Recent advances in remote sensing technology, especially in the area of Unmanned Aerial Vehicles (UAV) and Unmanned Aerial Systems (UASs) provide opportunities for turfgrass breeders to collect more comprehensive data during early stages of selection as well as in advanced trials. The goal of this study was to assess the use of UAV-based aerial imagery on replicated turfgrass field trials. Both visual (RGB) images and multispectral images were acquired with a small UAV platform on field trials of bermudagrass (Cynodon spp.) and zoysiagrass (Zoysia spp.) with plot sizes of 1.8 by 1.8 m and 0.9 by 0.9 m, respectively. Color indices and vegetation indices were calculated from the data extracted from UAV-based RGB images and multispectral images, respectively. Ground truth measurements including visual turfgrass quality, percent green cover, and normalized difference vegetation index (NDVI) were taken immediately following each UAV flight. Results from the study showed that ground-based NDVI can be predicted using UAV-based NDVI (R2 = 0.90, RMSE = 0.03). Ground percent green cover can be predicted using both UAV-based NDVI (R2 = 0.86, RMSE = 8.29) and visible atmospherically resistant index (VARI, R2 = 0.87, RMSE = 7.77), warranting the use of the more affordable RGB camera to estimate ground percent green cover. Out of the top ten entries identified using ground measurements, 92% (12 out of 13 in bermudagrass) and 80% (9 out of 11 in zoysiagrass) overlapped with those using UAV-based imagery. These results suggest that UAV-based high-resolution imagery is a reliable and powerful tool for assessing turfgrass performance during variety trials.

Current planting technology possesses the ability to increase crop productivity and improve field efficiency by precisely metering and placing crop seeds. Planter performance depends on determining and utilizing optimal settings for different planting variables such as seed depth, down pressure, and seed metering unit. The evolution of "Big Data" in agriculture today brings focus on the need for quality as-planted and yield mapping data. Therefore, an investigation was conducted to evaluate the performance of current planting technology for accurate placement of seeds while understanding the accuracy of as-planted data. Two studies consisting of two different setups on a 6-row, John Deere planter for seeding of maize (Zea mays L.) were conducted. The first study aimed at assessing planter performance at 2 depth settings (25 and 51 mm) and four different down pressure settings (varying from none to high), while the second study focused on evaluating planter performance during variable-rate seeding with treatments consisting of two seed metering units (John Deere Standard and Precision Planting's eSet setups) with five different seeding rates and four ground speed treatments which provided a combination of 20 different meter speeds. Field data collection consisted of measuring plant emergence, plant population and seed depth whereas plant spacing, plant population after emergence along with distance and location for rate changes within the field were also recorded for the variable-rate seeding study. Results indicated that both depth setting and downforce affected final seeding depth. Measured seed depth was significantly different from the target depth even though time was spent adjusting the units to achieve the desired prior to planting. Crop emergence did not vary significantly for the different depth and downforce settings except for target depth in Field 1. Results from the variable-rate study indicated that seeding rate changes were accomplished within a quick response time (< 1 s) at all ground speeds regardless of magnitude of rate change. Data showed that planter performance in terms of emergence and plant spacing CV was comparable for most of the meter speeds (17.4-33.5 rpm) among the two seed meters utilized in the study. Plant spacing CV increased with an increase in meter speed, however no significant differences existed among meter speeds in the range of 17.4-33.5 rpm. Results implied that correct seed metering unit setup is very critical to obtain expected performance of today's planting technology. A concerning find was that the quality of as-applied maps from the commercial variable-rate display was not reflective of the actual planter performance in the field. The study recommended that operators need Extended author information available on the last page of the article Precision Agriculture (2020) 21:603-619 1 3 to ensure the correct planter and display setups in order to achieve needed seed placement performance to support variable-rate seeding.

Ground speed variations are common and unavoidable during pesticide applications with agricultural sprayers. Field tests were conducted to evaluate the effect of varying ground speeds on spray deposition and quality with a commercial agricultural boom sprayer without a rate controller (CNS) in 2021 and equipped with a rate controller (SRC) in 2022. During each year, the sprayer boom was split evenly among three different nozzle types (XRC, AIXR, and TTI) to attain different droplet sizes (medium, very coarse, and ultra-coarse, respectively). Prior to testing, the sprayer was calibrated to deliver an application rate of 187 L ha−1 at a spray pressure of 207 kPa and ground speed of 9.7 km h−1. For spray deposition and quality assessment, pesticide applications were made at five different ground speeds of 9.7, 12.9, 16.1, 19.3, and 22.5 km h−1, and data were collected by placing water-sensitive paper at different locations across the sprayer boom and in the field. Results for CNS indicated that spray deposition reduced significantly (p < 0.05) with an increase in ground speed across all three nozzle types, primarily due to a decrease in the quantity of spray droplets applied per unit area. The quantity of spray droplets and spray deposition was more consistent among the ground speeds for SRC. Ground speed affected spray quality for both CNS and SRC; however, the spray quality variations were greater for SRC due to an increase in spray pressure with ground speed. Among nozzle types, the trends in spray deposition and quality were similar for the XRC and TTI nozzles as observed for CNS and SRC. However, the AIXR nozzle showed inconsistent spray deposition and quality as ground speed varied. The results of this study indicated agricultural sprayers equipped with a rate controller provide adequate and consistent spray deposition compared to conventional sprayers (no rate controller) when ground speed changes occur during pesticide applications. While spray quality is also affected when using a rate controller, best management practices including proper nozzle selection and application at nominal ground speeds should be followed to minimize these effects and ensure effective technology utilization.

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