The study was conducted between 2000 and 2004 in the Olsztyn micro-region in the north-east of Poland. A static field experiment, conducted using the random sub-blocks method, was located on class IIIb complex 2 soil, in three replications. The subject of the study was a crop rotation of silo corn, horse bean, and winter triticale. Six methods of nurturing were assessed, with two of each type: chemical nurturing based on herbicides applied to the leaves and the soil, and mechanical nurturing – traditional and intensified through multiplication of selected treatments, and biological nutrition which makes use of phytosanitary and allelopathic properties of so-called alternative plants. The study included analysis of potential (before and after the experiment was conducted) and actual weed infestation (at the beginning and at the peak of plant vegetation). The mass of the main harvest was converted into grain units. The significance of the differences between fields was established using variance analysis based on the Duncan test. The results show that among the tested nutritional treatments, it was the herbicides applied to the soil that were highly positively distinctive. From the very beginning of vegetation in the specified fields, the plants enjoyed much better conditions for growth and development, as weed infestation level was 70 to 81% lower than elsewhere. In the subsequent phenophases, the activity of those herbicides was reduced, but weeds still constituted the smallest group. The remaining nutritional treatments eliminated on average 66.5 to 76.0% of weeds from the tested fields. Herbicides applied to the soil proved the most effective in reducing the growth of weed diasporas in the soil. It amounted to as little as 15.4%, whereas in the fields protected mechanically it was 76.9% (3) and o 67.7% (4), and biologically – 141,5% (5) and 258.5%(6). The average crop yields in the crop rotation after conversion into grain units also positively distinguished the fields treated with herbicides applied to the soil (59.0 grain units from one hectare). They were significantly higher exclusively with respect to the yield from fields protected by alternative plants.