- 103 pounds of Nitrogen.
- 41 pounds of Phosphoric Acid.
- 65 pounds of Potash.
and yet experiment and experience have proved that the best fertilizer for such a crop contains the following amounts of plant food:
| Nitrogen | 20 pounds |
| Phosphoric Acid | 70 pounds |
| Potash | 20 pounds |
This means that cotton roots are fairly strong feeders of nitrogen and potash, but are weak on the phosphoric acid side.
The small grains, wheat, oats, barley and rye, can use tough phosphoric acid and potash, but are weak on nitrogen, and as they make the greater part of their growth in the cool spring before nitrification is rapid, they are benefitted by the application of nitrogen, particularly in the form of nitrate, which is quickly available.
Clover, peas, beans, etc., have the power of drawing nitrogen from the air, but draw from the soil lime, phosphoric acid and potash. Hence the phosphates, potash manures and lime are desirable for these crops.
Root and tuber crops are unable to use the insoluble mineral elements in the soil, hence they require application of all the important plant foods in readily available form. Nitrogen is especially beneficial to beets. Turnips are benefitted by liberal applications of soluble phosphoric acid. White and sweet potatoes require an abundance of potash.
If we are growing tender, succulent market garden crops, we need nitrogenous manures, which increase the growth of stem and foliage.
Fruit trees are slow growing plants and do not need quick acting fertilizers.
The small fruits, being more rapid in growth, require more of the soluble materials.