MINERAL MATTER FOR CORN LAND 145 



element is lacking in an available from, this element may 

 often be directly supplied at a profit; but ordinarily, 

 in order to obtain the highest availability from the min- 

 erals, fertilizers must be used in connection with barnyard 

 manures, and in a properly balanced crop rotation where 

 most of the nitrogen is supplied by legumes and the soil is 

 kept well supplied with decaying organic matter. 



A review of the experimental evidence regarding the 

 use of commercial fertilizers for corn seems to justify the 

 following principles. 



1. It seldom pays to use mineral fertilizers alone on 

 land in a low state of fertility or on land that would not 

 produce more thaii 20 bushels of corn per acre under 

 favorable conditions.' 



2. Even on good land it seldom pays to apply mineral 

 fertilizer alone directly to the corn crop.^ 



3., It seldom pays to use fertilizers where corn is grown 

 continuously or where it is rotated with grain crops only. 

 Under such conditions, according to the Ohio station, 

 only 60 per cent of the fertilizer is recovered in the crop.' 



4. Commercial fertilizer pays, as a rule, only when used 

 in connection with a rotation where manure or a legume 

 crop, or both, are plowed under.^ In this case it is usually 

 best to apply the fertilizer to the sod land, or, when wheat 

 is grown in the rotation, a part maybe applied to the wheat. 

 The above expecially applies to phosphates and potash. 

 Sodium nitrate is a partial exception to the above general 

 rule, as it is sometimes applied with profit to the growing 

 corn. 



1 XT. S. Dept. Agr., Farmers' Bui. I44 : 10 ; Farmers' Bui. 414 : 12. 

 1910. R. I. Agr. Exp. Sta., Bui. 113 : 113. 1906. 



2 Ind. Agr. Exp. Sta., Bui. 77 : 32. 1899. 



' Ohio Agr. Exp. Sta., Bui. 110 : 68. 1899. 



* U. S. Dept. Agr., Farmers' Bui. lU : 10. 1901. 



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