396 BOARD OF AGRICULTURE. [Pub. Doc. 



ber; and this result, according to his individual opinion, 

 might be atti-ibuted to a scarcity of the soja bean bacteria 

 in the soil. We have yet many experiments to make before 

 a fuller knowledije can be obtained. 



'O" 



D. The Darmstadt Experiment Station. 



The fourth and last of the German stations to which I 

 wish to call your attention is the one at Darmstadt, under 

 the direction of Prof. Paul Wagner. This station is engaijed 

 in fertilizer and fodder control, and in investigations of 

 problems in plant feeding. This investigator made ordinary 

 field experiments upon measured plats of land at first ; but, 

 after a thorough study of this method, he came to the 

 conclusion that to solve many of the problems in plant nour- 

 ishment it was not practicable. His reasons therefor, briefly 

 stated, are the following : * — 



1. It is very difficult to find a field or })ortion of a field 

 where the soil is so uniform that, without manure, each plat 

 will yield practically the same quantity. 



2. The selection and measuring of the plats, the manur- 

 in<r and seedins; of the same, as well as the harvesting of the 

 crop, is a work of great difficulty, wherein many mistakes 

 can be easily made, and where exact work is well-nigh im- 

 possible. When experiments are conducted upon a large 

 number of plats, the work must be done by diflferent work- 

 men, and it is therefore impossible to have the various 

 operations conducted in the same way. 



3. Injuries, varying in degree, are caused on the different 

 plats by insects, birds, mice, etc. 



4. The increase in the yield caused by a manure is often 

 too small in proportion to the errors in the experiment. The 

 deference in tJie yields of the plats unmanured is often larger 

 than the yields of the manured and unmanured i)Iats. 



5. In field experiments, one is too dependent ui)on the 

 differences in condition of the soil and subsoil, and upon 

 excess or lack of moisture ; in other words, it is impossible 



* For a thorough discussion of the subject of field ns. ])ot experiments see "Bei- 

 trilge zur Ausl)ildun,i; der Diiii^'uuirslclire," von I'liul Warner. " LandwirMiscliaft- 

 liclicr Jalirl)iiclier, 1883," and " Die Slicivstoffdungungen der Laudwirthscliaftlichen 

 Kullurpflanzen," voa Prof. Paul Wagiier. 



