OPERATING INSTITUTE: Forschungsinstitut für biologischen Landbau, FiBL and Eidgenössisches Volkswirtschafts departement (Agroscope Reckenholz-Tänikon Research Station) (EDV-ART).
MAIN PURPOSE: Sustainable food production and ecosystem services.
ECOSYSTEM TYPE: Agricultural site, rotation.
EXPERIMENTAL TREATMENTS: Fertilisation and crop protection in conventional and organic agricultural systems.
LOCALISATION: 47.534107938278844 7.5450897216796875
FACILITIES: The DOK experiment compares two organic and two conventional farming systems in a seven-year ley rotation on a loess soil. It was established in 1978 in 1978 in Therwil (Basel-Land) in the vicinity of Basel (Switzerland). Systems differ in terms of fertilisation and plant protection. The experiment is designed as a split plot with 4 replicates and a plot size of 5x20m, and comprises 96 plots in total. Data on yields, soil and plant assessments are stored in a data base. Plant and soil archive samples over 35 years are also available. Biogeo-chemical processes of N, C, and P are studied as well as plant-microbe interactions. The site has been equipped with chambers to study trace gases (CO2, N2O, CH4) in the next three years.
Quite recently, the DOK trial was upgraded by a GC system to measure greenhouse gases (GHG), which were sampled by the closed chamber technique. Since August 2012, soil-derived greenhouse gases (GHG) have been measured regularly for a time span of three years in conventional and organic farming systems in the DOK long-term field trial. For this, the closed chamber technique is applied to collect gas samples which are further measured for their concentrations using a GC system (Agilent Technologies, Santa Clara, California/USA) equipped with a CTC-Gerstel multi-purpose auto-sampler (Gerstel, Mühlheim/Ruhr, Germany). This device enables high-through-put analyses of the greenhouse gases CO2, N2O and CH4 within four minutes in a broad array of vials differing in size. Furthermore, the freely programmable CTC-Gerstel auto-sampler device eases the generation of sample aliquots for stable isotope analyses of the above-named gases through the implementation of so-called prep sequences. The CTC-Gerstel auto-sampler also facilitates the continuous measurement of GHG in the head space of laboratory incubations and therefore enables in-depth studies of phenomena observed in the field. Until now, the GHG fluxes were determined in a grass-clover/maize sequence and during the cropping of winter wheat in organic and conventional farming systems of the DOK trial.
The field research is accompanied by the conduction of global meta-analyses on soil carbon development and GHG fluxes in soils under organic and non-organic management (Gattinger et al., 2012; Skinner et al., 2014).