Real-Time Gauge Wheel Load Variability of a Row-Crop Planter During Field Operation

Abstract

Abstract. Planter downforce control allows row units to maintain a target gauge wheel load (GWL) across a range of soil resistance within a field. Downforce control is typically set for a target seed depth and can be implemented either as fixed or by automatic or active control to attain the desired GWL. Recent advances allow for the control of individual row units into sections for improved GWL application. However, little knowledge exists on the spatial variability of GWL, row-to-row GWL variability, and on the recommended GWL control requirements on planters operating in actual field conditions. Therefore, the objectives of this study were to (1) quantify real-time GWL variability across individual row units within a 12-row crop planter programmed to implement a constant downforce control during field operations; (2) evaluate gauge wheel load range (GWLR) across individual row units and within 2-row, 3-row, or 4-row control sections to determine the optimal downforce control section size; and (3) assess the impact of soil texture and soil compaction due to tire tracks on GWL variability. To address these objectives, a 12-row crop planter equipped with hydraulic downforce control was used to plant three fields. The planter was set to plant corn at 5.2 and 5.7 cm depths with fixed target GWL set at 334 ±223 N (111 to 557 N) and GWLR set at 0 to 883 N. A data acquisition system collected real-time GPS, planting speed, GWL, hydraulic pressure, and planter toolbar height data at 10 Hz. Real-time GWL data of individual row units were analyzed to determine the GWL distribution within or outside the set target GWL. Moreover, GWLR was measured in individual row units and across varying control section sizes. Soil electrical conductivity (EC) was measured using a Veris mobile sensor platform. Soil EC was used in defining zones of low, medium, and high textured soil. Results show that GWL was within the target range of 111 to 557 N at 33% of the total planting time across the three fields, and GWLR was within 0 to 441 N at 9% of the total planting time. Results also indicate that a 2-row, 3-row, and 4-row control section could provide GWLR within 0 to 441 N at 76%, 46%, and 28% of the total planting time, respectively. These findings suggest the need for automatic downforce systems with fewer row units per control section to maintain target GWL within an acceptable range for all row units. Regression analyses indicate that soil texture is a significant variable that can influence real-time GWL. Furthermore, compacted soil due to tractor tires contributed to significantly lower GWL. Our data suggest the need for active downforce control to achieve improved GWL uniformity under varying field-operating conditions. Keywords: Gauge wheel load, Planter downforce, Precision planters, Seeding depth, Variability.