Abstract
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.
Highlights
The main and most economical source of food for livestock in the Republic of Ecuador is grass
The present study aims to investigate the use of multitemporal UAVbased imagery and SfM photogrammetry to estimate the aboveground biomass (AGB) of pastures at a fine spatial scale
The aboveground biomass was calculated based on the difference in volume per parcel obtained from unmanned aerial vehicles (UAVs)-derived digital terrain models (DTMs) and crop surface models (CSMs) and the density factor (DF) of each sample crop
Summary
The main and most economical source of food for livestock in the Republic of Ecuador is grass. According to the National Institute of Statistics and Census (INEC), planted and natural pastures represented approximately 38.85% and 17.92%, respectively, of the total agricul tural working area of 5,110,549 ha in 2019. Grazing ach ieves the best yields among livestock feed systems (Grijalva et al, 1995). Agricultural treatments such as fertilizers or soil amendments are not commonly used for this type of crop; the achieved yields at the production level are not usually maximized. Increased knowledge about the dynamics of the biomass and net primary productivity of grasslands will facilitate better planning and use of resources
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
