Drainage and tillage effects on a crosby-kokomo soil association in Ohio IV. Soil physical properties

Bulk density, soil structure, penetrometer resistance, and moisture retention characteristics were examined for the Crosby-Kokomo Association near Columbus, Ohio. The soils are classified as fine mixed, mesic, Aeric Ochraqualf and fine, mixed, mesic, Typic Argiaquoll, respectively. Effects of four tillage methods were studied with and without subsurface drainage. Tillage methods were: no-till, raised beds, ridge till and moldboard plow. The tillage treatments were laid out according to a Randomized Block Design with three replicates on each drainage site.Soil samples obtained in August, 1987 to 50 cm depth in 10 cm increments, were analyzed for aggregate size distribution, and moisture retention characteristics. In addition, surface (0–10 cm and 10–20 cm depths) core samples were obtained in July 1989 for measurement of soil bulk density, and moisture retention characteristics. Penetrometer resistance and soil moisture content for the surface layers were also measured in July 1989.The mean weight diameter (MWD) was higher for undrained than drained treatment, 2.94 mm vs. 2.49 mm, respectively. Neither drainage nor tillage treatments had a significant effect on soil bulk density measured about 8 weeks after sowing. Penetrometer resistance was lower, and surface soil moisture content was higher in the undrained compared with the drained treatment. Soil moisture retention at all suctions and plant-available soil moisture reserves were more in undrained than drained soil. Differences in soil moisture retention among drainage treatments are attributed more to organic matter induced differences in pore size distribution than to total porosity. For these soils in central Ohio, drainage had a more significant effect on soil physical properties than tillage operations performed in the fall and/or spring.