160 GRASSES OF IOWA. 



Barley. — Of the cereals, with the exception of corn and sor- 

 ghum, barley is of a wider distribution than any of the others. 

 The white four-rowed barley {Hordeum tetrastlchum pallidum) 

 extends further northward than any other form, TO"^. Its 

 period of vegetation has been much shortened and it is less 

 sensitive to the unfavorable weather and niijht frosts in this 

 high nor hern latitude. According to Dr. Unger this barley is 

 sown in Umea on the 30th of May, and is harvested on the 25th 

 of August, the vegetative period being eighty-five to ninety 

 days. The average yield per acre in Iowa for the north half 

 of the state is thirty-one; for the south half, twenty-eight. 



Oats. — The distribution of oats is not so extensive as that of 

 barley or rye In the humid temperate regions it does not suc- 

 ceed. Oat culture is not extensive in the warm, dry climates, 

 especially with an intense beat. Its vegetative period is long 

 and for that reason it is not grown so far north as barley. The 

 vegetative period varies between eighty -eight and 150 days. 

 The units of heat required to develop different varieties is 

 between 1,404.37, for certain varieties in Germany and 2,060 

 for certain varieties in Paris. These figures are according to 

 Dr. Wittmack.* 



The place of the greatest production of oats is in the Missis- 

 sippi valley, which grows 63. 1 of the whole cr p. The reasons 

 for this are not so much the climate as the peculiar topographic 

 features. Ninety-one per cent of the crop is grown between an 

 altitude of 100 and 105 feet. Mr. Spring's studies show that in 

 Iowa the average yield per acre for the north half of the 

 state was thirty-nine bushels; for the south half, thirty- one. 



Sorghum. — This is the chief cereal crop in tropical and sub- 

 tropical Africa, and has also spread over parts of Arabia, Asia 

 Minor, India, China and Japan and is found also to some extent 

 in southern Europe where it succeeds admirably. The dry 

 climate of our own country, especially in Kansas and Nebraska, 

 is admirably suited to sorghum cultivation. In Europe, on 

 the steppes of Russia, it scarcely reaches beyond 48*^ north 

 latitude, according to Koernicke. Prof. Thos. A. Williams says 

 concerning irs growth in the United Statesf: "The sweet sor- 

 ghums are successfully grown in nearly every state and terri- 

 to-'y in the union, the only exception being some of the colder 

 New E gland states and those in the northwest which include 



•Koernicke-Werner.o Handbuch 2: 751. 



tSorghum as a forage crop. Farmers Bull. Of. Exp. Stat. D. S. Dept. of Agrl. 50. 



