In a two-year pot exp., the effect of soil fertilization with a corn. humic acids-based prepn. on yielding of maize and celery was studied and compared with the yields on soils fertilized with mineral and manure fertilizers. The use of humic acids increased the dry matter yield of aboveground parts of the plants by 10-22% and 15-41% by mass in comparison with mineral and manure fertilization, resp. In the same test, the yield of plant roots increased also by 19-35% and 13-64% by mass, resp. The studied humic acid prepn. showed low aliphaticity which was proofed by IR spectrum.