The Chickasha daily express. (Chickasha, Indian Territory [Okla.]) 1899-current, 1904-11-16
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-&y~ 81 x js,s.1.sy->
: AGRICULTURE
cowpea Bacteria.

The cowpea bacteria are already
quite widely distributed in southern
Illinois, especially where this crop ha:
been grown for several years, but
they are not common in the soils ol
other parts of the state. 1t is doubt
iul. however, If it is necessary or even
worth while to take the trouble to
inoculate soil for eowpeas. Some few
tubercles almost invariably develop
on cowpea roots the first year they
are seeded, even where they have
never been grown before, and if seed
ed the second year on the same LAND
the plants are usually abundantly
provided with root tubercles. Just
why the cowpea bacteria develop so
rapidly even without special inoeula-
tion is NOT definitely known. It may
be that the same bacteria also live
on some other leguminous plant which
is more or less widely distributed over
the state. but it seems more likely
that the bacteria are brought with the
seed. As matter of fact, the cowpea
harvest is usually dirty. This is an
annual plant, and consequently the
crop is grown on recently plowed land
and is sometimes cultivated during
the season. COwpeas are commonly
harvested with a moving machine and
then raked up on the loose ground
When they are threshed more or
less dirt remains with the seed. Fur
thermore, the seed coats are not in
frequently cracked. thus providing an
excellent place for the lodgment OF
particles Of soil.
Whether it would be profitable to
inoculate the land for cowpeas would
depend very largely upon the difficulty
or cost of obtaining the infected ma
terial. If soil thoroughly infected with
the cowpea bacteria can be scattered
over the land at the rate of about
1000 pounds to the acre at a cost Of
81 or less per ton, it might prove
profitable 1t is doubtful if a light
application of 100 or 200 pounds would
produce any very marked effect in
the yield the first season. After the
soil becomes well infected the COW
peas then obtain much nitrogen from
the air, and the yield of cowpeas is
likely to be largely increased. OF
course there is no fixation Of atmos-
pheric nitrogen il there are no tuber-
cles on the roots.
In 1902 several plots of cowpeas
were seeded on the soil experiment
field at the university. One of these
plots (40G had become thoroughly
infected with the cowpea bacteria, be
cause of its being so situated that
more or less surface drainage water
flowed over it from an adjacent field
upon which cowpeas had been grown
for three successive years. Another
plot (408), owing to a slightly differ.
ant situation, had not become in
'ected. The two plots were seeded I
n July after a crop of oats had been |
'emoved from the land. Within three |
weeks after seeding, numerous root |
ubercles could be found on the plants |
n the infected plot. Later on, ten
lverage consecutive plants were taken
lp as completely as possible, and 412
ubercles were found on the roots.
making an average of more than 40
ubercles to the plant On plot 40S
nly an occasional plant was found in
ected. and such plants would usually
ave only a single large tubercle on
heir roots.-Professor c. c. Hopkins
n Bulletin of Illinois Station.