Biomass production of Chenopodium album L. in spring barley sprayed with different herbicides at the recommended and at the reduced doses

Abstract

The aim of the work was to determine the influence of reduced doses herbicide and spring barley density on seed and biomass production of Chenopodium album L. The field experiments were carried out in the years 2000, 2002–2003 on podsolic soil made from heavy loamy sand. There were two factors in the experimental scheme: I. Seeding rate of spring barley (200, 100 seeds m^-2), II. Herbicide rate and time of herbicide application. Herbicides were applied at the recommended rate (3/3) and at 2/3 and 1/3 of the recommended dose. Three doses of herbicides were applied at the beginning of tillering (BBCH 21) and at the end of tillering of spring barley (BBCH 29). Competition between spring barley and Chenopodium album L. was studied in two experiments. The first field experiment was carried out with tribenuron methyl (Granstar 75 WG) and the second one with a mixture of mecoprop + MCPA + dicamba (Chwastox Trio 540 SL). Herbicides were applied at the recommended rate (3/3) and at 2/3 and 1/3 of the recommended dose. Weed biomass and seed production of Chenopodium album was reduced when spring barley was sown with the higher seeding rate. The average seed mass on the untreated plots was higher at low crop density (88.5 g·m^-2) than the seed mass at optimal density of spring barley (44.4 g·m^-2).

Reduction of Chenopodium album seeds production was observed after application of herbicides at the BBCH 21 of compared spring barley with the late application. Chenopodium album seed mass collected from the plots treated with mecoprop + MCPA + dicamba was higher than the mass collected from the plots treated with tribenuron methyl.