USE OF PHOSPHORUS IN DIFFERENT FORMS 237 



water supply, and fences, and some knowledge and skill in the live- 

 stock line, including business ability in the purchase and sale of 

 stock and animal products, in addition to the requirements for the 

 production of crops. 



The addition of phosphorus in farm manures is undoubtedly 

 one of the best methods for those who are able to practice it, and 

 by use of liberal proportions of grain and other concentrates rich 

 in phosphorus, especially bran from different grains, cake or meal 

 from various seeds from which the oil has been expressed, very 

 considerable amounts of phosphorus are added. It is important, 

 however, to understand and to keep in mind that average farm 

 manure is poor in phosphorus in comparison with its content of 

 nitrogen and potassium, especially when made from the produce 

 that remains after part of the grain has been sold from the farm, 

 and more especially when used in connection with a rotation in- 

 cluding legume crops and on soils abundantly supplied with po- 

 tassium but poor in phosphorus. In other words, under such con- 

 ditions average farm manure is a very poorly balanced fertilizer, 

 and if used even in moderate quantities the production of stalks 

 or straw is likely to be excessive in comparison with the yield of 

 grain; and the small grains are also likely to lodge, because the 

 unbalanced ration produces weakness even in straw of large growth. 



Considering the more concentrated phosphorus products, there 

 are four classes to be kept in mind: (i) natural bone, (2) natural 

 rock phosphate, (3) basic slag phosphate, and (4) acid phosphate. 



In the first group are raw bone meal, steamed bone meal, bone 

 tankage, and phosphatic guanos. In the second group are the va- 

 rious natural mineral phosphates, as the hard and soft phosphates 

 of Florida, the land rock and pebble phosphate of South Carolina, 

 the brown and blue phosphates of Tennessee, and the apatite of 

 Canada. The third group consists of basic slag only, sometimes 

 called Thomas phosphate. The fourth group includes all acidulated 

 phosphates, such as acidulated bone meal, acidulated bone black, 

 acidulated bone ash, common acid phosphate, and double super- 

 phosphate. The term dissolved is often used for acidulated goods. 



Non-acidulated bone black and bone ash are best considered as 

 belonging to the second group with the natural mineral phosphates- 



In groups i and 2, the phosphorus is present chiefly in the same 



