Rangeland soil quality--Aggregate stability (Soil Quality Information Sheet, Rangeland Sheet 3)

TitleRangeland soil quality--Aggregate stability (Soil Quality Information Sheet, Rangeland Sheet 3)
Publication TypeGovernment Report
Year of Publication2001
AuthorsHerrick JE, Tugel A.J., Shaver P.L., Pellant M.
PublisherUSDA, Natural Resources Conservation Service
ARIS Log Number142787
Keywordsgovernment publication
AbstractSoil aggregates are groups of soil particles that are bound to each other more strongly than to adjacent particles. Aggregate stability refers to the ability of aggregates to resist degradation. Additions of organic matter to the soil enhance the stability of aggregates. Raindrops, flowing water, and windblown sand grains can break apart soil aggregates, exposing organic matter to decomposition and loss. Stable aggregates are critical to erosion resistance, water availability, and root growth. Aggregate stability in rangelands is commonly measured on soil samples removed from the top one-fourth to one-half inch of the soil. This part of the soil is most likely to be removed by wind or water erosion. Deeper samples can also be analyzed. Samples should be collected both from beneath plants and from spaces between plants. Several samples should be collected from each area. The stability of aggregates is affected by soil properties that change relatively little and by properties that change in response to changes in vegetation and management. As a result, measurements of the aggregate stability of a given soil should be compared only with measurements for the same or similar soils with similar textures. Improving the productivity of rangeland through good range management normally increases aggregate stability. Include practices that maintain the optimum amount of live vegetation and litter in order to maintain the content of organic matter and soil structure and control erosion; decrease the number and size of bare areas; and, minimize soil surface disturbances, especially in arid areas.
Government BodySoil Quality Institute, Grazing Lands Technology Institute, and National Soil Survey Center, Natural Resources Conservation Service, USDA; the Jornada Experimental Range, Agricultural Research Service, USDA; and Bureau of Land Management, USDI