This study aimed to compare weed flora in conventionally and organically grown medicinal and aromatic plants (MAPs): basil, pot marigold, dill, and peppermint; in terms of weed composition and weed abundance. A total of 28 weed species (25 and 15 species in conventional and organic crops, respectively) were identified.The presence and abundance of certain weed species were affected by MAP species and farming system. Higher weed diversity and weediness, and lower floristic similarity were found in conventionally grown crops. Also, the analysed MAPs differed in weediness by individual weed species. Correspondence analysis pointed to conventional and organic MAPs with the most frequent and most abundant weed species. Setaria pumila and Portulaca oleracea were the most frequent species in conventional; and Amaranthus retroflexus, Datura stramonium, and Sorghum halepense in organic crops. In both conventional and organic farming systems, therophytes were the most dominant life forms indicating a strong anthropogenic influence. The results should contribute to establishing weed control measures that are adequate for the two farming systems.

This paper aims to point out the presence and distribution of honey plants along the canal network of the Banat region, and the relationship between their basic ecological (ecological group, ecological indices) and biological (life form, flowering time, pollination) characteristics. A total of 18 honey plants were observed, dominated by hemicryptophytes and phanerophytes (over 70%). Species Salix alba, Populus alba and invasive species Amorpha fruticosa were found along the largest number of canals. Correlation and PCA analyses determined that the flowering time of the honey plants depends on their ecological group, plant life form and habitat characteristics (pH, temperature, light, aeration, the nutrients content in the soil). Forest, wetland and woody plants have a shorter flowering time, compared with weed-ruderal species. Twelve species are invasive in Europe, while Acer negundo and Amorpha fruticosa are highly invasive species in Serbia. It has been ascertained that honey species which are not invasive in Serbia (but in the wider Europe region they are) are often recommended for planting, which can lead to their more intensive spread and increase the possibility of them becoming invasive in our country.

In this paper, aboveground biomass and basic nutrients removal, nitrogen (N) and phosphorus (P), was analyzed by the use of reed as the main component of Constructed Wetland System (CWS) “Gložan”. In almost ideal conditions of temperate continental climate, with favorable substrate humidity, due to the constant inflow of municipal wastewater, reed populations reach a high density, on average 217 ind/m². The reed produces significant aboveground biomass, fresh weight (FW) of 144.21 g/plant and dry weight (DW) of 77.04 g/plant, with the largest share being per tree (87.49 g FW/plant, 48.17 g DW/plant), then leaf (49.45 g FW/plant, 24.89 g DW/plant) and the smallest inflorescence (7.27 g FW/plant, 3.99 g DW/plant). The results obtained in this way indicate that the largest amount of nitrogen was removed by leaves, then by stems and, the smallest by inflorescences, 181.07 g/m², 97.73 g/m², 23.41 g/m², respectively. Thus, an average of 302.21 g/m² of nitrogen was removed by the entire aboveground part of the reed. Also, the largest amount of phosphorus was removed by leaves, then by stems, and the smallest by inflorescences, 5.72 g/m², 4.82 g/m² and 2.57 g/m², respectively, while the entire aboveground part of the reed is on average about 13.11 g/m². The contribution of this paper is reflected in the obtained results for population density, reed biomass, and reed efficiency in the process of accumulation and removal of nitrogen and phosphorus as the main factors of accelerated eutrophication of aquatic ecosystems, the recipients of municipal wastewater. These results are significant because there is not enough data concerning this topic in the temperate continental climate of Southeast Europe. In addition to this, Constructed Wetland System is the first system of this kind, developed in our country that has been functioning for past 18 years. Due to this, the results are encouraging the application of CWS for a large number of smaller settlements in Southeast Europe as well as in other similar areas. Also, the results obtained in this paper can be useful to all those who are committed to the environmental approach and are engaged in research related to the use of reed in the process of municipal wastewater treatment.

Perennial adventitious species Asclepias syriaca L. which originates from Northern America is spread across Serbia, and especially Vojvodina, along the banks of waterways and borders of floodplain forests. Based on floristic and phytocenological studies in Backa, the presence of ass. Asclepiadetum syriacae L?nikov? in Chytr? 2009 stands, in which A. syriaca is present with the highest degree of presence (V) and with substantial covering value (2850), can be confirmed. The study shows ecological analysis of stands of mentioned association for basic environmental factors (moisture - F, reaction - R, nutrients - N, humus - H, aeration - D, light - L, temperature - T, and continentality - K) based on floristic composition of stands and their ecological indices, considering population and every species coverage in a stand. Given that a combined scale for population and coverage of species in stands, along numerical, has descriptive marks, modification of evaluated values according to Westhoff & van der Maarel scale which is completely numerical was conducted, which enabled data processing. The obtained results of the ecological analysis point to favorable ecological conditions for development of stands of this association, which can help predict the possible directions of spread of this invasive species.

The analysis of weed flora in organic production of spices and medical herbs (nettle, basil, spearmint, dill, alpine savory, marigold and lemon balm) a total of 21 species were found. In the studied flora is dominated therophytes with 71.42%, while geophytes and hemicryptophytes are present both with 14.29%. The largest number of detected species were weed-ruderal plants (80.96%). They are followed by ruderal and segetal weeds, both present with the 9.52%. Phytogeographic analysis of weed flora indicates the dominance of the species which are widely distributed with 80.95% (Cosmopolitan - 47.62%, Eurasian - 19.05%, Adventive - 9.52% and Circumpolar - 4.76%). Plant species which are less distributed are present with 19.05% (Pontic- Central Asian - 9.52%; Sub-Atlantic - 4.76% and Central European - 4.76%). Ecological analysis of the weed flora was according Landolt (2010) and it showed that detected weeds are adapted to the conditions of moderately continental climate of the study area (Kx = 3.19). The studied agroecosystem is characterized as warm (Tx = 4.05) and well lit place (L = 3.91). It was found that the investigated site is fresh (Fx = 2.48), weakly acid to weakly neutral chemical reaction (Rx = 3.48), with a medium to relatively rich in mineral matter (Nx = 3.76), weakly saline (Ss - 33.33%), moderately rich in organic matter (Hx = 2.81) and moderately aerated (Dx = 2.62).