TEMPORAL DYNAMICS OF ACTUAL WEED INFESTATION IN SUNFLOWER CANOPIES PUBLISHEDŠtefan Týr, Tomáš Vereš
In the years 1994 – 2009 (15 years) was conducted weed survey on the farms in conventional farming system. The aim was to detect the most harmful weeds, as important biotic, environmental stress factor, on the farms in the canopies of sunflower in mays and sugar beet production region of the Slovak Republic. The actual weed infestation was evaluated by standard methods common used by a counting method per square. The four randomly established sample quadrants were situated minimally 20 m from field margin and apart each other, respectively. In the sunflower 34 weed species were detected, the most problematic were: perennial weed Cirsium arvense, Elytrigia repens, Convolvulus arvensis, annual weeds Chenopodium spp., Echinochloa crus galli, Persicaria spp., Amaranthus spp., Abutilon theophrasti, Ambrosia artemisiifolia, and cultural crops winter wheat, winter raps. Temporal dynamics in actual weed infestation depend on production region, early crops and canopy of sunflower in the last 15 years. The efficacy of herbicides was assessed according changes of weed population before and after herbicides application. Present study assessed the actual weed infestation of dominant weed species in canopy of sunflower in 1994 – 2009, presentation in graphic and statistic results. After herbicides control the significant changes in weed flora were noted in term of abundance and share of some weed species on total weed community. Contamination of live environment in integrated agricultural system and herbicide costs lead as to idea to grow agricultural crops by using only cultural, preventive and mechanical weed regulation methods, the same as in conventional system. This claim is feasibly only in sunflower crops infested level. The originality of result is mappings weeds species.
temporal dynamics; actual weed infestation; mapping; sunflower