LEGUMINOUS FORAGE CROPS 151 



159. Quantity of Seed. The amount of seed to sow varies 

 largely with the locality and the climatic conditions. The rain- 

 fall and the character of the soil in particular especially the 

 amount of organic matter are probably the determinant 

 factors. Ten pounds to the acre or nearly 85 seeds a square 

 foot are about the average when sown alone ; twice this quantity 

 is said to be sown in some localities. When sown with timothy 

 or other grass, six to eight pounds will usually suffice. The 

 Canada Station found that when seeded with oats or barley 

 10 pounds produced the largest yield. 



160. Weeds. The list of seeds given in the paragraph above 

 indicates the weeds which not uncommonly occur in clover 

 fields, but does not necessarily indicate the most common or 

 the most injurious weeds. The most common weed in both 

 timothy and clover meadows is Erigeron Sp., and yet the seeds 

 of this plant have not been reported as occurring in either 

 clover or timothy seed. The small seeded dodder, of which 

 there are two forms (Cuscnta epithymum Murr. and C. trifolii 

 Bab.), and the large seeded or field dodder (C. arvensis Beyr.) 

 occur on red clover, although more commonly on alfalfa 

 doubtless because the latter is perennial. (202) Since all 

 forms of dodder are easily eradicated by putting the land in 

 non-leguminous crops, it is not greatly to be feared in red 

 clover. Broom-rape (Orobanche minor J. E. Smith), though 

 quite a familiar plant in European countries, has been reported 

 as being abundant and destructive only in New Jersey. 1 



161. Clover Sickness. For a century it has been recognized 

 in Europe to be difficult to raise clover in short rotations. At 

 Rochamsted, England, it was found impossible to grow clover 

 oftener than once in four years, while Stebler states that on 

 some soils in Europe six and even nine to twelve years must 

 elapse before a good crop can be secured. Though in America 



Torr. Bot. Club Bui. No. 25 (1898), pp. 395-7. 



