The Biodiversify concept is based on the co-design of innovative Mediterranean cropping and farming systems based on Ecological Intensification, using high species diversification (HSD), for i) increased productivity and sustainability and reduced negative environmental and biotic impacts, ii) reduced input-dependence and increased use-efficiency of available resources, and iii) adaptation to current and future constraints of water availability and high climate variability due to climate change.
The concept of Biodiversify relies on the evidence-based notion that highly diversified cropping and farming systems are more efficient in the use of available abiotic resources than current simplified systems (Duru et al., 2015). At the cropping system level, rotating diverse crops, introducing multi-service cover crops, and mixing species enhances functional complementarity, beneficial biological interactions, and synergies between plant species and genotypes within the agroecosystem, both in time and in-field space. Exploiting the symbiotic fixation of air N2 as a major N source is a challenge because grain legumes have a reputation of low and unstable yields related to several factors, such as intolerance to water stress, harvest difficulties because of lodging, diseases, and weeds. Using legumes in association with other species is likely to alleviate these problems. Moreover, the project will study and develop the use of neglected and underutilized species, that can enter rotations (making them longer and more diverse), or be part of new crop mixtures, or species able to provide regulation services for controlling weeds, pests and diseases (e.g. Brassicaceae), to be used in species mixtures or cover crops for biofumigation to suppress soil pathogens (Couëdel et al., 2018; 2019).
To address the challenges of production in the Mediterranean area, and as a proof of concept, Biodiversify will favour species diversity over time (in rotation and during fallow periods) and space (intercropping and agroforestry) to enhance resource use efficiency (especially water and nutrients), increase resilience to abiotic stresses such as drought, and control of weeds, pests and diseases without the use of pesticides. The project will evaluate the effectiveness of high level of species and cultivars/landraces diversification to improve the production of grains for human consumption (durum/bread wheat, chickpea, lentil, etc.), and also for forage (grass/legume swards), both for on-farm self-consumption and for market use.
Thus, Biodiversify will analyse four steps in a gradient of biodiversity: i) a wider range of species used in crop rotations, ii) multi-services cover crops sown in fallow period in arable rotations or in alleys of perennial crops, iii) species mixtures in arable intercrops, and iv) agroforestry systems, providing a biodiverse agricultural framework.
This ecological intensification based on high species diversification (HSD) will then provide ecosystem services, such as 1) supporting soil fertility, input substitution, increased resource availability, 2) provisioning yield (food, feed, bioenergy) and product quality (protein, non-saturated fatty acids, nutritional composition, diet diversification, etc.), 3) controlling weeds, pests and diseases, and 4) regulating water, soil and air quality, and 5) supporting habitats and biodiversity conservation (Zhang et al., 2010). Reduced external use of inputs and improved efficiency of the use of natural resources and external inputs will result in improved biotic interactions between organisms, decreased pollution of agroecosystems (water, soil and air), and reduced consumption of non-renewable resources. Thus, the Biodiversify concept is based on HSD to conserve natural resources and improve yield stability. One of the pillars of species diversity is the re-introducion of legumes, allowing the use of natural N2. Indeed, legumes are known to provide multiple ecosystem services (Voisin et al., 2014). However, legumes are sensitive to water deficit; hence they must be selected for Mediterranean conditions. Moreover, the use of other species such as crucifers will allow favouring biotic regulations for the natural control of pests, diseases and weeds. We assume that high diversity is associated with a high adaptive capacity to climate variability and socio-economic changes, but also with more complexity for the farm management including higher labor needs (Power, 2010; Biggs et al., 2012).