274 Bulletin 238. 



this is a decided benefit and in some localities the practice of preceding 

 potatoes by buckwheat, for the purpose of securing this efitect, has come to 

 be common. The following rotation is sometimes recommended for such 

 soils : clover, buckwheat, potatoes, oats or wheat with clover seeds. The 

 first crop of clover is harvested early and the land immediately plowed 

 and sown to buckwheat as a preparation for potatoes. 



Varieties. — There are three principal varieties of buckwheat grown 

 in America, — the Common Gray. Silver Hull, and Japanese. The seed 

 of Silver Hull is slightly smaller than the Common Gray, — the color is 

 lighter and of a glossy, silvery appearance. The Japanese is larger than 

 the Gray, of somewdiat darker color and there is a tendency for the angles 

 or edges of the hull to extend into a wing, making the faces of the grain 

 more concave. The plant of the Japanese variety is a somewhat larger 

 grower than the others, the fresh stem has a green color and the flowers 

 seem not to be quite so subject to blasting from hot sunshine as the others. 

 On this account it is recommended in some localities to sow the Silver 

 Hull and Japanese varieties mixed, it being said that the later and hardier 

 Japanese will shade and protect the others from hot sunshine, thus avoid- 

 ing blasting and securing a larger zone of seed-bearing straw than is 

 furnished by either sort alone, a larger yield resulting. The Silver Hull 

 variety has a red stem and branches more freely than the others. The 

 leaves also are smaller. 



Each of these varieties has produced largest yield in certain tests. It 

 seems that there is adaptation of variety to soil or climate or, perhaps, to 

 weather conditions that has not yet been worked out, that produces these 

 contradictory results. However, the yielding quality of the Japanese 

 variety is usually conceded to be superior to that of the others. 



By reference to Table No. 2 it will be seen that plats 11, 12, 13, also 

 23, 24 and 25, give the comparative yields of the three varieties in the 

 1901 experiment. In each case the Japanese variety gives largest yield 

 and Silver Hull smallest. It was observed in these tests that Silver Hull 

 is much slower-growing and less vigorous in its early stages but comes on 

 later to make a good stand. In the case before us the average yields were : 



Japanese 27.5 busliels per acre 



Common Gray 26.8 bushels per acre 



Silver Hull 19.5 bushels per acre 



In this experiment there were eleven plats seeded with Japanese buck- 

 wheat and eleven with Silver Hull. The fertilizers and also the culture 

 treatment applied to one are duplicated on the other. The average of the 

 eleven plats sown to Japanese variety was 36.6 bushels and of the eleven 

 sown to Silver Hull was 23.1 bushels per acre. Probably these figures are 



