Nitrogen 4 per cent. Potash 5 " Available phosphoric acid 7 "
One thousand five hundred pounds of the above formula should be applied per acre. When possible apply twenty to forty tons of vegetable material, such as partially rotted rakings of barnyard manure. Where such vegetable matter is procurable, the quantity of nitrogen may be decreased proportionately. If manure is obtainable, allowance should be made for the fertilizing elements contained therein.
An excellent formula for one ton of asparagus fertilizer, given by Prof. W. F. Massey, consists of:
200 lbs. nitrate of soda 700 " cottonseed-meal 800 " acid phosphate (13 per cent.) 300 " muriate of potash
This will yield 4.9 per cent. ammonia, 6.1 per cent. available phosphoric acid, 8.4 per cent. potash.
The effects of the application of a scientifically balanced fertilizer ration upon asparagus is clearly illustrated in Fig. 21, which presents a photographic reproduction of an experimental plat of the North Carolina State Horticultural Society at Southern Pines, N. C., fertilized with
250 lbs. nitrate of soda 400 " acid phosphate 160 " muriate of potash
per acre, while Fig. 22 shows a plat of equal size which remained unfertilized.
[Illustration: FIG. 21--NORTH CAROLINA'S EXPERIMENT FARM ASPARAGUS PLOT; FERTILIZED]
The following table gives the amounts of different fertilizer materials necessary to give the desired quantity of each element:
_Element_ _Pounds of different materials for one acre_ { 800 to 1,000 lbs. cottonseed-meal; or Nitrogen { 350 to 400 " nitrate of soda; or { 275 to 300 " sulphate of ammonia; or { 400 to 600 " dried blood.
{ 300 to 500 lbs. kainit; or Potash { 150 lbs. muriate of potash; or { 150 to 300 lbs. sulphate of potash
Phosphoric acid { 750 to 1,000 lbs. acid phosphate; or { 600 to 800 dissolved bone.
[Illustration: FIG. 22--NORTH CAROLINA EXPERIMENT FARM ASPARAGUS PLOT; UNFERTILIZED]
"Asparagus requires very heavy manuring, and yet its composition would not indicate it," writes Mr. Charles V. Mapes. "The explanation is found in the fact that it must grow very rapidly, otherwise it is tough, stringy and flavorless, the same as with radishes. If it had a long season to grow in, like timothy hay, it might grow successfully in very poor soil. A half ton of timothy hay contains about as much plant food, and in similar proportions, as two thousand bunches of asparagus, or five thousand quarts of strawberries, and yet while this quantity of hay will grow on an acre of almost any poor soil, the strawberries or asparagus for a fair crop per acre require a rich garden soil. If the hay were obliged to make as rapid growth as the asparagus, then it also would require rich soil. With the strawberry there is but the lapse of a few weeks from the time of blossoming to the full development of its fruit. The plants need a superabundance of plant food within easy reach, otherwise the fruit is small and inferior. The plant can not bear profitable fruit and at the same time be compelled to struggle for existence. The same is the case with asparagus. Neither of these crops can take up out of the soil all the fertilizer that needs to be applied for their successful growth, and therefore there is necessarily a large quantity of plant food unused and left over in the soil."