Transverse Distribution Accuracy of Agricultural Drones in the Application of a Cover Crop Mixture Compared to a Traditional Cover Crop Spreader

<b><sc>Abstract.</sc></b> Rain-induced soil trafficability issues during Germany´s 2023 grain harvest increased interest in agricultural drones as an alternative for cover crop seeding. Uniform seed distribution is crucial for successful cover crop establishment. This study presents a field experiment comparing the transverse distribution accuracy of two agricultural drones with a conventional tractor-mounted snail bait spreader, commonly used in Germany for the application of slug bait in canola. Evaluation focused on spread system and pattern and coefficient of variation (CV) of DJI Agras T30 and XAG V40. Spread patterns were captured over a 10-m range for the drones and 13,5 m for the snail bait spreader, using a central and one overlapping flight path, with each trial repeated three times. Results revealed that the XAG V40 exhibited inconsistent overall spread patterns. In contrast, the DJI Agras T30 achieved a trapezoidal single spread pattern with a nearly uniform overall distribution. The difference between both drones may be due to the stronger rotor wind of the DJI Agras T30 mitigating crosswind effects. The snail bait spreader demonstrated consistent spread but produced a triangular, instead of a trapezoidal overall distribution due to excessive overlap. Regarding the CV for evaluating uniformity, the DJI Agras T30 outperformed other systems with a CV of 17.34%, followed by the XAG V40 (32.05%) and the snail bait spreader (38.91%). However, the results were influenced by operational errors, underestimation of the effective spreading width, crosswind, and data collection protocols. Based on the design and performance during spreading trials, the DJI Agras T30 demonstrated superior distribution for the tested cover crop seed mixture. The quality of seed distribution is significantly influenced by the preparation and expertise of drone operators.