SOIL AND GAS FLUX RESPONSE TO IMPROVED MANAGEMENT IN COLD, SEMIARID AGROECOSYSTEMS
Location: Northern Great Plains Research Laboratory
Title: 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.
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.