Evaluating plant populations and replant considerations across multiple peanut (Arachis hypogaea L.) production methods

Abstract

The University of Georgia Extension recommendation for optimum plant stand in peanut (Arachis hypogaea L.) is 13.1 plants m 1, although previous work has shown that yield potential can be maintained at plant stands lower than optimum. The unpredictable and often extreme weather and the ubiquity of pathogens in the region often contribute to poor emergence and a resultant poor plant stand. When plant stand is adversely affected, a point may be reached where replanting the field via either supplemental addition of seed or complete destruction and full replanting becomes a viable option. Field trials were conducted across peanut-growing regions in Georgia and Florida to determine i) the effect of plant stand on pod yield, market grade, and disease incidence, ii) at what plant stand peanut benefits from replanting, and iii) the best method for replanting peanut when an adequate stand is not achieved. Trials were conducted on peanut planted in single rows, twin rows, in strip tillage, and across multiple planting dates and time durations between initial planting and replanting. When seeded in single rows, pod yield increased linearly and tomato spotted wilt virus decreased linearly as plant stand was increased from 3.3 to 13.1 plants m-1. In twin rows, both pod yield and grade were maximized at 12.3 plants m-1, with losses observed by reducing plant stand and no gains observed by increasing stand. Yields were increased by supplementing the original stand at 3.3 and 8.2 plants m-1 in single rows and at 9.8 plants m-1 in twin rows. Completely replanting was never a viable option. In strip tillage, yield was increased by supplementing the initial stand and by completely replanting the initial stand in one of four site-years. Yield was generally reduced at a later planting date when testing planting dates and multiple replant dates, while yield was only improved by replanting in three of eight site-year by planting date combinations. Overall, this data stresses the importance of establishing an adequate plant stand at the initial planting date, as replanting below-optimum stands rarely restores pod yield to a level equal to an optimum stand at the initial planting date.