Long-Term Tillage and Diverse Crop Rotation Systems Impacts on Organic Carbon and Selected Soil Properties.

Oral Presentation at ASA/CSSA/SSSA International Annual Meeting at Minneapolis, MN from November 15-18, 2015

ASA Section: Agronomic Production Systems

Title: Soil & Environmental Quality Graduate Student Award

Long-term tillage and diverse crop rotation systems impacts on organic carbon and selected soil properties

A.H Alhameid*^a M.A. Ibrahim^a, S. Sandhu^a, E Ozlu^a, S. Kumar^a, S.L. Osborne^b, P. Sexton^a, T.E. Schumacher^a, and S. Ali^a

^aDepartment of Plant Science, South Dakota State University, Brookings, South Dakota (SD); ^bUSDA Agricultural Research Service, Brookings, South Dakota (SD).

Presenter: Abdullah Alhameid (Abdullah.Alhameid@sdstate.edu)

Oral Presentation Abstract

Using different management practices such as tillage and crop rotations can influence soil properties. However, short-term studies are unable to unambiguously explain their effects. This study was established to assess the long-term (about 25 years) tillage and rotation impacts on selected soil properties. A long-term experimental site comprised of two tillage systems [no tillage (NT) and conventional tillage (CT)], and three crop rotations [corn (Zea mays)-soybean (Glycine max), corn-soybean-wheat (Triticum aestivum), and corn-soybean-wheat-alfalfa (Medicago sativa)]. Soil samples were collected from four depths (0-7.5 cm, 7.5-15 cm, 15-30 cm, 30-60 cm) after harvest (November, 2014) and analyzed for soil organic carbon (SOC), total nitrogen (TN), bulk density, soil penetration resistance, and soil aggregate stability. Data show that the SOC was higher under NT compare to that of CT. Further; the 3-year rotation system was significantly lower compare to the 2-year and 4-year rotations. SOC under CT treatment with a 3-year rotation was significantly lower than all other treatments. There are no significant different in TN between the both the tillage systems. NT management under the 2-year crop rotation showed the lowest TN content. Plots under NT showed more stability in soil aggregates compare to CT. In general, preliminary findings conclude that the NT management improved soil properties compared to the conventional till system.