Long-term effect of cow congregation zone on soil penetrometer resistance: implications for soils and forage qualityGilbert C. Sigua and Samuel W. Coleman
United States Department of Agriculture, Agricultural Research Service, Subtropical Agricultural Research Station, Brooksville, FL, 34601, USA
Accepted 19 May 2009 ; published online 16 July 2009
Abstract - Higher degree of soil penetrometer resistance can reduce forage yields and can lead to water and soil quality degradation due to increased runoff and soil structure destruction. The inability of roots to penetrate in soils with high penetrometer resistance will result in decreased yield. With less root penetration into the soil, root mass is reduced and plant's ability to take up nutrients is reduced. To test whether cattle congregation sites typical on most forage-based cow-calf ranches, such as mineral feeders, water troughs, and shaded areas are more compacted and have greater soil penetrometer resistance than in other pasture locations under Florida conditions, soil penetrometer resistance data around and beneath three cattle congregation sites in established (>10 yr) grazed beef cattle pastures were collected in 2004, 2005 and 2006. Penetrometer readings were collected from two soil depths (0–20 and 20–40 cm) at different locations around the cattle congregation sites following radial (every 90 degrees: north, south, east, and west direction) sampling patterns at 0.9, 1.7, 3.3, 6.7, 13.3, 26.7 and 53.3 m away from the approximate center of cattle congregation sites . Results showed that area around or near cattle congregation sites tended to have higher soil penetrometer resistance values than in other locations within pasture field because of the frequent concentration of cattle around the different cattle congregation sites. Soil penetrometer resistance decreases linearly with distance away from the center of mineral feeders and water troughs; however, soil penetrometer resistance at the shaded areas was showing slight increase with distance away from the center. The least soil penetrometer resistance in all years were observed from shaded areas (1 200 103 Pa) while soil penetrometer resistance at water troughs was about 1 600 103 Pa and at mineral feeders of 1 800 103 Pa. These values were in the “fair” range of root penetration. Penetrometer resistance of soils can be a good predictor of root system performance and especially useful in predicting root extension into the deeper regions of the root zone at the congregation zone and grazing zone in pasture.
Key words: beef cattle / congregation sites / sustainability / agriculture / forage-based pastures
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