LEGUMINOUS FORAGE CROPS l8l 



adjusted screens. 1 As the plant grows upon the alfalfa, the 

 latter is killed and the dodder spreads to adjacent plants in an 

 ever-widening circle. The dodder may be destroyed by plowing 

 and using the field for cereal crops for two or more years, 

 taking care to apply the manure from the dodder-infested al- 

 falfa hay only to land that will be devoted to cereals, potatoes, 

 or other cultivated crops. If only a few small patches occur, 

 these may be mown, the stubble sprinkled with kerosene, covered 

 with the hay, and burned. According to the New York State 

 Station, the small seeded dodder rarely seeds in that locality, 

 but passes the winter on crowns of alfalfa, clover, black medic, 

 and fleabane (Erigeron ramosus (Walt.) B. S. P.). 



203. Germination and Viability. The standard of purity 

 should be 98, and the standard of germination 90 per cent. It 

 is said that the percentage of hard seed is often high, but 

 diminishes with age. While the viability of alfalfa seed is 

 not definitely known, two and three-year-old seed is considered 

 quite as good as fresh seed. The Colorado Station found that 

 prime seed lost only 2.5 per cent, of its germinating power in 

 ten years. Another sample showed a germinating power at 

 six years of 93, at ten years of 72, and at sixteen years of 63 

 per cent. 2 Dead seeds, instead of light olive-green, are brown. 



204. Varieties. A number of slightly different strains of 

 alfalfa have been grown by experiment stations, while Turkestan 

 and Grimm alfalfa have been tried somewhat more widely. 



Among these may be mentioned: American strain alfalfa, a hardy sort 

 recommended for northern United States; French alfalfa, originally from 

 France, but developed in North Dakota; Oasis alfalfa, obtained from Tunis, 

 North Africa, and said to be a promising drought-resistant sort; Solover or 



1 Construct a light wooden frame, 12 inches square by 3 inches deep, and 

 tack over the bottom 20x20 mesh steel wire cloth made of No. 34 (W. and M. 

 gauge) wire. Put in the sieve 4 to 8 ounces of seed and shake vigorously for 

 30 seconds. Samples of alfalfa seed for analysis should be taken from the 

 bottom of the bag, since jarring is likely to cause the small dodder seeds to 

 fall through the alfalfa seed. 



2 Colorado Sta. Bui. No. 110 (1906), p. 11. 



