Optimization of Herbicide Doses in Sustainable System of Maize Cultivation

Amendment to the EU standards has considerably reduced the list of biologically active substances of herbicides meeting the criteria of Good Agricultural Practice. The required usage of these substances at their maximum recommended rates ensures their fast action and high efficiency of a treatment with respect to a number of weed species, regardless their susceptibility. However, the herbicides have often been used in excess which has not always been justified by the true necessity of weed control and by their selectivity for the protected crop. The realistic knowledge of the weed infestation hazards in plough–system maize cultures maintaining appropriate crop rotation should enable meeting the most important goal of sustainable agriculture – reducing the rates of chemical pesticides to the indispensable minimum. At low weed infestation levels and at the reduced rates of herbicides it is necessary to assist the herbicide`s active ingredient by the addition of adjuvants. As a consequence, one may expect the improvement in the herbicide efficacy, even if it has been applied at the reduced rate, as well as stabilization of an herbicide performance under unfavorable weather conditions. On haplic phaeozems, it is possible to successfully control monocotyledonous and dicotyledonous weeds with Callisto 100 SC + Milagro 040 SC mixture supplied with Atpolan 80 EC adjuvant and applied in split recommended doses, as well as in the doses reduced by as much as 50%. On haplic cambisols, only sporadic occurrence of Echinochloa crus–galli (L.) P. Beauv and Setaria viridis (L.) P.Beauv. was recorded, but considerable incidence of Chenopodium album L. and Amaranthus retroflexus L., as well as individual plants of Artemisia vulgaris L. had been observed. In case of low infestation by monocot weeds, the satisfactory effect could only be achieved when the mixture was applied at the full recommended doses of its components and supplied with adjuvant. The addition of Atpolan 88 EC adjuvant provided effective control of such species as Viola arvensis Murray, Galium aparine L., Geranium pusillum Burm. f. ex L. and Artemisia vulgaris L., even when the dose was reduced by 1/3.