Amendment network

Coordination : Champenoux, 54280, France

Sites localisées en France métropolitaine

https://www6.nancy.inra.fr/bef

This network includes about thirty experimental sites distributed throughout France. Different species are represented (oak, beech, spruce, fir, douglas fir, pine), several of which may co-occur in the same experiment. The age of the stands when the trials were set up varies greatly, as do the amendments used (fertilisers, Ca or Ca-Mg carbonates, gypsum, slag, etc.) and the doses administered (from a few dozen kg to several tonnes per hectare). Expeimental sites vary in size from 1 to 6 hectares, depending on the methods applied, the number of blocks and the size of the plots (from 0.01 to 1 ha).

At set-up – and before any amendments were applied, most of the plots underwent a formal "initial condition" assessment.  Then, sampling campaigns and physico-chemical analyses (soil, humus, population) were carried out more or less regularly depending on the technical, human and financial resources available. Therefore, the frequency of measurements often varies from one experimetal site to another depending on the parameters monitored, the initial objectives and successive scientific projects related to each experimental site).

Different ecosystem components are concerned (soil, humus, individual trees, leaves/needles, the herbaceous layer, etc.). The effects of the amendments on the ecosystem can be deduced from comparisons between plots having received the fertiliser and control plots (ecosystems similar in all respects, but without inputs). Changes in each component and in the global ecosystem can then be studied by comparing the measurements, or scores, recorded during successive survey campaigns.

The most commonly performed analyses are: (i) pedological or systematic soil chemical analyses, horizon by horizon; (ii) chemical analyses of humus and evaluation of the quantities of dry matter per hectare; (iii) chemical analyses of leaves or needles, (iv) inventories in the middle of the stands; (v) species inventories for the tree, shrub, herbaceous and moss strata; and, for a few plots, (vi) stand biomass and mineralomass.

Data collected from all the sites is centralized and available for use in collaborative projects.

The network is managed by a research officer (for the scientific aspects) and a field technician (for the technical aspects) from the Biochemistry of Forest Ecosystems "BEF" unit (INRAE Grand Est Nancy). The collection of samples is carried out by BEF staff. Sample preparation and analyses are carried out in the BEF laboratory by an assistant engineer and a technician.

The work consists in collecting samples (soil, humus, plants), and pre-treating and analysising the samples. The network’s approach is to interact as much as possible with the user(s) to discuss all aspects of their project. These discussions allow the team to treat each request individually and to adapt their support to the request. The network mainly offers scientific, technical and logistical support. It is possible to use ANAEE-France's mobile platform (MPOETE) as additional support for field campaigns, experiments and data acquisition.

Access conditions are defined according to research projects or applications. We provide access to the Amendment Network sites, associated data and the various solid samples collected since the installation of the plots. We also offer laboratory space for sample preparation and processing. The cost of access is defined according to each research project or request.

The majority of the plots do not have permanent instrumentation. Nevertheless, some plots in the network have been selected as instrumented experimental in-situ sites (Potées, Breuil-Chenue, Fougères) where the focus is on studying biogeochemical cycles at the ecosystem scale and, as such, are fully equipped with a variety of instruments: soil moisture probes, litter collectors, porous filter candles and/or lysimetric plates, rainfall and trunk runoff collectors.