Aggregate Protected Carbon and Nitrogen Pools in Response to Different Tillage Systems.

The long-term effects of different tillage systems on soil aggregate stability and aggregate associated C and N pools were analyzed for the long-term tillage experiments established in 1962 at the Western Branch Experimental station (South Charleston, Ohio) of the Ohio State University. The experiment, also known as Triplett-Van Doren long-term tillage plots” is one of the longest running no-till experiments in the region. Treatments included moldboard plow tillage (PT), chisel plow tillage (CT), and no-till (NT) under continuous corn system with four replications. Each plot is about 5.0 by 61 m, with Crosby silt loam (fine, mixed, mesic Aeric Ochraqualf) soils. Composite undisturbed soil samples were collected from 0 to 30 cm depth at 7.5 cm increments, processed and analyzed for aggregate size distribution (using wet sieving technique) and aggregate protected C and N pools (using dry combustion FLASH elemental C and N analyzer , Thermo Electron Corp.). The detailed results and conclusions will be presented.