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ARS Home » Research » Publications at this Location » Publication #126586
Title: LONG-TERM GRAZING DENSITY IMPACTS ON SOIL COMPACTION

Author
item DANIEL, JOHN
item POTTER, KENNETH
item ALTOM, WADELL - NOBLE FOUNDATION, ARDMORE
item ALJOE, HUGH - NOBLE FOUNDATION, ARDMORE
item STEVENS, RUSSELL - NOBLE FOUNDATION, ARDMORE

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2002
Publication Date: 12/1/2002
Citation: N/A

Interpretive Summary: Livestock activity can possibly modify soil properties by compaction which can degrade soil structure, increase soil bulk density, and reduce water infiltration rates. Soil compaction on six paddocks, where each paddock was grazed for 10 years at either a low (12.5 cows/ha), medium (25 cows/ha) or high (50 cows/ha) stocking density of stocker cattle, was determined by penetration resistance, bulk density and infiltration measurements. Two adjacent ungrazed sites were used as controls. Results of this study show that long-term grazing at all levels of stocking density increased penetration resistance and bulk density, but only the top 10 cm of the high stocking density treatment had a significant impact. Infiltration rates were found to decrease from 28 cm/day to 5 to 7 cm/day for the grazed paddocks regardless of stocking density. Even though soil compaction occurred at the surface, the decrease in infiltration means a loss of water rfor available plant use and an increased potential for soil erosion and surface runoff.

Technical Abstract: Livestock activity can possibly modify soil properties by degrading soil structure, increasing soil bulk density, and reducing infiltration rate. Impacts of grazing on soil compaction were studied on rangeland in the tall-grass prairie region of Oklahoma. Rotational grazing treatments included low (12.5 cows/ha), medium (25 cows/ha) and high (50 cows/ha) stocking density with ungrazed pastures used as control sites. Soil compaction was assessed 10 years after grazing treatments were installed using penetration resistance, bulk density, and rate of water infiltration. Long-term livestock grazing increased resistance to penetration and bulk density values, but only in the upper 10 cm. The surface infiltration rate decreased from 28.5 cm/day for the ungrazed treatment to 7 cm/day under light grazing, 5 cm/day under moderate stocking, and 5 cm/day for the heavily-grazed treatment. The long-term grazing impacts were restricted to the soil surface, but infiltration of rainfall is substantially reduced suggesting less water is available for plant use and potential soil loss by erosion.