Publication Date


Advisor(s) - Committee Chair

John Shirley, Alvin Bedel, James Worthington

Degree Program

Department of Agriculture

Degree Type

Master of Science


The effect of three tillage methods confounded with three row widths on root length and depth, seed density, seeds per pod, pods per plant and yield of Glycine max was studied during the 1984 growing season. The study was conducted on class 1, Pembroke soil located in south Warren County, Kentucky. A barley crop was removed from the area just prior to the experimental plantings. A John Deere conservation tillage, plateless planter was used in all experimental treatments except the drilled plots. Plant populations were adjusted to conform to standard recommendations for drill (7 inch row widths), 15-inch row widths, and 30-inch row widths. Tillage methods were no-till (soybeans were seeded directly into barley stubble), conventional (the land was chisel plowed to a depth of 8 to 10 inches and then disced twice to a depth of four inches prior to planting), and ro-till (the ro-till machine prepared a 10 inch wide seed bed directly into barley stubble by utilizing a deep chisel preset to reach a depth of ten inches, four large disks preset to run at a depth of approximately six inches followed by a rolling steel basket designed to level the seed bed and macerate large particles of soil). All experimental plots were planted within a six hour time span.

The eight row width by tillage method treatments were fifteen inch no-till (15N), thirty inch no-till (30N), fifteen inch conventional (15C), thirty inch conventional (30N), fifteen inch ro-till (15R), thirty inch ro-till (30R), drill conventional (DC), and drill ro-till (DR).

Treatments were arranged in a randomized complete block design replicated six times. Each block contained all treatments arranged in a random fashion to reduce error due to side-row variation.

Root length and depth determinations were made at the crook, unifoliate, first trifoliate, third trifoliate, and fifth trifoliate stages of development. Seed density, seeds per pod, pods per plant, and yield were studied at physiological maturity. Rainfall was recorded daily throughout the growing season.

Results showed significant differences in root length, root depth, seed density, and yield; but no significant differences were found in seeds per pod or pods per plant. The ro-till tillage method improved root development (depth and length) over the conventional and no-till tillage method; however, yield data was not greatly affected by this improvement. Yield was seemingly affected most by row-width differences with drilled rows and 15-inch rows ranking above 30-inch rows in production.


Agriculture | Agronomy and Crop Sciences | Life Sciences | Plant Sciences