The studies were performed on the organic plot of AES of IUNG in Grabów in 2012. Experimental factors were: 4 legumegrass mixtures (the first factor): 1 - Trifolium repens (25%) + Trifolium pratense (25%) + Lolium perenne (15%) + Dactylis glomerata (15%) + Festuca pratensis (10%) + Festuca rubra (10%); 2 - Trifolium pratense (50%) + Lolium perenne (20%) + Festuca pratensis (20%) + Phleum pratense (10%); 3 - Medicago x varia (50%) + Dactylis glomerata (20%) + Festuca pratensis (20%) + Phleum pratense (10%); 4 - Trifolium repens (25%)+ Medicago x varia (25%) + Lolium perenne (15%)+Dactylis glomerata (15%) + Festuca pratensis (10%) + Festuca rubra (10%) and 2 ways of using sward: hay/pasture and pasture (the second factor). The purpose of the research was to assess the effects of the species composition of several legume-grass mixtures utilized in a hay/pasture or pasture way (periodic cow grazing) on the weight and content of nutrients in the aerial and underground fraction of post-harvest residues. The conducted studies have shown that legumegrass mixtures left behind a large weight of post-harvest residues with a high percentage of grasses. The weight of nutrients brought into the soil varied depending on their percentage in the post-harvest residues. Most of the post-harvest residues were left by a mixture of alfalfa with grasses. More potassium was left by mixtures on pastures, while the weight of other nutrients was similar in the tested ways of sward use.