Влияние на вегетационния хербицид Енвоке върху някои структурни елементи на продуктивността и добива от памук (Gossypium hirsutum L.)

Abstract

Weeding during the growing season of cotton suppresses and slows down the growth and development of plants, and can lead to a significant reduction in yield and deterioration of fiber quality. The aim of this research was to study the effect of vegetation applied herbicide Envoke on the yield of cotton and some structural elements of productivity such as percent of boll opening and boll weight, under different agro-meteorological conditions. The research was conducted during the period 2020-2022 in the experimental field of the Field Crops Institute in Chirpan. In a three-factor field experiment, the effect of vegetation applied herbicide Envoke, containing 75% trifloxysulforon-sodium, was tested on two cotton varieties. Factor A included the three years of study. Factor B included the cultivars Chirpan-539 and Helius. Factor C included the herbicide Envoke applied in 3 doses - 10 g.ha-1, 15 g.ha-1 and 20 g.ha-1, once and twice during the 4-5 leaf and budding stages of cotton. It was established that when treated with the herbicide Envoke, the highest yield was obtained with the single treatment in the budding phase at a dose of 20 g.ha-1 for the cultivar Chirpan-539 and at a dose of 15 g.ha-1 for the cultivar Helius. Technologically valuable were found all variants with the herbicide Envoke in the cultivar Chirpan-539 and the variants in doses of 15 g.ha-1 and 20 g.ha-1 in the cultivar Helius. These options combined high yield values and high stability of this indicator in different years. The untreated controls in both cultivars were the only ones that received negative scores. This was due to the high number of weeds and self-sown sunflower (Helianthus annuus L.) plants. The vegetation herbicide Envoke, applied in three doses, once and twice during the 4-5 leaf and budding stages of cotton, had little influence on the percentage of boll opening and did not affect the boll weight at the treated variants of the two cotton cultivars - Chirpan-539 and Helius.