Mechanical weed control in sunflower and soyabean crops using spring-tine harrow: results of two-year trials

The present study aimed to investigate the possibility of using spring-tine harrowing for weed control on sunflower and soyabean and to define the most efficient adjustments of the working tools for the different operative conditions. The experimental treatments included one or two passes with a spring-tine harrow combined with four tine adjustments (-30°, -15°, 0° and +15°), a conventional herbicide treatment and an unweeded control. The results of the trials indicated that it is possible to achieve efficient weed control on sunflower and soyabean crops with spring tine harrowing while also preserving the grain yield. The machine adjustments affected grain yield and weed control. Both the crops were sensitive to weed competition and direct weed control was needed. Spring tine harrowing was gentle towards the crops. Moreover the results obtained confirmed that the use of spring tine harrows allows substantial operative advantages and emphasized that soil mechanical characteristics strongly affect treatments performed with the spring tine harrow. However, in order to improve treatment efficiency there is a clear need for further trials with careful analysis of the interaction among tools and soil conditions, crop type and its management, weeds and their development.