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Chapter 7

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Chapter 7

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  1. Chapter 7 Soil Water Soil Science & Management, 4E

  2. Objectives • Identify the role of water in plant growth • Define the forces that act of soil water • Classify types of soil water • Discuss how water moves in the soil • Explain how plant roots remove water from the soil • Describe how to measure soil water content Soil Science & Management, 4E

  3. Adhesion Adhesion water Anaerobic Available water Bar Capillary Capillary rise Capillary water Cohesion Cohesion water Field capacity Gravimetric water content Gravitational flow Gravitational potential Gravitational water Hydrogen bond Terms to Know Soil Science & Management, 4E

  4. Hygroscopic water Matric potential Osmotic potential Permanent wilting point Potentiometer Preferential flow Resistance block Saturated flow Saturation Soil-moisture tension Soil-potential Temporary wilting point Unsaturated flow Volumetric water content Water content Terms to Know Soil Science & Management, 4E

  5. How Plants Use Water • Effect of water stress • Effect of excess water Soil Science & Management, 4E

  6. Forces on Soil Water Figure 7-2 Soil Science & Management, 4E

  7. Forces on Soil Water • Capillarity Figure 7-3 Soil Science & Management, 4E

  8. Forces on Soil Water • Soil-water potential Figure 7-4 Soil Science & Management, 4E

  9. Forces on Soil Water Figure 7-5 Soil Science & Management, 4E

  10. Types of Soil Water • Available water Figure 7-6 Soil Science & Management, 4E

  11. Water Retention and Movement • Water retention Figure 7-8 Soil Science & Management, 4E

  12. Water Retention and Movement • Water movement Figure 7-9 Soil Science & Management, 4E

  13. Water Retention and Movement • The wetting front • Capillary rise • Effect of soil horizons (See Figure 7-11) • Preferential flow Figure 7-11 Soil Science & Management, 4E

  14. How Roots Gather Water Figure 7-12 Soil Science & Management, 4E

  15. How Roots Gather Water • Pattern of water removal Figure 7-13 Soil Science & Management, 4E

  16. Measuring Soil Water • Gravimetric measurements • Weight basis • Soil depth basis Soil Science & Management, 4E

  17. Measuring Soil Water • Potentiometers Figure 7-14 Soil Science & Management, 4E

  18. Measuring Soil Water • Resistance blocks • Neutron probe Figure 7-17 Soil Science & Management, 4E

  19. Summary • Not unlimited resource • Conservation important • Improve water-use efficiency • Lower evapotranspiration • Pay attention to possible pollution sources Soil Science & Management, 4E