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 the vicinity of Basel. Systems are differing in fertilization and plant protection. The experiment is designed as split plot with 4 replicates and a plot size of 5 m x 20 m, 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 31 years are also available. Bio-geochemical processes of N, C, and P are studied as well as plant-microbe interactions. The site will be equipped with chambers to study trace gases (CO2, N2O, CH4) in the next three years