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three series.

The object of the experiment was to compare a systiem of hay-pasture manage-
ment with pasturing alone and to test summer seeding of pasture mixtures against
spring seeding. During 1941, Series I was subjected to four periods of intensive
grazing by a small herd of dairy cows: in May, July, August, and October.
Series II was first cut for hay before being subjected to three periods of grazing,
which coincided with the last three grazing periods of Series I. The spring-seeded
series (III) was grazed only lightly at the same time as Series II. The following
observations and results deserve mention:

1. Brome grass and meadow fescue (Svalof's early) showed the most promise
as being desirable companion grasses for Ladino Clover. The cutting of an
early hay crop followed by several periods of intensive grazing appeared to be the
most desirable way of utilizing these grasses.

2. Hay t3'pes of orchard grass (Scandia and Commercial) as well as the less
vigorous pasture types (S26 and S143) did not combine well with Ladino Clover.
The orchard grass, irrespective of how it was managed, tended to crowd out the
clover even during the first season. This occurred partly because orchard grass
grows vigorously throughout the season and partly because it produces tussocks
or bunches. Animals grazing on Ladino Clover mixtures with this grass tended
to graze the clover growing between the bunches of orchard grass much more
closely than they did the clumps of grass, even though the orchard grass was kept
in a young, active vegetative growth stage at all times. As a result of preferential
grazing, the stand of orchard grass continually improved and the stand of clover
deteriorated.

These observations may explain why, in Massachusetts, orchard grass in
Ladino Clover seeding mixtures invariabl}- crowds out Ladino Clover, com-
pletel}^ after three or four years and results in a pure stand of orchard grass.

The most promising mixtures using orchard grass were those which included
alfalfa and which were cut for hay before being grazed. For this purpose, the
later-maturing pasture strains (S26 and S143) were much superior to the hay
strains. There is a real need for a hay strain which will mature from a week to ten
days later than do any strains now available.

3. The hay-pasture system of management rather than pasture alone appears
to have excellent possibilities as a way of utilizing a number of these early matur-
ing grasses (brome, meadow fescue, orchard) not only in producing a good early
hay crop but also in providing e.xcellent feed for midsummer grazing. In these
experiments, about two tons of dry hay were cut to the acre in the middle of June,
followed roughly by three quarters of a ton of dry herbage as grazing the latter
part of July, about the same quantity again late in August, and another half ton
early in October.

4. Observations on palatability indicated that timothy ranked first among
the grasses, followed in order by brome grass, meadow fescue, red top, orchard
grass, and tall fescue (Alta strain). Alfalfa, red clover, and alsike, although quite
palatable as young plants, became less palatable than Ladino Clover as the plants
became older and developed woody stems. The woody, unpalatable stem growth
of alfalfa is a serious handicap to the use of this plant for grazing purp&s;;s.



ANNUAL REPORT, 1941 15

5. A good stand of alfalfa was obtained in all of the hay-pasture mixtures
(Series II), but only weak stands were obtained when an early period of grazing
took the place of a crop of hay (Series I). Apparently alfalfa must be allowed
to become well established before grazing is begun.

6. Bird's-foot trefoil, under the condition of these experiments, showed no
promise whatsoever.



COOPERATIVE TOBACCO INVESTIGATIONS

Conducted by the Bureau of Plant Industry, United States Department of Agri-
culture in Cooperation with the Massachusetts Agricultural Experiment

Station

C. V. Kightlinger, U. S. D. A., in Charge

Black Root-Rot. (C. V. Kightlinger.) Black root-rot is one of the most com-
mcn diseases of tobacco, and probably the most important disease of Havana
Seed and shade tobaccos in the Connecticut Valley at the present time. The
disease is recognized generally as being highly impcrtant on the basis of losses
caused by moderate to heavy infections which are easily recognized as black
root-rot. Its importance is not so generally recognized when losses are caused by
light to moderate infections, largely because of the tendency to accept the low
yields as a matter of course instead of attributing them to specific causes, and also
because black root-rot is not always easily recognized in cases of light infections,
even though they may be sufficient to cause low yields. It is reasonably certain
that black root-rot causes light to moderate damage to tobacco in the Connecticut
Valley much more generally than is commonly recognized at the present time.

An effective and convenient method of controlling the disease would mean
much to the tobacco growing industry. The disease and the conditions under
which it occurs are of such a nature, however, as to make resistance to the disease
the most feasible control method after soil conditions favorable to the disease
have become established; and the use of resistant strains, even before soil condi-
tions favorable to the development of the disease have become established,
would permit greater range in fertilizing practices, particularly in the use of lime,
than is otherwise advisable, which would often promote the production of better
tobacco. Consequently the attempt to develop strains of Havana Seed which
are more resistant to black root-rot and more acceptable in type, quality, yield,
and certain other characteristics, is being continued. The importance of the
disease and the prospects of eventual success seem to justify the continuation of
the project.

The plan as it is being worked at the present time is two-fold. In the first
place, selections of Havana 211, which is itself moderately to highly resistant to
black root-rot under Connecticut Valley conditions but which is not entirely
acceptable in type, quality, and certain habits of growth, have been made to
improve the strain in type and date of maturity. In the second place, new strains
have been produced by crossing strains of Havana Seed which are resistant to black
ro3t-rot but not entirely acceptable in type and quality, with strains of common
Havana Seed which are not resistant to black root-rot but are acceptable in type
and quality, in the hope of obtaining new strains which embody the desirable
features of both parents.

Tests of the selections of Havana 211 and of the crosses have been made, and
are being made, in the greenhouse and in the field, to determine their value.
Some of the selections of Havana 211 show improvements over the original
strain in certain characferistics, but little if any improvement in resistance to



16 MASS. EXPERIMENT STATION BULLETIN 388

black root-rot or in habits of growth. Earlier maturity, which was greatly de-
sired, was not obtained in any of the selections of Havana 21L Some of the
selections from the crosses possess sufficient resistance to yield well under black
root-rot conditions in the Connecticut Valley, and also show distinct improve-
ments in important characteristics of type and habits of growth, including earlier
maturity. Some of these selections are as early maturing as the strains of common
Havana Seed which were used in making the crosses. They seem, also, to be supe-
rior to either parent in some important characteristics such as shape of leaf and
size of veins. These particular strains deserve more testing to determine their
full resistance to black root-rot and also to determine the permanency of the im-
provements in type and habits of growth which have been manifested so far.
It seems reasonably certain, however, that definite progress has been made.

Brown Root-Rot. (C. V. Kightlingcr.) Brown root-rot causes some damage
to tobacco in the Connecticut Valley at the present time and probably would
cause much more damage if it were not that the circumstances under which the
disease ordinarily occurs are now known and are avoided in large measure in
present practices of growing tobacco in the Connecticut Valley. The practices
of not rotating tobacco with crops known to produce soil conditions favorable to
the development of brown root-rot and of growing tobacco continuously after
tobacco for as long a time as may be possible are applicable in the control of the
disease where the acreage of tobacco is being maintained or reduced somewhat,
as has been the case in the Connecticut Valley during the last few years. This
method of control, however, is restrictive and is not always convenient to follow
even under present circumstances, but the rather dilligent application of the
practice has reduced the prevalence and severity of the disease so that it has been
of minor importance economically in the Connecticut Valley during the last
several years.

Brown root-rot may become more prevalent and injurious in the Connecticut
Valley in case of an increase in acreage of tobacco, because of the necessity of
using additional land which, on account of previous cropping, may be in a condi-
tion favorable to the development cf the disease. If this occurs, it will contravene
the only measure for the control of brown root-rot of tobacco which is generally
recognized at the present time as being applicable to field use. Thsrefore, a meas-
ure which would control brown root-rot of tobacco satisfactorily under varied
circumstances and which would be convenient to use on considerable acreages
would mean much to the growing of tobacco in the Connecticut Valley in the
event that the acreage is increased. Such a measure would be useful also under
present circumstances, especially if it would permit rotation of tobacco with other
crops in general.

With this situation in mind, experiments were begun in 1939 to obtain further
information on the relationship of soil fertility conditions to the development
and to the control of brown root-rot of tobacco. One purpose in particular is to
study the effect of certain soil treatments on the fertility levels of the soil and to
study the effect of different degrees of fertility of the soil on the occurrence of
brown root-rot of tobacco following the crops used in the experiment. It is
desired especially to learn whether brown root-rot will develop in tobacco which
is grown continuously after tobacco under low fertility conditions of the soil.
And finally, in case brown root-rot of tobacco develops as a result of these ex-
periments, another purpose is to study means of hastening recovery.

The arrangement and procedure of the experiments designed to determine
whether low fertility of the soil may promote the development of brown root-rot
of tobacco, consists of four sets of six one-twentieth acre plots in which tobacco,
corn, millet, rye, clover, and timothy-red top mixture are grown in the same



ANNUAL REPORT, 1941 17

manner, except for differences in the use of fertilizers. On two sets of these
plots an application of 10-10-10 fertilizer has been made each spring at the rate
of 3000 pounds per acre to the plots planted to tobacco, and 2000 pounds per
acre to the plots planted to the other crops, in a manner suitable for fertilizing
each particular crop. On two other sets of plots no fertilizer has been used, except
nitrate of soda which has been applied to all plots alike at the rate of 400 to 500
pounds per acre, to aid in reducing the fertility level of the soil in these plots.
The crops were all harvested and removed from the plots each year according to
regular farming practices. In an additional experiment on a quarter-acre plot
considerably removed from the other experiments, tobacco is being grown con-
tinuously after tobacco without any fertilizer at all being used. No results can
be reported at this time.

The control phase of the experiment is contingent on the outcome of the other
phase; consequently the details of the control phase are not given here.

Soil Treatments for Tobacco Seedbeds. (C. V. Kightlinger.) Damping-ofif
diseases and weeds are troublesome in tobacco seedbeds in the Connecticut
Valley. Consequently treatments for their control are important.

Experimental work to test the effectiveness of spring and fall treatments of
seedbed soil by steaming and with formaldehyde, and of fall treatments with
chlorpicrin and with calcium cyanamid, was begun in 1940 and continued in 1941.
The seedbed used for these tests had been prepared especially for the purpose by
inoculating uniformly and heavily with damping-off organisms during the spring
of 1940. Evidence that the seedbed was abundantly infested with disease organ-
isms was shown by the damping-off of tobacco seedlings grown during the spring
and even into late summer of 1940. Care was taken also to make certain that
seeds of the more common weeds of tobacco seedbeds were disseminated evenly
throughout the soil.

The steaming was done by the pan method at a steam pressure of about 100
pounds applied for 20 minutes, with the pan kept in place for another 20 minutes
after steaming had been discontinued. The spring treatment with formaldehyde
consisted of a standard solution made of 1 gallon of formalin to 50 gallons of
water, applied at the rate of one-half gallon of solution to 1 square foot of soil
surface. The fall treatments were steaming, as described above; formaldehyde
solution of standard concentration and double the standard concentration,
applied in both cases at the rate of one-half gallon of solution to 1 square foot of
soil surface; chlorpicrin, applied at the rate of 2 cubic centimeters per square
foot of soil surface, and also at double this rate of application, to a depth of about
4 inches into the soil, by means of commercial applicator commonly used for the
purpose; calcium cyanamid, applied at the rate of one-half pound per square yard
of soil surface, and also at double this rate. In both cases, the calcium cyanamid
was worked into the soil thoroughly, three-fourths of the total amount to a depth
of 4 to 5 inches and cne-fourth to a depth of about 1 inch. The soil treated with
calcium cyanamid and chlorpicrin was of proper moisture content for effective
treatment at the time and was moistened daily for several days thereafter. The
soil temperature at the time formaldehyde, calcium cyanamid, and chlorpicrin
were applied in the fall was 67° F., and changed little for a considerable time fol-
lowing the treatments.

No damping-off of tobacco seedlings occurred during the season of 1941,
even in the untreated plots of the seedbed, in spite of the fact that tobacco was
seeded at double the usual rate and the bed was watered thoroughly every day,
and sometimes oftener, to promote damping-off. The unusually warm, dry weather
which occurred during the spring of 1941 was sufficient, apparently, to prevent
damping-off in spite of the effort that was made to promote its development.



18 MASS. EXPERIMENT STATION BULLETIN 388

Consequently the comparative value of the treatments for controlling damping-off
could not be determined.

The treatments all gave some control of weeds. There were wide differences,
however, in the different treatments and also in different replications of the same
treatment, except in the case of steaming, which gave consistently good control
in all replications of either the fall or the spring treatments. Some replications
of the treatments with calcium cyanam.id, chlorpicrin, and double-strength formal-
dehyde solution applied in the fall gave fairly good control of weeds; but these
were largely offset by unsatisfactory control in other replications of the same
treatments. Steaming was the only treatment that gave entirely satisfactory
control of weeds.

The experiment is being repeated.



DEPARTMENT OF ANIMAL HUSBANDRY

Victor A. Rice in Charge

A Study of the Mineral Elements of Cow's Milk. (J. G. Archibald and C. H "
Parsons.) During the winter of 1940-41 the possibilit\- of increasing the man-
ganese content of milk by feeding supplemental manganese was investiga.ted.
Eight cows in the college herd were divided into two groups of four each, and fed
manganous sulfate (1 ounce daily) by the double reversal system. Monthly
sampling and analyses of the milk of the individual cows from November through
April, showed that, regardless of group or individual, the feeding of the manganese
supplement definitely increased the manganese content of the milk. On the
average the amount of manganese in the milk of cows receiving the supplement
was just about double that in the milk from cows not receiving it. (46.1 gammas
of Mn per liter of milk as contrasted with 23.5 gammas per liter). Advance
announcement of this finding has been published in Milk Plant Monthly, Vol.
30, No. 9, September, 1941.

Investigation of the Merits of Legume and Grass Silage for Massachusetts
Agriculture. (J. G. Archibald and C. H. Parsons.) As a result of comparative
trials extending over three years with molasses and phosphoric acid as silage
preservatives, this station has discontinued the use of phosphoric acid as a pre-
servative. The reasons for this are:

1. Molasses silage has been definitely more palatable to milking cows than
phosphoric acid silage.

2. Molasses costs somewhat less, even when the much smaller amount of
phosphoric acid required is taken into consideration.

Work this past year with grass silage has centered chiefly around its effect on
milk flavor in contrast with the effect of corn silage. Part of the herd was fed
grass silage and another part corn silage, and the schedule was reversed at mid-
season. Individual milk samples from all cows milking at the time have been
taken for a period of three days in each month from November through April
and judged for flavor. There are some discrepancies among the results, and the
differences are not very marked, but in general the grass silage has produced milk
with a higher flavor score and with less incidence and persistence of the common
off-flavors. Individual off-flavors most reduced when grass silage was fed were
malt, bitter, rancid, and oxidized in the order named.

A Study of Urea as a Partial Substitute for Protein in the Rations of Dairy
Cows. (J. G. Archibald.) This project has been actively conducted throughout
the year. Results are available from two years of double reversal trials with eight



ANNUAL REPORT, 1941 19

cows and from a full lactation period of continuous feeding of urea to eight other
cows in comparison with a similar group continuously fed the regular herd ration.
Final conclusions cannot be drawn until the second year of continuous feeding of
urea to the eight cows, just referred to, has been completed, and until at least a
year's results are available from a group of cows more recently put onto a control
ration containing no urea. This last phase of the investigation has been in-
cluded in order to check more closely the adequacy of basal protein levels in the
ration. All things considered, to date the urea ration seems to be producing
results similar to those obtained on the regular ration.



DEPARTMENT OF BACTERIOLOGY
Leon A. Bradley in Charge

Nitrification in Soils Containing Plant Residues of High Lignin Content.

(James E. Fuller, cooperating with the Agronomy Department.) During the
growing season of 1940 thirteen plots were under observation. During the
growing season of 1939 one of these plots had remained fallow, and each of the
remaining twelve had been planted with a forage crop. There were no duplicates.
Then, in 1940, the whole area was planted with tcbacco, after the plant residues
of the preceding crop had been plowed under. Soil samples were taken in the
spring of 1941, in mid-season, and again after the harvest. The soils were studied
for their ability to nitrify their own nitrogen, added dried blood, and added
ammonium sulfate, respectively. The results of the nitrification studies were
compared with the quantity and quality of tobacco produced on the plots in
1940. There was some evidence, in the dried-blood study, that plots giving less
active nitrification gave poorer quantity and quality of tobacco.

The study was repeated on a second field in 1941. The set-up was replicated
six times, giving 78 plots instead of the 13 studied in 1940. Results of 1941 have
not been analyzed sufficiently to permit any statement at the present time.

Comparative Study of Certain Media Employed for Fecal-Flora Studies.

(James E. Fuller and Irwin Fried.) Much of the investigational work on fecal
bacteriology, in connection with nutritional studies, is based upon determining
the ratio of bacteria of the lactobacillus group to those of the coliform group,
because a predominance of lactobacilli is considered desirable for intestinal
health. It is desirable, also, to differentiate the members of the coliform group
present in order to make a useful interpretation of results.

The present study compared certain media commonly employed to enu-
merate coliform bacteria. Results were as follows: litmus-lactose agar, brom-
cresol-purple agar, and lactose agar with Andrade's indicator were not selective
for the coliform group of bacteria, and gave no differentiation within the group.
Endo's agar and E. M. B. (eosin-methylene blue) agar gave distinctive colonies of
the group and good differentiation, but both produced substantially fewer col-
onies than lactose agar when plates were made with these three media from pure
cultures of bacteria of the coliform group. This indicates that both Endo's and
E. M. B. media give low counts of coliform bacteria when they are used in fecal-
flora studies. Certain combinations of non-coliform bacteria produced reactions
on these media that could be confused with those of the coliform group. MacCon-
key's bile-salt agar inhibited growth of bacteria of the group to a greater extent
than did either Endo's or E. M. B. media, and did not give satisfactory differen-
tiation within the group.



20 MASS. EXPERIMENT STATION BULLETIN 388

The Bacteriology of Choc3late Syrups, Cocoa Powders, and Chocolate Milk.

(James E. Fuller and R. W. ^'wanson, in cooperation with W. S. Mueller of the
Department of Dairy Industry.) Bacteria counts showed wide variation in the
numbers of bacteria in the different syrups and powders. Most of the bacteria
identified were aerobic sporulating bacteria of the Bacillus subtilis group. No
Gram-negative bacteria of intestinal type were found, which would indicate
that the syrups and powders were free from intestinal contamination. Bacteria
of this type inoculated into solutions of the syrups and powders survived only
a few days.

Growth of bacteria was not as rapid, nor were the counts as large, in milk with
syrups or powders added as in the same milk supply without the addition. Thus,
it appears that the syrups and powders had some inhibitory effect on bacterial
growth. Further studies indicated that the tannins present in the syrups and
powders were responsible for the inhibition. Oxalic acid and theobromine, in
concentrations found in chocolate or cocoa, had no apparent effect on bacterial
growth. Molds and yeasts appeared to be more active than bacteria in causing
spoilage of chocolate milk.

Studies of Methods for Determining the Sanitary Quality of Drinking Utensils.

(Ralph L. France, W. E. Cas?idy, and James E. Fuller.) Work en this project
has been completed, with the following results: (1) A swabbing method is the best
for recovering bacteria from the lips of a glass. (2) A wet swab is more efficient
than a dry or moist swab. (3) The most satisfactory suspending fluid is one having
the following composition: 2.5 cc. of 0.04 M MgS04, 2.5 cc. of 0.01 M CaClg,
0.5 cc. of 0.001 M FeCla, and 1.25 cc. of Butterfield's buffered phosphate solu-
tion made up to 1003 cr. with distilled water. (4) The most satisfactory plating
medium was one with the following substances: Neopeptone, 10 grams; yeast
extract, 5 grams; de.>vtrose, 0.5 gram; NaCl, 5 grams; and agar, 15 grams. The
reaction of this medium is adjusted to pH 7.5. (5) Inoculation of a swab, or 1 cc.
of a 1/10 dilution of washings from the swab, into dextrose broth frequently re-
vealed the presence of mouth streptococci. This test has considerable sanitary
significance when used in conjunction with the count. The addition of potassium
tellurite to the dextrose broth failed to eliminate interfering organisms.

The Effectiveness of Certain Detergents and Procedures Employed for the



Online LibraryMassachusetts Agricultural Experiment StationBulletin - Massachusetts Agricultural Experiment Station (Volume no.379-398) → online text (page 30 of 77)