RESUMEN
The basis for the study was a field experiment conducted in 2012-2014 in the production fields of multi-branch Soleks company in Wojnów, the district of Siedlce in eastern Poland. The experiment was established in a split-plot arrangement as a two-factor experiment in three replications. The first factor were: three cultivars of edible potato-Bartek, Gawin, Honorata, and the second factor were: five objects of potato cultivation with herbicides and biostimulants: 1-Control object-without chemical protection, 2-herbicide Harrier 295 ZC, 3-herbicide Harrier 295 ZC + biostimulant Kelpak SL, 4-herbicide Sencor 70 WG, 5-herbicide Sencor 70 WG + biostimulant Asahi SL. The aim of the study was to reduce the non-commercial potato yield and improve the yield structure through the application of biostimulants and herbicides, and to determine the relationship between weed infestation and tuber yield. The least amount of weeds and the best destruction efficiency were obtained after the application of herbicide Sencor 70 WG + biostimulant Asahi SL and herbicide Harrier 295 ZC + biostimulant Kelpak SL. Effective reduction of weed infestation contributed to improvement of yield structure and reduction of potato non-commercial yield. Based on correlation coefficients, a significant relationship between weed infestation and potato non-commercial yield was shown.