Research of Centre for Crop Systems Analysis

Crop-weed interactions

Weeds are the most important biotic yield-reducing factor in terms of potential yield loss. Increased societal concern on the environmental and public health effects of herbicides result in restrictions on their use. This, in addition to evolution of weed resistance to herbicides, calls for a transition in weed control from primarily chemical to primarily ecological. We aim to understand the ecology and particularly the life-cycle of weeds to provide the scientific basis for this transition.

Crop climate adaptation

Climate change is arguably the greatest challenge facing agricultural production. We do field experiments and modelling studies on the potential impacts of climate change on crop production levels and stability, and we explore adaptive cropping strategies, focusing e.g. on cocoa agroforestry and on climate-smart potato cropping.

Genotype to phenotype

Using a systems biology approach, we deal with complex phenotypic traits (such as yield and quality aspects) expressed at crop level by using underlying biochemical and physiological understandings. We aim to bridge the genotype-phenotype gap and to strengthen marker-assisted breeding, via QTL (quantitative trait loci)-based physiological modelling.

Agrobiodiversity

Humanity depends for its calories and proteins intake on very few crops. Moreover, it has been demonstrated that the diets of the peoples of the different countries are becoming more and more similar worldwide, while the diversity of what they eat is increasing. The reliance on only a few crops is worrying. Similarly, within a crop, the diversity is also on the decline.

Farmers are increasingly market oriented. Nevertheless, there are many social, agronomic and ecological reasons why farmers maintain or do not maintain a certain level of diversity, both in their choices for crops and in the cultivars they grow.  Interesting examples are the coexistence of African rice, Asian rice and the interspecific hybrids in some areas of West Africa. This topic also requires synergy with social sciences and is very much related to the theme on seed systems. 

Crop landscape ecology

The crop field is in dynamic interaction with its abiotic and biotic environment, and not an island onto itself. Pests (e.g. aphids), natural enemies (e.g. ladybeetles, carabid beetles and parasitoids), pollinators (e.g. wild and managed honeybees), spores of pathogenic microorganisms (e.g. spores of Phytophthora infestans), and weed seeds (e.g. Cirsium arvense) travel in the wider landscape, often by aerial dispersal, but in the case of some insects, also by walking.

Hence, the composition of the landscape and its configuration effect crop health (pests and diseases) and production (pollination). In the crop landscape ecology theme we study these dynamic interactions by combining experiments, statistical analyses and modelling. This theme supports the design of landscapes that support healthy, productive crops with reduced reliance on pesticides for management.

Product quality

Product quality covers attributes of the harvested parts (‘the yield’) of crops, e.g., seeds, tubers, roots, or the full above-ground biomass. Quality attributes may be very diverse, like concentrations of desired nutrients or other compounds of interest, compositions, visible appealability, technical aspects for the industry, ripeness, unwanted compound or components, size or size distribution, homogeneity of the lot.

We use experimental and model approaches to understand and quantify how processes in crops influence quality attributes and how these are affected by environmental factors, crop management by the farmer and genotype. Besides, defining and measuring quality is a challenge by itself.

Intercropping

We analyse the effects of crop species mixture, agroforestry and variety mixture on plant-plant interactions and crop functioning in order. This way, we want to better understand the ecological mechanisms driving yields, resource-use efficiency and resilience to abiotic and biotic stresses caused by pests, diseases and weeds. We collaborate with social, engineering and breeding scientists to explore how intercropping can be part of a transition to a more sustainable biodiversity-positive form of agriculture. Methods include field studies, modelling and meta-analysis.

Nutrients

We analyse the role of crop nutrition with both macro- and micronutrients on crop productivity and product quality of major arable crops including forages. Often, the work on nutrients has direct links to other themes we work on like photosynthesis, product quality or production in species mixtures. We aim to both understand the underlying crop ecological and physiological processes and the relation to effects for human or animal nutrition or the processing in the industry.

Crop photosynthesis

We address the key question for future food production: to what extent can improved photosynthesis result in increased yields of major C3 and C4 crops. We aim to understand the biochemical and physiological drivers, interactions with the environment (temperature, water, light, CO₂, nitrogen and other nutrients) and seek for multiple avenues to improve photosynthesis at the leaf and at the canopy scale. We quantify the link between the regulation of photosynthesis at cellular level and the ultimate growth of crops, via a combined experimental and modelling approach.

Tropical perennials

Perennial crops produce a wide variety of products (coffee, cocoa, tea, fruits, etc.) essential to human life. They play a major role in local economies and contribute to livelihoods of millions of often poor farmers in the tropics.

The dramatic increase in demand for these products requires increased production, yet without a concomitant destruction of the natural environment (especially loss of carbon stocks and biodiversity through deforestation). In this theme we aim to better understand the factors underlying the functioning of these crops, particularly in agroforestry systems, to contribute to their sustainable, biodiversity-positive production.

Root biology and physiology

Roots are anchoring the plant to the soil while serving as the primary organs for water and nutrient uptake. Genotypic variations in root anatomy, morphology or architecture have a profound impact on a plants ability to efficiently acquire these essential resources. These characteristics are also influenced by a variety of growth conditions, including soil properties, nutrient availability, abiotic and biotic factors, as well as the plants developmental stage. Especially climate change, with its increasing incidence of flooding and drought, is likely to have a significant impact on the availability and uptake of water and nutrients by plants roots. We combine -omics-technologies with plant physiology approaches, to understand plant roots and their adaptation mechanisms to specific environments.

Agroecological redesign

We have crossed six out of nine planetary boundaries, with agricultural production being a major driver of these transgressions. To return to a safe operating space, we require a radical transformation of all aspects of the production system.

At the Centre for Crop Systems Analysis, we address this challenge by unleashing the "superpowers" of crop diversity. We study how the smart use of diversity in agroecosystems can enhance ecosystem services and restore biodiversity. Together with farmers, we test and co-create novel cropping systems tailored to their specific needs. This theme works closely with biodiversity functioning, intercropping, and plant health.

Digital crops

Plants compete for resources such as light, nutrient and water. Plants also sense each other through all sorts of signals above and below ground, and respond to each other's presence by adapting their growth and development. Such plant-plant interactions are important determinants of crop productivity. Only if the plants that make up the crop play well together, resources can be used efficiently to produce biomass and yield.

We capture these interactions between plants, their growth and performance in 3D computer simulation models. We use these digital plants to test how plant interactions result in a certain crop performance, and how this could be influenced by changing plant traits, crop management, or altering the spatial pattern at which the plants are growing. Digital plants even allow to test plant traits or even entire plants that do not exist in reality yet. We use this knowledge to aid the development of better functioning crops that are efficient in the use of resources.

Biodiversity functioning

The functioning of ecosystems depends on various factors such as the biodiversity of species, soil and climatic conditions, and human interference. Quantifying the effects of these factors, and the interactions among them for functioning is a multi-player challenge. Within CSA we address this challenge by focusing on improving the functioning of an agroecosystem by increasing biodiversity.

For example, we study how interactions among plant species affect functioning such as crop performance under different environmental conditions, how the presence of a diverse insect community affects crop performance via pollination or pest control, and how the availability of diverse crop products within regions can support food security for local and regional populations. This theme is highly related to other themes within CSA, such as intercropping, plant health and agroecological redesign.

Parasitic weeds

Plant-plant parasitism is a well-known and studied biological phenomenon, ranging from relative independence of the parasite on the host plant (the facultative and the hemi-parasites) to complete dependence (the holo-parasites). Parasitic plants are further subdivided into stem parasites and root parasites. Around the world, parasitic plants lead to severe economic losses, in particular when they parasitize food crops.

Parasitic weeds can significantly reduce both quantity and quality of the harvestable products. Species of parasitic weeds are found across many agro-climatic zones and cropping systems and represent the whole array of possible parasitism. The most important root parasitic weeds are Broomrapes (Orobanche spp. and Phelipanche spp.) in temperate and Mediterranean zones, and the Witchweeds (Striga spp. and Alectra spp.) and Rice Vampireweed (Rhamphicarpa fistulosa) in the tropics. We study different aspects of these parasitic weeds, ranging from their ecology and biology, the drivers and future directions of their distribution, to effective and affordable management strategies.

Remote sensing of crops

Some limitations in understanding and managing crop function arise from the challenges of measuring plants responses to their environment over time and space, as well as scaling our knowledge across various integration levels. To address this issues, we investigate the use of remote sensing tools, including spectroscopy, imaging sensors and drones, to improve our capacity for monitoring crops function at relevant scales, ranging from individual plants to entire fields.

This information has significant implications for disciplines such as high-throughput phenotyping in breeding programs and for enhancing empirical and mechanistic crop models, where integrating remote sensing data may lead to improvements in predictive capabilities.

Data and models

Quantitative methods are becoming increasingly important to understand and predict the complex interactions in crop systems. In addition, the exponential increase in computational power and data availability create numerous opportunities to enhance our methodologies. However, this comes at the expense of increasing complexity in our data and modelling workflows and the need to constantly update our toolbox. We explore how recent techniques in statistics, machine learning (AI), dynamic modelling and software development can boost our research, and we aim to bridge the gap between the technical domains and our ecological and physiological research.