Fertilizer Problems 103 



III. Fertility of soil. 



a. Does the soil possess the required amount of plant - 



food, or does it "run down" quickly and need 



enriching ? 

 &. Have manures or fertilizers been applied in past 



years ? If so, how often, what kinds, and how 



much per acre ? 



IV. History of crops previous to test. 



What crops have been grown, and with how much 

 yield per acre, in past years ? In case of cereals, 

 consider the number of bushels of grain and 

 tons of straw or stalks per acre. 



Whilst the gardener must regulate his fertilizer prac- 

 tice by his own experiments and experience, he is not 

 wholly dependent on his own resources. Scientific in- 

 vestigation and general agricultural experience indicate 

 what will probably take place in a given case. The 

 general advice, for example, is to apply a complete 

 fertilizer, that is, one containing nitrogen, potash and 

 phosphoric acid in about the proportions which experi- 

 ence has found to be useful. This advice is particu- 

 larly good when the person does not wish to experiment 

 or to give the subject careful study. It is less useful, 

 perhaps, when one does not wish to enrich the land as 

 much as to give a stimulus to the young plant. It is 

 generally considered that nitrogen promotes rapid vege- 

 tative growth. It therefore may be used most freely 

 on plants which are desired for their foliage parts. If 

 it promotes growth, it also delays maturity. Therefore 

 it should be used sparingly, or only early in the season, 

 on fruit-bearing plants which tend to mature too late, 

 as tomatoes and eggplants. Experiments at Cornell 



