Lucerne (Medicago sativa) or grass-clover as cut-and-carry fertilizers in organic agriculture

Abstract

Onfarm nitrogen fixation is a driving force in organic agriculture. The efficiency with which this nitrogen is used can be increased by using lucerne (Medicago sativa) or grassclover directly as sources of fertilizer on arable land: cutandcarry fertilizers. In two arable crops, the use of lucerne and grassclover as fertilizers was compared with the use of poultry manure and slurry. The nitrogenuse efficiency at crop level was comparable or better for the cutandcarry fertilizers as compared to the animal manures. The relative P and K content of these fertilizers came closer to the crop demand than that of the poultry manure. Crop yields were comparable or better when using lucerne or grassclover as fertilizer. It is concluded that cutandcarry fertilizers are a serious alternative for manure as part of an overall farm soil fertility strategy