1897.] PUBLIC DOCUMENT — No. 33. 179 



certain amount of soil, taken from a field where the crop to 

 be raised has been successfully grown, over the surface of 

 the new land before ploughing it. This method has been 

 successfully practised bj' us on various occasions. Another 

 is to abstract with water some of the soil, which from previ- 

 ous bliservation is known to contain the desire'^ ''oot bacte- 

 rium germs, and sprinkle the watery extract over tix^ ""il 

 before ploughing. 



One of the latest developments in this direction is the 

 appearance in the general market of patented germ fertilizer 

 for leguminous crops. Considering the whole subject from 

 a practical stand-point of sufficient interest, I insert below a 

 copy of a circular received at this office. The connection of 

 two German investigators of excellent reputation with the 

 enterprise invites attention. 



Three different kinds of germ fertilizers, for medium red 

 clover, for crimson clover and for sweet or Bokhara clover, 

 have been imported during the past season and are on trial 

 upon the grounds of the station. 



NiTRAGlN. 



Germ Fertilizers for Leguminous Crops. 

 (Prepared according to Drs. Xobbe and Hiltner.) 



The principal food materials abstracted from the soil by plants, 

 and which therefore require to be replaced in the form of manures, 

 are potash, phosphoric acid, lime and nitrogen. 



Respecting the last it has been known that leguminous crops, 

 such as clover, vetches, peas, beans, lupines, etc., do not usually 

 require to be manured with nitrogen (in form of nitre or auuno- 

 niacal compounds), and yet under favorable conditions yield rich 

 harvests, whilst the soil is even enriched with nitrogen. 



The reason of this peculiar behavior for many years remained 

 unexplained, but the onward march of modern science has now 

 demonstrated the ability of leguminous plants to abstract nitrogen 

 from the air, only, however, by the aid of a specific kind of micro- 

 organism, a bacterium that resides in the characteristic nodules on 

 the roots. If these bacteria are not at the disposal of the plant 

 then it looses its ability to utilize the atmospheric nitrogen, and 

 hence it is found that not every leguminous plant is able to flourisli 

 luxuriantly without nitrogenous manure ; many remain small and 

 stunted under conditions otherwise favorable, and evidently suffer 

 from the lack of nitrooen. 



