 This study used super high-resolution, multi-temporal crop surface models, CSMs, derived from red, green, blue, RGB, images captured from a small unmanned aerial vehicle, UAV, to estimate fresh and dry biomass on a summer barley test site with 18 cultivars and two nitrogen treatments. The method showed high accuracy in estimating biomass, with an R2 of 0.92 for plant height reference measurements and R2 values of 0.81 and 0.82 for fresh and dry biomass estimation, respectively. Five models were tested by cross-validation, and the best results were obtained when modeling biomass between different nitrogen treatments for fresh biomass, R2 equals 0.71. The method has potential for future application by non-professionals, such as farmers. This article was authored by Julian Bendig, Andreas Bolton, Simon Bennett and others.