This study examined the allelopathic effect of different concentration of aqueous extracts of Parkia biglobosa stem bark on the germination and growth of weed seeds species. Seeds of Eragorastis tenella, Eragorastis atrovirens, Pannicum pedicellata, Pennisetum sub albidum, Hypharrhenia rufa and Brcichiaria brizantha were tested for plumule germination and radicle growth with three different concentrations of 1%, 5%, 10% plant extract while ordinary water was used as control. Growth parameters including germinated weeds population were measured; the highest germinated weeds population was at the control (8.06±3.97) and the least was obtained from the 10% concentration with the mean of (4.42±2.59). Weeds population decreased as the concentration increased. The highest mean of weeds height was recorded from 1% concentration (11.46±7.08) which is statistically significant while the least mean was recorded from 10% concentration (7.69±6.70) statistically not significant. The family emergence by concentration indicated that, the experiment under control had (4 families) for 1% (2 families), 5% (2 families) and 10% (4 families) emerged. The germination, radicle and plumule length were inhibited when compare with control and the inhibition was statistically not significant at.

A study covering cherry, walnut, apple, almond and pear orchards in Edirne, Kırklareli and Tekirdağ provinces was carried out in 2015-2018 with the aim of determination of weed flora, weed frequencies and densities. Total of 64 species belonging to 30 families were identified in fruit tree orchards. Among all the families the most members were in Asteraceae 13 species, Poaceae, 11 species, Brassicaceae 5 species and Lamiaceae 3 species families. The dominant weed species were Amaranthus retroflexus L., Polygonum aviculare L., Capsella-bursa pastoris L. (Medik)., Concolvulus arvensis L., Lepidium draba L., Raphanus raphanistrum L., Chenopodium album L., Cichorium intybus L. in Tekirdağ while Datura stramonium L. distribution in Edirne Uzunköprü and Kırklareli was remarkably high. Semi parazitic weed Viscum album and full parasite Cuscuta campestris Yunck were also detected in some orchards. V. album was widespread among pear trees while Cuscuta campestris Yunck was detected only in suckers emerged in apple and cherry orchards. According to density A. retroflexus has received the first order with 76 plant/m2, following C. album with 54 plant/m2, Lactuca serriola with 27 plant/m2, D. stramonium L. with 24 plant/m2, Portulaca oleracea with 21 plant/m2

Many allelopathic crops are cultivated in agricultural fields, and these plants can influence the growth of other plants in the cultivation environment with their phytotoxic compounds. One of these plants is the faba bean. In this study conducted under the ecological conditions of Sakarya/Arifiye, the allelopathic effects of Eresen-87, Salkim, Bilecik, and Sakarya faba bean genotypes on weeds such as Johnson grass (Sorghum halepense L.), curly dock (Rumex crispus L.), purslane (Portulaca oleracea L.), and wild mustard (Sinapis arvensis L.) were investigated. Weed seeds used in the experiment were collected from agricultural fields in the Sakarya province. Extracts from dried plant parts of faba bean genotypes were prepared and applied to petri dishes containing weed seeds at concentrations of 5% and 10%, with four replications. At the end of the research, it was observed that all faba bean genotypes at all application doses caused a decrease in germination rate (%), root length (cm), and shoot length (cm) parameters in the four weed species tested. The best results were determined as Eresen-87 and Bilecik at 10% concentration. When the activities of fresh and dry extracts of faba bean genotypes was compared, it was determined that dry application had a higher allelopathic effect.