ARS | Publication request: Soil aggregation and glomalin in a soil quality management study in a cold, semi-arid region

Submitted to: International Soil and Water Conservation Conference
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 2012
Publication Date: July 22, 2012
Citation: Nichols, K.A., Liebig, M.A., Tanaka, D.L. 2012. Soil aggregation and glomalin in a soil quality management study in a cold, semi-arid region. International Soil and Water Conservation Conference. Abstract 138.

Technical Abstract: Global food insecurity and rapidly diminishing water, soil, and energy resources are putting pressure on agroecosystems to efficiently produce more food while maintaining or enhancing soil quality, particularly soil aggregation. A field study established in 1993 near Mandan, ND sought to evaluate impacts of cropping sequence and tillage (minimum and no-till) on grain and biomass production, precipitation use efficiency, and soil properties. In 2006, surface (0-15 cm) soil samples were collected from four crop sequences (continuous spring wheat with residue removed, continuous spring wheat with residue retained, spring wheat-chemical fallow, and spring wheat-safflower-rye) under both tillage treatments, and analyzed for dry aggregate size distribution (DASD), water-stable aggregation (WSA), and glomalin production. Hypotheses tested were: 1. treatments under no-till (NT) would have higher amounts of macroaggregates (greater than 0.25 mm), levels of WSA, and glomalin; and 2. treatments which contained a fallow period would have lower soil macroaggregation and glomalin values. Macroaggregate concentration was higher under NT than minimum till. A whole soil stability index calculated from DASD and WSA was about 15% higher under continuous cropping than under spring wheat-chemical fallow. There was no significant difference in glomalin across tillage and cropping treatments, but 1-2 mm aggregates had the highest glomalin levels of all aggregate size classes. The results indicate that in a cold, semi-arid region, NT and continuous cropping improves soil aggregation.