Marushchak O. Biological features of Chenopodium genus weeds and protection of sugar beet stands from them in the steppe zone Ukraine

Degree of a negative influence of plants of Chenopodium album L. and Chenopodium hybridum L. on the productivity of sugar beet stands was determined. Agricultural thresholds (-5 % yielding ability) on the 30 day of common vegetation of sugar beet with fat hen were 1276 g/m2, an the 140 day they were 86 g/m2. Biological thresholds were from 63 g/m2 17 g/m2 respectively. It was established that an optimal for germination of Chenopodium album L. seeds interval of medium acidity was pH 7,0-7,5. Concentration of NO3 up to 0,3 % stimulated seed domination, while a higher one inhibited it. Reactions of juvenile plants of Chenopodium album L. at different stages of their development to mechanical injuries were evaluated. Destruction of 50 % of leaf blade surface and an apical bud of Chenopodium album L. plants at stages cotyledon resulted in their death. On the basis of evaluation of efficiency of the system of successive sprayings with different herbicide compositions, a reliable system of protection of sugarbeet stands from weed seedling complex including representatives of the botanic genus Chenopodium. A suggested system of protection of sugar beet stands from weeds guarantees the increase of profitability by 26,6 %, comparing the traditional system.