Evaluation of no-tillage planter systems and components for seeding soybeans in wheat stubble

Eight commercially available no-tillage planter systems were evaluated while seeding soybeans in wheat stubble at the Milan Experiment Station in West Tennessee. Evaluations were based upon the consistency of depth of seed placement, uniformity of spacing between seeds within the row, and seed coverage. Planter systems were also observed during operation, and equipment performance characteristics which affected seed placement were noted.

Data were collected from row segments randomly selected in each area seeded with a particular planter system. Seed depth and seed spacing were determined by digging into each row segment to expose the seed. Seed coverage was based upon counts of seeds which were not covered with soil.

Seed depth and seed spacing data were analyzed to determine mean values and coefficients of variation for each planter system. Seed coverage was expressed as a percentage of total seeds metered within the sample row segment. A 1-inch ripple coulter was compared to a 1-inch fluted coulter for consistency of seed placement under similar field and operating conditions.

All planters evaluated performed satisfactorily, but not without minor problems. Coefficients of variation for seed spacing ranged from 53 to 92 percent, with a mean spacing of 1.5 inches. Coefficient of variation for depth of seed placement ranged from 16 to 45 percent, with a mean seed depth of 1.25 inches. Comparisons between the 1-inch ripple and l-inch fluted coulter revealed no significant difference in seed spacing uniformity, but significant differences in depth of seed placement were found. The 1-inch ripple coulter penetrated the soil to a greater depth than the 1-inch fluted coulter under similar field and operating conditions.