana; de Vries, Franciska T.; Fiore-Donno, Anna Maria; Geisen, Stefan; Goldmann, Kezia; Merges, Anna; Saifutdinov, Ruslan A.; Simons, Nadja K.; Tobias, Joseph A.; Zaitsev, Andrey S.; Gossner, Martin M.; Jung, Kirsten; Kandeler, Ellen; Krauss, Jochen; Penone, Caterina; Schloter, Michael; Schulz, Stefanie; Staab, Michael; Wolters, Volkmar; Apostolakis, Antonios; Birkhofer, Klaus; Boch, Steffen; Boeddinghaus, Runa S.; Bolliger, Ralph; Bonkowski, Michael; Buscot, François; Dumack, Kenneth; Fischer, Markus; Gan, Huei Ying; Heinze, Johannes; Hölzel, Norbert; John, Katharina; Klaus, Valentin H.; Kleinebecker, Till; Marhan, Sven; Müller, Jörg; Renner, Swen C.; Rillig, Matthias C.; Schenk, Noëlle V.; Schöning, Ingo; Schrumpf, Marion; Seibold, Sebastian; Socher, Stephanie A.; Solly, Emily F.; Teuscher, Miriam; van Kleunen, Mark; Wubet, Tesfaye; Manning, Peter
Organismal functional strategies form a continuum from slow- to fast-growing organisms, in response to common drivers such as resource availability and disturbance. However, whether there is synchronisation of these strategies at the entire community level is unclear. Here, we combine trait data for >2800 above- and belowground taxa from 14 trophic guilds spanning a disturbance and resource availability gradient in German grasslands. The results indicate that most guilds consistently respond to these drivers through both direct and trophically mediated effects, resulting in a ‘slow-fast’ axis at the level of the entire community. Using 15 indicators of carbon and nutrient fluxes, biomass production and decomposition, we also show that fast trait communities are associated with faster rates of ecosystem functioning. These findings demonstrate that ‘slow’ and ‘fast’ strategies can be manifested at the level of whole communities, opening new avenues of ecosystem-level functional classification.
Quantification of soil microbial functional genes as potential new method in environmental risk assessment of pesticides
(2025) Stache, Fabian; Ditterich, Franziska; Hochmanová, Zuzana; Hofman, Jakub; Poll, Christian; Kandeler, Ellen
Pesticides can have adverse effects on soil microorganisms, but they are underrepresented in the currently required OECD 216 test for environmental risk assessment of plant protection products (PPP). The guideline monitors soil microbial nitrogen transformation over 28 days, potentially missing long-term effects of persistent pesticides. Additionally, nitrate alone may be not sensitive enough to detect disruptions in microbial functions. We investigated whether functional gene analysis could provide a more sensitive bioindicator of pesticide impact. To compare this method with the standard test, we conducted a microcosm experiment following the OECD 216 experimental setup. To capture long-term effects beyond the typical test period, we extended the incubation duration to 56 days. Four different concentrations of the persistent fungicide boscalid were added based on predicted environmental concentration. We also assessed microbial responses to fungicide exposure by measuring classical soil microbial parameters. According to the standard test, boscalid had no harmful long-term effects on soil microbiota. In contrast, our analysis of functional genes found an overall reduction in the acid phosphatase-encoding phoN gene abundance on Day 56, and correspondingly, in acid phosphatase activity in the highest fungicide treatment. Simultaneously, we observed a tendency towards lower fungal abundance based on measured copy numbers of an ITS region of nuclear ribosomal DNA (rDNA) and increased cumulative CO2 production. These results indicate a fungicide-related response of the microbial community and impaired microbial phosphorus cycling. Extending the experimental period to 56 days revealed long-term effects that would have otherwise been undetected under the typical 28-day test duration.
Spatiotemporal climatic signals in cereal yield variability and trends in Ethiopia
(2025) Abera, Kidist; Gayler, Sebastian; Piepho, Hans‑Peter; Streck, Thilo
Climatic variability and recurrent drought can strongly affect the variability of crop yield and are therefore frequently considered a risk to food security in Ethiopia. A better understanding of how crop yields vary in space and time, and their relationship to climatic and other driving factors, can assist in enhancing agricultural production and adapting to and mitigating the impacts of climate change. We applied a multiple linear regression model to examine the spatiotemporal climatic signal (air temperature, precipitation, and solar radiation) in the yields of the most important crops (maize, sorghum, tef, and wheat) over the period 1995–2018. An analysis of the climatic data indicated that growing season temperature increased significantly in most regions, but the trends in precipitation were not significant. The yields of maize, sorghum, tef, and wheat tended to increase across most crop-growing areas, particularly in the west, but was highly variable. The results highlight large spatial differences in the contribution of climatic trends to crop-yield variability across Ethiopian regions. The trends in climatic variability did not significantly affect crop yields in some areas, whereas in the main crop-growing areas, up to − 39.2% of yield variability could be attributed to the climatic trends. Specifically, the climatic trends negatively affected maize yields but positively affected sorghum, tef, and wheat yields. Nationally, the average impacts of climatic trends on crop yields was relatively small, ranging from a 3.2% decrease for maize to a 0.7% increase for wheat. In contrast, technological advancements contributed substantially more to yield gains, with annual increases ranging from 4.3% for wheat to 5.1% for sorghum. These findings highlight the dominant role of non-climatic drivers, particularly improved agricultural technology, in shaping crop yield trends. Our findings underscore the spatial heterogeneity of climate impacts on agriculture and highlight the critical importance of technological progress in enhancing crop productivity. They also provide actionable insights for designing crop- and location-specific adaptation strategies, and stress the need for integrated, climate-resilient development pathways in the region.
A global database of soil microbial phospholipid fatty acids and enzyme activities
(2025) van Galen, Laura G.; Smith, Gabriel Reuben; Margenot, Andrew J.; Waldrop, Mark P.; Crowther, Thomas W.; Peay, Kabir G.; Jackson, Robert B.; Yu, Kailiang; Abrahão, Anna; Ahmed, Talaat A.; Alatalo, Juha M.; Anslan, Sten; Anthony, Mark A.; Araujo, Ademir Sergio Ferreira; Ascher-Jenull, Judith; Bach, Elizabeth M.; Bahram, Mohammad; Baker, Christopher C. M.; Baldrian, Petr; Bardgett, Richard D.; Barrios-Garcia, M. Noelia; Bastida, Felipe; Beggi, Francesca; Benning, Liane G.; Bragazza, Luca; Broadbent, Arthur A. D.; Cano-Díaz, Concha; Cates, Anna M.; Cerri, Carlos E. P.; Cesarz, Simone; Chen, Baodong; Classen, Aimeé T.; Dahl, Mathilde Borg; Delgado-Baquerizo, Manuel; Eisenhauer, Nico; Evgrafova, Svetlana Yu.; Fanin, Nicolas; Fornasier, Flavio; Francisco, Romeu; Franco, André L. C.; Frey, Serita D.; Fritze, Hannu; García, Carlos; García-Palacios, Pablo; Gómez-Brandón, María; Gonzalez-Polo, Marina; Gozalo, Beatriz; Griffiths, Robert; Guerra, Carlos; Hallama, Moritz; Hiiesalu, Inga; Hossain, Mohammad Zabed; Hu, Yajun; Insam, Heribert; Jassey, Vincent E. J.; Jiang, Lili; Kandeler, Ellen; Kohout, Petr; Kõljalg, Urmas; Krashevska, Valentyna; Li, Xiaofei; Lu, Jing-Zhong; Lu, Xiankai; Luo, Shan; Lutz, Stefanie; Mackie-Haas, Kathleen Allison; Maestre, Fernando T.; Malmivaara-Lämsä, Minna; Mangelsdorf, Kai; Manjarrez, Maria; Marhan, Sven; Martin, Ashley; Mason, Kelly E.; Mayor, Jordan; McCulley, Rebecca L.; Moora, Mari; Morais, Paula V.; Muñoz-Rojas, Miriam; Murugan, Rajasekaran; Nottingham, Andrew T.; Ochoa, Victoria; Ochoa-Hueso, Raúl; Oja, Jane; Olsson, Pål Axel; Öpik, Maarja; Ostle, Nick; Peltoniemi, Krista; Pennanen, Taina; Pescador, David S.; Png, G. Kenny; Poll, Christian; Põlme, Sergei; Potapov, Anton M.; Priemé, Anders; Pritchard, William; Puissant, Jeremy; Rocha, Sandra Mara Barbosa; Rosinger, Christoph; Ruess, Liliane; Sayer, Emma J.; Scheu, Stefan; Sinsabaugh, Robert L.; Slaughter, Lindsey C.; Soudzilovskaia, Nadejda A.; Sousa, José Paulo; Stanish, Lee; Sugiyama, Shu-ichi; Tedersoo, Leho; Trivedi, Pankaj; Vahter, Tanel; Voriskova, Jana; Wagner, Dirk; Wang, Cong; Wardle, David A.; Whitaker, Jeanette; Yang, Yuanhe; Zhong, Zhiwei; Zhu, Kai; Ziolkowski, Lori A.; Zobel, Martin; van den Hoogen, Johan
Soil microbes drive ecosystem function and play a critical role in how ecosystems respond to global change. Research surrounding soil microbial communities has rapidly increased in recent decades, and substantial data relating to phospholipid fatty acids (PLFAs) and potential enzyme activity have been collected and analysed. However, studies have mostly been restricted to local and regional scales, and their accuracy and usefulness are limited by the extent of accessible data. Here we aim to improve data availability by collating a global database of soil PLFA and potential enzyme activity measurements from 12,258 georeferenced samples located across all continents, 5.1% of which have not previously been published. The database contains data relating to 113 PLFAs and 26 enzyme activities, and includes metadata such as sampling date, sample depth, and soil pH, total carbon, and total nitrogen. This database will help researchers in conducting both global- and local-scale studies to better understand soil microbial biomass and function.
Estimating effects of ocean environmental conditions on summer flounder (Paralichthys dentatus) distribution
(2025) Deen, Samar; Jauss, Verena; Sullivan, Patrick J.
The relative abundance of summer flounder ( Paralichthys dentatus ) differs over space and time with changes in environmental factors, such as depth, bottom temperature, sea surface temperature (SST) and bottom salinity. We use the integrated nested Laplace approximation (INLA) approach to account for the random effects arising from either over-dispersion, or spatial and temporal autocorrelation. We explore how the different assumptions in the spatial temporal models result in varying model predictions. The results indicate that the distribution of summer flounder is correlated with depth, regional increases in bottom temperature, SST and bottom salinity. We find that in the Fall relative abundance increased 10–15% with a 1∘C increase in SST, by 12% with each 1∘C increase in bottom temperature and 3–4% with each meter increase in depth across all models. In the spring, relative abundance increased by about 30% with each 1∘C increase in SST with an upper preferred temperature between 10-20∘C. Our study also shows that models that include spatio-temporally correlated variables can inadvertently be over parameterized when including higher order interaction terms between spatial and temporal random effects. This can lead to inflated variances in the estimates and predictions as well as lengthening model convergence times. Therefore, care should be taken in identifying the level of model complexity given the indirect implications of these results on fisheries management and marine ecology.
Drought impacts on plant–soil carbon allocation - integrating future mean climatic conditions
(2025) Leyrer, Vinzent; Blum, Juliette; Marhan, Sven; Kandeler, Ellen; Zimmermann, Telse; Berauer, Bernd J.; Schweiger, Andreas H.; Canarini, Alberto; Richter, Andreas; Poll, Christian
Droughts affect soil microbial abundance and functions—key parameters of plant–soil carbon (C) allocation dynamics. However, the impact of drought may be modified by the mean climatic conditions to which the soil microbiome has previously been exposed. In a future warmer and drier world, effects of drought may therefore differ from those observed in studies that simulate drought under current climatic conditions. To investigate this, we used the field experiment ‘Hohenheim Climate Change,’ an arable field where predicted drier and warmer mean climatic conditions had been simulated for 12 years. In April 2021, we exposed this agroecosystem to 8 weeks of drought with subsequent rewetting. Before drought, at peak drought, and after rewetting, we pulse‐labelled winter wheat in situ with 13CO2 to trace recently assimilated C from plants to soil microorganisms and back to the atmosphere. Severe drought decreased soil respiration (−35%) and abundance of gram‐positive bacteria (−15%) but had no effect on gram‐negative bacteria, fungi, and total microbial biomass C. This pattern was not affected by the mean precipitation regime to which the microbes had been pre‐exposed. Reduced mean precipitation had, however, a legacy effect by decreasing the proportion of recently assimilated C allocated to the microbial biomass C pool (−50%). Apart from that, continuous soil warming was an important driver of C fluxes throughout our experiment, increasing plant biomass, root sugar concentration, labile C, and respiration. Warming also shifted microorganisms toward utilizing soil organic matter as a C source instead of recently assimilated compounds. Our study found that moderate shifts in mean precipitation patterns can impose a legacy on how plant‐derived C is allocated in the microbial biomass of a temperate agroecosystem during drought. The overarching effect of soil warming, however, suggests that how temperate agroecosystems respond to drought will mainly be affected by future temperature increases.
High-resolution CMIP6 climate projections for Ethiopia using the gridded statistical downscaling method
(2023) Rettie, Fasil M.; Gayler, Sebastian; Weber, Tobias K. D.; Tesfaye, Kindie; Streck, Thilo
High-resolution climate model projections for a range of emission scenarios are needed for designing regional and local adaptation strategies and planning in the context of climate change. To this end, the future climate simulations of global circulation models (GCMs) are the main sources of critical information. However, these simulations are not only coarse in resolution but also associated with biases and high uncertainty. To make the simulations useful for impact modeling at regional and local level, we utilized the bias correction constructed analogues with quantile mapping reordering (BCCAQ) statistical downscaling technique to produce a 10 km spatial resolution climate change projections database based on 16 CMIP6 GCMs under three emission scenarios (SSP2-4.5, SSP3-7.0, and SSP5-8.5). The downscaling strategy was evaluated using a perfect sibling approach and detailed results are presented by taking two contrasting (the worst and best performing models) GCMs as a showcase. The evaluation results demonstrate that the downscaling approach substantially reduced model biases and generated higher resolution daily data compared to the original GCM outputs.
Effects of Bacillus spp. inoculation on suggested shoot tolerance mechanisms in lowland rice (Oryza sativa L.) grown under iron toxicity
(2025) Weinand, Tanja; Asch, Julia; Asch, Folkard
Background: In areas of lowland rice production, high iron concentrations in the soil often lead to yield reductions. Local adapted varieties possess different adaptation mechanisms, which, however, are not fully understood. Previous studies have shown that endophytic bacteria can influence plant tolerance to abiotic stresses, including iron toxicity. Aim: This study aims at analyzing the effects of different Bacillus isolates on distinct shoot tolerance mechanism in different rice cultivars grown under iron toxicity. Methods: Three lowland rice cultivars, varying in their tolerance against iron toxicity (IR31785‐58‐1‐2‐3‐3, Sahel 108, Suakoko 8), were inoculated with three Bacillus strains (two of B. pumilus and one of B. megaterium ). One week after Bacillus inoculation plants were subjected to high iron levels (1000 ppm) for 7 days. Leaf symptom scoring was used to assess tolerance levels. Activities of ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (PRX) were measured by spectrophotometric assays. Transcription of genes related to iron toxicity ( OsFER, OsFRO1, OsNRAMP6 ) was determined by RT‐qPCR. Bacterial production of NO was evaluated by measuring nitrite levels in the culture supernatants. Results: In general, iron toxicity affected the activities of APX, GR, CAT, and PRX but not SOD activity. Only PRX activity in response to iron differed between cultivars with a significantly stronger increase in IR31785‐58‐1‐2‐3‐3. Inoculation with B. pumilus Ni9MO12 led to higher activity of CAT in the leaf sheaths of all cultivars and an increase in GR activity in the sheaths that was significantly higher in Suakoko 8. In the young leaf blades of IR31785‐58‐1‐2‐3‐3, transcription of OsFRO1 and OsNRAMP6 was not significantly affected by Bacillus inoculation, whereas accumulation of OsFER mRNA was significantly higher in iron‐stressed, B. pumilus Ni9MO12 inoculated plants compared to non‐inoculated, non‐iron‐stressed plants. Nitrite concentration as an indicator for NO production was increased in B. pumilus Ni9MO12 culture supernatants. Conclusion: Our results show that in the sensitive cultivar IR31785‐58‐1‐2‐3‐3 tolerance to iron toxicity increases when inoculated with B. pumilus Ni9MO12, coinciding with higher levels of ferritin transcription. NO production by the Bacillus isolate might confer the promotion of OsFER gene transcription in the inoculated plants.
Effects of MCPA and difenoconazole on glyphosate degradation and soil microorganisms
(2024) Mäder, Philipp; Stache, Fabian; Engelbart, Lisa; Huhn, Carolin; Hochmanová, Zuzana; Hofman, Jakub; Poll, Christian; Kandeler, Ellen
Modern agriculture relies heavily on pesticide use to meet the demands of food quality and quantity. Therefore, pesticides are often applied in mixtures, leading to a diverse cocktail of chemicals and their metabolites in soils, which can affect non-target organisms such as soil microorganisms. Pesticides are tested for their single effects, but studies on their interactive effects are scarce. This study aimed to determine the effects of up to three simultaneously applied pesticides on the soil microbial community and on their special function in pesticide degradation. Agricultural soil without previous pesticide application was exposed to different mixtures of the herbicide glyphosate (GLP), the phenoxy herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid) and the fungicide difenoconazole (DFC) for up to 56 days. Isotopic and molecular methods were used to investigate effects of the mixtures on the microbial community and to follow the mineralization and utilization of GLP. An initial increase in the metabolic quotient by up to 35 % in the presence of MCPA indicated a stress reaction of the microbial community. The presence of multiple pesticides reduced both gram positive bacterial fatty acid methyl esters (FAMEs) by 13 % and the abundance of microorganisms with the genetic potential for GLP degradation via the AMPA (aminomethylphosphonic acid) pathway. Both the number of pesticides and the identities of individual pesticides played major roles. Surprisingly, an increase in 13C-labelled GLP mineralization of up to 40 % was observed while carbon use efficiency (CUE) decreased. Interactions between multiple pesticides might alter the behavior of individual pesticides and be reflected in the microbial community. Our results highlight the importance of investigating not only single pesticides, but also pesticide mixtures and their interactions.
Spatiotemporal climate variability and food security implications in the Central Ethiopia Region
(2024) Senbeta, Abate Feyissa; Worku, Walelign; Gayler, Sebastian
Studies focusing on the spatiotemporal distribution of climatic parameters and meteorological drought are of paramount significance for countries like Ethiopia, where climate change and variability cause major losses to rain-dependent agriculture. In this study, the National Meteorology Institute of Ethiopia provided an Enhanced National Climate Services (ENACTS) dataset at a spatial resolution of approximately 4 km by 4 km over 38 years (1981–2018) was used to study climate trends, spatiotemporal variability, and meteorological drought in the Central Ethiopia Region. Coefficient of variation (CV), Standardized Rainfall Anomaly (SRA), Standardized Precipitation Index (SPI), Mann-Kendall trend test, and Sen's slope were used for the analysis. The findings suggest that Belg rainfall (also known as "small-rain") varied greatly in space and time over the study area, with area-averaged CV of 29 % and pixel-level CVs ranging from 63 to 93 %. The average precipitation during Belg experienced a 15 % decrease from 2000 to 2019 compared to the preceding two decades, from 1981 to 1999. The maximum temperature has increased significantly during the Annual, Belg, and Bega seasons. The SPI and SRA showed that there have been multiple drought episodes with rising negative rainfall anomalies, with a drought occurring every 2.9 years during the Kiremt (also called "big rain", spanning from June to September) and Belg seasons. The growing negative rainfall anomaly, high CV, and highly significant increase in mean maximum temperature during the Belg season is concerning for food security and poverty eradication. The notable rise in rainfall during the June (sowing period) and November (harvesting period) also hurts crop production during the main cropping season. Thus, developing appropriate adaptation strategies and policies oriented toward climate-resilient agriculture is crucial to meet the global sustainable development goals (SDGs) and Africa Union's Agenda 2063.
Revisiting soil fungal biomarkers and conversion factors: interspecific variability in phospholipid fatty acids, ergosterol and rDNA copy numbers
(2024) Camenzind, Tessa; Haslwimmer, Heike; Rillig, Matthias C.; Ruess, Liliane; Finn, Damien R.; Tebbe, Christoph C.; Hempel, Stefan; Marhan, Sven
Refined conversion factors for soil fungal biomarkers are proposed. High interspecific variability is present in all fungal biomarkers. A modeling approach supports the validity of biomarker estimates in diverse soils. ITS1 copies vary strongly, but are fungal-specific with least phylogenetic bias. A combination of fungal biomarkers will reveal soil fungal physiology and activity. The abundances of fungi and bacteria in soil are used as simple predictors for carbon dynamics, and represent widely available microbial traits. Soil biomarkers serve as quantitative estimates of these microbial groups, though not quantifying microbial biomass per se. The accurate conversion to microbial carbon pools, and an understanding of its comparability among soils is therefore needed. We refined conversion factors for classical fungal biomarkers, and evaluated the application of quantitative PCR (qPCR, rDNA copies) as a biomarker for soil fungi. Based on biomarker contents in pure fungal cultures of 30 isolates tested here, combined with comparable published datasets, we propose average conversion factors of 95.3 g fungal C g −1 ergosterol, 32.0 mg fungal C µmol −1 PLFA 18:2ω6,9 and 0.264 pg fungal C ITS1 DNA copy −1 . As expected, interspecific variability was most pronounced in rDNA copies, though qPCR results showed the least phylogenetic bias. A modeling approach based on exemplary agricultural soils further supported the hypothesis that high diversity in soil buffers against biomarker variability, whereas also phylogenetic biases impact the accuracy of comparisons in biomarker estimates. Our analyses suggest that qPCR results cover the fungal community in soil best, though with a variability only partly offset in highly diverse soils. PLFA 18:2ω6,9 and ergosterol represent accurate biomarkers to quantify Ascomycota and Basidiomycota . To conclude, the ecological interpretation and coverage of biomarker data prior to their application in global models is important, where the combination of different biomarkers may be most insightful.
Dependence of the abundance of reed glass-winged cicadas (Pentastiridius leporinus (Linnaeus, 1761)) on weather and climate in the Upper Rhine Valley, Southwest Germany
(2025) Kakarla, Sai Kiran; Schall, Eric; Dettweiler, Anna; Stohl, Jana; Glaser, Elisabeth; Adam, Hannah; Teubler, Franziska; Ingwersen, Joachim; Sauer, Tilmann; Piepho, Hans-Peter; Lang, Christian; Streck, Thilo; Guo, Jianying
The planthopper Pentastiridius leporinus , commonly called reed glass-winged cicada, transmits the pathogens “ Candidatus Arsenophonus phytopathogenicus” and “ Candidatus Phytoplasma solani”, which are infesting sugar beet and, most recently, also potato in the Upper Rhine valley area of Germany. They cause the “Syndrome Basses Richesses” associated with reduced yield and sugar content in sugar beet, leading to substantial monetary losses to farmers in the region. No effective solutions exist currently. This study uses statistical models to understand to what extent the abundance of cicadas depends on climate regions during the vegetation period (April–October). We further investigated what influence temperature and precipitation have on the abundance of the cicadas in sugar beet fields. Furthermore, we investigated the possible impacts of future climate on cicada abundance. Also, 22 °C and 8 mm/day were found to be the optimal temperature and precipitation conditions for peak male cicada flight activity, while 28 °C and 8 mm/day were the optimum for females. By the end of the 21st century, daily male cicada abundance is projected to increase significantly under the worst-case high greenhouse gas emission scenario RCP8.5 (RCP-Representative Concentration Pathways), with confidence intervals suggesting a possible 5–15-fold increase compared to current levels. In contrast, under the low-emission scenario RCP2.6, male cicada populations are projected to be 60–70% lower than RCP8.5. An understanding of the influence of changing temperature and precipitation conditions is crucial for predicting the spread of this pest to different regions of Germany and other European countries.
Impact of construction measures and heat emissions from the operation of underground power cables on spelt (Triticum spelta L.) growth and yield
(2025) Trenz, Jonas; Ingwersen, Joachim; Schade, Alexander; Memic, Emir; Hartung, Jens; Graeff-Hönninger, Simone
Germany decided to promote the energy supply toward low or zero-carbon sources by the middle of the century. Therefore, massive infrastructural investments in grid expansion are needed. These grid expansions will be conducted with 525 kV High-Voltage Direct Current (HVDC) cables, buried at a depth of 1.5 m, passing mainly through arable land. The expected main effects of these cables on soils and crops are caused by construction measures (soil excavation and backfilling of soil material) and soil warming caused by heat dissipation using HVDC. To date, the impact of subsoil warming on crop growth and yield has not been studied in detail. This study investigates the effects of construction measures and subsoil warming on a field scale level for a 2-yr data set (2022 and 2023) in South Germany. The intricate dynamics between construction measures and subsoil heating on spelt (Triticum spelta L.) growth and yield were analyzed in three treatments: 1) Heated Trench (HT), 2) Unheated Trench (UT), and 3) Control. Construction measures were conducted by excavating the soil with a triple lift method (separated into three layers: A-, B-, and C-layer), storing them separately in ground heaps, and backfilling according to their natural layering. The triple lift method resulted in a 12.1 % decrease in bulk density (BD) for UT and 8.9 % for HT in the subsoil compared to the Control. The changes in soil properties affected spelt growth and yield, resulting in a yield increase of 14 % for the UT treatment. Additional subsoil warming in the HT treatment increased the topsoil temperature by 1.2 °C and spelt yield by 24 %. The triple lift method showed promising results, minimizing the impacts on soil compaction and maintaining the spelt growth and yield level.
Unveiling wheat’s future amidst climate change in the Central Ethiopia Region
(2024) Senbeta, Abate Feyissa; Worku, Walelign; Gayler, Sebastian; Naimi, Babak; Kuhn, Arnd Jürgen; Fenu, Giuseppe
Quantifying how climatic change affects wheat production, and accurately predicting its potential distributions in the face of future climate, are highly important for ensuring food security in Ethiopia. This study leverages advanced machine learning algorithms including Random Forest, Maxent, Boosted Regression Tree, and Generalised Linear Model alongside an ensemble approach to accurately predict shifts in wheat habitat suitability in the Central Ethiopia Region over the upcoming decades. An extensive dataset consisting of 19 bioclimatic variables (Bio1–Bio19), elevation, solar radiation, and topographic positioning index was refined by excluding collinear predictors to increase model accuracy. The analysis revealed that the precipitation of the wettest month, minimum temperature of the coldest month, temperature seasonality, and precipitation of the coldest quarter are the most influential factors, which collectively account for a significant proportion of habitat suitability changes. The future projections revealed that up to 100% of the regions currently classified as moderately or highly suitable for wheat could become unsuitable by 2050, 2070, and 2090, illustrating a dramatic potential decline in wheat production. Generally, the future of wheat cultivation will depend heavily on developing varieties that can thrive under altered conditions; thus, immediate and informed action is needed to safeguard the food security of the region.

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