ALFALFA ROOT STUDIES. 5 



;han plants from the plats harvested 7 and 18 times. This experi- 

 nent showed that root development of alfalfa is retarded and 

 i^itality reduced by frequent clipping. It is probable that close 

 rrazing would have much the same effect. (Figs. 1, 2, and 3.) 



Thick seeclings which result in crowding, especially during the 

 jarly life of the plant, tend to produce small crowns and root systems. 

 To determine the relations between space available to the plant and 

 he diameter of the taproot, measurements were made on plants 

 shat were removed from the nurseries at Redfield in August and 

 Dctober, 1919. The results are given in Table 2. 



i'lG. 2. 



-Alfalfa roots from a plat clipped seven times during the second season. The 

 alfalfa was clipped each time when 6 inches tall. 



Pable 2. — Relation of diameter of the taiwoots of alfalfa plants to thickness 

 of stand in nursery plantings at Redfield, S, Dak., in 1919. 



Average length of 

 row from which 

 25 consecutive 

 plants were re- 

 moved.i 



Plants considered. 



Average 

 diameter 



of each 

 taproot 2 



(miUi- 

 meters). 



Average 

 distance 



apart 

 (inches). 



Number. 



4 inches 



0.96 

 1.12 

 1.21 



100 

 100 

 175 



9.588 

 9.715 

 10. 259 



8 inches 



0.4 inches 







Average length of 

 row from which 

 25 consecutive 

 plants were re- 

 moved.i 



41.7 inches 

 48 inches . . 

 64 inches . . 



Plants considered. 



Average 

 distance 



apart 

 (inches). 



1.66 

 1.92 

 2.56 



Number. 



100 

 50 

 25 



Average 

 diameter 



of each 

 taproot 3 



(milli- 

 meters). 



11.334 

 12.065 

 12.700 



1 All rows 36 inches apart. 



2 Measurements made 1 inch below the base of the crown. 



It is clearly shown in Table 2 that there is an increase in diameter 

 of taproot with the increase in the space between plants, indicating 

 at least in similar varieties of alfalfa that the size attained by the 

 taproot is determined more by the space the plant occupies than by 

 its varietal tendencies. While this is true of the taproot the branch- 

 root development seems to depend more upon the variety than upon 

 the number of plants that occupy a given space. 



