CONTENTS IX 



tion of fertilizers ; Forms of nitrogen, phosphoric acid and potash 

 in commercial fertilizers; Misleading statements on fertilizer bags ; 

 Estimating the value of a fertilizer ; Home mixing ; Fertilizers and 

 tillage ; Abuse of commercial fertilizers ; Judicious use of ; Field 

 tests ; Preliminary experiments ; Verifying results ; Deficiency of 

 nitrogen, phosphoric acid, potash and of two elements ; Import- 

 ance of field trials ; Will it pay to use fertilizers? Amount to use 

 per acre ; Influence of excessive applications ; Fertilizing special 

 crops; Commercial fertilizers and farm manures. Pages 196-214. 



CHAPTER XI 



Food Requirements of Crops. Amount of fertility removed by 

 crops ; Assimilative powers of crops compared ; Way in which 

 plants obtain their food ; Cereal crops, general food requirements ; 

 Wheat ; Barley ; Oats; Corn ; Miscellaneous crops ; Flax ; Potatoes ; 

 Sugar-beets ; Roots ; Turnips ; Rape ; Buckwheat ; Cotton ; Hops ; 

 Hay and grass crops ; Leguminous crops ; Garden crops ; Fruit 

 trees ; Lawns. Pages 217-229. 



CHAPTER XII 



Rotation of Crops. Object of rotating crops; Principles involved 

 in crop rotation ; Deep and shallow rooted crops ; Humus-consum- 

 ing and humus-producing crops ; Crop residues ; Nitrogen-consum- 

 ing and nitrogen-producing crops ; Rotation and mechanical con- 

 dition of soil ; Economic use of soil water ; Rotation and farm 

 labor ; Economic use of manures ; Salable crops ; Rotations advan- 

 tageous in other ways ; Long- and short-course rotations ; Problems 

 in rotations ; Conservation of fertility ; Necessity of manures; Use 

 of crops ; Two systems of farming compared ; Losses of fertility 

 with different methods of farming ; Problems on income and outgo 

 of fertility from farm. Pages 230-246. 



CHAPTER XIII 



Preparation of Soils for Crops, Importance of good physical 

 condition of seed bed ; Influence of Methods of Plowing upon 

 the condition of the seed bed ; Influence of moisture content of 

 the soil at the time of plowing ; Influence upon the seed 

 bed of pulverizing and fining the soil ; Aeration of seed bed 

 necessary ; Preparation of seed bed without plowing ; Mixing 

 of sub soil with seed bed ; Cultivation to destroy weeds ; 



