زیست سنجی پسماند علف کش های گندم در شرایط آب و هوایی کردستان

The persistence of herbicides in the soil depends on the contents of organic matter, moisture, pH, and soil temperature, the activity of microorganisms and chemical composition of the herbicide. Residues of herbicides on the soil may cause damage to the next crops in rotation. In this experiment, bioassay of wheat herbicide residues in two different climate conditions in Kurdistan province i.e. Kamyaran and Dehgolan carried out using Cress (Lepidium sativum). The soil samples of plots were collected after harvesting and stored in plastic bags until the test was carried out. The study was carried out in pot experiment as factorial based on randomized complete block design with four replications at Faculty of Agriculture, Kurdistan University from July to October 2017. Factors included eight herbicide treatments (Apirus, Total, Atlantis, Axial and othello of registered herbicides and three new herbicides Perun ،Attribute super and Lancelot with recommended dose) and three periods after herbicide application in the field (120, 150 and 180 days). Pots were filled with two Kgs of experimental plots soil, and then seeds of cress were sown in it. The moisture of pots was supplied as sub-irrigation by filling the container under the pots with water. Cress plants of each pot were cut from the soil surface 30 days after emergence, transferred to oven at 60˚C for 48 hours, and then dry weight as % of control was calculated. Results showed that emergence percentage, emergence rate and dry mater of cress in Kamyaran was 16.16, 14.8 and 21.9% greater than Dehgolan. Increasing the period of time after herbicide application-due to reduction of herbicide residue- resulted in increasing the percentage of emergence, the rate of emergence and shoot dry matter. So that at 120, 150 and 180 days after herbicide spraying, the emergence percentage 61.5, 63.6 and 72.25, the rate of emergence 2.4, 2.44 and 2.8, and the shoot dry matter were 10.3, 11.5 and 13.4 gr. Atlantis, Apirus, Axial, Perun, Lancelot, Attribute super, Othello and Total reduced emergence percentage (24.1, 21.5, 26, 31.3, 30.5, 40.8, 55.4 and 66.8), emergence rate (23.8, 22.45, 27.5, 35.3, 33.95, 44.6, 48.9 and 55) and shoot dry weight of cress (26.9, 29, 31.7, 37, 37.1, 47.5, 58.6, 64.5). According to the results, in order to reduce the herbicide damage on the next crop in rotation, Atlantis, Apirus, Axial, Perun, Lancelot, Attribute super, othello and Total can be recommended respectively.