EXPERIMENT STATION RECORD. 



Vol. III. ISSUED DECEMBER, 1891. No. 5. 



EDITORIAL NOTES. 



To obviate the difficulties met with in field experiments, various 

 methods have been suggested. The chief aim has been to bring as 

 many conditions as ])ossible under tlie control of the ex]ierinH^nter and 

 to cliiiiiiiatc those irregnlaritics of soil, moistnrc, and ])lant food which 

 ol'tcn \itiate tlie results of ticld cxpcriiiiciits. For this purpose use has 

 been made <»f small (inantities of soil placed in ]>ots or boxes or in small 

 plats sci>arated by partition walls snnk in the ground. 



The leading representative of this tendency of experimental inquiry 

 Just now is Prof. P. Wagner, of the experinuMit station at Darmstadt, 

 whose methods of experiinentingMvith soil in ])ots have proven most 

 useful and are coming to be Avidely adopted. Wagner's system con- 

 sists essentially in using cylindrical pots of zinc to hold the soil, which 

 is carcfnlly prepared and thoroughly mixed so as to have the portions 

 ill the ditt'erent pots as nearly alike as possible. Any desired soil 

 can be nsed. The pots are pjaced on small i)latform cars which run 

 oil rails, are easily moved, and can be put under shelter when necessary 

 to protect Uw jdants from rain, hail, severe wind, or frost. To regu- 

 late the water supply, the jiots are weighed by a convenient a])paratns, 

 and water is added as often as is necessary to maintain the ]»ercentage 

 of moisture in the soil best fitted for the growth of the ])lants. Wagner 

 also uses larger cylinders set in the soil. In these the water supply can 

 not be regulated so well, nor can the plants be pnt nnder sln^lter. 



Noteworthy as is the success of the system which Wagner has been 

 elal)orating for more than a decade, a success i)roven by his own results 

 and confirmed by the exi^erience of others Avho have followed his method, 

 it does not meet all the needs, and other experimenters are trying to 

 improve upon it. The plan of inclosing the soil in boxes, which was 

 undertaken over a score of years ago by Woltf and Jlenneberg and has 

 been prosecuted by Hamunaun, Lawes and Gilbert, Wohltmann, and 

 others, has several advantages over that of pot exi)eriments. Larger 

 (pmntities of soil are nsed so that more i>lants nuvy be grown. The ]»laiits 



21b 



