158 BOARD OF AGRICULTURE. [Pub. Doc. 



evidence of marked benefit from the presence of magnesium, 

 even when a[)plied as a chlorid, which by many writers is 

 said, without qualification, to act as a plant poison. If fur- 

 ther investio-ations indicate a more g-eneral need of mao;nesia 

 than has been supposed, it can be bought at a low price as 

 ground Ivieserite and as a constituent of Kainit and of double 

 sulfate of potash and magnesia. Magnesiau lime * could also 

 be employed, particularly wherever soils stand in need of 

 carbonate of lime. Where considerable magnesia is present 

 and lime is lacking it has been shown by Loew to act very 

 poisonously upon plants ; it is therefore important to see 

 that the soil is sufficiently supplied with lime wherever mag- 

 nesia is to be employed. Wood ashes usually contain from 

 about three to four per cent of magnesia, associated with 

 about thirty-five per cent of lime, thus making them a 

 splendid source of magnesia. It is not improbable that this 

 ingredient is often responsible in some degree for the bene- 

 ficial efl'ect which such ashes exert. 



Lime. 

 Lime, like magnesia, is essential to plant growth, though 

 it has been generally considered in the United States as 

 being present in soils to a sufiicient extent to supply the 

 demands. As notable exceptions to this, it may be men- 

 tioned that it has long been applied to certain soils in Xew 

 York and Pennsylvania with marked benefit. Early in the 

 present century it was employed in Virginia by Ruffin and 

 others with great success. Its use upon the acid soils of 

 Limmousin and other portions of France has utterly revo- 

 lutionized their agriculture, and made prosperous, regions 

 where formerly only a miserable existence was possible. It 

 is to-day the key to successful agriculture in certain sections 

 of Germany, and upon some of the moorlands (peat and 

 muck soils) successful agriculture is impossible without it, — 

 a fact most vividly brought out by the experiments in prog- 

 ress by the Moor Experiment Station of Bremen. Prob- 

 ably no single ingredient of soils fulfils so many functions 

 and exerts so marked an influence upon the character of soils 

 and the growth of plants as lime. 



* Buraed lime, coataiaing much magnesia. 



