KVÄVEREDUKTION VID ÖVERSILNING / Nitrogen Reduction on Inundated Meadows

Inundation of meadows is an old farming system, where the water from a river is used to flood the nearby meadows during a number of days, in order to increase the production. During 1991 it has been tested, in two places in Scania (the southernmost part of Sweden), as a system for removing nitrogen from river water. The nitrogen removal measured through mass balance budget is compared with directly measured plant uptake and denitrification. At the first site, Vombs ängar near Vombsjön, where the soil is mostly sand, the water and nitrogen balance has been established for four two-week periods (two during late spring and two during late autumn). During spring the infiltration of 3,000 mm/month with 2-3 mg/l results in a nitrogen removal of 50 kg/ha•month. The same rate of infiltration and the nitrogen level of 4 mg/l during autumn gives no removal. For a whole year this amounts to 300 kg/ha. This can be compared with the natural nitrogen removal rate for cultivated sandy soil, 130 kg/ha. “Complete abstract not presented.”