290 FIELD CROPS 



wheat is the better nurse crop. In Maine and some of the 

 other important potato-growing sections, the common rota- 

 tion is potatoes, oats, hay. This hay crop is usually clover; 

 a fuller discussion of this rotation will be found in the chapter 

 on that crop (Sec. 465). In the South and West, perennial 

 hay crops other than alfalfa are so seldom grown that defi- 

 nite rotations have not been devised. 



LABORATORY EXERCISES 



It is suggested that samples of seed of the common forage grasses 

 grown in the vicinity be obtained and examinations made of them 

 for purity and germination. As soon as the seeds of the common 

 grasses become familiar, mixtures containing two, three, or more of 

 them may be separated into their component parts. At this time, all 

 that need be done would be to separate the weed seeds, chaff, etc., from 

 the good seed without any attempt to identify the weeds. Later, the 

 different weed seeds might be identified. Several laboratory periods 

 may well be devoted to this work. The student should also familiarize 

 himself with the common grasses, clovers, and weeds growing in 

 meadows in the neighborhood. 



SUPPLEMENTARY READING 



Bailey's Cyclopedia of American Agriculture, Vol. II, pp. 434-455. 



Real's Grasses of North America. 



Hunt's Forage and Fiber Crops in America, pp. 1-200. 



Shaw's Grasses and How to Grow Them, pp. 1-48, 403-434. 



Spillman's Farm Grasses of the United States, pp. 14-55. 



Wing's Meadows and Pastures. 



