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Background and aim Plant pathogenic and mycotoxin-producing Fusarium species are globally widespread and lead to large annual yield losses in maize production (ecosystem disservice). Systems with reduced tillage and mulching are particularly under threat. In the present study, the bioregulatory performance (ecosystem service) of the common earthworm species Lumbricus terrestris was analysed regarding the suppression of three economically relevant Fusarium species, and the reduction of their mycotoxins in the maize mulch layer, taking into account the size of maize residues. Methods A mesocosm field experiment was conducted in a reduced tillage long-term field trial on loam soil. Artificially Fusarium-infected maize residues of two size classes were used as a mulch layer. Impacts of the earthworm species on DNA amounts of Fusarium graminearum, F. culmorum, and F. verticillioides and concentrations of the mycotoxins deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), and zearalenone (ZEN) were analysed. Results The results reflect that Fusarium regulation by L. terrestris was species-specific and covered the whole spectrum from suppression (F. graminearum) to slight promotion (F. verticillioides). Regarding the mycotoxins, a significant acceleration of the degradation of all three toxins was detected. Fine chopping of the chaff (< 2 cm) did not significantly alter the earthworms’ regulatory capacity. Conclusion While L. terrestris can shift the ecosystem service/disservice balance in both directions with respect to Fusarium regulation, it shifts it towards ecosystem services with respect to mycotoxin degradation. In synergy with adapted agricultural management, this natural bottom-up effect can help to keep soils healthy for sustainable production in the long run.

Regenwurmer sind Leistungstrager innerhalb des Bodennahrungsnetzes und erbringen zahlreiche okologische Dienstleistungen. So fordern sie Bodenstrukturbildung, Bodengesundheit, Nahrstoffverfugbarkeit, Beluftung, Wasserspeicherung sowie Widerstands- und Regenerationsfahigkeit von Boden. Dieses grose Leistungsspektrum hilft Fruchtbarkeit und Produktivitat landwirtschaftlich genutzter Boden nachhaltig zu gewahrleisten. Eine Forderung der Regenwurmer durch angepasste, bodenschonende Managementmasnahmen ist unerlasslich, um die naturlichen Ressourcen der Regenwurmer optimal zu nutzen. Ein synergistisches Zusammenspiel aus Leistungen der Regenwurmer und landwirtschaftlichem Management ist daher ein erfolgversprechender Ansatz, um Bodenfruchtbarkeit und Ertragssicherheit zukunftig nachhaltig zu sichern.

A sustainable agricultural management can contribute to promoting soil biodiversity performance, thereby preserving soil functions and ensuring the provision of soil biota-induced ecosystem services. In order to make the best possible use of these services for the benefit of agricultural production, a better understanding of interlinkages between management measures, ecosystem service/disservice balance and soil self-regulation potential is essential. In this context, it is well known that the reduction of soil tillage intensity combined with mulching techniques, on the one hand, promote the survival, development and spread of plant pathogenic mycotoxin-producing soil-borne fungi, but, on the other hand, enhance the diversity of antagonistic mycotoxin-degrading fungivorous soil animals. However, up to now it is still unclear, which ecosystem service/disservice balance results from both pathways and which self-regulation mechanisms are involved. To analyse and assess the bioregulation potential of fungivorous soil faunal key species (earthworms: Lumbricus terrestris, collembolans: Proisotoma minuta, enchytraeids: Enchytraeus crypticus and E. christenseni) on economically relevant plant pathogenic species of the fungal genus Fusarium (F. graminearum, F. culmorum, F. verticillioides) and its mycotoxins (deoxynivalenol (DON), zearalenon (ZEN), 3-acetyl-deoxynivalenol (3AcDON) and fumonisin B1 (FB1)) in maize residues, field and laboratory experiments were performed as part of the EU BiodivERsA project SoilMan. Based on these studies the following hypotheses were tested: (1) soil faunal key organisms supress Fusarium species and reduce their mycotoxins in maize residues, (2) the bioregulation potential depends on substrate size and soil texture (3) interactions between fungivorous key species affect their bioregulation potential, (4) leaching of mycotoxins represents a potential risk for arable soils. The results reflect that soil faunal key species regulate amounts of F. graminearum and F. culmorum in maize residues depending on substrate size and soil texture, but did not affect amounts of F. verticillioides. Fungivorous soil animals significantly accelerate degradation rates of Fusarium mycotoxins by up to 300%, depending on soil faunal species, respective mycotoxin and soil texture. In particular, primary decomposers within the earthworm community (L. terrestris) are pivotal for the bioregulation of Fusarium species and their mycotoxins in the mulch layer. The bioregulation potential of the mesofauna (collembolans and enchytraeids) strongly depends on soil faunal interactions. The findings further indicate that the mycotoxins DON and ZEN leach from infected maize residues. The present studies contribute to improve understanding of the complex interrelations between arable management and ecosystem service/disservice balance in agroecosystems.

By means of a literature survey, earthworm species of significant relevance for soil functions in different biogeographical regions of Europe (Atlantic, Boreal, Mediterranean) were identified. These focal earthworm species, defined here according to the EFSA Guidance Document on the environmental risk assessment (ERA) of genetically modified plants, are typical for arable soils under crop rotations with maize and/or potatoes within the three regions represented by Ireland, Sweden and Spain, respectively. Focal earthworm species were selected following a matrix of four steps: Identification of functional groups, categorization of non-target species, ranking species on ecological criteria, and final selection of focal species. They are recommended as appropriate non-target organisms to assess environmental risks of genetically modified (GM) crops; in this case maize and potatoes. In total, 44 literature sources on earthworms in arable cropping systems including maize or potato from Ireland, Sweden and Spain were collected, which present information on species diversity, individual density and specific relevance for soil functions. By means of condensed literature data, those species were identified which (i) play an important functional role in respective soil systems, (ii) are well adapted to the biogeographical regions, (iii) are expected to occur in high abundances under cultivation of maize or potato and (iv) fulfill the requirements for an ERA test system based on life-history traits. First, primary and secondary decomposers were identified as functional groups being exposed to the GM crops. In a second step, anecic and endogeic species were categorized as potential species. In step three, eight anecic and endogeic earthworm species belonging to the family Lumbricidae were ranked as relevant species: Aporrectodea caliginosa, Aporrectodea rosea, Aporrectodea longa, Allolobophora chlorotica, Lumbricus terrestris, Lumbricus friendi, Octodrilus complanatus and Octolasion cyaneum. Five out of these eight species are relevant for each biogeographical region with an overlap in the species. Finally, the earthworm species Ap. caliginosa (endogeic, secondary decomposer) and L. terrestris (anecic, primary decomposer) were selected as focal species. In the Mediterranean region L. terrestris may be substituted by the more relevant anecic species L. friendi. The selected focal species are recommended to be included in a standardized laboratory ERA test system based on life-history traits. © 2016 Elsevier B.V.

An assessment of the functional and structural biodiversity in arable soils, considering the impact of different tillage systems, is needed in the interest of conserving biodiversity and the ecosystem services provided by organisms. Thus, a survey of the scientific literature published over the past six decades was conducted. We concentrated on data from agro-ecosystems in Germany as they cover a wide range of different soils representative for temperate regions. The state of knowledge was analyzed with regard to the impact of conventional, conservation and no-tillage management on lumbricids, collembolans, mites, enchytraeids, nematodes and microbiota. Interaction effects between tillage intensity and parameters characterizing the respective system (e.g., soil texture and crop) were considered. Besides the abundance and biomass of soil organisms, species richness and individual densities of taxonomical and functional units, enzyme activities, various quotients indicating microbial-driven soil processes and infestation rates of soil-borne pathogens were included in the analysis. The integrating analysis of the datasets indicates that soil biota responds specifically to tillage systems. Whereas abundances and species diversity of lumbricids increased significantly, individual density and species diversity of collembolans decreased significantly when tillage intensity was reduced. Tillage-driven impacts on lumbricids and collembolans differed depending on soil texture, whereas those on nematodes and microbial communities varied depending on soil depth. Functional groups within certain taxa show differing tillage-induced impacts. Linking several datasets on various indicator organisms clearly show that the decision on which tillage system should be applied must be taken for each individual case considering local soil characteristics.

Im Rahmen einer Literaturstudie wurde analysiert, welche Rolle die Bodenbearbeitungsintensitat fur die Bedeutung von Pflanzenschadlingen in landwirtschaftlichen Systemen spielt. Einige wirtschaftlich relevante Vertreter der Bodenpilze (Erreger von Halmbruch und Schwarzbeinigkeit) und der Bodenfauna (Nematoden und Collembolen) geben exemplarisch Aufschluss daruber, inwiefern sich ihr Auftreten und ihre Haufigkeit, und somit der Befallsdruck, in Abhangigkeit vom Bearbeitungssystem verandern, und welche Wechselwirkungen mit potentiellen Antagonisten auftreten. Die Auswertung der Datensatze zeigt, dass der Befallsdruck durch bodenburtige Schaderreger in Systemen mit konservierender im Vergleich zu konventioneller Bodenbearbeitung durch die Forderung antagonistischer Bodenorganismen haufig zuruck geht. In Abhangigkeit von standortspezifischen Bodeneigenschaften erfordert eine Reduktion der Bearbeitungsintensitat somit nicht zwingend einen erhohten Einsatz von Pflanzenschutzmitteln.

Soil biodiversity enhancement in European agroecosystems to promote their stability and resilience by external inputs reduction and crop performance increase This work was funded by the European Commission Horizon 2020 project SoildiverAgro [grant agreement 817819]

Soil biodiversity enhancement in European agroecosystems to promote their stability and resilience by external inputs reduction and crop performance increase This work was funded by the European Commission Horizon 2020 project SoildiverAgro [grant agreement 817819].