CONTENTS Xlll 



PAGES 



matter in fertilizers ; Inspection of fertilizers ; Mechanical 

 condition 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 ; 

 Importance of field trials; Will it pay to use fertilizers? 

 Amount to use per acre ; Influence of excessive applica- 

 tions ; Fertilizing special crops ; Commercial fertilizers 

 and farm manures. 



CHAPTER XI 

 FOOD REQUIREMENTS OF CROPS 255-272 



Amount of fertility removed by crops ; Assimilative 

 powers of crops compared ; Ways in which plants obtain 

 their food ; Cereal crops, general food requirements ; 

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

 Potatoes ; Sugar beets ; Roots ; Turnips ; Rape ; Buck- 

 wheat ; Cotton ; Hops ; Hay and grass crops ; Leguminous 

 crops; Garden crops; Fruit trees; Small fruits; Lawns. 



CHAPTER XII 



ROTATION OF CROPS AND CONSERVATION OF SOIL FER- 

 TILITY , 273-290 



Object of rotating crops ; Principles involved in crop 

 rotation ; Deep- and shallow-rooted crops ; Humus-con- 

 suming and humus-producing crops ; Crop residues ; Ni- 

 trogen-consuming and nitrogen-producing crops ; Rotation 

 and mechanical condition of soil ; Economic use of soil 

 water; Rotation and farm labor; Economic use of ma- 

 nures ; Salable crops ; Rotations advantageous in other 



