Advancing on‐farm research with UAVs: Cover crop effects on crop growth and yield

Abstract

AbstractMore on‐farm research is necessary to determine the practical benefits and drawbacks of cover crops at the field‐scale. The objective of this study was to advance the use of unmanned aerial vehicle (UAV) platforms for evaluating the effects of cover crop biomass on crop growth and grain yield in two corn (Zea mays L.) fields and two soybean [Glycine max (L.) Merr.] fields in Illinois. Experiments were 17–29 ha in size with cover crop and non‐cover crop treatment strips replicated four times. Flights were conducted with a multispectral sensor at three early‐ to mid‐season crop growth stages. On the same day, 40 biomass samples were collected to ground‐truth reflectance data. Results indicated that normalized difference vegetation index (NDVI) could predict crop biomass (V3–V10 in corn, V5–R1 in soybean) with moderate accuracy (R2 = .40–.64) using an exponential model in corn and a linear regression model in soybean. Cover crops significantly (p < .1) reduced early‐ to mid‐season corn and soybean NDVI at several sampling events, yet no yield penalty was detected across fields. Correlations between cover crops, crop growth, and grain yield were low and inconsistent when using NDVI maps and estimated biomass and N uptake maps. This study highlights an opportunity for utilizing high‐resolution datasets in on‐farm experiments to investigate the impact of cover crops on crop growth and yield on a field‐specific basis.