Blackgap soil series
Profile of Blackgap very gravelly loam in an area of Blackgap-Rock outcrop complex, 10 to 30 percent slopes. Hard limestone bedrock ranges in depth from 7 to 20 inches (18 cm to 51 cm). (Soil Survey of Big Bend National Park, Texas by James Gordon, Soil Scientist, James A. Douglass, Soil Scientist, and Dr. Lynn E. Loomis, Soil Scientist, Natural Resources Conservation Service)
The Blackgap series consists of very shallow to shallow, well drained, moderately permeable soils over very slowly permeable bedrock. These soils formed in cobbly, loamy residuum and colluvium derived from thick-bedded limestone bedrock. These nearly level to very steep soils have slopes ranging from 0 to 60 percent. The mean annual precipitation is about 280 mm (11 in) and the mean annual air temperature is about 21.1 degrees C (70 degrees F).
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, hyperthermic Lithic Ustic Haplocalcids
Because the epipedon has calcium carbonate equivalent greater than 40% and color value of 5 or less, it meets the color requirements for mollic epipedon. However, the soil does not meet the moisture requirement for a mollic epipedon because it is moist in some part of the epipedon for less than 90 days (cumulative) in normal years during times when the soil temperature at a depth of 50 cm (20 in) is 5 degrees C (41 degrees F).
Soil moisture: The moisture control section is dry in all parts more than three fourths of the time the soil temperature exceeds 5.0 degrees C (41 degrees F). Intermittently moist in some part of the soil moisture control section during June to September. More than 60 percent of the annual rainfall occurs during that period. The soil does not receive significant amounts of moisture during winter months. Ustic aridic soil moisture regime.
USE AND VEGETATION: Rangeland used for livestock grazing, wildlife habitat, and recreation. Vegetation physiognomy is desert shrubland. Dominant woody plants are creosotebush, ocotillo, lechuguilla, and dalea species. Grasses include Chino grama, red grama, and tridens species. Other characteristic plants include leatherstem, candelilla, and false agave.
DISTRIBUTION AND EXTENT: LRR I, MLRA 81D, Southern Edwards Plateau. The series is extensive. Blackgap soils were formerly included in the Lozier series.
For additional information about the survey area, visit:
www.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/texas/bigbendT...
For a detailed soil description, visit:
soilseries.sc.egov.usda.gov/OSD_Docs/B/BLACKGAP.html
For acreage and geographic distribution, visit:
Blackgap soil series
Profile of Blackgap very gravelly loam in an area of Blackgap-Rock outcrop complex, 10 to 30 percent slopes. Hard limestone bedrock ranges in depth from 7 to 20 inches (18 cm to 51 cm). (Soil Survey of Big Bend National Park, Texas by James Gordon, Soil Scientist, James A. Douglass, Soil Scientist, and Dr. Lynn E. Loomis, Soil Scientist, Natural Resources Conservation Service)
The Blackgap series consists of very shallow to shallow, well drained, moderately permeable soils over very slowly permeable bedrock. These soils formed in cobbly, loamy residuum and colluvium derived from thick-bedded limestone bedrock. These nearly level to very steep soils have slopes ranging from 0 to 60 percent. The mean annual precipitation is about 280 mm (11 in) and the mean annual air temperature is about 21.1 degrees C (70 degrees F).
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, hyperthermic Lithic Ustic Haplocalcids
Because the epipedon has calcium carbonate equivalent greater than 40% and color value of 5 or less, it meets the color requirements for mollic epipedon. However, the soil does not meet the moisture requirement for a mollic epipedon because it is moist in some part of the epipedon for less than 90 days (cumulative) in normal years during times when the soil temperature at a depth of 50 cm (20 in) is 5 degrees C (41 degrees F).
Soil moisture: The moisture control section is dry in all parts more than three fourths of the time the soil temperature exceeds 5.0 degrees C (41 degrees F). Intermittently moist in some part of the soil moisture control section during June to September. More than 60 percent of the annual rainfall occurs during that period. The soil does not receive significant amounts of moisture during winter months. Ustic aridic soil moisture regime.
USE AND VEGETATION: Rangeland used for livestock grazing, wildlife habitat, and recreation. Vegetation physiognomy is desert shrubland. Dominant woody plants are creosotebush, ocotillo, lechuguilla, and dalea species. Grasses include Chino grama, red grama, and tridens species. Other characteristic plants include leatherstem, candelilla, and false agave.
DISTRIBUTION AND EXTENT: LRR I, MLRA 81D, Southern Edwards Plateau. The series is extensive. Blackgap soils were formerly included in the Lozier series.
For additional information about the survey area, visit:
www.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/texas/bigbendT...
For a detailed soil description, visit:
soilseries.sc.egov.usda.gov/OSD_Docs/B/BLACKGAP.html
For acreage and geographic distribution, visit: