|Millar, J -|
Submitted to: Open Journal of Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 28, 2013
Publication Date: December 15, 2013
Repository URL: http://handle.nal.usda.gov/10113/58374
Citation: Nichols, K.A., Millar, J. 2013. Glomalin and soil aggregation under six management systems in the Northern Great Plains, USA. Open Journal of Soil Science. 3:374-378. Interpretive Summary: Aboveground and belowground processes are linked by levels of disturbance and amounts and types of photosynthetically-derived carbon going belowground. Measurements of soil quality parameters, such as soil aggregation, water infiltration rate, and water retention, and the activity of arbuscular mycorrhizal fungi (a plant-fungal symbiont) are tests which may be utilized to examine this linkage. However, the interacting biological, chemical, and physical processes occurring in the soil, particularly in the rhizosphere, frequently make results from these tests inconclusive. In this study, the data from these tests were all highly correlated, but some of the results were unexpected based on other results from the literature. More research exploring the soil environment and how it relates to aboveground management, especially in rangelands, will help to model above- and belowground relationships.
Technical Abstract: The soil environment is linked to aboveground management including plant species composition, grazing intensity, lev-els of soil disturbance, residue management, and the length of time of a living plant is growing. Soil samples were col-lected under rangeland [native grass, rotational grazing (NGRG); tame grass, heavy grazing (TGRG); and tame grass, rotational grazing (TGHG)] and cropland [conventional till (CT); CT plus manure (CTM); and long term no till (NT)] systems. The rangeland systems were hypothesized to have higher glomalin content [measured as Bradford-reactive soil protein (BRSP)] and water stable aggregation (WSA) than the cropland systems. In addition, within both rangeland and cropland systems, BRSP and WSA were expected to decline with increased disturbance due to grazing or tillage and going from native to introduced plant species. Differences were detected for BRSP with NGRG and CTM having the highest values in range and cropland systems, respectively. However, the CTM system had higher BRSP values than one or both of the tame grass systems while the CT and NT systems had similar values. Correlation analysis showed strong relationships between all of the BRSP values and WSA.