DiverIMPACTS

Background and Objective

DiverIMPACTS is

• assessing performances of crop diversification through rotation, intercropping and multiple cropping,
• providing rural areas actors with those key enablers and innovations that would remove existing barriers and ensure actual uptake of benefits of crop diversification at farm, value chain and territory levels and
• making recommendations to policy-makers to facilitate the coordination of all relevant actors within the value chain.

DiverIMPACTS will build on existing experiences of crop diversification by networking and expanding 10 existing field experiments to quantify impacts of crop diversification and by accompanying 25 multi-actor case studies in their dynamic transition.

DiverIMPACTS will propose a range of technical and organisational innovations to remove lock-ins from farmers to consumers as well as strategies and recommendations to sustain crop diversification.

Target Group

EU and national policy

Farmers

Science

Approach

DiverIMPACTS has 34 partners and is coordinated by Dr. Antoine Messéan of INRA, the French National Institute for Agricultural Research. Dr. Didier Stilmant of  CRA-W, Belgium, acts as deputy coordinator.

The Thünen Institute of Biodiversity is in particular involved in work package 3: Quantification of the benefits from diversified cropping systems through field experiments.

WP 3 is setting up a network of field experiments (FEs) to assess crop diversification impacts and test combination of intercropping, multiple cropping and crop rotation. A network of already existing or planned field experiments is used

• to demonstrate field benefits of different strategies (rotation, intercropping and multiple cropping) with different species under a range of diverse soil and climatic conditions in Europe and
• to test new temporal and spatial arrangement of species and management (low input practices including machinery), to better achieve expected benefits both for farmers and for the requirements of value chains.

A series of measurements, including yield (per ha and per year, Land-Equivalent Ratio), use of resources (light, water, nutrients) input use (fertilisers, pesticides, energy, water), weed, pest and diseases pressure, soil fertility and biodiversity, are carried out following common protocols to allow benchmarking.

Data and Methods

Within DiverIMPACTS, the Thünen Institute of Biodiversity will focus on two major research activities:

1. Soil biodiversity measurements

   During the first year of DIVERIMPACTS, three field experiments will be selected where the implications of different cropping systems for structural and functional microbial diversity will be assessed with annual replications. This assessment will be based on analyzing soil DNA (the soil metagenome) by quantitative PCR and DNA 16S rRNA gene amplicon sequencing to determine the population sizes and diversity of bacteria, archaea and fungi, and in addition of genes encoding for enzymes involved in the turnover of nitrogen, the latter being most limiting factor for crop growth and yield. To avoid a PCR-based bias, one selected site with treatments differing in the diversity of their cropping systems will also be studied by direct sequencing of the soil metagenome. Regarding the selection of sites, we would clearly prefer long-term experiments which we would accompany with one sampling before the cultivation period starts and with one annual replication.

2. Ecosystem services (biocontrol potential)

   A combination of established long-term on-station experiments, newly developed innovative experiments (to test new and risky temporal and spatial arrangement of species and management) and on-farm experiments (to test diversification effects at a farm level) will be used to test effects of diversification strategies involving farming practices on the diversity and abundance of natural enemies, alternative prey and indicators of regulating ecosystem services. We will test the hypothesis that diversification strategies can only positively affect natural enemy abundance and biocontrol potential if they are accompanied by lower inputs (plant protection and fertilization) and fewer disturbances of natural enemies’ habitats.

Our Research Questions

1. Soil biodiversity

The metabolic activities of the soil inhabiting microbial communities support nutrient cycling, plant growth and protect groundwater quality. On the other hand, microbial activities can be a concern if not properly managed, e.g. by releasing climate-damaging methane or nitrogen oxides, or damaging crops as pathogens. Crop diversification is expected to support microbial diversity at a structural and functional level and thereby stabilize the beneficial microbial services, but data confirming this assumption are still very scarce. Only recently, due to a revolutionary progress in DNA sequencing technologies and bioinformatic data analyses, it became possible and financially feasible to assess soil microbial diversity and functions. DIVERIMPACTS recognizes this data gap which does not allow the assessment and evaluation of below-ground microbial biodiversity of different cropping systems by meta-analyses.

2. Ecosystem services (biocontrol potential)

Diversification of cropping systems can affect pest population cycles and biocontrol by natural enemies through cut off or disturbance of pest population cycles, destruction of the breeding habitat of pests, disturbance of pest hosts and enhanced activity, abundance, and species diversity of natural enemies by providing alternative hosts and refuges. There is evidence that diversified farming systems compared with conventional farming systems including monocultures support substantially greater biodiversity and also enhance control of weeds, diseases, and arthropod pests. Meta-analyses suggest that diversification schemes generally achieve significant positive outcomes including natural enemy enhancement, reduction of herbivore abundance, and reduction of crop damage, from a combination of bottom-up and top-down effects. Available evidence, however, also suggests that these practices may often be insufficient to control pests. Diversification of a cropping system per se may not be sufficient for enhancing ecosystem services such as pest control if those schemes are not accompanied by farming practices which encourage species richness and population growth of natural enemies such as sufficient winter cover, management of landscape structure, or reduced pesticide use. Little is known about combined effects in diversification schemes combining for example rotation, intercropping and cover crops, in particular in combination with changing levels of plant protection, fertilization and soil management. For many cropping systems, there is still limited empirical information to guide farmers on how best to utilize diversified farming techniques to consistently regulate arthropod pest populations below economic thresholds.

Results

not yet available

Links and Downloads

www.diverimpacts.net