1. To appreciate the value of the soil survey as a tool to obtain important information about soils and vegetation in given geographic areas

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1 Lab 5: Soil Survey - Objectives 1. To appreciate the value of the soil survey as a tool to obtain important information about soils and vegetation in given geographic areas 2. To learn how to use the soil survey to obtain information about the selected soils Introduction In today's laboratory you will work through a series of questions designed to familiarize you with the use of an important resource for soil scientists known as the soil survey manual. The Soil Survey Manual is an invaluable resource for agriculturalists, range managers, foresters, or any individuals or organizations involved in the management of natural resources. The overall aim of conducting a soil survey and publishing the results is to locate and describe the soils of an area and indicate the potential use of those soils. In today's lab we will complete an exercise designed to acquaint us with the many types of information available in the Soil Survey for La Plata County, Colorado. Procedure Obtain a copy of the La Plata County Soil Survey manual from your instructor and answer the following questions. To help you complete this assignment, the pages where the information is found are noted in parentheses after the question. 1. What agencies are involved in producing the soil survey? [i] 2. The total area of La Plata County is acres, and the population of the survey area is. [1] Soils Lab 5 1 of 7

2 3. The average annual temperature of the county seat,, is F and the average annual precipitation is about inches. [1,3] 4. The first known European explorer in the area was in [1] 5. One of the important early industries in the area, which played and important role in the settlement of La Plata county, was. [1] 6. List 5 of the most important natural resources of the survey area: [3] What is the main origin of stored water in the area and where is much of it stored? [3] Soils Lab 5 2 of 7

3 8. List 2 non-irrigated crops grown in the area, and list 2 of Irrigated crops grown in the area: [3] 9. According to the survey, what two enterprises are probably the largest sources of income for the area? [3] 10. Look in the back of the survey manual and find the GENERAL SOIL MAP. This is the map shown in color. The numbered sections or units correspond to different soil associations. A soil association is a group or a mixture of several types of soils in a given geographic region. Locate the unit which includes Perins Peak and Barnroof Point. Which soil association is associated with Perins Peak and Barnroof Point? [map legend] 11. Go to page 5 of the survey. Beginning on this page is a series of descriptions of the associations indicated on the General Soil Map. What is the general description of the association you located in the previous question? [9, in italics] Soils Lab 5 3 of 7

4 12. Go to the back of the manual and locate the INDEX TO MAP SHEETS. This map is divided into numbered units that correspond to numbered aerial photographs of the region. Find the unit number which contains Barnroof Point and Perins Peak. Pull out the corresponding aerial photograph. The sheet number is given at the top of the page and the sheets are printed on both sides. In other words, if you find sheet No. 5, you will find sheet No. 6 on the other side of the page. 13. Locate Perins Peak on the map. To the south and west of Perins Peak is an area outlined in black with the number 7. This corresponds to a numbered soil [also called a map unit] that is described in detail in the soil survey manual. In fact, soil descriptions are given in two places in the manual. The first section of soil descriptions is found beginning on page 14. On page 19 you will find a detailed description of soil number 7, also known as the Archuleta-Sanchez complex. You will use this information to answer the following questions. 14. What are the names of the two soils that make up most (75%) of this complex? [19] 15. What is the parent material of the two soils? 16. List 5 plant species that are part of the native vegetation on this unit. Soils Lab 5 4 of 7

5 17. What wildlife are normally present on this unit? 18. As previously mentioned, there are two places in the survey that give detailed information about the different soils or map units. The second place is found beginning on page 99, in a section entitled "Classification of the Soils". In this section of the manual, the soil series are arranged alphabetically. In addition, in this section information is given about soil horizons. The information about the Archuleta series is given on page 102. Use this to answer the following questions. Important Note: If you attempt to complete this lab relatively early in the term, there may be a few questions that relate to concepts not yet covered in lecture. Ask your instructor for help on these questions or simply make a note to come back and complete them at a later date. 19. What is the suborder name for this soil? 20. What is the order name for this soil? Soils Lab 5 5 of 7

6 21. What is the grade of structure present in the A horizon? What is the class? What is the type? 22. Write the Munsell notation for moist color in the C horizon. 23. What is the ph of the A horizon? 24. The soil survey also contains information about vegetation associated with particular soils. Specifically, beginning on page 166 [Table 6], there is a table containing information about the rangeland productivity and characteristic plant communities of different soils. The soils are arranged numerically, with the numbers corresponding to the map unit numbers. According to Table 6, what is the dry matter production of vegetation in lb/acre that would be expected in an unfavorable year for a Clayburn soil (mountain loam range site)? [167] 25. According to Table 6, what species would be included in the characteristic plant community for the Clayburn Mountain Loam range site? [167] 26. Table 9 gives information about factors that would limit the suitability of different soils or map units for recreational development. Based on table 9, what is the main limiting factor of the Clayburn soil for use as a playground area? [182] Soils Lab 5 6 of 7

7 27. Table 5 [page 162] gives information about the land capability classes for the different soil map units. What is the capability class for the Clayburn soil under non-irrigated conditions [look in the N column]? [162] 28. To find out what the capability rating given in Table 5 means, turn to page 85 in the survey. Write down the first sentence of the section entitled "Land Capability Classification". This provides a brief definition of the term capability class. 29. What does the small letter 'e' in the rating refer to? [85] Soils Lab 5 7 of 7

Web Soil Survey National Cooperative Soil Survey

Web Soil Survey National Cooperative Soil Survey 122 14' 27'' W () 122 13' 37'' W 40 8' 40'' N 564700 564800 564900 565000 565100 565200 565300 565400 565500 565600 565700 565800 40 8' 40'' N 4443400 4443500 4443600 4443700 4443800 4443900 4444000 4443400