74 
EIGHTH REPORT. 
Row. 
No. of plants. 
Av. No. nodules. 
12 . 
. 20 . 
8 45 
13 . 
21 54 
14 . 
. 35 . 
16 17 
15 . 
. 32 
22 28 
16 . 
16 81 
17 . 
14 62 
18 . 
12 81 
19 . 
13 69 
20 . 
10 26 
21 . 
7 00 
22 . 
. 25 . 
. 10.03 
Average of uninoculated . 12.24 
On a strip of poor sandy soil, impoverished by six consecutive crops 
of sugar beets, the south third was sown to soy beans, the middle third 
to cowpeas and the north third to buckwheat. The next year strips 
of soy beans and cowpeas were sown north and south over the same 
area. In the fall the nodules were counted on the roots of the legumes. 
Taking the soy beans first we found that where the soys followed 
soys, the number of nodules on ten plants was 991, where they followed 
cowpeas 108, and when they followed buckwheat 458. Again the form 
of the nodule and the style of distribution was entirely different over 
the three areas. Where the soys followed the soys the nodules were 
small and well scattered over the entire root system, seldom or never 
grouped into masses, but usually strung along the root at regular in¬ 
tervals. Where the soys followed the cowpeas the nodules were larger, 
much fewer in number and in shape resembling more nearly the nodule 
of the cowpea. Where following buckwheat the nodules were not un¬ 
like those where they followed soys. 
In the case of the cowpeas, where they followed cowpeas, 
the number of nodules on ten plants was 448, where follow¬ 
ing buckwheat 229, and where following soys 210. Here too a tendency 
to smaller size was noted where the cowpeas followed the soys. 
A later count, when the crops were riper confirmed these figures. In 
fact so conspicuous is the difference in form and distribution of the 
nodules on soy beans following soys and following cowpeas, that it was 
entirely possible to recognize at sight whether a given plant grew on 
one plot or on the other. Several trials resulted in not a single mistake. 
Agricultural College. 
