-The application of the organic fertilizers in soils is essential to maintain soil fertility and increase crop productivity. Organic fertilizers improve the physical, chemical and biological characteristics of soils. Different compost derived from the composting of the waste fermentable, are used in this experiment. The composts have different particle sizes (10 mm and 40 mm). The latter has basic pH values (8-9), C/N ratios varying between 17, 7 and 19, 7. The organic matter rate, answer to norm NFU 44 051 (varying between 34% and 48%). The analyses of the elements trace metallic show that the rates are in conformity with the international standards of organic amendments. The results of phytotoxicity show that the composts are mature. The different compost (fine and coarse) added to mineral fertilizers gives of the rates high of potatoes (50 %, 50, 8 %) and turnips (59, 5%, 62 %), whose the caliber is over 55 mm. This shows that compost is a necessary additive to minerals fertilizers since it acts as an organic amendment for the fertility of arable soils, and it acts as a mineral amendment for a better productivity of the different cultures.