THE NEED OF COMMERCIAL FERTILIZERS 159-170 Loss of plant-food 159 Prejudice against commercial fertilizers 160 Are fertilizers stimulants? 161 Soil analysis 162 Physical analysis 163 The use of nitrogen 164 Phosphoric-acid requirements 165 The need of potash 166 Fertilizer tests 167 Variation in soil 168 CHAPTER XVII COMMERCIAL SOURCES OF PLANT-FOOD 171-187 Acquaintance with terms 171 Nitrate of soda 171 Sulphate of ammonia 178 Dried blood 173 Tankage 174 Fish 175 Animal bone 175 Raw bone 177 Steamed bone 178 Rock-phosphate 178 Acid phosphate 180 Basic slag 183 Muriate of potash 184 Sulphate of potash 185 Kainit 185 Wood-ashes 185 Other fertilizers 186 Salt 186 Coal-ashes 187 Muck 187 Sawdust 187 CHAPTER XVIII PURCHASING PLANT-FOOD 188-197 Necessity of purchase 188 Fertilizer control 189 Brand names 191 Statement of analysis 191 Valuation of fertilizers 193 A bit of arithmetic 194 High-grade fertilizers 196 CHAPTER XIX HOME-MIXING OF FERTILIZERS 198-208 The practice of home-mixing 198 Effectiveness of home-mixing 198 Criticisms of home-mixing 199 The filler 202 Ingredients in the mixture 203 Materials that should not be combined 207 Making a good mixture 207 Buying unmixed materials 208 CHAPTER XX