to $20; (3) medium high grade, from $20 to $25; (4) high grade over $25. For the sake of comparison a few of the basic materials are included in the table.

AVERAGE COST OF ONE POUND OF PLANT FOOD TO CON

It will be seen that the price a pound of plant food is very much less in the high grade goods than in the low grade. If the fertilizer is to be shipped any distance there is another point in favor of the high grade goods for it costs no more for freight on a ton of a high priced fertilizer than on a ton of a low priced one, while the former may contain twice as much plant food as the latter.

Home Mixed Fertilizers.-The above table not only shows that plant food is cheaper in high grade fertilizers than in low grade, but also that the essential elements can be purchased more cheaply in the basic materials than in any mixed fertilizer. This is due to the fact that the manufacturer must be paid for

mixing, bagging, etc. Voorhees has shown by careful investigation that the average charges of the manufacturer for this work amount to $8.50 a ton. In other words, the plant food in one ton of a mixed fertilizer can be purchased by the farmer for from $6 to $10 less in unmixed materials. This fact suggests the thought that it might be possible for the farmer to buy the basic materials and prepare his own mixed fertilizers. The matter of home mixtures has been carefully studied by a number of experiment stations and it has been shown conclusively that the materials can

be evenly mixed on the farm, that the mechanical condition is good, and that the results obtained from their use are entirely satisfactory. It would not be advisable to try to make the superphosphate on the farm, but the plain rock-superphosphate can be purchased to mix with the other materials. There are some obvious advantages other than cheapness in home mixing over the purchase of mixed fertilizers. The usual analysis of a mixed fertilizer gives no clue as to the condition or source of the nitrogen, and it is difficult to determine its availability, while in the home made mixture the condition of the nitrogen should always be known.

Home mixing permits the uniting of the different elements in the proportions which have been found to meet the requirements of the crop best and the soil on which it is to be raised, something that is not easily managed with factory mixed fertilizers. By buying the basic materials separately it is possible to apply the different elements at different times, a point that is sometimes of great advantage in feeding a crop, especially if it is one that needs large quantities of nitro

Marketable potatoes on the left. Com

pare with cut on opposite page. Fertilizers not only increase the yield, but improve the quality as well

gen. In fact the only advantage that can consistently be claimed for the mixed goods is that they are more generally distributed in the market than the basic materials and can, therefore, be more easily purchased in such amounts and at such times as are convenient.

The conditions existing upon the majority of farms, are such that an elaborate arrangement, even for mixing small quantities at a time, will not be brought into use, and a tight barn floor and square pointed shovel will be the only requisites at disposal. Under such

circumstances after weighing out the quantities to be mixed they should be spread upon the floor in layers one upon the other. Then beginning at one side and working across, the whole should be shoveled over; this may be leveled somewhat and the operation re

An outfit for the home mixing of fertilizers. The grinding machine is necessary if the materials are lumpy, but if they are fine the screen and shovel alone are needed

peated until the mixing is satisfactory. In addition to the shovel and the barn floor a large screen such as is used in screening gravel or coal ashes, may be employed with decided advantage; the material at the first can be thrown upon the screen and by this means lumps may be separted and more easily broken up and the thoroughness of the mixing will be increased.

CHAPTER XX

USING COMMERCIAL FERTILIZERS

Fertilizers are used primarily in order to obtain an increased profit through the larger yield of the crop to which they are applied. From what has already been said, it must be evident that the fertilizer to be used depends on the soil and the particular crop to be raised. An economical and profitable use of commercial fertilizers calls for much more thought and study than the farmer has been accustomed to devote to the subject, for until he has a fair knowledge of the nature of his soil and the requirements of the crop he desires to produce he is not prepared to use good judgment in the selection of his fertilizing materials. Every farmer should conduct certain experiments on his own soil to ascertain what substances give the best results, but the majority of them are loath to undertake these experiments and prefer to follow some more general system (or lack of system) in the use of fertilizers. Commercial fertilizers have been on the market for a sufficient length of time to have been widely employed and as might have been surmised there have been developed a number of different plans or systems for their use which vary somewhat in the principles on which they are based, and which will be discussed. briefly.

Ville System.-"The one which has perhaps received the most attention, doubtless largely because