CONTENTS . IX 



§ 52 ; Organic matter and drainage, § 53 ; Organic 

 matter and soil color, § 54 ; Organic matter a source 

 of plant-food material, § 55 ; Organic matter and 

 nitrogen, § 56 ; Organic matter and soil microorgan- 

 isms, § 57 ; Organic matter forms acids, § 58 ; In- 

 jurious effect of organic matter, § 59 ; Management 

 of organic matter in soils, § 60 ; Sources of organic 

 matter, § 61. 



Questions on Chapter V ...... 57 



Laboratory Exercises .......' 58-60 



Examination of soil — organic matter, I ; Exami- 

 nation of peat and muck, II ; Estimation of organic 

 matter, III; Extraction of decomposed organic 

 matter, IV ; Influence of organic matter on percola- 

 tion through soils, V ; Influence of organic matter on 

 percentage of moisture held in soil, VI ; Influence of 

 organic matter on percentage of moisture held in soil, 

 VII. 



CHAPTER VI 



Soil Water 61-85 



Forms of water in soils, § 62 ; How the three forms 

 of water differ, § 63 ; Hygroscopic water, § 64 ; Capil- 

 lary water, § 65 ; Capillary water capacity, § 66 ; 

 Movement of capillary water, § 67 ; Effect of tex- 

 ture on capillary movement, § 68 ; Effect of struc- 

 ture on capillary movement, § 69 ; Height of water 

 column and capillary movement, § 70 ; Gravitational 

 water, § 71 ; The water table, § 72 ; Relations of soil 

 water to plants, § 73 ; Ways in which water is useful 

 to plants, § 74 ; Water requirements of plants, § 75 ; 

 Transpiration by different crops, § 76 ; Effect of 

 moisture on transpiration, § 77 ; Effect of humidity, 

 wind and temperature of the air, § 78 ; Effect of soil 

 fertility on transpiration, § 79 ; Quantity of water 

 required to mature a crop, § 80 ; Capillary move- 

 ment and plant requirement, § 81 ; Optimum mois- 

 ture for plant growth, § 82 ; The control of soil mois- 

 ture, § 83; Run-off, § 84; Percolation, § 85; Evap- 



