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A STUDY OF THE GROWTH CYCLE

OF SUDAN GRASS

B!

DONALD FRANCIS RESTOOL

A THESIS

Submitted to the School of Graduate Studiee of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Botany and Plant Pathology

November, 1949

I. Introduction ........... ..... .... ............. ...... ........... .
II. Experimental methods. .............. ........ ............. ........
A. Experiment 1 ................................................
B. Experiment 2 ................................................

III. Emerimental reenlts......OOOOIOOOOOOOOOO0.0.00.0.........OOOOOO

A. Section I. Sudan Grass cut at daily intervals...............

1.
2.
3.
u.
5.
6.
7.
8.

9.

TABLE OF CONTENTS

IntrOductionoeeeeeeeeeeeeeeeeeeoeeeeeOOOeeeeeeeeeoeeeoOO
FreSh Weight Of the plantBOeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Amount Of meisture Per plantUOOOOOOOODOOO.......OOOIOOOO

~o (m (n ~q -q \3 ox c- c- t4

Percentage of moisture in the plants. ................ ...
Amount of dry matter per plant..........................11
Percentage of dry matter in the plants..................12
Amount of nitrogen per plant............................12
Percentage of nitrogen in the plants....................13

Percentage survival of the plants after cutting.........14

3. Section II. Sudan Grass produced by roots of different

age Oeeooooootooeeeeeeeeeeeeeeeee eeeeeeeee eeeeeeeeeeeee000016

1.
2.
3.
h.
5.
6.

Introduction ................................ ......... ..16
Fresh weight per p1ant..................................18
Amount of moisture per plant............................19
Percentage of moisture in the plants ...................20
Amount of dry matter per plant .........................20

Percentage of dry matter in the plants..................21

7. Amount of nitrogen per plant. ...... .....................22
8. Percentage of nitrogen in the plants....................22
Iv. smary and conCIuSions...................... .......... 0.000.000.2u

v. Literature CitedOeeee eeeeeee eeeeeeeeeeeeeeoee eeeeeeeee e eeeeeeeeee 27

A STUDY OF THE GROWTH CYCLE OF SUDAN GRASS

I. INTRODUCTION

There is considerable evidence suggesting that the change from
vegetative to reproductive growth in annual plants takes place prin-
cipally at the time of the formation of floral primordia. Loehwing
(8) states that the first observable indication of this floral
inception is a rather abrupt increase in the rate of transpiration
which can be measured by the amount of water necessary to maintain
pots of soil, and the plants grown in them, at a constant weight. He
further states that tissue analyses show a lower moisture content and,
consequently, a higher percentage of dry weight at this time. The
decrease in the moisture content of the tissues was regarded as a
reliable index to the onset of flowering. Loehwing (9) summarizes
the published data by stating that ”thg_mg§§_progound gompogitional and_
developmental chagges la the plants' entire existence occur ipflthg
b;1gfi_pggigd,g§,floral differentiation.I He goes on to say that these-
changes are often overlooked because they are localized in certain
tissues, are of small numerical magnitude, and occur only during a
brief period.

Loehwigg (7), in a review of the published data on the nutrition
of annuals, summarized the literature concerning the changes in their

moisture content, mineral nutrients, proteins, and carbohydrates during

2.

the period of transition from the vegetative to the reproductive
phases of development.

In view of Loehwipg's statement (7) that '§§_flowerigg.gg
approached a_pre-flowering drop ip moisture content ig_gften associated
with, and hence §_convenient indengg, the presence g§_flower primordia
2; m E12 2 many annuals“, the present study was carried out in
order to determine if this generalization could be applied to Sudan
Grass.

Most publications which report data on the dry weight and chemical
compositions of various plants are based on examinations at intervals
of several days: hence it is obvious that a sudden change in percen-
tages of moisture might have passed unobserved. In order to avoid this
possibility, observations were made daily during the growth period of
Sudan Grass.

Sudan Grass was used in this experiment because of its agricul-
tural value as a forage crop in the eastern and southwestern areas
of the United States. It has been reported that sometimes, during a
series of successive cuttings, the grass does not recover vegetatively
as it should. There is a possibility that this inability to recover v”
after cutting may be related to the physiological condition of the
plant existing at the time of cutting.

At this point a short resumé of the history of Sudan Grass is

not out of place to show its agricultural importance. Sudan Grass

3.

was introduced into the United States from Africa as a result of a
search for a species of wild Andronogon.which did not possess root-

C. V. Piper (13), of the Office

stocks as does Johnson Grass (20).
of Forage Crop Investigations, organized the search and on March 16,
1909, obtained a grass called "garawi" from the Director of Agricul-
ture and Lands of the Sudan Government at Khartum. This grass gave
considerable promise as a forage crop and in order to assist in its
distribution the unique name Sudan Grass was given to it (20). The
superiority of Sudan Grass over Johnson Grass, which it closely re-
sembles, lies in the fact that it is easily controlled in the field
because of its lack of rootstocks. Hillman (4) and Lgpg;(lO) discuss
the history of these grasses and the distinguishing features between
them. Space does not permit a discussion of the subsequent deve10pment
of the uses of Sudan Grass, but several references are included in the
bibliography concerning the agricultural importance of this species

(3, 6, 13, 15, 18, 19, 21, 23), a disease resulting in chlorosis

of the leaves (22), and the problem of its cyanogen content (2, 5,

11, 12, 16, 17).

II. EXPERIMENTAL METHODS

A. Experiment 1

The greenhouse used for this experiment was large enough to
contain a central concrete bench fifty-three feet long and five feet
wide. One hundred and forty-seven pots, nine inches in diameter, were
filled with a loamy farm soil and spaced six inches apart in four rows
running lengthpwise along the bench. The pots were far enough apart
to receive sufficient light to promote the subsequent growth of the
plants.

Thirty Sudan Grass seeds were planted in each.pot on October 22,
19h6. The seeds were spaced so that each was separated from the others
by a distance of about one inch. Each pot was lightly watered daily.

The plants were allowed to develop undisturbed for a period of
thirty-six days. After this time, they were large enough to begin the
daily cuttings. .A sufficient number of plants was cut so that about
five grams of dried plant material were obtained for chemical analyses.
The number of plants in each daily cutting was such that sampling
errors were minimized. The plants were cut at noon each day one inch
above the surface of the soil. The harvested plants were counted and
quickly weighed to the nearest tenth of a gram.

not more than twenty minutes later, the fresh material was
placed in an oven and dried for twentybfour hours at a temperature

of 100 degrees Centigrade. The oven-dried plants were weighed and

5e

stored in envelopes. From the recorded gross data, the following

calculations were made:
1. Average fresh weight per plant.
2. Average dry weight per plant.
3. Average weight of moisture per plant.
h. Percentage dry matter.
5. Percentage moisture.

The percentage of nitrogen in each daily cutting was determined
on the dry weight basis by the Kjeldahl method modified to include
the nitrogen of nitrates (l). Twenty-three consecutive daily cuttings
were analyzed in this manner.

The stubble was allowed to recover after each cutting. On
January 30, l9h7, the surviving plants were counted and compared
with the number of plants originally present. A second survival
count was made on February 27, 19b7, the results of which did not
differ materially from the first. On February 27, 19h?, all the
plants representing the second growth were cut and the material was
labelled to correspond to its previous daily cutting dates. In other
words, all the plants recovering from any particular daily cutting
were grouped together resulting in twenty-three lots corresponding
to the original twenty-three daily cuttings. These groups were
weighed immediately, and were then oven-dried for twenty-four hours
at 100 degrees Centigrade. As before, the dry weights were taken and

the percentage nitrogen was determined. The same calculations were

made and recorded as for the daily cuttings.

3. Experiment 2

Sudan Grass, under favorable field growing conditions, can be
expected to attain a dry weight per plant of 5.35 grams in 92 days
(1h). Inasmuch as the dry weight of plants of Experiment 1 did not
weigh more than an average of 1.00 gram per plant after 62 days, the
growth obviously was subnormal. The temperature of the greenhouse
on the dates the cuttings were made varied from 50° F. to 900 It with
lower temperatures at night. Based upon the experience gained from
Experiment 1, it appeared advisable to raise the temperature of the
greenhouse as well as to increase the length of day artificially.
Accordingly, additional steam pipes were laid along the walls of the
greenhouse and BOO-watt electric bulbs were hung four feet above the
plants at intervals of seven feet along the entire length of the bench.

One hundred and eighty-four pots were arranged in four rows.
running the length of the bench, on March 12, 1947. There were forty-
six pots in each row. Two rows were fertilized with 2.8 grams of
ammonium nitrate, which corresponded to 600 pounds per acre, and the
other two rows were left unfertilized. Thirty-six seeds of Sudan Grass
were planted in each pot. Because of the better growing conditions
resulting from increased temperature and the use of an eighteen hour
day, the plants thrived much better than those of the previous experi-

ment. This was especially true for the nitrogen-fertilized plants.

7.

The first daily cutting was made on April 7, l9h7, when the
plants were twentyhsix days old. Daily cuttings were made after
this date as in Experiment 1 except that there were two sets of daily
cuttings-~the fertilized and the unfertilized. There were enough
pots to permit thirtybthree daily cuttings instead of the twenty—
three in Experiment 1. The same data and calculations were made and

recorded as for the first experiment.

III. EXPERIMENTAL RESULTS

A. Section I. Sudan Grass gpt_§t,ga;;z,intervals

1. Introduction: Tables 1, 2, and 3 and figures 1 to 8, inclusive,
present the data based on the daily cuttings of the Sudan Grass. In
the figures, curve 1 represents the data obtained from the first ere
periment. It should be borne in mind that the growing conditions were
very poor because of the low temperature in the greenhouse, the short
day length, and the comparatively infertile soil. Yet in spite of
these conditions, the plants flowered and ultimately produced normal
seeds.

Curves 2 and 3 represent data based on the second experiment.
The growing conditions for these plants were much improved since
additional steam pipes had been installed in the greenhouse, the in-
stallation of a row of electric lights over the bench provided an

18¥hour day, and half of the pots were fertilized with ammonium nitrate

in amounts corresponding to 600 pounds per acre. The growth of these
plants, of course, was very much greater than that obtained in the
earlier experiment. But it is important to note that the flowering
of these plants was greatly delayed, apparently because of the longer
day length. It is apparent that the physiological state of the plants
in experiment 2 was fundamentally different from that existing in
experiment 1. It should not be inferred that the very rapid growth
of the plants of the second experiment was related to the process of
flowering. It is more probable that the long day length provided,
artificially disturbed the normal reproduction processes of the plants.
2. Eggsh,w§ighfi,2§_thg plants: The average fresh weights per
plant are presented in tables 1, 2, and 3 and in figure 1. The data
are typical of usual growth rates, in as much as the total fresh.weight
per plant increased as would be expected. The rate of increase was
almost constant in experiment 1. In experiment 2, a more rapid growth
was initiated after about 45 days. Curve 3 indicates that the addition
of ammonium nitrate to the soil significantly increased the total
fresh.weight of the plants, but this effect became apparent only
after #5 days.
3. Amount 9;.mgisture per plgpt; Tables 1, 2, and 3 and figure
2 indicate the average amounts of moisture per plant, during the growth
period. The similarity of the curves in figure 2 to those representing

the total average fresh weight per plant is apparent. On one hand,

this similarity would be expected since the fresh weight is comprised
of such a high percentage of moisture. But on the other hand, a
dissimilarity would be expected during a brief period before flowering,
if it is true that a general dehydration of the plant preceeds flower-_
ing in accordance with the theory of the existence of a ”sensitive
period" at this stage of development. Careful comparison of the curves
in figures 1 and 2 suggest that a period of tissue dehydration did not
occur. It is not impossible, however, that small differences in the
moisture content of the plants would not be detected by these gross
measurements. This possibility will be discussed below.

b. Percentage 2§_moisture ig,th§_plants: The percentage of moisture
in the plants should give a clearer picture of periods of protoplasmic
dehydration than.would the total amount of moisture per plant. The
data assembled in tables 1, 2, and 3 and in figure 3 were obtained
with great care. Their irregularities in magnitude cannot be ascribed
to experimental error in the moisture determination.

The less vigorous plants of the first experiment contained a
higher percentage of moisture after the hSth day than did any of the
vigorously growing plants of the second experiment. Curves 2 and 3
show that the plants fertilized.with ammonium nitrate contained con-
spicuously higher percentages of moisture than the unfertilized plants.

The variations in the percentage of moisture in the plants are
difficult to interpret. The less vigorous plants of the first experi-

ment appear to contain increasing percentages of moisture until the

10.

“Oth day, then a diminishing moisture content appear which reached a
minimum on the h3rd day. After this minimum, a second period of in-
crease appeared, followed by the expected gradually lessened moisture
content associated with approaching maturity.

The unfertilized plants of the second experiment contained a
smaller percentage of moisture than did the other two series. There
was a continually decreasing percentage until the h7th day after which
there was an increase until the 53rd day. The final decrease was
associated with the maturity of the plants. The nitrogen fertilized
plants of the second experiment appear to contain a continually de-
creasing percentage of moisture.

A comparison of the percentages of moisture in the plants of
all three series during the early part of their growth suggests cer-
tain similarities, although each series varied significantly in the
conditions of growth. One might ask the following questions:

In the comparison of curves 2 and 3, do the minima occurring
successively in curve 3 at 36, 39, #2, and #5 days correspond to the
minima exhibited by curve 2 which occurred at 3h, 36, b0, and #7
days? If this be true, then these variations are not only physiologi-

cally significant, but the unfertilized plants lag behind the ferti-
lized by 2 or 3 days. These minima could not be caused by differences

in the weather since they occur on different days.

11.

If curve 1 is compared to curves 2 and 3, the following questions
arise: Is the minimum in curve 1 at 43 days indicative of a period
of tissue dehydration, and if so, is it related to the minima in curve
2 on the h7th day and in curve 3 on the hSth day? These ouestions
will be discussed in a later section of this report.

5. Aggggt g; dry matter per plant: The average amounts of dry
matter per plant are presented in tables 1, 2, and 3 and in figure h.
The very poor growth obtained in experiment 1 is easily seen from the
figure. The maximum dry weight attained by these plants was only about
0.1 gram, while the thriving plants of experiment 2 attained a final
dry weight of about 0.8 gram. Nothing of significance is evident in
curve 1, but an interesting comparison may be made between curves 2
and 3. It will be noted that maxima appear in the dry weight of the
nitrogen fertilized plants on the 30th, 33rd, 37th, 39th, 41st, 43rd,
46th, h9th, Slst, 5hth, and 56th days. A similar series of maxima
appear in curve 2 representing the unfertilized plants, on the 3lst,
33rd, 35th, 38th, 40th, hhth, h7th, 51st, and 57th days. If these
maxima have physiological significance, then it is apparent that
nitrogen fertilized plants were 1 or 2 days ahead of the unfertilized
plants in their rhythmically occurring accumulation of dry material.

It is interesting to note that the actual amount of dry
matter in the fertilized plants was less than in the unfertilized,

except during the last few days of the observation period.

12.

6. Percentage gf_dry matter in_ he plants: The percentages of

 

dry matter in the plants obviously are reciprocally related to the
percentages of moisture discussed above. The data are assembled in
tables 1, 2, and 3 and in figure 5. Curve 1, in figure 5, shows that
the percentage of dry material in the plants of the first experiment
decreased to a minimum on the hOth day, then increased to a maximum on
the h3rd day, again decreased to a second minimum on the h9th day, and
finally rose to a second maximum as the plants approached maturity.

Comparison of curves 2 and 3 indicates that the nitrogen fertilized
plants contained a significantly less percentage of dry matter than
did the plants of the unfertilized series. This difference was es-
pecially evident during the period from the 31st to the h9th day.
Again a comparison may be made between the recurrent maxima exhibited v
by the unfertilized and fertilized plants. The unfertilized series
exhibited maxima on the 27th, 29th, 3hth,,37th, hOth, bSth, h7th,
52nd, Suth, and 59th days. A similar series of recurrent maxima
appeared in the percentages dry weight of the fertilized plants on
the 27th, 29th, 33rd, 36th, 39th, 1+2nd, u5th, 50th, 52nd, 55th, and
60th days. Again it is apparent that if these variations are physio-
logically significant, the fertilized plants are l to 3 days ahead
of those in the unfertilized series.

7. Agggn£_gf nitrogen per plant: The average amounts of nitrogen,
expressed as milligrams per plant, are indicated in tables 1, 2, and

3 and in figure 6. The unthrifty plants of experiment 1 gradually

.LJ.

accumulated nitrogen until about the 5bth day. The slight decrease
after that time was due to the loss of the lower withered leaf. The
maximum nitrogen absorbed per plant in the first experiment was about
3.5 milligrams, while the maximum absorbed from the same soil during
the better growing conditions of the second experiment was 10.0
milligrams. The nitrogen fertilized plants of the second experiment
absorbed a maximum of almost 18 milligrams. The effect of fertiliza-
tion on the nitrogen absorbed is not evident during the earlier stages
of growth, but it becomes conspicuously great during the later period
of growth.

The variability in the amount of nitrogen in the daily cuttings
was not due to errors in the nitrogen determination, but represents
real differences. A series of recurrent maxima is evident from
figure 6, but it is difficult to compare the maxima of curves 2 and
3. In several instances, however, it again appears that these
maxima appear 1 or 2 days earlier in the fertilized plants.

8. Percentage g£_nitrogen ippthg_plants: The data for the per-
centage of nitrogen in the daily cuttings of Sudan Grass are presented
in tables 1, 2, and 3 and in figure 7. The plants of the first experi-
ment exhibited a decreasing percentage of nitrogen throughout their
growth period. The minimum which.occurred on the h7th day, and the
gradual increase until the h9th day should be especially noted in
connection with the discussion of the percentage of the plants which

survived cutting.

14.

It is noteworthy that the percentages of nitrogen in the more
vigorous plants obtained in the second experiment were considerably
lower than occurred during the first experiment. This is especially
true for the unfertilized plants of the second series. This result
is to be expected since the same, rather poor soil was used, and the
better growing conditions caused the production of a greater amount
of plant material.

The nitrogen fertilized plants of the second series contained
greater percentages of nitrogen than the unfertilized plants grown
at the same time, b2£_pgt §§_gg§§§_§§ the percentages of nitrogen in
the poorer plants of the first experiment. The minimum which appeared
in the unfertilized plants of the second experiment on the h7th day
should be especially noted in connection with the discussion of the
percentage of the plants which survived cutting.

9. Percentage survival gf_th§_plants after cutting: The present
study was designed especially to discover if there is a period during
the growth cycle of Sudan Grass during which the plant is sensitive
to cutting. The amount of recovery was not investigated, but atten-
tion.was centered on the ability of the plant to merely survive.

The data indicating the percentage survival of the plants, cut
on successive days, are presented in tables 1, 2, and 3 and in figure
8. The data for the first experiment are especially interesting when

it is recalled that these plants flowered, in spite of their poor

15.

growing conditions and their reduced growth. There seems to be an
increasing sensitivity to cutting which became increasingly acute as
shown by the minima which occurred on the 40th, b6th, and h9th days.
If minor differences are ignored, the sensitivity to cutting began
on about the #3rd day and became acute on the h9th day. A decrease
in sensitivity to cutting occurred from the h9th to the 55th day.
A comparison of figures 1 and 8 shows no relationship between the
”sensitive period" during the growth of the Sudan Grass and the fresh
weight of the plants. Figure 2 shows that the amount of moisture in
the plant also was not related to the sensitive period. Figure 3
shows that the beginning of the sensitive period coincided with a
pronounced minimum in the percentage of moisture in the plants,
namely, the 43rd day. However, the percentage moisture increased to
a maximum on the 49th day, even though the sensitivity to cutting was
becoming more acute. The relationship between the period between the
maximum dehydration of the tissue and the return to normal, to this
“sensitive period“ is suggestive.

Figure a shows that the average dry weights of the plants of
eXperiment l were not related to sensitivity to cutting.

Figure 5 indicates that the relationship between the percentage
of dry matter in the plants of experiment 1 was at a maximum on the
h3rd day, which.was the beginning of the sensitive period. This perk

centage decreased throughout the development of the sensitive period,

 

ll|||l'|lllllllzllllvli'llllllilllllllllll.'3 1141'

16.

or until the 49th day. After that day, a steady increase in the
percentage of dry matter occurred.

Figure 6 shows that the amounts of nitrogen in the plants of
experiment 1 were not related to the sensitivity of the plants to
cutting. Figure 7 indicates that the percentage of nitrogen also was
unrelated to the sensitive period.

The plants studied in experiment 2 did not exhibit any discernible
period sensitive to cutting. The minor differences in the percentage
recovery of the plants of different ages recorded in tables 2 and 3
and in figure 8 are not related to corresponding variations in any
of the observations made during their growth cycle. The absence of
a sensitive period in these series of plants is ascribed to the effect

of the long day length under which they were grown.

B. Section II. Spdan Qragg produced by_rogts Qfi_different Egg,

1. Introduction: The plants of all three series described above
were allowed to recover after the daily cuttings described in Section 1
of this report. All plants of each series were harvested at the same
time. A.group of samples of the top growth for each series was ob-
tained which not only differed in age but which had been produced by
roots of different age. For example, at one end of the series the
original cutting described in Section 1 was made from young roots.
The same roots, therefore, had a longer period for producing the

second crop of teps to be described in the present section. At the

17.

other end of the series, the original cutting was made from the
oldest roots, and consequently, the tops described in the present
Section were the youngest of the group.

The purpose of the observations described in Section 1 was to
discover if there was a period in the growth cycle of Sudan Grass
during which the cutting of the tops would kill the plants. This was
seen to be true for the plants of experiment 1 which were grown under
a comparatively short day length. 0n the other hand, no sensitive
period was observed for the 2 series of plants of experiment 2, which
were grown under an 18 hour day.

If a true sensitive period occurs during the growth cycle of
Sudan Grass, during which recovery after cutting is depressed or
impossible, it appears logical to ascribe its physiological basis to
some property or condition of the roots, rather than to the tops. If
the roots from which the tops had been removed were allowed to produce
new tops, in so far as they were able, no sensitive period should be
observed when the tops were cut. The reason for this assumption is
apparent since the youngest roots which might be presumed to undergo
a sensitive period during the period of the second growth of the tops
had a comparatively long period before their tops were cut, and any
sensitive period would be safely passed. The older roots, which had
a short period in which to produce tops would be presumed to have

passed their sensitive period while they were producing their first

18.

crop of tops.

Although a sensitive period appeared as described in Section 1,

a fgg_plants did survive, probably because the physiological age of the
individual plants in each pot differed slightly and the few which sur-
vived cutting were not in the sensitive stage. The data described in
this section are based on all the plants which survived although‘it
§§§m§.1ikely that those few plants which survived the sengitivejperigd
mild p91; 23 gompletely comparable £9 t_h_e_ m ma; plants. The
observations described below were especially directed towards the
recovery growth from the roots which were harvested during the sen-
sitive period.

2. flesh geight m3}; 229...: The data representing the average
fresh weight per plant of the recovered plants are assembled in tables
h, 5, and 6 and in figures 9 and 10. One base line indicates the
actual age of the tops when harvested; the other base line indicates
the age of the root at the time when the recovery growth began, in
other words, when the.fig§t cutting was made.

The plants of the first experiment (figure 1, curve 1) show a
very irregular magnitude of the recovery growth. Of course, the
amount of recovery growth diminishes as the age of the tops diminishes,
but even in view of the erratic data, it appears that the average
fresh.weight of the tops was more or less the same, in spite of their

very different age, until the age of the roots was about #7 days. This

19.

age, it will be recalled, is about midway in the sensitive period of
these plants described in Section 1. With the exception of this
abrupt decrease in the weight of the recovered plants, there seems
to be a slight general decrease as the age of the teps lessened and
the age of the roots which produced them increased. One may suspect
that the older roots which produced the youngest tops were effective
in augmenting the speed of recovery.

The unfertilized, long-day plants of experiment 2 (figure 2, curve
1) show a remarkable equality in the average weight of the tops, even
though they differed greatly in age. In fact one might even presume
a gradual increase in the weight of the tops when the roots were about
#9 days old. The effect of the older roots in speeding the rate of
top growth again suggests itself.

The nitrogen-fertilized plants of experiment 2 are seen from
table 6 and figure 10 to show a much greater difference in the amount
of top growth recovery as the tops differed in age. The effect of
the older roots in speeding the recovery growth is not apparent.
There seems to be a more rapid decline in the amount of recovery
growth after the roots were about 49 days old. It is interesting
to recall that this age was about when the sensitive period appeared
in the reproductive plants of experiment 1.

3. Amount g;_moisture per plant: The amounts of moisture per
plant observed in experiment 1 and recorded in table h and in figure

11 show about the same variation.with the age of the recovered tops

20.

as did the total fresh weight. The youngest tops contained less
moisture per plant.

Tables 5 and 6 and figure 12 show a decrease in the moisture per
plant for the plants obtained in experiment. This decrease was very
small in the unfertilized series. EVen though this decrease is more
pronounced for the nitrogen fertilized series, it is less accentuated
than was the decrease in the total fresh weight shown in figure 10.
There seems to be a more rapid decrease after the roots were #9 days
old.

h. Percentage g§_moigture ip,thg_plant§: The data in table a and
in figure 13 show that the percentage of moisture in the plants of
experiment 1 increased as the taps were younger. One might assume
from the data a period of general tissue dehydration when the tops
were from 70 to 75 days old.

The data in tables 5 and 6 and in figure In show a gradual increase
in the percentage moisture in the tape as they become younger. This
increase seems to be more rapid when the tape were less than #8 days
old, and the roots were more than 38 days old.

The older fertilized plants contained a smaller percentage of
moisture than did the unfertilized plants in their more mature stages,
but the percentages of both series were about equal in the younger
tops.

5. Amount g£_dry matter per plgpt: The data recorded in table h

and in figure 15 show in grams the average amount of dry matter per

2]..

plant for the plants obtained in experiment 1. Comparison of figures
13 and 15 shows that, in general, the amount of dry matter per plant
varied inversely, as would be expected, as the percentage of moisture.
There was a decrease in the average amount of dry material per plant
as the tops became younger.

Tables 5 and 6 and figure 16 show a more rapid decrease in the dry
weight per plant for the fertilized group. The older tops of the fer-
tilized plants weighed about twice as much as the unfertilized, yet
the weights of the younger plants of both the fertilized and unferti-
lized group were almost equal. The effect of the ammonium nitrate
fertilizer was increasingly greater as the tops became older.

6. Percentag§,g£_dgy_matter ;p_the plants: Table h and figure 21

 

indicate the percentages of dry material in the tops of the plants.
These data, of course, are reciprocal to the percentages of moisture.
The period of a probable dehydration of the tissue again is apparent,
when the tops were from 70 to 75 days old, and were produced by roots
from 58 to 53 days old. The general minimum in the percentage of dry
matter which appeared when the tops were from 76 to 83 days old and
when the roots which produced them were from 52 to 45 days old occurs
on the same plants which exhibited the sensitive period described in
Section I.

Figure 22 shows the gradual decrease in the percentage of dry
matter in the tops of the two groups of plants in experiment 2 with

the decreasing age of the tops. In general, the nitrogen fertilized

22.

plants contained the greater percentage of dry matter in the more
mature stage, but the values were about equal to those of the unfer-
tilized plants when the tops were younger.

7. Amount g§Initrogen p§§_p;gp§: The data in table b and figure
17 show that the amounts of nitrogen in the tOps of the plants of
experiment 1 varied from about 9 milligrams in the older tops to about
5 milligrams in the younger tops. The amount was about equal in all
tops having an age greater than about 82 days. Tops younger than 82
days showed very irregular nitrogen contents, but in general much
lower.

The effect of nitrogen fertilizer on the nitrogen content of the
tops is shown strikingly in figure 18. The older fertilized plants
contained more than twice as much nitrogen in the tops. The total
nitrogen did not vary greatly in the unfertilized series. The effect
of the fertilizer is more pronounced in the nitrogen content than in
the total growth.

8. Pgrcentgge gf_nitrogen ip_§hg_plants: The data in table h
and figure 19 are especially interesting. The percentage of nitrogen
in the tops was almost identical during the later stages of growth,
when the tops were from about 81 to 92 days old, when the roots which

produced the tops were from 36 to 47 days old. There was a sudden

maximum in the percentage of nitrogen in the tops when they were from

about 81 to 73 days old, and when the roots which produced them were

23.

from 4# to 55 days old. This is especially interesting since these
same roots exhibited a "sensitive period" during their original
growth, between the ages of an and 53 days.

Tables 5 and 6 and figure 20 show that the percentage d'nitrogen
in the tOps was about the same for the plants of the second experiment,
after they had attained an age of about #5 days. Tops younger than
#5 days exhibited a small progressive increase in.percentage of nitro-
gen with decreasing age. The nitrogen fertilized plants contained a
slightly higher percentage of nitrogen throughout their growth cycle.
No conspicuous maximum in the concentration of nitrogen occurred, in

contradiction to the reproductive plants of the first experiment.

214.

IV. SUIvfliARY AND CONCLUSIONS

1. Sudan Grass was grown in pots of soil in the greenhouse under
the conditions of low and high temperature, short and long days, and
low and high nitrogen content of the soil. Daily cuttings were made
and the following data were obtained: (1) total fresh weights,
moisture, dry matter, and nitrogen: (2) the percentages of moisture,
dry matter, and nitrogen; (3) percentage of the plants surviving
cutting: (h) the amount of recovery growth and the amount of fresh

weight, moisture, dry matter, and nitrogen which it contained.

Effects g; nitrogen fertilizer
2. The addition of ammonium nitrate at the rate of 600 pounds
per acre did not greatly affect the fresh weight of the plants nor
the amount of nitrogen absorbed _e__x_c__e_p_t_ 3}; the later stages 23: M.
3. Nitrogen fertilization caused a higher percentage of moisture
and a lower percentage of dry matter in the plants.
h. Nitrogen fertilization markedly increased the nitrogen con-

centration of the vigorous, long-day plants.

Effects 91 Mt £131
5. The percentages of moisture and of nitrogen in the plants
grown under unfavorably cool temperatures and short days were ggeater
than in the more vigorous plants grown under favorable temperature
and a long day length, even when ammonium nitrate was added to the

long day plants at the rate of 600 pounds per acre.

25.

6. A brief sensitive period during the growth of Sudan Grass
was detected during which the plants could not gprvive cutting.

7. The sensitive period existed between the h3rd and h9th days
from planting.

8. Increasing the day length to 18 hours eliminated the sensitive
period.

9. The sensitive period was not related to the general vigor of
the plants, nor to the total fresh weights, dry weights or nitrogen
content of the plants.

10. The sensitive period was not related to the percentage of
nitrogen in the plants.

11. The sensitive period was preceeded by a well defined period
of general tissue dehydration as indicated either by the percentages
of moisture or by the percentages of dry matter in the plants.

12. The appearance of the maximum percentage of dry matter and
the lowest percentage of moisture occurred at the beginnipg of the

sensitive period.

Recovery ggpwth
13. The amount of recovery growth.was about the same for all plants
which had been out before the sensitive period. When the plants were
cut gffigg_the sensitive period, the amount of recovery growth was re-

lated to the actual age of the tops when they were harvested.

26.

14. The amount of recovery growth pg£_d§y_appeared to be greater
if it was produced by the older roots, that is, if the original
cutting had been made g££g§_the sensitive period.

15. The percentage of nitrogen was greater in the recovery growth

of the plants which had been cut previously during the sensitive period.

1.

2.

3.

5.

7.

9.

10.

27.

V. LITERATURE CITED
Association of Official Agricultural Chemists. ”Official and
tentative methods of analysis.“ Sixth Ed., Assoc. Official
Agricult. Chemgglg, Wash., D. 0., p. 27, (1935)
Boyd, F. T., Aamodt, O. S., Bohstedt, G., and Truog, E. ”Sudan
Grass management for control of cyanide poisoning." éggg, §g§,

£2011. JOUI‘o, 39.9 569.582! (1938)

 

Gaessler, W. G. and McCandlish, A. C. “Composition and digesti-
bility of Sudan Grass hay.“ 1. Ag; Beau 11;, 176-185, (1918)

Hillman, F. H. "Distinguishing characters of the seeds of Sudan
Grass and Johnson Grass.‘ ELM. £21. £21., #06, (1916)

Hogg, P. G. “Environmental, breeding, and inheritance studies of
hydrocyanie acid in Sorghum vulggre var. sudanensig.” g; Agg,
figs" _61. 195-210, (19143)

Karper, R. E. "Sudan Grass.” Okla. Agr. Exp. Sta. Bul., 103,
(1915)

Loehwing, W. F. "Nutritional factors in plant growth and deve10p-
ment.‘l Igwa Academy g§_Science, Q2, 61, (19h2)

Loehwing, W. F. “Mineral nutrients in relation to flower develop-
ment." _s_g_1_.. 2;, 517-520, (19%)

Loehwing, W. F. "Photoperiodic aspects of phasic develOpment.'
.5524... 20.. 552-555. (1939)

Long, Betty. "Spikelets of Johnson Grass and Sudan Grass."

1321. 92s.. :32. 154—169. (1930)

11.

12.

13.

1h.

15.

16.

17.

18.

19.

20.

21.

28.

Menual, P. and Dowell, C. T. "Cyogenesis in Sudan Grass." £211.41.
AE.- Bran lé. 447-450. (1920)

Nowosad, F. S. and MacVicar, R. M. ”Adaptation of the picric
acid test method for selecting hydrocyanic acid-free lines in
Sudan Grass.“ 10;. Ag), 2Q, 566-569, (19140)

Piper, C. V. "Sudan Grass, a new drought resistant hay plant."
..U.-..S.° 29.13.2- Ass. 1.32:1.” flamm- 9L1:- 125. (1913)

Popp, W. H. "A physiological study of the effect of light of
various ranges of wave length on the growth of plants." Am; ,1.
1391.. 11, 706-735. (1926)

Schmitz, Nickolas. "Sudan Grass.“ an. Air. Fxp. Sta. 33111.. 123,
47-62, (1916)

Swanson, C. O. "Hydrocyanic acid in Sudan Grass and its effect on
cattle." ;L_m_e_1_‘_. s93. m. _._I_o_u_1;.. 13,. 33-36, (1921)

Swanson, C. 0. I'Hydrocyanic acid in Sudan Grass." fill};- .512.
3.9g" 22, 125-138, (1921)

Thompson, G. E. "Sudan Grass in Kansas." Kane. Agr. Exp. Sta.
gas, 212

Vinall, H. N. "Sudan Grass.” g._s_. 2911;. £22. 1331., 1126, (1921)

Vinall, H. N. "Sudan Grass as a forage crop.“ E.§_. 2923. fig;
armers' 331.. 605. (1914)

Williams, C. G. "Sudan Grass.” Ohio Aer. Ebtp. Sta. Mo. 3331., l,

67:70. (1916)

29.

22. Wynd, F. L. "Chlorosis in Sudan Grass." 2;. Physiol” E.

303-305 . (1993)

23. Youngblood, B. and Connor, A. B. "Sudan Grass." Texas Ag;

E32. £322.- B_ulu 172. (1915)

300

Table 1. Experiment 1. Data concerning daily cuttings of
Sudan Grass.

 

Age in Fresh Weight Moisture

days per Plant

Dry Matter

 

Wt. per plant Percentage Wt. per plant Percentage

 

(amen) (ems. (ems.)
36 0.18 0.15 85.8 0.03 14.2
37 0.18 0.15 86.5 0.03 13.5
38 0.21 0.18 86.8 0.03 13.2
39 0.25 0.22 87.5 0.03 12.5
no 0.33 0.29 88.8 0.0u 11.6
#1 0.3a 0.30 87.2 0.04 12.8
A2 0.34 0.30 87.9 0.04 12.6
43 0.32 0.27 85.5 0.05 1u.5
an 0.u6 0.40 87.5 0.06 12.5
#5 0.99 0.b3 87.5 0.06 12.5
u6 0.63 0.55 88.0 0.08 12.0
47 0.56 0.49 87.7 0.07 12.3
u8 0.61 0.59 88.5 0.07 11.5
09 0.63 0.56 88.6 0.07 11.u
50 0.78 0.68 87.3 0.10 12.7
51 0.75 0.66 87.9 0.09 12.1
52 0.59 0.51 86.6 0.08 13.u
53 0.71 0.61 86.1 0.10 13.9
50 0.99 0.86 86.7 0.13 13.3
55 0.71 0.61 86.u 0.10 13.6
56 0.90 0.78 87.1 0.12 12.9
58 0.7u 0.63 85.6 0.11 1b.n

 

31.

Table 1. Concluded

 

 

 

Nitrogen Survival
Age in Imount per plant Percentage after
days (mgs.) cutting
(percentage)
36 0.9 3.56 99.5
37 0.9 3.80 95.6
38 1.0 3.76 96.5
39 1.2 3.87 83.6
no 1.6 h.10 71.3
#1 1.7 3.75 90-0
82 1.7, 3.88 92.5
#3 1.7 3.59 91.6
as 2.2 3.8h 78.3
as 2.2 3.63 70.5
46 2.9 3.79 56.2
#7 2.3 3.32 73.u
88 2.5 3.58 29.u
49 2.6 3.61 2h.7
50 3.2 3.27 32.5
51 2.8 3.04 58.8
52 2.2 2.82 57.1
53 2.9 2.91 61.0
5h 3.6 2.75 70.7
55 2.6 2.72 83.2
56 3.3 2.83 75.0
57 2.8 2.78 72.6
58 2.7 2.57 71.3

 

Table 2. Experiment 2. Data concerning daily cuttings 0f
unfertilized Sudan Grass.
Age in Fresh Weight Moisture Dry Matter
days per Plant Wt. per plant Tercentage Wt. per plant Percefiage

 

 

(ngo) (83118.) (ngO)
26 0.37 0.33 89.0 0.04 11.0
27 0.37 0.32 86.9 0.05 13.1
28 0.61 0.54 89.0 0.07 11.0
29 0.49 0.44 88.8 0.05 11.2
30 0.80 0.72 89.9 0.08 10.1
31 0.87 0.78 89.2 0.09 10.8
32 0.64 0.56 88.1 0.08 11.9
33 0.83 0.72 87.2 0.11 12.8
34 0.77 0.66 85.9 0.11 14.1
35 0.98 0.84 86.3 0.14 13.7
36 1.12 0.97 86.2 0.15 13.8
37 1.02 0.87 85.3 0.15 14.7
38 1.29 1.10 85.5 0.19 14.5
39 1.30 1.13 86.6 0.17 13.4 ‘
40 1.35 1.13 84.1 0.22 15.9
41 1.36 1.15 84.9 0.21 15.1
42 1.22 1.04 85.0 0.18 15.0
43 1.26 1.07 85.0 0.19 15.0
44 1.51 1.28 85.0 0.23 15.0
45 1.18 0.97 82.3 0.21 17.7
46 1.44 1.20 83.6 0,24 16,4
47 1.67 1.37 82.0 0.30 18.0
48 1.59 1.31 82.7 0.28 17.3
49 1.80 1.50 83.4 0.30 16.6
50 2.35 2.00 85.0 0.35 15.0
51 3.01 2.57 85.5 0.44 14.5
52 2.04 1.64 85.3 0.40 14.7
53 2.18 1.86 85.6 0.32 14.4
54 2.21 1.84 83.4 0.37 15-5
55 2.72 2.29 84.2 0.43 15-8
56 3.39 2.86 84.5 0.53 15-5
57 3.75 3.19 85.1 0.56 14.9
58 3.11 2.59 83.4 0.52 16-6

 

33-

Table 2. Concluded

 

 

 

80591951“-
Nitrogen after
Age in Imount’per plant Percentage cutting
days (mgs.) (percentage)

26 1.6 4.10 100.0
27 1.8 3.69 100.0
28 2.9 4.07 95.8
29 1.9 3.85 98.7
30 3.3 4.09 94.2
31 3.3 3.68 100.0
32 2.8 3.51 97.4
33 3.6 3.29 100.0
34 2.9 2.62 100.0
35 4.1 2.94 97.1
36 4.6 2.86 100.0
37 308 2052 9502
38 4.9 2.56 96.2
39 4.4 2.59 100.0
40 5.0 2.28 98.0
41 4.9 2.31 98.0
42 4.3 2.36 100.0
43 4.0 2.10 100.0
44 6.0 2.61 100.0
45 4.7 2.25 100.0
46 5.2 2.16 100.0
48 4.8 1.71 93.3
49 4.3 1.44 95.8
50 6.2 1.76 97.9
51 8.3 1.89 97.5
52 9.4 2.36 94.5
53 7.1 2.21 97.7
54 7.6 2.05 100.0
55 6.0 1.40 100.0
56 7.5 1.42 97.7
57 10.5 1.88 100.0
58 6.4 1.23 97.0

 

34.

Table 3. Experiment 2. Data concerning daily cuttings of
fertilized Sudan Grass.

 

Age in Fresh Weight Moisture Dry Matter
days per Plant Wt. per plant Percentage Wt. per plant DPercentage

 

(ems.) (ems.) (gms.)
26 0.30 0.27 88.8 0.03 11.2
27 0.36 0.32 88.1 0.04 11.9
28 0.47 0.42 89.1 0.05 10.9
29 0.58 0.52 89.1 0.06 10.9
30 0.63 0.56 89.6 0.07 10.4
31 0.57 0.51 89.3 0.06 10.7
32 0.56 0.49 88.5 0.07 11.5
33 0.94 0.83 88.3 0.11 11.7
34 0.79 0.70 88.2 0.09 11.8
35 0.88 0.77 87.6 0.11 12.4
36 0.96 0.84 87.5 0.12 12.5
37 -1.27 1.11 87.6 0.16 12.4
38 1.25 1.10 88.1 0.15 11.9
39 1.17 1.02 87.2 0.15 12.8
40 1.00 0.88 88.4 0.12 11.6
41 1.74 1.54 88.3 0.20 11.7
42 1.02 0.88 86.1 0.14 13.9
43 1.63 1.42 87.0 0.21 13.0
44 1.39 1.21 87.3 0.18 12.7
45 1.48 1.25 84.5 0.23 15.5
46 2.81 2.42 86.3 0.39 13.7
47 2.59 2.24 86.3 0.35 13.7
48 1.97 1.71 86.8 0.26 13.2
49 2.47 2.13 86.5 0.34 13.5
50 2.36 2.00 84.9 0.36 15.1
51 2.90 2.49 85.8 0.41 14.2
52 2.07 1.76 85.0 0.31 15.0
53 2.95 2.53 85.7 0.42 14.3
54 3.56 3.06 85.9 0.50 14.1
55 3.21 2.73 84.9 0.48 15.1
56 4.10 3.45 84.1 0.65 15.9
57 4.61 3.96 86.0 0.65 14.0
58 5.29 4.51 85.2 0.78 14.8

 

cutting
(percentage)

Survival
after

Percentage

Nitrogen

35.
Age in Amount per plant

(mes.)

 

Concluded

days

 

 

Table 3.

362
o o
112

26
27
28

29
30
31

97.2
97.0
100.0

3.83
3.59
3.66

703
2.43

32
33
34

939

042
O.
zoww

o/o/ .

3.93
3.54
3.37

931
55.4

38
39
40

98.1
97.7
100.0
100.0
100.0
97.5
100.0
100.0
100.0
91.
93.
96.
100.0
95.6
97.4

2.96
2.43
3.05
2.16
2.08
2.19
2.25
2.38
2.21

9.
10.
10.
14.
15.
17.7

41
42
43
53
54
55
56
57
58

 

36.

Table 9. Experiment 1. Data concerning recovery growth of
Sudan Grass.

 

 

 

Age of Roots Age of Tops Fresh Weight Moisture
at lst cutting after lst cutting per Plant Wt. per Plant Percentage
(Days) (DayS) (ems.) (gms.)
36 92 1.60 1.23 76.7
37 91 1.76 1.36 77.3
38 90 2.37 1.79 75.6
39 89 2.53 1.93 76.1
40 88 2.70 2.11 78.2
41 87 2.64 2.01 76.1
42 86 2.22 1.66 75.1
43 85 1.61 1.21 75.2
44 84 2.62 2.01 76.5
45 83 2.29 1.81 78.9
46 82 2.91 2.26 77.6
47 81 1.24 0.96 77.4
48 80 1.55 1.24 79.7
50 78 2.43 1.91 78.5
51 77 1.03 0.82 79.7
52 76 0.87 0.69 79.2
53 75 1.27 0.99 78.1
54 74 1.64 1.26 76.9
55 73 1.30 1.00 76.7
56 72 1.75 1.37 78.2
57 71 1.28 0.99 77.7
58 70 0.87 0.69 78.8

 

37.

 

 

 

Table 4. Concluded
Age of Roots Age of Tops Dry Matter Nitrogen
at let cutting after lst cutting Wt. per Per— Amt. per Per-
(Days) (Days) Plant centage Plant centage
' (gms.) (mgs.)
36 92 0.37 23.3 6.5 1.75
37 91 0.40 22.7 7.1 1.78
38 90 0.58 24.4 9.5 1.64
39 89 0.60 23.9 9.8 1.64
40 88 0.59 21.8 9.6 1.63
41 87 0.63 23.9 9.8 1.56
42 86 0.56 24.9 8.8 1.58
43 85 0.40 24.8 7.1 1.78
44 84 0.61 23.5 9.5 1.55
45 83 0.48 21.1 9.0 1.88
46 82 0.65 22.4 10.4 1.60
47 81 0.28 22.6 5.1 1.83
48 80 0.31 20.3 8.2 2.65
49 79 0.25 20.7 8.0 3.19
50 78 0.52 21.5 12.1 2.33
51 77 0.21 20.3 6.4 3.05
52 76 0.18 20.8 4.2 2.35
53 75 0.28 21.9 6.0 2.13
54 74 0.38 23.1 6.7 1.76
56 72 0.38 21.8 8.0 2.12
57 71 0.29 22.3 6.5 2.24
58 70 0.18 21.2 3.3 1.84

 

38-

Table 5. Experiment 2. Data concerning recovery growth of
unfertilized Sudan Grass.

 

 

 

Age of Roots Age of Tops Fresh Weight Moisture
at let cutting after lst cutting per Plant Wt. periPlant'_Percentage
(Dave) (Dare) (gm8.) (gm8.)
26 60 4.18 3.46 82.7
27 59 4.35 3.54 81.3
28 58 3.64 2.91 80.0
29 57 3.50 2.89 82.6
30 56 4.05 3.41 81.7
31 55 2.94 2.35 80.1
32 54 3.47 2.87 82.7
33 53 4.46 3.70 83.0
34 52 3.34 2.80 83.7
35 51 4.18 3.45 82.5
36 50 3.70 3.04 82.3
37 “9 3.48 2.90 83.2
38 48 3.04 2.49 61.9
39 47 3.45 2.84 82.4
40 46 3.13 2.60 83.1
41 45 3.09 2.56 82.8
42 44 3.87 3.27 84.6
43 43 2.18 1.82 85.3
44 42 3.91 3.27 83.6
45 41 2.87 2.52 87.8
46 40 2.21 1.78 80.5
47 39 1.54 1.30 84.5
48 38 3.44 2.97 86.4
49 37 1.62 1.38 85.2
50 36 1.73 1.47 84.9
51 35 2.47 2.14 86.5
52 34 3.50 3.01 86.1
53 33 2.14 1.81 84.5
54 32 2.72 2.33 85.9
55 31 1.71 1.46 85.4
56 30 1.56 1.32 84.8
57 29 2.98 2.55 85.6
58 28 2.08 1.80 86.5

39.

Table 5. Concluded

 

 

 

Age of Roots Age of Tops Dry Matter Nitrogen
at 1st cutting after lst cutting Wt. per Pér- Amt. per ‘Perb‘_-
(Days) (Days) Plant centage Plant centage
(gmso) (mgs.)
26 60 0.72 17.3 9.2 1.28
27 59 0.81 18.7 10.3 1.27
28 58 ‘ 0.73 20.0 7.3 1.00
29 57 0.61 17.4 8.8 1.44
30 56 0.74 18.3 8.7 1.17
31 55 0.59 19.9 5.7 0.96
32 54 0.60 17.3 8.3 1.38
33 53 0.76 17.0 9.8 1.30
34 52 0.54 16.3 7.8 1.45
35 51 0.73 17.5 8.1 1.11
36 50 0.66 17.7 7.7 1.17
37 49 0.58 16.8 7.6 1.31
38 48 0.55 18.1 5.0 0.91
39 47 0.61 17.6 6.0 0.98
40 46 0.53 16.9 7.6 1.44
43 43 0.36 16.5 5.0 1.38
44 42 0.64 16.4 9.7 1.52
45 41 0.35 12.2 5.2 1.49
46 40 ’0.43 19.5 5.8 1.35
47 39 0.24 15.5 3.1 ' 1.30
48 38 0.47 13.6 8.8 1.88
49 37 0.24 14.8 3.4 1.41
50 36 0.26 15.1 3.7 1.41
51 35 0.33 13.5 5.6 1.70
53 33 0.33 15.5 5.5 1.66
54 32 0.39 14.1 7.5 1.91
55 31 0.25 14.6 4.5 1.79
56 30 0.24 15.2 4.7 2.01
57 29 0.43 14.4 8.0 1.85
58 28 0.28 13.5 5.6 1.99

40.

Table 6. Experiment 2. Data concerning recovery growth of
fertilized Sudan Grass.

 

 

 

Age of Roots Age of Teps . Fresh Weight Moisture
at 1st cutting after lst cutting per Plant WW. per Plant Percentage

(Days) (Days) (gm3.) (ems.)

26 60 6.32 80.8
28 58 8.09 81.6
30 56 7.62 80.2
31 55 6.65 81.3
32 54 6.55 80.8
35 51 6.12 80.1
37 49 7.70 80.3
38 48 7.28 80.4
39 47 5.08 81.7
40 46 5.07 80.7
41 115 6.44 80.7
42 44 5.97 82.1
43 43 5.73 82.9
44 42 5.80 83.8
45 41 7.10 83.3
46 40 5.48 83.6
47 39 7.50 83.2
48 38 6.33 84.5
49 37 6.27 84.4
50 36 4.78 83.3
52 311 4.70 86.9
53 33 3-89 85.6
54 32 3.73 86.0
55 31 3.30 85.2
56 30 2.50 83.7
57 29 3.89 85.9
58 28 3.80 85.8

 

41.

Table 6. Concluded

 

 

 

Age of Roots Age of Tops Dry Matter Nitrogen
at 1st cutting after 1st cutting WE: per ’Per- *Imt. per ’Per— “-
(Days) (Days) Plant centage Plant centage
(nge) ' (”15:30)
26 60 1.21 19.2 1.64
27 59 1.49 20.3 1.57
28 58 1.48 18.4 1.31
29 57 1.43 20.3 1.34
30 56 1.51 19.8 1.44
31 55 1.24 18.7 1.42
32 54 1.26 19.2 2 1.75
33 53 1.52 18.8 4 1.60
34 52 1.23 19.4 6 1.30
35 51 1.22 19.9 8 5 1.52
36 50 1.23 20.3 0 8 1.69
37 49 1.52 19.7 3 3 1.53
38 48 1.43 19.6 14 2 0.99
39 47 0.93 18.3 13.9 1.50
40 46 0.98 19.3 16.5 1.69
41 45 1.24 19.3 12.8 1.03
42 44 1.07 17.9 20.8 1.94
43 43 0.98 17.1 14.8 1.51
44 42 0.94 16.2 20.1 2.14
4 41 1.19 16.7 26.5 2.23
46 40 0.90 16.4 13.7 1.52
47 39 1.26 16.8 18.8 1.49
48 38 0.98 15.5 17.1 1.75
49 37 0.98 15.6 20.4 2.08
50 36 0.80 16.7 15.1 1.88
51 35 0.71 16.4 14.2 2.00
52 34 0.61 13.1 16.0 2.63
53 ‘ 33 0.56 14.4 12.0 2114
54 32 0.52 14.0 10.8 2.07
55 31 0.49 14.8 10.6 2.17
56 30 0.41 16.3 6.8 1.65
57 29 0.55 14.1 10.7 1.94
58 28 0.54 14.2 10.3 1.90

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