INDEX 



Acidity in soils, 96 



Air in soil, 30 



Alkali soils, 54 



American soils, some main groups, 



54 

 Ammonia production in soils, 42 ; 



nitrate of, use as fertiliser, 136 ; 



sulphate of, use as fertiliser, 133 

 Ashpit refuse as manure, 203 

 Azotobacter, 45 



Barber, Samalkota experiments, 



167 

 Basic slag, 147; comparison with 



superphosphate, 152 

 Berry, K. A. , on proper time to apply 



farmyard manure, 185 

 Black soils, 40, 55 

 Blood, dried for manure, 195 

 Bones as fertilisers, 140 

 Bracken as litter, 169 

 Bracken ash as source of potash, 



156 



Cake feeding improves dung, 168, 

 ISO 



Calcium carbonate, effect on soil, 

 219; in soil, estimation of, 228; 

 in soil, loss of, 50, 224. See also 

 Chalk 



Calcium cyanamide asfertiliser, 137 



Carr, 40 



Catch crops, 63 



Cattle and soil fertility, 117 



Cellulose, decomposition in soil, 37 



Chalk, as manure, 219; composition 

 and properties, 24 ; origin of, in 

 soil, 27; soils, 122. See also Cal- 

 cium carbonate 



Clay, properties of, 21 ; soils, two 

 kinds, 108 



Climate, effect in determining the 



general character of the soil, 48; 



effect in determining what crops 



can he grown, 63 

 Climatic zones and soil belts, 



52 

 Clover, effect on soil fertility, 45, 



121 

 Clover sickness, 121 

 Cockle Park experiments with phos- 



phatic fertilisers, 151, 153; with 



potassic fertilisers, 163 

 Colloids, 21 

 Composts, 187 

 Compound fertilisers, 187 

 "Condition" of soil, 76 

 Conditions necessary for plant 



growth, 2 

 Crop maps, 67, 68, 73 

 Crops, manures for different, 211 

 Crops suitable for different climatic 



conditions, 64 

 Crops suitable for different soil, 



48, 125 

 Cultivations, 63, 76 

 Cyanides, toxic effect of, 155 



Darwin on earthworms, 85 

 Defiocculation of clay, 109 

 Denitrification, 44 

 Depth of soil, 97 

 Destructor dust as manure, 203 

 Diameters of soil particles, 16 

 Digger ploughs, 79 

 Diminishing returns, law of, 214 

 Disk cultivators, 85, 87, 111 

 Dissolved bones, 141 

 Dongas in S. Africa, 51 

 Drainage, 98; water, 50, 61 

 Drain gauges, 62 

 Dry farming, 74 



