The crops of high commercial value, as a rule, mature in a short time, are materially affected in their quality by the lack of an abundance of available food in the soil, and when removed from the soil carry away a relatively small amount of the fertility elements; hence the returns per unit of plant-food applied are relatively large. In the case of the crops of low commercial value, their period of growth is much longer and the quality is not so largely influenced by lack of an excess of available food, while, when removed from the farm, they carry away a relatively large proportion of the constituent elements, and hence the returns per unit of plant-food applied are very much less. In the case of the third group, the crops are enabled to get their atmospheric nitrogen in proportion as they are well supplied with mineral food. In the first case, therefore, a large expenditure for fertilizers may cause a very large increase in yield, and a profitable return from their use; in the second class, a very large expenditure for fertilizers may be followed by a proportionate increase in yield, but could not

With these principles clearly understood, it will be seen that the variations in the kind and quantity of fertilizers used, as well as their time of application, are influenced by the character of the crop, the period of rapid growth, and the objects of its growth,-whether it shall be harvested in its green state or whether it is allowed to mature. Take, for example, a crop of cabbage, tomatoes, celery or early beets: it has been demonstrated by careful investigations that these plants require very liberal applications of nitrogen in order that maxi

give a large profit on the investment in fertilizers. It does not follow, however, that very large applications may not be desirable in the building up of soil, though the returns would be less than in the case of the other crops, and be distributed throughout a longer period of time.

Systems of fertilizing.

This question of the fertilizer requirements of crops and possible returns from their use, has led to a system of fertilization that is highly commendable, and in many lines of practice the two methods of fertilization indicated may be combined with very great advantage. For example, crops such as potatoes, tomatoes, or others of high commercial value, may have a place in the rotation with corn, wheat and hay. The modern fertilizer farmer then makes his excessive application on the money crop, in order to guarantee a large growth should other conditions be favorable; and the remainder of the crops in the rotation, of low commercial value, are influenced in their growth by the residues from the application made to the money crop. Thus the direct fertilization of the crops of low commercial value may be very materially reduced, indirectly making the money crop, which, because of the large increase in yield, has already paid for the fertilizer applied, and left a profit, pay for the fertilizers that cause a profitincrease in the growth of the other crops.

mum returns may be secured, and, while belonging to the crops of high commercial value, they differ from potatoes, asparagus, fruits and the like, which are more especially influenced by an abundance of the mineral elements, in the fact that they can utilize to fuller advantage the nitrogen in less soluble forms.

Fertilizer formulas.

In the making up of formulas for these specialized crops, the question of nitrogen becomes of the first importance. Practical growers now use as their initial application what may be regarded as a basic formula, one containing a high content of all of the three essential constituents, in immediately available forms, these being applied in such quantity as to satisfy any possible demands of the crop for mineral elements, but providing less nitrogen than the crops can fully utilize. The nitrogen required in excess is applied in the nitrate form during the period of growth, thus satisfying all demands for food, and in such a way as to enable the plant to make use of it most economically in the production of first quality products. In the case of celery, it has been shown that when 1,000 pounds of a basic fertilizer containing nitrogen 4.5 per cent, available phosphoric acid 8 per cent, potash 7.5 per cent, has been applied when the plants were set, with an application of 400 to 600 pounds of nitrate of

Fig. 657. Modern methods of fertilizing sweet-potatoes. Area one-tenth acre. Applied 611⁄2 lbs. acid phosphate; 20 lbs. nitrate of soda. Yield, 1334 baskets No. 1 grade; 10 baskets No. 2 grade: 13 baskets No. 3 grade. Rate, 367 baskets per acre (% peach baskets). (J. W. Killen, Felton, Delaware.)

soda per acre in two or three fractional dressings, the yield has been largely increased, and the selling price of the crop grown with the maximum amount of food more than doubled, making an increased value of crop of $150 to $250 per acre. Naturally, the amount of nitrate of soda to be applied, and the time the applications should be made, are influenced by the character of the season: it will require heavier fertilizing in a wet season than in a dry season, because of the greater liability of loss in the first instance.

It may, therefore, be regarded as a safe rule in the growing of such market-garden crops as early

though there will be no necessity for additional applications of nitrogen, and residues of constituents left after the potato crop is removed will usually be sufficient to guarantee a good crop of hay or wheat. When the land is left for the hay crops three or four years, top-dressings of a fertilizer rich in nitrates have been found most advantageous. Formulas for these may be made up to contain nitrogen 8 per cent, available phosphoric acid 3 per cent, potash 5 per cent, which would be secured from the following mixture:

An application of 200 to 300 pounds per acre of this mixture will guarantee an abundance of available food at the time that the plant is in greatest need of it. If, in the use of this rotation, yard manure is available, it should be applied previous to planting corn, and would be sufficient to supply an abundance of the elements for this crop.

In the case of fruits, the necessity for quickly available food is not usually apparent, even on medium soils, until the trees are in full bearing. Hence, in order to guarantee a sufficient wood growth, a formula containing a relatively high content of the minerals, and of nitrogen in slowly available forms, as in bone, may be used to advantage, preferably on light land. One made up of ground bone 250 pounds, acid phosphate 450 pounds, muriate of potash 300 pounds, will furnish the constituents in good forms. On heavier land, a mixture of three parts of ground bone

tomatoes, early table beets, early turnips, early cabbage, muskmelons, cucumbers, celery, onions, peppers and early potatoes, that a formula as indicated, and made up, for example, as follows:

may be applied at the rate of 1,000 pounds per acre, at the time of setting the plants, or sowing the seed, to be followed by fractional applications of nitrate of soda at the rate of 100 to 200 pounds in each application, two or three times during the season. Of course, it is not necessary for maximum growth that the applications should be made in this way, but if the greatest economy in the use of the materials is to be made, then such practice is preferable.

When potatoes or tomatoes are the money crops in a rotation with wheat, hay and corn, the same basic formula may be used, and at the same rate,

Fig. 659. Modern methods of fertilizing sweet-potatoes. Area one-tenth acre. Applied 61 lbs. acid phosphate: 20 lbs. nitrate of soda: 12 lbs. muriate of potash. Yield, 26 baskets No. 1 grade; 121⁄2 baskets No. 2 grade; 11 baskets No. 3 grade. Rate, 490 baskets per acre (%% peach baskets). (J. W. Killen, Felton, Delaware.)

and two of muriate of potash would possibly be quite as useful. The application of these mixtures, varying in amount from 300 to 500 pounds per year, will usually insure a continuous and normal growth of tree. When trees are in full bearing, additional nitrogen may be required, in which case it may be secured from yard manure, or by the plowing down of green crops, or by the early spring application of light top dressings, 100 to 200 pounds per acre, of nitrate of soda.

For legumes, a basic formula made up of ground bone 150 pounds, acid phosphate 600 pounds, muriate of potash 250 pounds, applied at the rate of 200 to 300 pounds per acre, would be sufficient to supply the mineral needs of red clover, alfalfa and vetches, and enable the plant to exercise its function of securing its nitrogen from the air; in the case of summer legumes, as the cowpea and soy bean, the application may be increased by at least one-half, as these plants must secure the

able constituents likely to be deficient in soils early in spring, when this crop must make a rapid growth if maximum crops are to be secured. Fertilizers for corn should be rich in minerals in any case, and when grown on raw ground, as distinguished from sod, should also be well supplied with nitrogen in organic forms. A good clover sod on good soils will usually furnish sufficient nitrogen, which, under good seasonal conditions, will decay rapidly enough to supply the needs for this element. For wheat and rye, formulas rich in phosphates are desirable, as the need for phosphates in early fall growth is apparently greater than for potash, and an excess of nitrogen would be liable to be wasted, or, if not, to cause too large a growth of top in the fall.

Forage crops.

These require somewhat different treatment from the same crops grown for their grain, as the

entire amount of food needed for their growth and development during a short period. In the growing of peas and beans for the cannery, or for early market, the fact that the crop is a legume should be largely ignored, and the fertilizing made the same as for other market-garden crops, because when grown for these purposes the crop must be largely made before soil conditions are favorable for the activities which permit of the appropriation of atmospheric nitrogen.

General grain rotations.

When no money crop is introduced into the rotation, such as potatoes or tomatoes, and only cereals and hay are grown, as in a rotation consisting of corn, oats, wheat and clover, the fertilizer applications should be more carefully adjusted to the individual requirements of the different plants, though owing to the low commercial value of these crops, financial returns proportionate to those secured from the fertilizing of the others mentioned cannot be expected; however, the applications should be sufficiently liberal to guarantee a maximum crop. In the case of wheat and grass, top-dressings of nitrate in spring will prove advantageous and more economical than if large proportions of nitrogen are contained in the formula used at time of seeding. In a general way, fertilizers for oats should consist chiefly of nitrates and soluble phosphates, as these provide the avail

object is to secure the largest yield of succulent food. Therefore, such an abundance of available food must be supplied as to insure, as far as possible, not only a continuous growth, but one in which the proportion of forage is greater than for the grain crop. This may be accomplished by increasing the proportion of available nitrogen in the formulas used for the same crops when the purpose is the matured grain.

Fertilizer formulas and guarantees.

Probably more than nine-tenths of the fertilizers used in this country are purchased in the form of mixtures containing all three of the essential constituents, nitrogen, phosphorus and potassium. The various brands are prepared from formulas designed to be especially suitable for different crops and soils. This method of purchase saves labor and thought on the part of the farmer, but the cost of the constituents is greater than if the fertilizer materials are bought and home-mixed; besides, in the mixtures, the farmer does not always obtain such proportions of the constituents as are best adapted to his conditions. These mixed fertilizers, as a rule, are, and should always be, accompanied by a statement of guaranteed composition. This is very essential, because purchasers are unable to tell, by mere visual inspection, what kinds and proportions of fertilizing materials have entered into the mixture. In many states the laws

require that the source of the materials also shall be distinctly stated, in order to insure the use of good products, as the mixing permits the disguising of poor forms, especially of those containing the element nitrogen.

Guarantees, however, sometimes confuse the purchaser, because the method of stating the guarantee is such as to mislead, provided he does not understand the meaning of the terms, or is unable to convert the percentages into their equivalents. It is entirely legitimate, when there are no laws forbidding, for the manufacturer to guarantee ammonia, instead of nitrogen; bone phosphate, instead of phosphoric acid; and sulfate of potash, instead of actual potash. The statement of the guarantee of the constituents in combination increases the percentage, thus leading ignorant purchasers to think that they are obtaining a larger percentage of the constituents than is really the case.

In the case of raw materials, a guarantee based on the purity of the chemical salts is very frequently used. That is, a substance when pure contains 100 per cent of the specific salt, and the guarantee which accompanies this product is merely a statement that indicates its purity. For example, when nitrate of soda is guaranteed to contain 95 per cent nitrate, it means that it is 95 per cent pure nitrate, or that 5 per cent of the total substance consists of impurities. The same is true in the case of sulfate of ammonia, sulfate of potash, muriate of potash, and other potash salts that may be offered. In order that the farmer may have a simple method of determining the actual content of the constituents, however guaranteed, the following tables are given to show the terms that are used, their equivalent of actual elements, and the factors to use in converting the one into the other:

It will be observed that the guarantee in the one case means the same as in the other. Different methods of stating guarantees should not mislead those who will familiarize themselves with the terms used, and with the conversion factors.

In the case of the mixed fertilizers, the percentage of the constituent elements that are given on the basis of equivalents represents the amounts when they exist in combination with other elements, viz., nitrogen, as ammonia; phosphoric acid, as bone phosphate; and potash, as sulfate. Commercial valuations.

In order that farmers may have a basis for comparing the commercial values of brands of different

1.214

Ammonia.
Nitrogen
Phosphoric acid . 0.458
Bone phosphate. 2.183
Actual potash. . 0.632
Muriate of potash 1.583
Actual potash. . 0.54
Sulfate of potash. 1.85

The following tables show the methods of stating guarantees on the basis of purity, in the case of many raw materials, and the equivalent percentage on the basis of actual constituents:

RAW MATERIALS.

Guarantee on basis of purity:

Nitrate of soda 95 per cent, or containing 95 per cent pure nitrate.

Muriate of potash 80 per cent, or containing 80 per cent pure muriate.

Sulfate of potash 98 per cent, or containing 98 per cent pure sulfate.

Kainit 25 per cent, or containing 25 per cent pure sulfate.

Fig. 661. Showing large crops of oats. Pot 76, soil from Kansas; pot 82, soil from Missouri; pot 90, soil from Wisconsin. To be contrasted with Fig. 662. These two sets of cultures were grown under the same conditions of moisture, sunshine, temperature and tillage. The two illustrations show how the soil itself determines the yield when other conditions are equal.

percentage composition, the various state boards of agriculture or experiment stations, charged with the inspection of fertilizers, usually adopt what is called "a schedule of trade values," which, applied to the various constituents, represents what the constituents in their unmixed state would cost, if purchased in that form, in large lots at the

factory. In fixing these values, it is assumed that at points of supply, that is, from jobbers or brokers, the cost of a pound of nitrogen, phosphoric acid or potash, in the various forms, would be practically the same for all manufacturers. The values are secured by averaging the wholesale prices per ton of all the various fertilizer supplies for the six months preceding March 1; to these wholesale prices is added a certain sum sufficient to cover expenses of handling, usually 20 per cent, and then calculating from this price per ton the cost per pound of the ingredients in the various materials. For example, suppose that the average price of acid phosphate, containing 14 per cent of 'available," is $10.50 per ton for the six months. To this price is added 20 per cent, or $2.10, which would make the wholesale price at factory $12.60 per ton. Each ton, which costs $12.60, contains 280 pounds of "available" phosphoric acid; or the phosphoric acid costs 4.5 cents per pound, which is then fixed as the trade value.

SCHEDULE OF TRADE VALUES FOR 1906.

The valuation obtained by the use of this schedule is merely a guide as to the commercial value, and is not intended to indicate even a possible agricultural value. This point needs to be emphasized. The agricultural value of a fertilizer is a variable factor, depending both on the availability of the constituents in it and on the value of the increased crop produced from its use. [If the reader wants tables of the fertilizer constituents of various substances, he will find thirty pages of them in Roberts' "Fertility of the Land," and shorter lists in various books and bulletins.]

How to figure the trade value of a fertilizer.

It is assumed that the mixed fertilizer is guaranteed to contain

and that the nitrogen exists in three forms, as nitrate, as ammonia, and as organic; the phosphoric acid in three forms, soluble, reverted and insoluble; and potash in two forms, sulfate and muriate. The 4 per cent ammonia would be equivalent to 3.28 per cent nitrogen, 1 per cent of which is nitrate-nitrogen, per cent sulfate of ammonianitrogen, and 1.78 per cent is derived from organic forms. Of the total phosphoric acid, 6 per cent is soluble, 2 per cent reverted, and 1 per cent is insoluble; of the total potash, 3 per cent is derived from muriate and 3 per cent from sulfate.

The first column in Table A shows the percentage of the constituents contained, which, multiplied by 20, gives the pounds per ton in the second column, which, multiplied by the schedule prices per pound, gives the valuation per ton, as shown in the fourth column.

In the case of ground bone, the guarantee is 4 per cent ammonia and 48 per cent bone phosphate, which are equivalent to 3.28 per cent nitrogen and 22 per cent phosphoric acid. It is assumed that 60 per cent of the material is finer than of an inch, and is regarded as "fine," and 40 per cent is coarser than of an inch, and is regarded as coarse."

5

Total estimated value per ton

2

Nitrogen, as nitrates. Nitrogen, as ammonia salts Nitrogen, as organic matter

Total nitrogen

Phosphoric acid, soluble

pounds per 100

3.28

Pounds per ton

=

20.0 X 16.5 10.0 X 17.5 35.6 X 18.5

$3 30

1 75

6 59

Phosphoric acid, reverted

Phosphoric acid, insoluble

Total phosphoric acid