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Abstract
In recent years, increased input costs and unfavorable market conditions have motivated US cotton producers to adopt precision agriculture technology and practices that can ensure efficient utilization of crop inputs and maximize returns. Currently, there is an increased focus on planting technologies and management practices to improve row-crop planter performance as planting represents a critical field operation. Optimal planter performance requires selection of adequate downforce to achieve consistent and uniform seeding depth specifically in variable field conditions. Limited research exists on the effect of planter downforce on crop emergence and yield in cotton, and even less information is available on how planter downforce needs to be adjusted for different at-plant field conditions when planting cotton. Research studies were conducted to investigate planter downforce in: (1) three different soil moisture conditions at planting (characterized as dry, normal and wet field conditions), (2) two different seeding configurations (single seed per hill – singulated and two seeds per hill – hill-drop), and (3) varying soil textures (delineated using soil electrical conductivity measurements) within grower fields. The main goal of these studies was to identify how planter downforce can be adjusted, and effectively utilized in different field conditions at planting to improve crop emergence and yield in cotton. Field results suggested that planter downforce effect on crop emergence varied by seeding depth and selection of cultivar (small- or large-seeded) in dry and wet soil moisture conditions. Overall, the large-seeded cultivar and the nominal seeding depth of 2.5 cm exhibited increased emergence and higher lint yield across all field conditions. In a two-year seeding configuration study, a higher planter downforce of 890 N resulted in reduced crop emergence in singulated cotton, however no downforce effect on emergence or yield existed in hill-drop cotton or between the cultivars. On-farm study results showed that crop emergence was affected by soil texture. Delayed and reduced emergence (10% or greater) was observed in some fields due to lack of adequate planter downforce in heavy textured soils. In the future, the development and integration of rapid soil sensing devices with active downforce systems on planting equipment would help in optimizing planter performance (including depth and downforce) in variable field conditions.