Forage production of rotational set-aside land in Belgium after the legal set-aside period

摘要

In the European Union, set-aside was introduced in 1992 in order to reduce production. Farmers growing more than 92 t/ha cereals and wishing to receive compensatory payments were to submit to the setaside system. Several reasons incited farmers to sow a plant cover: control of weeds and diseases, limitation of erosion and of nitrate leaching. In Belgium, the rotational set-aside period begins on 15 January and ends on 31 August (with a compulsory cut during the second fortnight of August). On mixed farms harvesting the plant cover after the legal set-aside period can supply a non negligible forage complement. The yields of various plant covers in Central Belgium after the legal set-aside period were analysed. These comprised: perennial ryegrass alone (with 60 or 80 kg N/ha) or associated to white or red clover, red clover alone or associated to Italian ryegrass, lucerne/meadow fescue. Several covers had quite variable yields. The sowing date (before or after winter) hardly influenced the yield. Best yields however were achieved by taking a last cut as soon as possible after 15 August. It was shown that the best sowing mixtures combined perennial ryegrass and red clover, with the yields rangeing from 2.0 to 2.6 t DM/ha. Moreover infestation by weeds was strongly reduced without any excess of plant matter being produced during the set-aside period.