On-farm evaluation of planter downforce in varying soil textures within grower fields

Abstract

Maintaining adequate planter downforce is critical for achieving timely and uniform crop emergence across the field. On-farm research studies were conducted in different regions across South Georgia, USA to investigate the effect of planter downforce in varying soil textures. Six fields were planted in cotton with four different growers from 2017 to 2019. Soil electrical conductivity (EC) was mapped in each field to characterize areas of varying soil textures into low, medium and high soil EC zones. For each field, the downforce treatments consisted of a grower-preferred downforce along with a relatively lower and higher downforce dependent on prevalent field conditions and the downforce system available on the grower’s planter. Results varied from field to field depending on soil texture variability or the type of downforce system. In three out of six fields, emergence was delayed and reduced in areas of high soil EC (heavy textured soils) whereas soil EC or downforce did not affect crop emergence in two fields. In one field, increasing planter downforce from the grower preferred value of 555 N to 1110 N improved crop emergence in heavy textured soils. In some cases, it was noted that even the highest downforce (1110 N) was not sufficient to place seeds at the desired seeding depth in the heavy textured soils. More on-farm studies are required to thoroughly understand planter downforce response in varying field conditions that exist during planting. Future studies should consider better quantification of in-field soil variability and changes in planter downforce during field operation.