ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 



253 



be 



r, being limited to regions with deficient rainfall^ need 

 [considered here. But it is different where the quan- 

 lime in the soil is concerned. Though the loess is 



bedded 



substratum 



but most 

 comes ui 



The analysis of the bluff soil, 



former chapter, shows a very 



limestone * though to attain the highest product 



be 



Not only 



is the presence of lime in a soil beneficial, since, as before 



men 



causes the 



assume a darker color, but 



men 



of Liebenber 



beneficial to germination 



His 



* results agree with those obtained by Claud< 

 telle, t whose experiments are discussed by 



and 



t who, 



in a resume of the work of the French investigators says : 



^'Alkaline substances with a basis of lime or of potash 

 favorfifl in a marked deeree the termination of certain seeds. 



notably those of the Leguminosae. 



used 



better 



same 



ments conducted to obtain information concerning the acids 

 set free or originating during the germination of seeds, which 



acids thus formed 



concluded 



't-)} 



and liquid 



manure 



amounts formed. Also, that the loss of phosphoric acid, 

 which is excreted in considerable amount in the germination 

 of wheat, for instance, is hindered by these alkaline sub- 

 stances, and thus conserved for the use of the young plant. 

 These conclusions, in the opinion of Claude! and Crochetclle, 

 explain to a certain extent the beneficial effect of lime, slag, 

 and ashes upon acid soils. Seeds of clover were found to 

 nrndiirp more af.id for ft ffiven weiffht than anv other seeds 



* Hilgard, E. Soils. 497. ' 



t Annales Agronomique. 131. 1896. 



t Hicks, G. H. The germination of Seeds as affected by certain 



Chemical 



U. S. D. A. Div. Bot. Bui. 24. 1900. 



