ALFALFA ROOT STUDIES. 

 NONHARDY ALFALFAS. 



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As the term indicates, the group of nonhardy alfalfas includes 

 those varieties and strains that can be grown successfully only in 

 regions having such a mild climate that little or no winterkilling 

 occurs. The Peruvian alfalfa is the only well-known variety of this 

 group in the United States, and the area to which it is adapted is 

 limited to sections where the minimum temperature seldom falls 

 below 10° F. 



Fig. 8. — Root systems of plants of Grimm alfalfa, indicating considerable injury but 

 only a small percentage of mortality in this variety during the G-year period from 

 1915 to 1920, inclusive. The root marked X represents a dead plant. 



PEETJVIAN ALFALFA. 



As few plants of the Peruvian variety survive the winter at Eed- 

 field, it was necessary to make observations on roots of plants of one 

 season's growth. This is a purple-flowered alfalfa having a nar- 

 row, upright crown, few crown branches, and only occasional root- 

 ing rhizomes. The taproots are very prominent, and branch roots 

 are few, small, irregularly distributed, and seldom rebranched. 

 Fibrous roots, which are generally more abundant near the surface 

 in the hardier alfalfas, are sparse and uniformly distributed over 

 the entire root system. With the exception of the Poona alfalfa, the 

 Peruvian alfalfa made the smallest root growth in the first season 

 of any of the alfalfas studied at Eedfield. The differences between 

 the root systems of this variety and other varieties and strains of 

 one season's growth are well shown by comparing Figure 10 with 

 Figures 11 to 14, inclusive. 

 103923°— 22 3 



