Persistance of Metribuzin in Soils with Different Characteristics and Utilization History and Their Effects on Cultivated Oat (Avena sativa)

This experiment was conducted to study the effect of metribuzin on cultivated oat in soils with different characteristics and utilization history as factorial on the base of randomized complete block design with three replications in Institue of Plant Protection in 2012. First factor was soil type in six levels (Hamedan with 15 years and without utilization history, Jiroft with 15 years and without utilization history, Isfahan with 2 years utilization hisrory and Mashhadwith 3 years utilization history) and second factor was different amounts of metribuzin in six levels (0, 0.1, 0.3, 0.7, 1 and 1.5 kg/ha). Three months before cultivating, the pots with mentioned soils were treated with metribuzin and were irrigated every three days. Then oat seeds was cultivated in pots and harvested after four weeks. Shoot length, root lenght, shoot wet weight and root wet weight was measured and dose- response curves were drawn. According to results, more oats were burned due to increase of herbicide amounts, but the effects of metribuzin residue were decreased by increase of amounts of clay, organic matter and utilization history. The highest and lowest phytotoxicity was observed in soils of Jiroft without utilization history and Hamedan with 15 years utilization history, respectively.