174 TwENTY-FiEST Biennial Bbpoet 



to restore nitrogen and organic matter to th.e soil. Tlie 

 use of pkospliates, therefore, is the very foundation of 

 permanent soil improvement on such soils. In view of 

 the fact that the returns from the use of phosphates are 

 so much greater than from potash, granting that the 

 latter does give returns in some cases, we cannot recom- 

 mend the buying of potash until the farmer has first 

 bought sufficient phosphorus to use on all of his soU. A 

 fact worthy of notice in passing is that three-fourths of 

 the phosphorus required for grain crops is in the grain 

 itself. Hence if grain is sold there is a large loss from 

 the soil. Animals retain on the average one-fourth of 

 the phosphorus of the feed given them, so that both in 

 grain farming and live-stock farming there is an un- 

 avoidable loss of an element already deficient in nearly 

 all soils. 



Our teachings always emphasize permanent fertil- 

 ity, and the absolute necessity of providing nitrogen 

 and organic matter. 



We recommend the use of limestone on acid soils as 

 a means of increasing the growth of nitrogen-gathering 

 crops and through them all other crops. ' However, all 

 the evidence we have at hand indicates that on soils de- 

 ficient in phosphorus, limestone does not prove profit- 

 able without the use of phosphates, but when used in 

 connection with phosphates it is highly profitable. We 

 can unhesitatingly recommend the use of limestone and 

 phosphates on most Kentucky soils before potash, even 

 if potash is to be used at all. 



Let us see what the commercial aspects of the fore- 

 going teachings are so far as the farmer is concerned. It 

 means that if he wishes to use acid phosphate he will 

 buy it wherever he can get it in good mechanical condi- 

 tion at the lowest price per pound for the phosphorus 

 contained. If he wants to use potash he will buy it 

 wherever he can get it at the lowest price. Likewise for 

 materials carrying nitrogen. Formulas should not worry 

 him. If he wants to use more than one element and 

 wants to mix the materials for convenience in applica- 

 tion (this is the only advantage in mixing) then he should 

 determine how much of each element of plant food he 

 wants to use per acre, and use the necessary amount of 



