CONTENTS 



PAGE 



Instructions Concerning Laboratory Work in Soils 11 



Exercise 1. — Field Study of the Processes of Soil Formation 13 



Exercise 2. — Taking Soil Samples 16 



Exercise 3. — Study of Soil Grains 18 



Exercise 4. — Composition of Soils 20 



Exercise 5. — Soil Classification 22 



Exercise 6. — Volume-Weight or Apparent Specific Gravity 23 



Exercise 7. — True Specific Gravity 26 



Exercise 8. — Heavy and Light Soils 28 



Exercise 9.— Effects of Organic Matter 30 



Exercise 10. — Other Effects of Organic Matter 32 



Exercise 11. — Influence of Weathering, Organic Matter, Sand and Lime on a Clay Soil 34 



Exercise 12. — Effect of Lime and Other Chemicals on a Clay Soil 36 



Exercise 13. — Total Moi.sture Determination 38 



Exercise 14. — Capillary Moisture 40 



Exercise 15. — Hygroscopic Moisture 42 



Exercise 16. — Capillary Rise of Water in Soils of Different Texture 44 



Exercise 17. — Effect of Too Much Organic Matter on Rise of Water 46 



Exercise 18. — Percolation of Water Through Soils 48 



Exercise 19. — Clod Formation 51 



Exercise 20. — Soil Surface and Percolation. . 53 



Exercise 21. — Capacity of Loose and Compact Soils to Hold Water 55 



Exercise 22. — Effect of Evaporation on Soil Temperature 58 



Exercise 23. — Value of Mulches in the Retention of Moisture 60 



Exerci.se 24. — Optimum and Critical Moisture 63 



Exercise 25. — Drainage and Soil Temperature 66 



Exercise 26. — Color and Temperature 6S 



Exercise 27. — Soil Ventilation 71 



Exercise 28. — Amount of Organic Matter in Soils 74 



Exercise 29. — Absorption of Plant Food by Soils 76 



Exercise 30. — Testing Soils for Acidity 7S 



Exercise 31. — Examination of Chemical Fertilizers SO 



Exercise 32.— Study of Plowing 82 



Exercise 33. — Examination anrl Discussion of Tillage Machinery 85 



