78 SUCCESSFUL FARMING 



and commercial value as applied to fertilizers are not synonymous and 

 should not be confused. The agricultural value is measured by the value 

 of the increase in crops secured through the use of the fertilizer. The 

 commercial value is determined by the trade conditions. It is based 

 upon the composition of the fertilizer and the price per pound of the 

 different forms of the several constituents that enter into it. Commercial 

 value is merely a matter of arithmetic. Agricultural value varies great ry 

 and depends upon a number of factors, among which the knowledge of 

 the farmer plays no small part. 



Mechanical Condition. — The mechanical condition of a commercial 

 fertilizer deserves consideration by the farmer. The degree of pulveriza- 

 tion controls the rate of solubility to no small extent. The finer the 

 pulverization the more thorough can be the distribution made in the soil. 

 The greater the number of points at which there are particles of fertilizer 

 in the soil, the more rapid will be the solution and the diffusion of the 

 plant-food material. Mechanical condition is also important from the 

 standpoint of distribution through fertilizer drills. The material should 

 be in what is known as a drillable condition. It should not only be 

 thoroughly pulverized, but also should be sufficiently dry to feed through 

 the mechanism of the drill at a uniform rate. Wet, sticky material clogs 

 up the drill and causes faulty distribution. 



High-Grade vs. Low-Grade Fertilizers. — Thousands of tons of low- 

 grade fertilizer are bought by farmers because the price is low, when, as 

 a matter of fact, the same money invested in a lesser amount of high- 

 grade fertilizer would have given them better results. Low-grade fertil- 

 izers, as a rule, contain varying amounts of filler or inert matter. This 

 sometimes constitutes as much as one-half the weight of the fertilizer. 

 It costs just as much to provide bags and handle this material as it does 

 the more active portion. Furthermore, the farmer pays for the bags 

 and freight on this worthless material. At the same time, he hauls it 

 from the railway station to his farm, unloads it and afterwards applies 

 it to his fields with much more expenditure of time and effort than would 

 be required for a smaller amount of high-grade material containing equally 

 as much plant food. 



Use of Fertilizers. — The most economical use of commercial fertil- 

 izers is secured only when a systematic crop rotation is practiced and 

 the soil is maintained in good physical condition and well supplied with 

 organic matter and moisture. The soil should contain sufficient lime to 

 prevent the accumulation of acids, so that legumes such as clover will 

 thrive. Every crop rotation should have a suitable legume occurring 

 once every third to fifth year. The presence of legumes will lessen the 

 necessity for nitrogen in the fertilizer. It is estimated that nitrogen can 

 be secured through the growing of legumes at a cost of approximately 

 four cents per pound, whereas it costs fifteen to twenty cents when pur- 

 chased in a commercial form. 



