Onder het Maaiveld is een driejarig programma van IUCN NL, De Vlinderstichting, NIOO-KNAW, WUR en het Centrum voor Bodemecologie. Samen met andere organisaties werken wij aan een structurele verandering in de omgang met onze waardevolle bodem. Ons doel? Herstel van het bodemleven in Nederland, als basis voor een gezonde natuur en een gezonde maatschappij.

Plant-growth promoting microbes (PGPM) are a viable alternative to traditional fertilizers for enhancing plant productivity and improving soil quality without environmental pollution. The use of PGPM in agriculture has been hampered by a lack of reproducible results and the difficulty of transferring this technology to the field. This inconsistent success primarily reflects competition or resistance of the original soil microbiome to inoculants, as well as the negative effects of management practices such as fertilization on plant interactions with the soil microbiome and the efficiency of ecosystem services delivered by PGPM. We were the first to circumvent this problem under field conditions by manipulating the soil microbiome to successfully obtain consistent, positive effects of inoculated microbes on plant productivity (Cipriano et al., 2016;https://doi.org/10.1093/femsec/fiw197). However, the influence of the indigenous soil microbiome on plants remains largely unknown. We propose to investigate this tripartite, PGPM-plant-soil microbiome interaction in plant quality and productivity using state-of-the-art ‘omics’ and bioinformatics approaches to investigate facilitation (positive interactions) and competition (negative interactions) by both microbes and PGPM within the plant realized niche following gradients of both soil diversity and nutrient availability. This research will facilitate the development of innovative methods for agricultural and horticultural starting material production using PGPM for sustainable crop production by combining techniques to reduce nutrient input and enhance the efficiency and long-lasting effects of PGPM. This research proposal will integrate approaches to obtain a fundamental understanding of these tripartite interactions in a smart microbiome engineered plant production system for sustainable high-quality crop production.

KNAW funded research on the role of biointeractions in causing fungal virulence in asparagus.

This project will investigate residue-stimulated atmospheric methane oxidation, and aims to elucidate its occurrence in field conditions, responsible microorganisms, underlying mechanisms and controlling factors.

A current challenge for modern agriculture is to meet the food production needs for an increasing global population while improving resource use efficiency and attenuating impacts on human health and environment. In order to maximize reliability and stability in agriculture, optimization of crop management and resource use efficiency have been considered the best approaches for a sustainable increase of crop yields under variable agro-ecological conditions, environments and years. For this purpose, one interesting and sustainable method is the use of natural plant biostimulants, a diverse class of products and microorganisms that enhance plant growth and other plant parameters, such as flowering, fruit set, crop productivity and nutrient use efficiency. In this context, several studies already demonstrated that plant biostimulants can induce morpho-anatomical, biochemical, physiological and molecular plant responses, not only improving crop productivity but also promoting protection against abiotic stresses, such as drought and salinity. Among the different biostimulant classes there are protein hydrolysates (PH), mixtures of polypeptides, oligopeptides and aminoacids originated from partially hydrolyzed animal and vegetal tissues. Even though the effect of PH were already observed in diverse crops, the mechanisms and behind their action are still scarcely studied, and their action can vary depending on their origin, characteristics, crop species, cultivars, growing conditions, time and mode of applications, among other parameters. The objective of this project is to evaluate the effect of protein hydrolysates in the growth, nutrient content and microbial communities of crops, if microbes are responsible for these effects, which are the mechanisms and if such effects are long-lasting.

Since recently, Dutch farmers are required to grow cover crops in mixtures of at least two plant species.
In the Clever Cropping Project we investigated whether mixtures of cover crops have beneficial effects on soil microbiology and associated functions.
In long-term field experiments and laboratory incubations, we assessed emissions of greenhouse gasses and the diversity, abundance, and activity of microbial groups involved in environmentally relevant processes.
While in laboratory incubations we could clearly find increased beneficial microbial functioning associated with mixtures of cover crop residues, we could not observe this in a 5-year field experiment.
Overall, the use of cover crop mixtures did not have significant beneficial effects on soil microbial functioning but also no negative effects on for example greenhouse gas emissions.

To mitigate climate change, global agricultural soils needs to store more carbon and emit less greenhouse gasses (GHG). In ClipsMicro, together with partners in agro-business, this is realised by steering soil microbes by application of novel, refined compost and crops that can reduce emissions of GHG.

Sufficient Phosphorus (P) and Iron (Fe) supply is essential for crop production. Most of the P and Fe in soil is not readily available for the plant, making agriculture depending on inorganic fertilizers mainly derived from depletable resources. An alternative to this unsustainable practice is to use recycled compounds recovered during wastewater treatment. This project focuses on the use of the two recycled compounds struvite (MgNH4PO4·6H2O) and vivianite (Fe3(PO4)2·8H2O) which are both insoluble and hard to synchronize with the nutrient needs during early plant development. To increase efficient nutrient release of these recycled sources, we propose the use of microbes that can solubilize P and release siderophore, both recognized traits of plant growth promoting microbes. Several plant growth-promoting microbes have been isolated, but their transfer to agriculture, so far, resulted in an inconsistent success, due to competition or resistance of the resident soil microbiome to inoculants. This project will circumvent this challenge by steering the local microbiome with the addition of recycled nutrients and will further optimize the microbiome by microbial community breeding. Overall, this project will focus on identifying microbial community members with struvite and vivianite solubilizing function, optimizing these communities, determining the role of these communities on increasing the nutrient release as well as monitoring the recruitment of these beneficial microbes in the rhizosphere and the effect on plant growth.

The aim of this project is to determine the ecological relationship between bacteria and soil aggregates. We inoculate individual beneficial bacteria and different microbial communities from different natural soils in simulated Mars soil, attempting to explain their improvement in soil aggregate stability by bacterial exudates (EPS), necromass and microbial functional traits.

The goal of this project is to decipher the role of fungal denitrifiers in N2O production from soils under sustainable management practices. Here we apply mesocosms experiments combined with SIP and meta-omics approaches targeting the functional genes of N cycle. In addition, we design primers for fungal denitrifiers based on complete fungal genomes and soil metagenomics data.