The Bulletin. 61 



COMMERCIAL FERTILIZERS AND THEIR USES. 



By T. E. BROWNE, of Hertford County. 



The subject of commercial fertilizers has grown in importance during the 

 last few decades ; first, because of the need of adding plant food in order to 

 reap the maximum crops from our farm lands; second, because of the in- 

 creasing interest in agriculture through the country and the more scientific 

 methods used in this industry ; third, because of the growing tendency toward 

 intensive rather than extensive farming. 



Originally, the soils were quite rich in all the elements of plant food 

 necessary for plant growth. The original soil, as it was newly turned by the 

 crude plowshare of our forefathers, was well stocked by the Maker of the 

 Universe with all that was necessary to reproduce the plants of the forest 

 and meadow. When our forefathers began the tillage of the soil, they did not 

 realize the necessity of returning something to the land to replace the food 

 taken out by the growing crops, so they soon found the lands growing less 

 productive. As they knew nothing about fertilizers, they thought the soil was 

 "worn-out," so they would abandon the old fields, go into the forest and "clear 

 up" new land. This custom was followed until they found a way of renewing 

 the fertility artificially. 



There are in all about thirteen elements of plant food necessary for the 

 growth and maturity of farm crops, but it seems that nature has supplied 

 ten of these in such abundance, and they are so little used by plants, that 

 we do not concern ourselves about them. There are three, however, that 

 are used up quite rapidly, and are so essential for plant growth that the 

 scientific world has bestirred itself to devise a plan of keeping the soil re- 

 plenished with these, instead of having to abandon the old fields and clear 

 up new. 



These three elements about which we are most concerned and which, I may 

 say, are most essential to plant growth, are: Phosphoric Acid, Potash, and 

 Ammonia or Nitrogen. When we buy commercial fertilizers we always buy 

 them for these three elements contained therein, the purchase price being 

 based on the amount of these elements of plant food the ton contains. 



Each of these elements is derived from one or more definite sources, and 

 are put on the market in various forms. Their agricultural value is largely 

 dependent on the source from which the element is derived and the form in 

 which it is supplied. We know that the plant roots cannot use any element 

 of plant food until it is in a soluble state, and therefore for an element to be 

 of agricultural value it must be soluble in water. Therefore, for us farmers 

 to be able to buy and use fertilizers intelligently it is necessary for us to know 

 something of the source and form of the elements of plant food we are buying. 



I want to say right here that we should learn to distinguish between the 

 commercial and agricultural value of a fertilizer. We usually know only of 

 the first. The commercial value of a fertilizer is the added cost of the raw 

 material, cost of digging or dredging in case of mineral elements, cost of 

 treating and handling, and cost of mixing and bagging. The agricultural value 

 of a fertilizer is measured by the increased production per acre by the use 

 thereof. Whenever, fellow farmers, the commercial value exceeds the agricul- 

 tural value, there should we discontinue the use of that particular brand and 

 seek something better. 



I want to name, in this connection, a few of the most common sources from 

 which these elements are derived, in order that we may become familiar with 

 them, and also that we may the better be able to determine, after a careful 

 study of the question, which is better for us to buy, the raw material or the 

 ready-mixed goods. 



Phosphoric acid, that element which is used more largely than any other, 

 is derived mainly from the South Carolina. Tennessee and Florida phosphate 

 rocks. In the raw (or natural) state this rock is not in such a condition 



