| Abstract [eng] |
Agroecosystems in Europe cover approximately 40 % of land size, the ecosystem services they provide are of great importance. The intensification of farming technologies from the mid-20th century has strongly altered segetal flora, thus the decline of weed diversity has been observed across Europe. The aim of this master‘s thesis is to assess the diversity, characteristics and changes of segetal flora in Joniškėlis and Semeliškės districts. Objectives: to evaluate changes in the abundance of weed species; to evaluate changes in segetal flora diversity; to determine the composition of segetal plant families; to determine the composition of weed growth forms; to evaluate the dependence of weed species on the characteristics of crop plants; to evaluate the importance of soil agrochemical properties to the diversity of segetal flora. The study subject was weed communities in crop fields. Data on weed communities was collected in 2025 in Joniškėlis and Semeliškės areas and it was compared with data from 2001 and 2016. There was a significant drop in the number of weed species in both areas. Weed diversity has decreased significantly in Joniškėlis area. In both areas the most abundant systematic families in weed species number were Asteraceae, Poaceae, Plantaginaceae, Fabaceae and Caryophyllaceae. Most of the weed species observed were annuals, a significant proportion were clonal, while the fewest were monocarpic perennial non-clonal and polycarpic perennial non-clonal. There was a significant decrease in the number of weed species within all growth forms in Joniškėlis area, while only annuals decreased significantly in Semeliškės area. The number of weed species was significantly lower among Brassica napus, Triticum aestivum and Vicia faba crops. There were significant positive correlations between the number of weed species and both mobile and total potassium in soil. |
