26 The Bulletin. 



lightly considered. As a rule, farmers sboiild buy the "raw materials" — acid 

 phosphate, cotton-seed meal, tankage, nitrate of soda, and potash salts, and 

 do their own mixing. They will thus not only be al)le to mix according to ap- 

 proved formulas, but they will find that the home-mixed goods will cost from 

 three to five dollars less than the price asked for ready-mixed or manipulated 

 guano. Any intelligent farmer, if he knows what material to buy, may make 

 as good, and certainly a better balanced, fertilizer than a majority of the 

 brands on the market. 



According to long-continued field tests made at the several Experiment Sta- 

 tions in the South — particularly at the Georgia Experiment Station — and the 

 confirmatory experience of many farmers, a fertilizer for cotton on the average 

 worn uplands of the South should contain the three "valuable elements" of 

 plant food in about the following proportions : Available phosphoric acid, 3% 

 parts ; nitrogen, 1 part ; potash, 1 part. Raising the terms to a higher degree, 

 these proportions are precisely the same as : Available phosphoric acid, 10 per 

 cent ; nitrogen. 3 per cent ; potash, 3 per cent. 



So, in the ordinary statement prevalent among fertilizer dealers and farmers, 

 a proportion of 10-3-3 may be adopted as a high-grade, standard formula for 

 cotton. Lower grades, preserving practically the same ratio, will answer just 

 as well, provided a larger application per acre be made in inverse proportion 

 to the grade or qualitv. To illustrate, the following analysis would prove pre- 

 cisely the same proportions: 9-2.70-2.70; 8-2.40-2.40; 7-2.10-2.10; 6-1.80-1.80; 

 5-1.50-1.50. 



In order to get the same results on a crop with either of the above analyses 

 it will be only necessary to apply an amount inversely proportioned to the 

 grade. For instance, it would require 1.000 pounds of the 5-1.50-1.50 formula 

 per acre to supply the same amount of plant food to the acre as would be sup- 

 plied by 500 pounds of the 10-3-3 formula. As a rule, however, it will gener- 

 ally be"^ found advisable to buy high-grade ingredients and produce the higher 

 formulas, because the freight rates are the same on the low as they are on the 

 high-grade ingredients. 



When very moderate or light fertilizing is intended — as on fresh or new 

 soils, bottom lands, etc. — the above formula may be modified according to the 

 supposed exigency of the case, reducing the proportion of nitrogen and potash, 

 or even applying acid phosphate alone. When liberal amounts of fertilizers 

 are to be applied the general rule should be to fertilize the crop, and not the 

 soil. 



INGREDIENTS. 



The proposition can be maintained that with acid phosphate of any grade, 

 cotton-seed meal and any potash salt — these three ingredients — any desired 

 fornmla may be constructed, suited to any crop and to any soil whatever. 

 Acid phosphate stands by itself; there is practically no substitute for it. In- 

 stead of cotton-seed meal, several other nitrogenous ingredients may be sub- 

 stituted as convenience or cost may dictate, such as tankage, dried blood, ni- 

 trate of soda, sulphate of ammonia, etc. ; but in the South, fortunately, cotton- 

 seed meal is almost always cheaper and more convenient than any one of the 

 substitutes just named. Instead of muriate of potash, sulphate of potash, 

 kainit, sylvinit, or other potash salt may be used, but as a rule, the muriate 

 is the cheapest source of potash, as well as being high-grade. 



So, then, acid phosphate, cotton-seed meal and muriate of i)otash may be 

 considered as the three standard fertilizer ingredients for the use of the cotton 

 grower in compounding his fertilizers. In what proportions should they be 

 mixed in order to secure a formula 10-3-3, or any lower, relative formula. In 

 practice the three standard ingredients cannot be mixed .so as to secure so 



