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L'Unité Expérimentale de Gotheron développe des programmes d'expérimentation-recherche sur les systèmes de production durable en  ARBORICULTURE  fruitière (abricotiers, pêchers, pommiers, poiriers). © MAITRE Christophe

Water and agriculture

Territorial water management 

The long-term management of natural water resources, just like forests and biodiversity, needs to be planned on a territorial level. INRA has developed models to optimise water distribution between different uses.

As water becomes increasingly scarce and its quality diminishes, problems have arisen which go beyond single farms, plots and even the planet. The issue lies in use conflicts at the territorial level. As a consumer of water, agriculture must compete not only with domestic (drinking water) and industrial uses, but with environmental uses as well. INRA has worked for several years to take into account this new scale of analysis that provides a base for numerous public policies (land and economic development, environmental protection, etc.).

 

Better water distribution

 

To help those managing water take decisions, researchers from the UMR AGIR and LERNA at INRA’s centre in Toulouse have created a model which factors in multiple criteria and uses. It simulates water demand and the profits related to each use. Agricultural activity is particularly detailed thanks to a mechanical model that is able to take into account different crop needs and irrigation requirements. Additionally, a hydraulic model quantifies the water offer at any point along the hydrographic network. The generic model obtained was applied to the Neste catchment area in southwestern France. Crop irrigation here leads to water shortages during periods of dry weather. The model provides a way to test out hypotheses regarding optimal allocation depending on changes to climatic, economic, and agronomic parameters as well as regulations. Suitable public policies can then be tested to reach specific goals. This model was already used to examine innovative tariff systems for irrigation.

               

Simulating consequences of crop redistribution

For the Neste system, UMR AGIR researchers developed a tool that can build and assess scenarios for crop distribution systems around a region.. © ©Compagnie d’Aménagement des Coteaux de Gascogne
For the Neste system, UMR AGIR researchers developed a tool that can build and assess scenarios for crop distribution systems around a region. © ©Compagnie d’Aménagement des Coteaux de Gascogne
 

For the Neste system, UMR AGIR researchers developed a tool that can build and assess scenarios for crop distribution systems around a region. The model describes in great detail the current crop system distribution and details about their location (soil type and gradient, farm size, type of farming practiced, climate, etc.). The simulations provide indicators such as irrigation water demand or crop yield profits according to the various scenarios.

The model lets all the different players build a case for their view of how the land in the region should be used. “This need came about during a public debate on the construction of the Charlas Dam,” says Delphine Leenhardt, researcher at the UMR AGIR. “A group who opposed the project called for a significant reduction in irrigated maize farmland, but could not offer suggestions as to what crops should replace the maize or where. This could weaken the proposal.”