Hierarchy for Ecological Sites (LRR, MLRA, LRU, Soil-Landscape Properties)

1. Hierarchy for Ecological Sites(LRR, MLRA, LRU, Soil-Landscape Properties) Interagency Ecological Site Applications Workshop Winnemucca, NV June 5-7, 2012 Herman B. Garcia Ecological Site Inventory Specialist USDA-NRCS Phoenix AZ

2. Land Resource Regions (LRRs ) are a group of geographically associated major land resource areas. What are Land Resource Regions? There are 28 LRRs described across the conterminous United States, Alaska, Pacific Basin Region, Hawaiian Region, and the Caribbean Region. United States Department of Agriculture Handbook 296 Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin

3. LRR - DWestern Range and Irrigated Region D

4. SE receive warm summer rains … elsewhere in the region, however, most of the precipitation falls during the cool season. freeze-free period ranges from 105-260 days soils are dominantly Aridisols, Entisols, and Mollisols dominantly mesic soil temperature regimearidic soil moisture regime and mixed mineralogy This is a semidesert or desert region of plateaus, plains, basins, and many isolated mountain ranges. 549,725 square miles average annual precipitation 6 – 42 inches average annual temperature 40-60 degrees F

6. Major land resource areas are geographically associated land resource units. What are Major Land Resource Areas (MLRAs)? Over 300 MLRAs are currently described 23 MLRAs are identified within LRR D

7. Nevada MLRAs 24—Humboldt Area Area is in Nevada and Oregon -12,680 square miles. -Winnemucca Nevada Physiography…the Great Basin Section of the Basin and Range Province of the Intermontane Plateaus Elevation 3,950-5,900 feet to 8,850 feet mountain peaks Geology… wide valleys , N to S trending isolated ranges are uplifted fault-block mountains Climate…average annual precipitation is 6-12 inches as much as 40 inches…Summers are dry. The average annual temperature is 38-53 degrees F… freeze-free period averages 135 days and ranges from 100 to 175 days… Soils… dominant soil order is Aridisols Torriorthents (Boton series) in loess and alluvium over lacustrine sediments… Biological Resources… Shrub-grass veg

8. Nevada MLRAs 25—Owyhee High Plateau Area is in Nevada, Idaho, Oregon, and Utah -28,930 square miles -Elko, Nevada, Physiography…within the Intermontane Plateaus... separated by narrow, aggraded Desert … N. half within the Columbia Plateaus Province...NE corner has deep, narrow canyons draining into the Snake River…. Elevation ranges 3,000 -7,550 feet …9,840 feet on some steep mtns. Geology… dominant rock types in the area are volcanic - andesite, basalt, and rhyolite… Cretaceous granitic rocks occur in the mountains. Only a few narrow valleys occur in this area . Climate… AAP is 7-16 inches and exceed 50 Inches…Ppt evenly - fall, winter, and spring The average annual temperature is 35-53 degrees F… freeze-free period avg 135 days Soils… dominant order are Aridisols and mollisols Biological Resources… Shrub-grass veg- high plateaus support juniper and mahogany

9. Land resource units (LRUs) are the basic units from which major land resource areas (MLRAs) are determined. What are Land Resource Units (LRUs)? LRUs are generally several thousand acres in size Synonymous with Common Resource Areas (CRAs) in 2005 Ecological Sites are the building blocks for LRUs

11. Regions with similar climate, land use Geographic areas with similar soils Similar landscape patterns Groups of Ecological Sites -share landscapes Intermingled ecological sites or single site One individual representative of the site An observation of plant-soil relationships

12. Ecological Cross-References Source: USDA Ag Handbook 296;Appendix I