The University of Arizona

Matric potential of clay loam soils on arid rangelands in southern New Mexico.

C.H. Herbel, R.P. Gibbens


The matric potential of soil water is presented for 6 clay loam sites on floodplains of arid rangelands. Gypsum resistance blocks impregnated with plaster of paris were placed at 6 soil depths to 122 cm. At 4 locations, blocks were placed inside and outside a buried sheet metal cylinder so that estimates could be obtained of matric potential due to precipitation and due to precipitation plus run-in. The average annual precipitation during the approximate 20-year study period was 242 mm, slightly above the long-time average. Haplargids dominated by tobosa [Hilaria mutica (Buckl.)Benth.] had a greater probability of the matric potential greater than or equal to -1.5 MPa (wet soil) than the Calciorthids dominated by burrograss (Scleropogon brevifolius Phil.). The probability of matric potential greater than or equal to -1.5 MPa (wet soil) was as great or greater in winter as during the summer growing season. The factors affecting matric potential were amount and nature of precipitation, amount of run-in water, soil and vegetation type, position on the landscape, and microrelief.


matric potential;clay loam soils;New Mexico

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