28 FARM GRASSES OF THE UNITED STATES 



the most satisfadlory implement yet invented. Re- 

 cleaned blue-grass seed can be sown with this imple- 

 ment, but the uncleaned seed should be sown by hand. 

 Grass-seeders are frequently attached to grain-drills. 

 They answer very well for timothy to be sown with 

 grain, but are hard to keep in order. There are sev- 

 eral cheap grass-seeding machines which scatter the 

 seed by mechanical means. They are satisfactory for 

 seeds that feed through them readily, but it requires 

 some patience to regulate them properly, and the sower 

 must walk at a uniform rate or the seed will not be 

 scattered evenly. 



Seeds of approximately the same size and weight 

 may be mixed before sowing. Very large seeds should 

 never be mixed with small ones, or the small seed will 

 feed out first. If heavy seeds are mixed with light ones, 

 even of the same size, the heavy ones will feed out first 

 unless the mixture is kept well stirred. In sowing 

 such mixtures it is well to put only a small amount of 

 seed in the machine at a time. By this means the 

 separation of the heavy and light seeds is largely 

 avoided. 



NURSE CROP 



Just why wheat or other grain sown with the 

 grasses should be called a nurse crop is not clear. It 

 would be more appropriate to call it a robber crop. 

 The idea that it protects the grass probably arose from 

 the facft that, when the grain is removed in hot, dry 

 weather, the grasses are apt to dry up. Having been 

 shaded and weakened by the grain, they are unable to 

 bear the full heat of the sun, particularly when the 

 supply of moisture is short and the grain crop has 



