XIV OUTLINE AND TABLE OF CONTENTS 



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III. Movement of soil-water 165 



a. Gravitational movement (80). 



b. Capillary or film movement (81). 



1. Principles governing capillary movement (82). 



2. Extent, rate and importance of capillary move- 



ment (83). 

 Determined by 



(a) Texture (84). 



(b) Dampness of soil particles (85). 



(c) Structure (86). 



(d) Surface tension (87). 



(e) Condition of surfaces of particles (88). 



3. Examples of amount of water moved (89). 



c. Thermal movement (90). 



IV. Control of soil-water 190 



a. Means of increasing water-content of the soil (91). 



1. Decreasing loss (92). 



(a) Percolation (93). 

 (6) Evaporation (94). 



(1) Mulches (95). 



(a') Mulching plow land (96). 

 (b') Fall and spring plowing (97). 



(2) Other surface treatments (98) 



2. Increasing the water capacity (99). 



3. Irrigation (100). 



(a) Factors affecting the duty of water (101). 

 (6) Methods of applying water (102). 



(1) Floodings (103). 



(2) Furrows (104). 



(3) Overhead sprays (105). 



(4) Sub-irrigation (106). 



b. Means of decreasing the water-content of the soil (107). 



1. Drainage by ditches (108). 

 (a) Effects of drainage (109). 



(1) Firms the soil (110). 



(2) Improves the structure (111). 



(3) Increases the available water (112). 



