Crops and Methods for Soil Improvement
Chapter 16
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