TABLE OF CONTENTS 



A. INTRODUCTION 

 CHAPTER I 



PAGES 



THE MEANING OF IRRIGATION 1-7 



Annual rainfall, 1 Seasonal rainfall, 2 Variations in 

 rainfall, 2 Conservation of rainfall on farms, 3 Condi- 

 tions of dry-farming, 3 Conditions of irrigation, 4 

 Irrigation defined, 4 Geographical need of irrigation, 5 

 Possible extent of irrigation, 5 Mission of irrigation 

 and dry-farming, 7. 



B. THE RELATION OF WATER TO SOILS 



CHAPTER II 



SOIL MOISTURE 8-20 



Attraction between near bodies, 8 Soil particles, 9 

 The soil-moisture film, 11 Thickness of film and diame- 

 ter of particles, 12 Hygroscopic coefficient, 13 The 

 wilting coefficient, 14 Lento-capillary point, 16 

 Maximum capillary capacity, 17 Free water, 17 

 Summary, 19. 



CHAPTER III 



THE SOIL AS WATER RESERVOIR 21-39 



Irrigated soils are unsaturated, 22 The movement of soil 

 moisture, 23 The distribution of soil moisture, 25 

 Field moisture capacity, 29 Water distribution in 

 furrow irrigation, 30 Effect of hardpan^ 32 Effect of 

 gravel, 34 Water table near surfaceTsJ^Soil treatment, 

 35 How much water can be stored, 35 Absorption of 

 water by soils, 38. 



(xiii) 



