2020 ASA-CSSA-SSSA International Annual Meeting | November 9-13, 2020
Monitoring Cover Crop Biomass and Starter Nitrogen Effects on Corn Using in Season UAV Imagery
For field crops research, the use of drones presents the opportunity to monitor in season crop growth and provide additional metrics to measure treatment effects. For agronomic projects, harvest data is the most common response variable measured, while biomass or tissue samples require greater labor and cost. As part of a regional project, a rye cover crop study was performed in Delaware to observe the effects of rye termination timing (tillering, boot, and anthesis), stater nitrogen [N] (0, 28, 56, 84 kg ha-1), and total nitrogen (0, 168, 285 kg ha-1) on corn growth and yield. Throughout the cover crop and corn growing seasons, a UAV with a multispectral camera was used to photograph weekly crop progress. Imagery from both 2018 and 2019 successfully observed treatment differences in termination timing, starter N, and total N using vegetative indexes (NDVI, NDRE, and GNDVI). The effects of each treatment factor varied over the growing season, with termination timing important in the early growth stages (June) and the N treatments having greater effects during reproductive stages (August). Starter N rates could be separated by NDVI in early vegetative and late reproductive stages, while NDRE and GNDVI could separate between treatments from late vegetative through blacklayer. These differences in starter rates became apparent after sidedress, or total N applications were made. Measurable differences between total N rates could be performed through reproductive stages with all three indexes. For this N study, all three indexes had their greatest correlation to yield between the R1 to R4 stages and NDRE often had the greatest correlation to yield. As a research tool, multi-spectral done imagery can provide additional in-season measurements with less labor, potentially providing additional insights into the treatment effects on yield.
Monitoring Cover Crop Biomass and Starter Nitrogen Effects on Corn Using in Season UAV Imagery
For field crops research, the use of drones presents the opportunity to monitor in season crop growth and provide additional metrics to measure treatment effects. For agronomic projects, harvest data is the most common response variable measured, while biomass or tissue samples require greater labor and cost. As part of a regional project, a rye cover crop study was performed in Delaware to observe the effects of rye termination timing (tillering, boot, and anthesis), stater nitrogen [N] (0, 28, 56, 84 kg ha-1), and total nitrogen (0, 168, 285 kg ha-1) on corn growth and yield. Throughout the cover crop and corn growing seasons, a UAV with a multispectral camera was used to photograph weekly crop progress. Imagery from both 2018 and 2019 successfully observed treatment differences in termination timing, starter N, and total N using vegetative indexes (NDVI, NDRE, and GNDVI). The effects of each treatment factor varied over the growing season, with termination timing important in the early growth stages (June) and the N treatments having greater effects during reproductive stages (August). Starter N rates could be separated by NDVI in early vegetative and late reproductive stages, while NDRE and GNDVI could separate between treatments from late vegetative through blacklayer. These differences in starter rates became apparent after sidedress, or total N applications were made. Measurable differences between total N rates could be performed through reproductive stages with all three indexes. For this N study, all three indexes had their greatest correlation to yield between the R1 to R4 stages and NDRE often had the greatest correlation to yield. As a research tool, multi-spectral done imagery can provide additional in-season measurements with less labor, potentially providing additional insights into the treatment effects on yield.