ATCHA

Agriculture is increasingly relying on groundwater irrigation. The Indian context is an extreme case: the “groundwater revolution” which started three decades ago and induced a well identified “groundwater crisis” with tremendous impacts on water resources and ecosystems, is the result of millions of very small farmers owning individual borewells, with a large diversity of practices and strategies. Groundwater depletion is expected to worsen with climate change. Thus, it is critical to develop reliable and practical methods for assessing the sustainability of agricultural systems under climate change. The ATCHA project aims to combine an integrated biophysical model with a participatory approach to help adapt farming systems to climate change in a network of experimental watersheds in Southern India.
A wide variety of models have been developed for ex-ante evaluation of management policies or assessment of the impacts of land-use changes. They are commonly used to support decision making by stakeholders through participatory approaches. However, the models rarely represent both the complex biophysical processes at stake in agricultural watersheds and the farmer adaptation strategies to changes. Consequently, these models are not able to adequately account for the spatial and temporal interactions and feedback between these two components. Through a unique trans-disciplinary approach, involving hydrologists, geochemists, soil scientists, agronomists, geographers, economists and sociologists with a strong participation of Indian scientists and stakeholders, we aim at demonstrating the ability of researchers and through the International Joint Laboratory “IndoFrench Cell for Water Sciences” (IFCWS, involving the Indian Institute of Science, Bangalore) (2) a Critical Zone Observatory (ORE BVET) which has built an extensive hydro-geochemical database in the Berambadi experimental watershed and (3) a preliminary version of an integrated model combining hydrology (AMBHAS), agronomy (STICS), economy (MoGire) and farmer decision (Namaste) that was developed for the Berambadi in a former Indo-French project (IFCPAR AICHA, 2013-2016). The ATCHA project will complement and in which IFCWS takes part in the coordination of the hydrological monitoring carried out in 14 experimental watersheds across the Karnataka state.

The project is composed of 3 challenging work packages: i) development of novel methodologies to gather information on soils and land use at high spatial and temporal resolution by using both ground and multisatellite data ii) provide a realistic biophysical model based on a thorough study of nutrient cycles in tropical irrigated agro-systems iii) development of a participatory approach to build and assess scenarios of adaptation to climate change. WP1 and 2 will provide information that will sustain the scenario construction in WP3. WP3 will provide integrated assessment of scenarios and feedback to WP1 and 2 for an iterative process.
The ATCHA project is expected to produce significant scientific advances on the functioning of agrohydrosystems under high anthropogenic pressure. It will also have a strong socio-economic impact, particularly in improving the relevance of public policies and of advice given to farmers by extension services.