Continuous Application of No‐Tillage to Ohio Soils

Abstract

No‐tillage (NT) crop production practices have been continuously maintained at four sites in Ohio for more than 25 yr. The original experiments involving NT were designed to determine how much tillage was required to produce crops with satisfactory yields and how tillage and rotation interact to effect crop yields, especially corn (Zen mays L.). Long‐term effects of NT on crop yields and soil properties are generally not known because few sites exist with histories of ≥20 yr of NT. This paper reports yield trends of corn and soybean [Glycine max (L.) Merr.] and changes in soil properties that occurred when NT was continuously practiced on soils in Ohio. Significantly lower yields for NT, as compared to conventional tillage (CT), were observed for monoculture corn and for soybean in rotation during the first 18 yr on a very poorly drained Mollic Ochraqualf soil. The yield differences observed for corn could be largely eliminated by crop rotation and for soybean by the use of phytophthera resistant/tolerant soybean cultivars. On a well‐drained Typic Fragiudalf soil, crop yields were always higher with NT than with CT. After 18 yr, yield trends indicated the negative impact of NT on the very poorly drained soil was greatly decreased and the yield advantages associated with NT on the well‐drained soil became even more pronounced. The change in yield trends did not appear to be associated with change in weather patterns. The long‐term NT sites also revealed organic matter, nutrients, and soil enzymes accumulated at the soil surface but decreased deeper (>20 cm) in the soil profile. Surface water runoff was found to be greatly decreased from the long‐term NT watershed site (≈9% slope) with only 12 mm of runoff measured between 1979 and 1985.

Modeling soil organic carbon in corn ( Zea mays L.)-based systems in Ohio under climate change

“…This corresponds with earlier results published for these same two sites, which found significantly higher levels of TOC under NT as compared to PT, as well as stratification (Dick et al 1986a(Dick et al , 1986b(Dick et al , 1991. Considering the large body of evidence in the literature that NT methods usually result in higher TOC than PT in the top 20 cm (8 in) of soil, and that PT methods usually result in TOC declines, the corroborative evidence in this study is no surprise.…”

Nitrogen dynamics in soil management systems. I - flux of inorganic nitrogen (NH4+ and NO3-)

“…The results reported by Dick et al (1991) in systems under NT for over 25 years signify that N accumulation in the surface layers is mainly due to the return and maintenance of crop residues on the surface and not the tilling of the soil. In contrast, CT exposes the crop residues to a more intense microbial attack, which accelerates the decomposition of organic material (Souza & Melo, 2000).…”

Effect of tillage systems on soil properties, humus and water conservation

“…STC involves reducing the number of tillage to direct sowing and plant remains at the soil surface in the ratio of at least 30%. STC aims to ensure an appropriate aerohydric regim for the biological activity and balance in nutrient solubilisation [2,4,6]. Plant debris left on the soil surface or superficial incorporated contributes to increased biological activity and is an important source of CO 2 .…”