Regarding the ‘Think Global’ part, it is difficult at this stage to evaluate in detail the expected results since they will be defined by the stakeholders during the first symposium at Les Courmettes (see Workpackage 1). Under the aegis of the National Environmental Alliance, work will focus on the following three main topics:
– The potential size of ecological agriculture
Estimating the potential of this sector will facilitate the implementation of financing methods and means.
– Financing methods
The innovation of financing models seems crucial considering the current difficulties encountered by stakeholders in accompanying the biological transition in the territories. Several possible orientations could lead to original and well-understood financing solutions in the interest of the stakeholders (private and public) and the improvement of the environment.
– Designing transition Social Business Models
Current models mainly adapted to conventional agriculture may need to be redesigned. Unleashing energies, including from untrained contenders, will require the design of innovative and sustainable transition structures (otherwise not subject to the ‘short-termism’ incompatible with the sustainability issues of the models).
Regarding the ‘Act Local’ part, the implementation of the experiments will allow providing elements to meet the objectives set out in this project.
Due to their complexity, the agrosystems implemented will enrich the taxonomic diversity of the soil and potentially its functionality. Fruit quality will be improved given the essential role of soil microorganisms in the synthesis of some secondary metabolites. The choice of vegetable varieties and fruit trees, and the way they are associated in the fields will also be a fundamental aspect in selecting specific communities of beneficial soil microorganisms in the specific context of the experiment, especially marked on average by severe water stress during the summer period. The fruits from these varieties, often referred to as ‘heirloom’, will be of a higher nutritional and organoleptic quality than varieties dependent on synthetic chemicals and which come from a selection not adapted to the characteristics of agroecosystems.
The planted trees will serve as a reservoir of biodiversity in the broadest sense, particularly for microorganisms that are beneficial to the soil because of their sustainability; this will improve soil quality in the long term. The roots of vegetable plants, which are annual, will then be colonized more quickly by beneficial soil microorganisms; this will reduce mortality after transplanting into the field.
Intensive and permanent occupation of the plots, but also the development of coherent crop successions, will reduce the pressure of competing weeds of cultivated plants on trophic resources. In addition, non-competing weed species that are potentially providing ecosystem services (e.g. pollination or bio-indicators) will then be identified and valued.
The trees planted, being at an early stage of development, will not cause competition for light for vegetable plants; they will also favour freshness by promoting North-South orientations. The trees will also provide an interesting and renewable plant amendment (leaf loss).
Concerning nutrient inputs, the combination of plants belonging to the Fabaceae family, i.e. characterized by their ability to form a mandatory mutualist symbiosis with soil-borne atmospheric nitrogen fixing bacteria, will allow promoting nitrogen flows in the soil but also to store stable organic nitrogen in the soil, and thus limit nitrogen fertilization. The storage of nitrogen in the soil will involve the burial of healthy crop residues and thus tillage, which could impact not only the soil structure but also the mycorrhizal networks.
Nutrient loss through leaching, especially in the steep configuration of the test plots, as well as soil erosion will be limited by the presence of fruit trees and surface tillage or soil conservation. Similarly, increasing organic matter in the soil through organic fertilization and vegetation cover will improve soil structure stability and nutrient fixation.
Finally, the complex analysis of the resilience of the agroecosystems tested will allow identifying the candidates best suited to the soil and climate conditions of the experiment. At a time of climate change, more and more agricultural land will be affected by exceptional climatic phenomena, such as high heat or intense rainfall. Therefore, it will be necessary to consider the stability and development of these ecosystems over time.