热博体育

Issues

Agroecology is emerging as an alternative to conventional agriculture, which generated an increase in agricultural yields through the use of synthetic inputs (mineral fertilisers and pesticides) during the Green Revolution, but is now considered unsustainable. This agroecological transition, based on ecological processes and in particular the relocalisation of nutrient cycles, has significant implications for land use. In Africa, where population growth is particularly high and dietary changes tend to increase demand for animal products, the agroecological transition could result in the expansion of cultivated and grazed areas at the expense of natural spaces, especially forests. At the heart of these issues of soil fertility and land use is the question of biodiversity preservation, which is addressed through modelling of material balances at the level of final food and non-food demand, as well as nitrogen cycle closure

Description

The objective is to identify the physical limitations to the widespread adoption of an agroecological model in Africa, under the constraint of reducing the continent's food dependency and with a view to strong sustainability. The project will build on the GLOBAGRI accounting model developed by 热博体育, which uses balances to define the cultivated areas needed to ensure equilibrium between the supply of agricultural products (production and imports) and demand for these products (domestic demand, exports, stocks). The preservation of natural capital will be a constraint applied to the conservation of wooded areas the limitation of fossil-based inputs and agricultural pollution, and the maintenance of soil fertility. Changes in diets, population, yields, and nitrogen fertiliser use will be the main input variables for the model. The spatialisation of local fertility transfers will be modelled and aligned with national-level balance models. The project will improve these models, particularly in order to make them more relevant to Africa (livestock mobility, transfer of fertility between regions, etc.).

Expected results

The results should clarify the implications of expanding an agroecological scenario for the degree of food dependence – or independence – of African countries, taking account of different assumptions regarding dietary changes and varying constraints on the use of natural spaces. More localised analyses on the potential to mobilise biomass to close nitrogen cycles should provide a better understanding of the potential for reducing mineral fertiliser use. Observing the balance between food needs and supply under different nitrogen fertiliser use scenarios, while respecting natural areas and avoiding pollution levels harmful to biodiversity, will enable the production of GHG balances according to land use. Ultimately, this will foster political dialogue with the authorities in African countries on the opportunities and constraints of an agroecological transition in their national context.