Pastures account for more than 56% of the total agricultural area of Ecuador and constitute the main food source for livestock. Hence, the agile, affordable, and reliable quantification of aboveground biomass (AGB) is an essential task in grazing utilization and management. In this paper, a method to estimate the AGB via aerial photogrammetry with a low-cost UAV multirotor is proposed. Digital terrain models and crop surface models were generated from data captured during two flights at different times, and the volume between them was calculated. An empirical relationship between volume and dry biomass was obtained by harvesting and weighing some samples and deriving a density factor (DF). The method was tested over 54 plots with different types of forage under differential fertilization treatments. Fertilized annual ryegrass exhibited the best growth and highest biomass (2632 kg/ha). The estimation and calculation of the crop volume via UAV-based photogrammetry saves time and generates notably precise (R² = 0.78) information on the dry biomass.

牧场占厄瓜多尔农业总面积的56％以上，是牲畜的主要食物来源。因此，对地上生物量（AGB）进行灵活，负担得起且可靠的定量分析是放牧利用和管理中的一项基本任务。提出了一种低成本的无人机多旋翼飞机航测法估计AGB的方法。根据两次飞行在不同时间捕获的数据生成数字地形模型和作物表面模型，并计算它们之间的体积。通过收获和称重一些样品并推导出密度因子（DF），可以得出体积与干燥生物量之间的经验关系。在不同的施肥处理下，在54种不同草料地块上对该方法进行了测试。受精的一年生黑麦草表现出最佳的生长和最高的生物量（2632 kg / ha）。通过基于无人机的摄影测量法对作物体积进行估计和计算可以节省时间并产生显着的精确度（R²  = 0.78）有关干燥生物质的信息。