Potential nitrogen supply of annual forage legumes for organic farming in a mediterranean environment

Abstract

The need of information about new species of annual forage legumes as green manure crops for Mediterranean environments, led us to this study with the objective of evaluating the nitrogen replacement value of these crops.

We evaluated the effects of six forage legumes: balansa clover, crimson clover, gland clover, arrowleaf clover, french serradella and yellow lupine; one grass (ryegrass); one mixture (ryegrass with balansa clover) e one control treatment (semi-natural vegetation) in two different sowing dates: September e October 2007.

Results on dry matter yield, nitrogen concentration e nitrogen uptake were obtained for these treatments in 2007/08. In most treatments the better results of dry matter yield, nitrogen concentration e nitrogen uptake/supply were found on the second sowing date. The french serradella had the highest yield of dry matter (7179 kg ha^-1). Balansa clover had the highest value of nitrogen concentration (26.85 g kg^-1) e nitrogen uptake (124 kg N ha^-1).