Row-crop planter performance to support variable-rate seeding of maize

摘要

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 to ensure the correct planter and display setups in order to achieve needed seed placement performance to support variable-rate seeding.