MANGANESE AS A FEETILIZEE. 3 



has produced increased yields. In large amounts both have been 

 more toxic than the dioxide or carbonate. In a number of cases, even 

 in very large amounts, the carbonate has given beneficial rather than 

 injurious results. 



In this country little work has been done on the value of manganese 

 as an accessory fertilizer. Before any recommendation can be made 

 as to its value in general farm practice, pot and field experiments 

 must be made with a variety of crops on widely varying soils and 

 under different climatic conditions. 



Manganese for fertilizer purposes should not be expensive, since 

 manganese sulphate, according to the English quotations, can be 

 bought for about $75 a ton. 



The application of manganese salts, of which the sulphate seems 

 to be the most effective, should not exceed 100 pounds to the acre, and 

 probably better results would be obtained from smaller quantities. 

 Such small amounts can not be applied effectively to the soil unless 

 ground fine and intimately mixed with comparatively large amounts 

 of some other material, such as commercial fertilizers or barnyard 

 manures. 



The soil is complex and the seat of vast chemical, physical, and 

 biological actions which are varying and differently modified by the 

 addition of fertilizer ingredients. In view of this complexity and 

 the discrepancy that has been found in the use of manganese fer- 

 tilizers, manganese can not now be recommended in any way other 

 than in experimentation and as a fertilizer complementary to the 

 usual chemical fertilizers, nitrate^ phosphoric acid, potash, and lime. 



Approved : 



JAMES WILSON, 



Secretary of Agriculture. 



WASHINGTON, D. C., October 30, 1912. 



ADDITIONAL COPIES of this publication 

 -fi- may be procured from the SUPERINTEND- 

 ENT OF DOCUMENTS, Government Printing 

 Office, Washington, D. C., at 5 cents per copy 



