ALFALFA ROOT STUDIES. 5 
than plants from the plats harvested 7 and 18 times. This experi- 
ment showed that root development of alfalfa is retarded and 
vitality reduced by frequent clipping. It is probable that close 
grazing would have much the same effect. (Figs. 1, 2, and 3.) 
Thick seedings which result in crowding, especially during the 
early life of the plant, tend to produce small crowns and root systems. 
To determine the relations between space available to the plant and 
the diameter of the taproot, measurements were made on plants 
that were removed from the nurseries at Kedfield in August and 
October, 1919. The results are given in Table 2. 
Fig. 2. 
Table 
— Alfalfa roots from a plat clipped seven times during the second season. The 
alfalfa was clipped each time when 6 inches tall. 
2. — Relation of diameter of the taproots of alfalfa plants to thickness 
of stand in nursery plantings at Red field, S. Dak., in 1919. 
Average length of 
Plants considered. 
Average 
diameter 
of each 
taproot 2 
(milli- 
meters). 
Average length of 
row from which 
25 consecutive 
plants were re- 
moved. 1 
Plants considered. 
Average 
diameter 
of each 
taproot 2 
(milli- 
meters). 
row from which 
25 consecutive 
plants were re- 
moved. 1 
Average 
distance 
apart 
(inches). 
Number. 
Average 
distance 
apart 
(inches). 
Number. 
0.96 
1.12 
1.21 
100 
100 
175 
9.588 
9.715 
10.259 
41.7 inches 
1.66 
1.92 
2.56 
100 
50 
25 
11.334 
48 inches 
12. 065 
12.700 
All rows 36 inches apart. 
2 Measurements made 1 inch below the base of the crown. 
It is clearhy 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. 
