CONTENTS 



XI 



Quantities of plant-food materials in drainage, § 120 ; 

 Effect of crop growth on loss of plant nutrients in 

 drainage, § 121 ; Effect of fertilizers on loss of plant- 

 food materials in drainage, § 122; Drainage water 

 from different soils, § 123 ; Absorption of good mate- 

 rials by plants, § 124 ; How plants absorb nutrients, 

 § 125; How roots aid in solution of soil, § 126; Pro- 

 duction of carbon dioxide by microorganisms, § 127 ; 

 Solvent action of roots in other ways, § 128 ; Differ- 

 ence in absorptive power of crops, § 129 ; Substances 

 needed by plants and substances merely absorbed, 

 § 130; Quantities of plant-food materials removed 

 by crops, § 131 ; Possible exhaustion of mineral 

 nutrients, § 132. 



Questions on Chapter VII ...... 



Laboratory Exercises ....... 



Soluble matter of soil, I ; Absorptive power of soil 

 for dyes, II ; Selective absorption by soil, III ; Ab- 

 sorptive power of the soil for gas, IV. 



110-111 

 111 



CHAPTER VIII 



Acid Soils and Alkali Soils . . . . . 

 Nature of soil acidity, § 133; Positive acidity, 

 § 134 ; Negative acidity, § 135 ; Ways by which soils 

 become sour, § 136 ; Drainage as a cause of acidity, 

 § 137 ; Effect of plant growth on soil acidity, § 138 ; 

 Effect of fertilizers on soil acidity, § 139 ; Effect of 

 green-manures on acidity, § 140 ; Weeds that flourish 

 on sour soils, § 141 ; Crops adapted to sour soils, 

 § 142 ; Crops that are injured by acid soils, § 143 ; 

 Litmus paper test for soil acidity, § 144; Litmus 

 paper and potassium nitrate, § 145 ; The Truog test, 

 § 146; Alkali soils, § 147; Nature and movements 

 of alkali, § 148 ; Effect of alkali on crops, § 149 ; 

 Tolerance of different plants to alkali, § 150 ; Irriga- 

 tion and alkali, § 151 ; Removal of alkali, § 152 ; 

 Control of alkali, § 153. 



112-121 



Questions on Chapter VIII 



121-122 



