1. For purposes of classification, the lower boundary of soil is arbitrarily set at ?? below the surface 1

2. What are the 6 levels of USDA Soil Taxonomy? __a__ ___b___ ____C____ ____d____ ____e____ How many? Which level is named after the place where it was first identified? 2

3. Diagnostic sub- surface horizons Why does USDA Soil Taxonomy place so much emphasis on sub-surface diagnostic horizons? 3

4. What is the soil order ? “new soils” sands, river bottoms 4

5. What is the soil order? “immature soils” Which master horizon is just starting to form in this soil? 5

6. The central concept of ????? is that of soils with an argillic, a kandic, or a natric subsurface diagnostic horizon and a base saturation ≥ 35% “fertile forest soils” What is the soil order? Thin A horizon well developed B horizon weak E horizon rich in Ca and Mg 6

7. What is the soil order? “red and yellow acid soils” Only recently mapped in southern IL strongly developed B horizon distinct E horizon Thin A horizon low in Ca and Mg 7

8. What is the soil order? “black prairie soils” thick A horizon(s) well developed B horizon 8

9. What is the soil order? “muck or peat soils” 9

10. Richter and Markewitz (2001) a b c d Identify the soil orders (labeled a,b,c and d) in this conceptual chronosequence E 10

11. Geographic extent of the Drummer soil series Family = Fine-silty, mixed, superactive, mesic Typic Endoaquolls What is the soil order? 11

12. What is the soil order? 12

13. What is the hue of the Ap horizon? What is the chroma of the Bt1 horizon? 13

14. What is the term for “soils that are found together”? NCSU Soils technical bulletin 314 14

15. What is soil micromorphology ? 15

16. Matric forces + a + b Soil Skin 16

17. a b What is the name of the soil water status when all the water susceptible to the pull of gravity has drained? Identify realistic soil water tensions in bars or kPa for points a and b on this diagram 17

18. H20H20 H20H20 H20H20 H20H20 Just like a ball rolling down hill, water molecules travel upward through plants when the water tension along the path from soil to the atmosphere is increasingly negative b a -0.3 bars Identify realistic soil water tensions (in bars) for points a and b on this diagram 18

19. Soil water is a switch that activates or deactivates soil biology Water is considered biologically available, when soil organisms are able to win the “tug of war” with the soil Is it harder or easier for organisms to win the water tug of war in a salty soil. Briefly explain. 19

20. What is the purpose of a characteristic curve? What is the volumetric water content at field capacity in the soil represented by this curve? If the rooting depth is 100 cm, how many cm of water are plant available in this soil? 20

21. Which texture can hold the most water? Available water Brady and Weil, 2002 Which texture can hold the most plant available water? 21

22. At what soil water tension (in bars) would you want to start irrigating a tough crop like corn growing in a clay soil ? Wimpy crops Tough crops Critical moisture levels to avoid crop stress 22

23. How does a gypsum block soil moisture sensor work? 23

24. Coarse textured layer Fine textured layer How does the presence of a coarse textured layer under a fine textured layer affect percolation ? Be sure to explain your answer. 24

25. Briefly discuss something interesting related to soil that you learned about in the last month that you have not yet discussed on this quiz. 25