Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Osur

ORE agro-hydrosystèmes

Zone de texte éditable et éditée

Soils and geology

The geological bedrock of the catchment of Kervidy-Naizin is composed of fissured and fractured upper Proterozoic schists. The soils, developed into a loamy material derived from weathered schists and eolian Quaternary deposits, exhibit facies variations, which are locally dominated by silt, clay or sanstone materials. The mineralogical composition of schist, as determined from drill cutting analysis, include (in decreasing relative proportion): quartz, muscovite, chlorite, K-feldspar and plagioclase (Pauwels et al ., 1998).

The soil horizons whose total thickness may be highly variable at the scale of the catchment (from 35 to roughly 5 m) comprise a large number of secondary mineral phases including illite, smectite, kaolinite, various Fe-oxides and Fe-oxi-hydroxides (hematite, goethite,...) and Mn oxides. The soils are organized following the topography with well-drained ”Luvisols” in the upland areas while in bottomlands poorly-drained domains consist of "Luvisols –Redoxisols" and "Luvisols – Redoxisols dégradés" resulting from an increasing development of hydromorphy and degradation in originally well-drained horizons due to an excess of water of topographical origin. These soils are acid (pH from 5 to 7 in surface, from 4.6 to 6.7 in the regolith).

The content of organic matter varies from 2.5-6.5% in the upper layers to 0.3-2% in deeper zones and in the regolith. Organic layers are 30-40 cm deep. The hydraulic conductivity is around 10-5 m/s in upslope soils to 10-6 m/s in bottolands. The weathered zone is 1 to more than 30 m deep and its hydraulic conductivity is between 4.10-5 and 2.10-6 m/s. The conductivity of the geological bedrock is estimated around 3.5 10-6 m/s (Pauwels et al., 1996).