Crop rotation systems, weed species, their damage status,and the rates of weed seed contamination in field crops ofthe Çukurova region

This study was conducted to determine the crop rotation pattern in the Çukurova Region for sustainable weed management, to reveal the harmful/beneficial effects of weeds in commonly cultivated crops within this pattern, and to detect weed seeds that can contaminate products during harvest. Crop rotation and weed surveys were carried out across nine different routes in the Çukurova Region between 2021 and 2023. The weed surveys were done on five different crops such as sunflower, wheat, maize, cotton and soybean in the region, the harmful-beneficial effects of weed species, their densities (plants/m²) were recorded and were assessed using the "Weed Harmful-Beneficial Algorithm". To assess the success of the weed management in the region and pay attention to weed seeds contaminating crop seeds, samples of sunflower, wheat, corn, and soybean products were collected. They were examined at the laboratory and weed seed identification was carried out through comparison with reference collections and with the assistance of specialists. At the end of the study, crop rotation surveys established that although 15 different field crops are cultivated in the region, crop rotation practices are generally weak. It was also located that areas with irrigation systems and those located in the southern parts of the region exhibit more diverse crop rotation patterns. According to the "Weed Harmful-Beneficial Algorithm", 12 main and 9 potential main harmful weed species in sunflower; 13 main and 9 potential main harmful weed species in wheat; 20 main and 5 potential main harmful weed species in maize; 17 main and 6 potential main harmful weed species in cotton; and 17 main and 8 potential main harmful weed species in soybean fields were figured out in Çukurova Region. Although there are a total of 193 weed species in sunflower, wheat, maize, cotton, and soybean cultivation areas in the region, 58 of these species are harmful (main and potential main harmful weeds) and the other weeds were revealed beneficial to the agroecosystem, as their benefits outweighed their harms. During harvest, it was found that 63 weed seeds in sunflower, 106 weed seeds in wheat, 22 weed seeds in maize, and 36 weed seeds in soybean had contaminated. As a result, to ensure sustainability in production and yield in the region, crop rotation patterns should be diversified and integrated with herbicide rotation; management strategies should be developed based on the main/potential main harmful weed species; and the effectiveness of management should be investigated by monitoring weed seeds contaminated with the harvested product.