Effect of Crop Rotations on Winter Wild Oat (Avena sterilis L.) Populations in Osmaniye Province Wheat Sown Areas

This study was carried out to determine the impact of three-year crop rotation in sampling fields on winter wild oat (Avena sterilis L.) populations in Osmaniye wheat sown areas. The study was conducted in Osmaniye province between the years 2013-2015. A total of 103 fields in 7 districts’ wheat sown areas were determined; these sampling fields were visited every year during May-August and effects of different crops sown on winter wild oat populations were observed. Besides determining frequency of occurrence, randomly chosen general coverage in 1 decare and special coverage in 1 m^2 in three points were specified. As a result of the study, it was determined that all of the crops except wheat decreased winter wild oat populations and it was found that the changes were related to the crop rotations. It was determined that corn, sunflower, soybean and peanut sown in 2nd and 3rd year instead of wheat decreased the frequency of winter wild oat at 2% and below. Moreover, when the three-year crop rotation system was analyzed, it was revealed that the maximum decrease in winter wild oat population general coverage occurred in 4 crop rotation period. It can be found that populations decrease can be up to more than 90% when compared to 2 and 3 crop rotation systems. It was concluded that crop rotations are sufficient in controlling winter wild oat that are problematic in wheat fields.