A pot experiment in a greenhouse was conducted to follow the question how to esti-mate dominance of legumes in legume/grass swards by image analysis. Pure swards and binary legume/grass mixtures of red clover, white clover, lucerne and perennial ryegrass were sown in two week intervals and harvested together 35, 49 or 63 days after sowing to have different old swards. Digital photos of all variants were taken one day before harvesting. Sward composition was detected by fractionating biomass in grass, legumes and unsown species as reference.
Eight images of the oldest swards were selected for determining an optimal image analysis procedure with Optimas®. This image analysis procedure was used for all variants of all ages. The estimated dominances of legumes were compared to the references. Using image analysis for estimating the dominance of legumes we could detect first good results. Red and white clover both pure and mixtures show a closer relationship with the reference than lucerne and grass. Legumes identification in pure grass swards with image analysis can be caused by weeds with rounded leaves (Stel-laria media) and visible ground. The dominance of lucerne determined by image analysis was lower then the measured dry matter yield (%). The younger the swards the more inexactly are the calculations because the visible ground increases. Next intended steps are verifying a relationship for swards of different ages and checking further procedures of image analysis
