BUEBAU OF AoBICtJLTUEB. 157 



The Teachings of the Kenttjoky AGBicuLTtTEAL Expebi- 

 MENT Station Relative to Soil Febtilitt, 



By Geoege Eobebts, Ageonomist. 



The requirements for a productive soil are : 



1. Good drainage. 



2. Good texture. 



3. Sufficient supply of plant food. 



4. Sufficient organic matter (humus). 



5. For its highest productiveness, carbonate of 



lime. 



From the foregoing statement it will be seen that 

 not all the emphasis is by any means laid upon plant 

 food. However, if all the conditions for a highly pro- 

 ductive soil exist save a sufficient supply of plant food, 

 the soil will not produce maximum crops. 



With all other conditions favorable for maximum 

 production, a soil will be limited in production by the 

 available supply of the most deficient element of plant 

 food. For example, if all the elements were present in 

 available quantities sufficient to produce 100 bushels of 

 com per acre, save one element, say nitrogen, and the 

 available supply of this element were sufficient for only 

 25 bushels, then the yield could not be raised beyond 25 

 bushels without the addition of more nitrogen. In other 

 words, a soil is no more productive than its most defi- 

 cient element permits it to be. The deficiencies of a soil, 

 and not the crop growing on it, become the chief factors 

 in determining the fertilization that shall be employed. 

 In a word, the basis of increasing and maintaining the 

 fertility of a soil consists in supplying in the most profit- 

 able form and amount, those elements the total amounts 

 of which are shown to be too small for the most profitable 

 production, and in adopting means for making available 

 those other elements that are shown to be already pres- 

 ent in large amounts. 



Most of the soils of the State possess all the require- 

 ments for producing fair to large yields except phos- 

 phorus, lime, and organic matter (humus), which sup- 

 plies nitrogen. That is to say, most of the soils are nor- 

 mal. By a normal soil is meant one containing the plant 



