DIAMS

The issues at stake

In a context of agroecological transition and increasing climate-related hazards in Mediterranean regions, agricultural systems must reconcile production, soil preservation, and adaptation to water deficit. Intra-plot agroforestry consists of integrating tree rows within cropped fields. It is considered a promising approach to enhance carbon sequestration, promote biodiversity, and regulate water and nutrient flows. However, scientific references based on long-term, instrumented experimental facilities remain scarce in Mediterranean climates. The DIAMS facility was designed to compare the biogeochemical and ecological functioning of an agroforestry system with that of a conventional arable cropping system and a forest plantation under different water regimes.

The device

Established in 2017, the facility is based on a split-plot factorial design with three blocks, comparing three land-use types:

• Agricultural system without trees: a low-input rotation of cereals and grain legumes;
• Forest plantation: monoculture of black locust (Robinia pseudoacacia) at a density of 1,666 trees/ha;
• Agroforestry system: an intra-plot association of black locust trees planted in rows 17 m apart, with crops grown between the rows (294 trees/ha).

Since 2022, two water treatments (irrigated / non-irrigated) have been applied to each land-use typeTwo hydric treatments (irrigated / non-irrigated) have been applied since 2022.

The site covers 7 hectares and includes:

• 1.8 ha of agroforestry,
• 0.8 ha of arable crops,
• 0.52 ha of forest plantation,
• buffer zones between the experimental plots.

The facility is heavily instrumented, with:

• pits equipped with multi-depth sensors (down to 3 m),
• soil temperature, moisture, and water potential sensors,
• porous cups for soil solution sampling,
• buried scanners for monitoring roots and soil fauna,
• microclimatic sensors (PAR radiation, air temperature and humidity, wind speed and direction),
• dendrometers for monitoring tree growth,
• a weather station integrated into the INRAE CLIMATIK network,
• centimetre-precision geolocation (dGPS).

The site

The DIAMS platform is established on the grounds of the DiaScope Experimental Unit (INRAE) in Mauguio, in a Mediterranean environment. The climate is characterised by hot, dry summers and strong intra- and interannual variability in rainfall. The facility was set up in 2017 on former alfalfa land. An initial soil characterisation was carried out at 374 sampling points, with archived samples retained. The site is instrumented for continuous monitoring of soil and climatic conditions, and regular measurements are conducted on tree, crop, and herbaceous plant phenology, tree growth and litter production, the diversity of fauna and flora in the different compartments, as well as crop growth and yield.