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Several measures were tested to improve the soil quality on a reclaimed peatsoil in the North-East of the Netherlands in the period 2014-2021. The effects of the measures on the crop yields, crop quality, soil fertility, nutrient balances, soil nematodes, soil biology, soil structure, plant available water and weeds were monitored. Replacing spring barley by Marigold in the crop rotation was the most successful in increasing the crop yields of potatoes, by reducing the population of the plant parasitic nematode P. penetrans. The cultivation of Marigold once every four years was more successful than once every eight years. The application of compost increased the yield of sugar beet. The application of compost was also associated with nutrient surpluses and a increase in soil nutrients. The application of compost also led to an increase in some aspects of the soil biology. The other measures, including non-inversion tillage, the Base-Cation saturation ratio and applying rockdust were not successful in increasing the crop yields. Overall, large improvements in the soil quality as a result of the measures was not found.

The chemical composition of 134 organic soil improvers including bokashi and various forms of treated and untreated clippings and/or leaves collected from green spaces in cities has been determined. The samples originate from pilots associated with ‘Circulair Terreinbeheer’. In 2021 and 2022 the focus was on the determination of macro- and micronutrients, organic matter and relevant contaminants including heavy metals, PAH’s, dioxins, various PFC’s and residues from plant protection chemicals. These data are needed to evaluate the agricultural and environmental impact of such organic soil improvers. To estimate long term effects on soil organic matter, the stability (humification coefficients) as well as agronomic value (availability of N and P) has been measured in a selection of these products. These selected products also have been used in a large-scale field experiment at three experimental farms of WUR (Lelystad, de Marke and Vredepeel). Here, these products have been applied in a regular agricultural production system (maïze) in a randomized block design. In 2021 and 2022 the effects of these products on microbiological parameters as well as organic matter and the soil nutrient content and crop production have been determined., De samenstelling van 134 organische bodemverbeteraars zoals bokashi en verschillende vormen van bewerkt en onbewerkt maaisel en/of blad uit het groenbeheer in de stad, is gemeten in pilots aangesloten bij het Circulair Terreinbeheer. In 2021 en 2022 lag daarbij de nadruk op het bepalen van de gehalten aan macro- en micronutriënten, organische stof en relevante contaminanten, zoals metalen, fysieke verontreinigingen, PAK’s, dioxines, PFAS en residuen van bestrijdingsmiddelen. Deze data zijn nodig om een oordeel te kunnen vormen over de landbouwkundige en milieukundige geschiktheid van deze producten. Om de langjarige effecten op onder meer organische stof te kunnen schatten, is onder laboratoriumcondities de humificatiecoëfficiënt bepaald. Om de landbouwkundige waarde te bepalen, is onder meer de gewasbeschikbaarheid van N en P bepaald in een selectie van deze producten. Deze geselecteerde producten zijn ook in een drietal proefbedrijven van WUR (Lelystad, Vredepeel en De Marke) aangewend in een regulier landbouwkundig systeem met mais als productiegewas. In een randomized block design (72 plots per proefbedrijf) is daarbij onderzocht in welke mate de bodemverbeteraars invloed hebben op o.a. de microbiologische activiteit, gehalten aan macrochemische parameters van de bodem (o.a. organische stof en pH) en op de gewasproductie.

Het Bedrijvennetwerk Bodemmetingen van de PPS Beter Bodembeheer is in het najaar 2018 opgezet met als doel om bodemmetingen op praktijkbedrijven te testen en te kijken naar de samenhang van bodemindicatoren onderling en met de bedrijfsvoering. De 16 bedrijven vertegenwoordigen de variatie in de akkerbouw in Nederland en vormen daarmee een land dekkend netwerk. De deelnemende bedrijven zijn geselecteerd en geworven in afstemming met de sectororganisaties. Bij elk bedrijf hebben we met de ondernemers twee percelen geselecteerd voor uitvoering van de metingen. In het najaar van 2019 zijn meer dan 30 verschillende bodemindicatoren gemeten op twee percelen van elk bedrijf vanuit de werkpakketten rond organische stof, bodembiologie en bodemweerbaarheid en meten van bodemkwaliteit in de PPS Beter Bodembeheer. Deze metingen zijn in najaar 2020 en 2021 herhaald op dezelfde percelen. Hierbij zijn zowel alle indicatoren uit de BLN-indicatorset gemeten, zowel met de klassieke meetmethodes als de alternatieve (goedkopere en/of snellere) meetmethodes als een aantal andere indicatoren. Hiernaast zijn ook teeltgegevens en historische gegevens van de percelen verzameld. Doel van de metingen was om 1) een beter zicht te krijgen op de toepasbaarheid van de indicatoren en meetmethoden in de BLN, 2) alternatieve indicatoren en meetmethoden te testen, 3) een beter inzicht te krijgen in de relatie tussen indicatoren onderling, de indicatoren en de fysieke omstandigheden (bodemtype, klimaat, grondwater) en de indicatoren en het management, 4) na te gaan welke set aan indicatoren leidt tot een goed beeld van de integrale bodemkwaliteit mede gezien ook het management en de fysieke omstandigheden. In dit rapport worden de resultaten gericht op de eerste twee doelen gepresenteerd. De meetwaarden van de indicatoren worden voor alle percelen gepresenteerd met referentiewaarden en streefwaarden indien beschikbaar. Daarnaast is er gekeken waar beschikbaar hoe de klassieke en de alternatieve method

The chemical composition of 41 organic soil improvers including bokashi and various forms of treated and untreated clippings and/or leaves collected from green spaces in cities has been determined. The samples originate from pilots associated with the ‘Stichting Circulair Terreinbeheer’. In 2021 the focus was on the determination of macro- and micronutrients, organic matter and relevant contaminants including heavy metals, PAH’s, dioxins, various PFC’s and residues from plant protection chemicals. These data are needed to evaluate the agricultural and environmental impact of such organic soil improvers. To estimate long term effects on soil organic matter, the stability (humification coefficients) has been measured on a selection of these products. These selected products also have been used in a large-scale field experiment at three experimental farms of WUR (Lelystad, de Marke and Vredepeel). Here these products have been applied in a regular agricultural production system (2021: mais) in a randomized block design. In 2021 effects of these products on microbiological parameters as well as organic matter and the soil nutrient content and crop production have been determined., De samenstelling van 41 organische bodemverbeteraars zoals bokashi en verschillende vormen van bewerkt en onbewerkt maaisel en/of blad uit het groenbeheer in de stad zijn gemeten in pilots aangesloten bij de stichting Circulair Terreinbeheer. In 2021 ligt daarbij de nadruk op het bepalen van de gehalten aan macro- en micronutriënten, organische stof en relevante contaminanten zoals metalen, fysieke verontreinigingen, PAK’s, dioxines, PFAS en residuen van bestrijdingsmiddelen. Deze data zijn nodig om een oordeel te kunnen vormen over de landbouwkundige en milieukundige geschiktheid van deze producten. Om de langjarige effecten op onder meer organische stof te kunnen schatten, is onder laboratoriumcondities de humificatiecoëfficiënt bepaald in een selectie van deze producten. Deze geselecteerde producten zijn ook in een drietal proefbedrijven van WUR (Lelystad, Vredepeel en De Marke) aangewend in een regulier landbouwkundig systeem met mais als productiegewas. In een randomized block design (72 plots per proefbedrijf) is daarbij onderzocht in welke mate de bodemverbeteraars invloed hebben op o.a. de microbiologische activiteit, de gehalten aan macrochemische parameters van de bodem (o.a. organische stof en pH) en op de gewasproductie.

De bodem onder onze voeten vormt letterlijk de basis van ons bestaan. Bodems en de daarin en daarop groeiende vegetatie leveren immers zuurstof en voedsel. Elke bodem beschikt over een veelheid aan chemische, fysische en biologische eigenschappen, die elkaar bovendien beïnvloeden. Het ligt dan ook voor de hand om bodems integraal te beoordelen op hun kwaliteit en bodemleven. Meestal zijn de grondsoort en de locatie bepalend voor welk bodemleven aanwezig ais. Daarna volgt vaak het bodemgebruik als sterk bepalende factor voor de bodembiodiversiteit en het functioneren van de bodem. Hoe kan de onderzoeksdiscipline bodembiologie bijdragen aan herstel, stimulering dan wel versterking van de belangrijkste bodemorganismen en hun functies, en welke meetinstrumenten zijn daarbij voorhanden of in ontwikkeling?

The health and functioning of soil ecosystems are the foundation of sustainable food production and land management. Of key importance in achieving sustainability, is the frequent measurement of soil health, and indices based on the community structure of nematodes are amongst the most widely used toolsets by soil ecologists. Thirty years after the development of the Maturity Index, we aimed to evaluate the application, utility, and future directions of nematode-based indices (NBIs). This review focused on NBIs that are calculated using the coloniser-persister classification of nematodes. Data from 672 empirical studies in terrestrial environments revealed that the NBIs presented a dissimilar usage trend. The Channel Index and Metabolic Footprints showed the strongest increase in application rates over time, thus indicating a greater interest in studying decomposition pathways and ecosystem functioning, respectively. Furthermore, nematode-based indices were mostly applied in agricultural systems associated with herbaceous crops and in studies investigating, for example, soil nutrient enrichment following manure and/or inorganic fertilizer application. We further provide a framework for selecting a focus-orientated subset of NBIs for testing hypotheses based on the underlying ecological mechanisms. Also, we highlight important considerations, including the unexpected behaviour of some nematode taxa, in the interpretation of NBIs. The improvement of NBIs relies on advancing our understanding of the autecology of nematodes. Finally, we deliver insight into the further development of NBIs considering recent methodological advancements. We highlight that NBIs have been and might become increasingly important in providing valuable information on soil ecosystem health and functioning, especially considering the urgent need for more sustainable land use.

Het stedelijk gebied moet groener, biodiverser en weerbaarder tegen het veranderende klimaat worden. Kan bodemleven hieraan bijdragen? Wat weten we al van het bodemleven dat hier zit? Hoe kunnen we het bodemleven hier stimuleren? In dit artikel gaan we in op deze vragen.

Met het doel meer inzicht te krijgen in het beoordelen van de bodemkwaliteit is er een Bedrijvennetwerk Bodemmetingen opgezet. In het najaar van 2019 heeft een uitgebreide meetronde plaatsgevonden op 32 percelen van de 16 deelnemende akkerbouwerbedrijven, daarnaast is er uitgebreide teeltinformatie verzameld. In totaal zijn er meer dan 30 metingen verricht aan de bodem organische stof, bodemchemie en bodemweerbaarheid. Deze omvatte zowel de klassieke als alternatieve metingen van de BLN-indicatoren, en een aantal aanvullende indicatoren. Dit rapport presenteert de meetresultaten van de klassieke en alternatieve meetmethode, in relatie tot de beschikbare streef- en referentiewaarden. Deze resultaten vormen een eerste test in het ontwikkelen van een robuuste systematiek voor het beoordelen van de bodemkwaliteit.

Met het doel meer inzicht te krijgen in het beoordelen van de bodemkwaliteit is er een Bedrijvennetwerk Bodemmetingen opgezet. In het najaar van 2019 heeft een uitgebreide meetronde plaatsgevonden op 32 percelen van de 16 deelnemende akkerbouwerbedrijven, daarnaast is er uitgebreide teeltinformatie verzameld. In totaal zijn er meer dan 30 metingen verricht aan de bodem organische stof, bodemchemie en bodemweerbaarheid. Deze omvatte zowel de klassieke als alternatieve metingen van de BLN-indicatoren, en een aantal aanvullende indicatoren. Dit rapport presenteert de meetresultaten van de klassieke en alternatieve meetmethode, in relatie tot de beschikbare streef- en referentiewaarden. Deze resultaten vormen een eerste test in het ontwikkelen van een robuuste systematiek voor het beoordelen van de bodemkwaliteit.

Litter decomposition and nutrient mineralization are crucial in agricultural systems to maintain soil fertility and plant growth. Given that these processes are governed by soil microbial activity, agricultural management that affects soil microbial communities may significantly alter rates of decomposition and N release of the same litter. We hypothesized that organic compared to conventional management enhances litter decomposition and litter N release, and that this effect is stronger for litter of low quality (high C:N ratio).We tested these hypotheses using litter from 4 maize cultivars with varying initial litter quality (different C:N ratios and lignocellulose index). These litters were left to decompose in soil with different management history, yet in the same experimental field site. The field experiment consisted of randomized plots with 11 years of organic or conventional agricultural management (organic vs. mineral fertilization). During the 11 years, in year 3 and 4, two specific organic amendments were applied as soil health treatments (SHT: chitin or compost, and a control without SHT). The maize litter was contained in litter bags, buried in the top 10–15 cm soil and collected after 1, 2 and 3 months. We quantified the litter carbon (C) and nitrogen (N) loss, and soil dissolved organic carbon (DOC), mineral and dissolved organic nitrogen (DON) at each sampling time. We also determined the fungal biomass in the decomposing litter after 3 months of decomposition.Litter C loss was higher in soil under organic compared to conventional management, irrespective of litter quality. In contrast, the rate of N release from the litter was determined by initial litter quality (higher N release from low C:N litter) and not by agricultural management. In soil under organic management the concentrations of DOC, mineral N and DON were larger than in conventional managed soil, which may have stimulated microbial activity and therefore, litter decomposition. Fungal b

Soil microbiome and multi-trophic relationships are essential for the stability and functioning of agroecosystems. However, little is known about how farming systems and alternative methods for controlling plant pathogens modulate microbial communities, soil mesofauna and plant productivity. In this study, we assessed the composition of eukaryotic microbial groups using a high-throughput sequencing approach (18S rRNA gene marker), the populations of parasitic and free-living nematodes, plant productivity and their inter-relationships in long-term conventional and organic farming systems. The diversity of the fungal community increased in the organic farming system compared to the conventional farming system, whereas the diversity of the protist community was similar between the two farming systems. Compared to conventional farming, organic farming increased the population of free-living nematodes and suppressed plant parasitic nematodes belonging to Meloidogynidae and Pratylenchidae. Fungal diversity and community structure appeared to be related to nematode suppression in the system receiving organic fertilizer, which was characterized by component microbial groups known to be involved in the suppression of soil pathogens. Unraveling the microbiome and multi-trophic interactions in different farming systems may permit the management of the soil environment toward more sustainable control of plant pathogens.

Recent demonstrations of the role of plant–soil biota interactions have challenged the conventional view that vegetation changes are mainly driven by changing abiotic conditions. However, while this concept has been validated under natural conditions, our understanding of the long‐term consequences of plant–soil interactions for above‐belowground community assembly is restricted to mathematical and conceptual model projections. Here, we demonstrate experimentally that one‐time additions of soil biota and plant seeds alter soil‐borne nematode and plant community composition in semi‐natural grassland for 20 years. Over time, aboveground and belowground community composition became increasingly correlated, suggesting an increasing connectedness of soil biota and plants. We conclude that the initial composition of not only plant communities, but also soil communities has a long‐lasting impact on the trajectory of community assembly.

1.The ecosystem services that humans obtain from the soil are strongly linked to the soil's biota. There is ample evidence that intensive agriculture has a negative effect on the soil's biological diversity. While in other ecosystems, habitat specialists are at a higher risk of extinction due to human impacts than generalists, we have no evidence of whether this holds true for soil biota. We calculated the realized niche width for soil nematodes using co‐occurrence data. We compared these with ecological traits. We then calculated an index of community specialization and tested whether land use intensity leads to decreases in the index of community specialization, taxon richness, diversity and to changes in nematode abundance.2.The resulting realized niche widths did not correlate with ecological traits such as feeding group, body mass or c‐p class. While it is possible that there are no relationships between these traits and the realized niche width, it is likelier that food availability, pH tolerance, or host breadth are more important factors in explaining niche width.3.Contrary to our expectations, the lowest community specialization levels were found in soils with the lowest human intervention (shrubland–woodland ecosystems), while grasslands, dairy farms and arable farms had an overall higher level of specialization. Weather variables and land use intensity explained 66% of the variation in the index of community specialization in sandy soils. We found highest richness and diversity at intermediate levels of disturbance (grasslands and dairy farms). The lowest abundances were found on shrubland–woodland systems. Dairy farms on sand and clay had similar indices of community specialization, whereas peaty soils fostered a higher proportion of habitat specialists.4.We argue that farmland supposes a stable environment for organisms with shorter life spans. Agricultural management strives to lower disturbances, allowing shorter lived organisms to escape pressures ot

Organic fertilizers have been shown to stimulate CH4 uptake from agricultural soils. Managing fertilizer application to maximize this effect and to minimize emission of other greenhouse gasses offers possibilities to increase sustainability of agriculture. To tackle this challenge, we incubated an agricultural soil with different organic amendments (compost, sewage sludge, digestate, cover crop residues mixture), either as single application or in a mixture and subjected it to different soil moisture concentrations using different amounts of organic amendments. GHG fluxes and in vitro CH4 oxidation rates were measured repeatedly, while changes in organic matter and abundance of GHG relevant microbial groups (nitrifiers, denitrifiers, methanotrophs, methanogens) were measured at the end of the incubation. Overall the dynamics of the analyzed GHGs differed significantly. While CO2 and N2O differed considerably between the treatments, CH4 fluxes remained stable. In contrast, in vitro CH4 oxidation showed a clear increase for all amendments over time. CO2 fluxes were mostly dependent on the amount of organic residue that was used, while N2O fluxes were affected more by soil moisture. Several combinations of amendments led to reductions of CO2, CH4, and/or N2O emissions compared to un-amended soil. Most optimal GHG balance was obtained by compost amendments, which resulted in a similar overall GHG balance as compared to the un-amended soil. However, compost is not very nutrient rich potentially leading to lower crop yield when applied as single fertilizer. Hence, the combination of compost with one of the more nutrient rich organic amendments (sewage sludge, digestate) provides a trade-off between maintaining crop yield and minimizing GHG emissions. Additionally, we could observe a strong increase in microbial communities involved in GHG consumption in all amendments, with the strongest increase associated with cover crop residue mixtures. Future research should focus on

Organic farming system and sustainable management of soil pathogens aim at reducing the use of agricultural chemicals in order to improve ecosystem health. Despite the essential role of microbial communities in agro-ecosystems, we still have limited understanding of the complex response of microbial diversity and composition to organic and conventional farming systems and to alternative methods for controlling plant pathogens. In this study we assessed the microbial community structure, diversity and richness using 16S rRNA gene next generation sequences and report that conventional and organic farming systems had major influence on soil microbial diversity and community composition while the effects of the soil health treatments (sustainable alternatives for chemical control) in both farming systems were of smaller magnitude. Organically managed system increased taxonomic and phylogenetic richness, diversity and heterogeneity of the soil microbiota when compared with conventional farming system. The composition of microbial communities, but not the diversity nor heterogeneity, were altered by soil health treatments. Soil health treatments exhibited an overrepresentation of specific microbial taxa which are known to be involved in soil suppressiveness to pathogens (plant-parasitic nematodes and soil-borne fungi). Our results provide a comprehensive survey on the response of microbial communities to different agricultural systems and to soil treatments for controlling plant pathogens and give novel insights to improve the sustainability of agro-ecosystems by means of beneficial microorganisms.