Liebig's 

 Discovery 



Insoluble 

 Phosphates 

 of Little 

 Value 



The last two phosphates, 1-lime and 2-hme, are what 

 constitute the "available" phosphoric acid in acid phosphate, 

 dissolved bone black and in chemically prepared fertilizers. 



Liebig, the founder of agricultural chemistry and the father 

 of the chemical fertilizer industry, discovered that if we treated 

 bone, a 3-Hme phosphate, with sulphuric acid, we robbed it 

 of two parts of its lime and that the remaining one part was 

 soluble in water, in which form plants could readily absorb it, 

 and in which form, for some reason unknown at the time, it 

 was found to hasten maturity. On this discovery was based, 

 and is still based, the chemical fertilizer industry, which in 

 seventy years has grown to enormous proportions all over the 

 world. 



Professor Chester, of the Delaware Agricultural College, 

 states* that an average of forty-nine analyses of soils shows 

 enough potential phosphoric acid to produce fourteen bushels of 

 wheat per acre per year for five hundred years. The question 

 then arises, "Should the commercial farmer, who is dependent 

 upon quick crops for quick returns, apply unavailable fertili- 

 zers, and especially insoluble phosphates, which neither supply 

 the needed available phosphoric acid nor have any catalytic 

 influence in the soil? In a word, shall he in this latitude, where 

 the growing season is limited practically to 120 days, and 

 where there is often a short supply of water, apply insoluble 

 and unavailable plant food, while the soluble and available can 

 be obtained at a relatively small cost over the insoluble?" 



Ground Phosphates or ''Floats" 



Ground mineral phosphates, sometimes called "floats," are 

 being recommended as absorbents under cattle and horses. 

 They are, no doubt, a good absorbent, but no better than fine, 

 dry earth. It is contended that in the manure pile, by the action 

 of decomposition and nitrification of the manure, a certain part 

 of the phosphoric acid will be rendered available, but how much 

 will be rendered available is unknown. No prudent commer- 

 cial farmer Vv^ill depend upon it as a source of available phos- 

 phoric acid for hoed crops. He might as well depend entirely 

 on hay for milch cows. 



♦See also page 27. 



10 



