The aim of this research is to understand how cover crop species combined with different times of N application affect the cover crop straw, nutrition and productivity of cash crop, soil chemical properties and soil microbial composition and function in a holistic approach of the entire agricultural system under tropical no-till system. Focus is on microbiome that immediately respond to the N application disturbances and in a long period to the plant cultivation, N inputs and soil properties changes. We use 3-year field experiment with palisade grass and ruzigrass cover crops and subsequent maize cash crop combined with different N management strategies to quantify the microbial genes of the N cycle and the bacterial and fungal communities’ structure and composition in the agricultural system.

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.  

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.

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 Maasheggen area is a unique cultivated landscape in the Netherlands (near Boxmeer, province Noord-Brabant) and has been designated as a UNESCO biosphere reserve (https://www.maasheggenunesco.com/en/). Its mosaic of hedgerows, small arable fields and meadows make this a very interesting area to study the effects of land use and landscape elements on functional biodiversity and ecosystem services.