“(FEE EFFECT OF PWSPHDRUS AND POTASSIUM
ON THE gamma; éiND CHEMICAL COMPOSEHON
‘fiEm, m5: PERSE‘E‘ENtE OF ALFALFA AND
(TERTMN GRASSES GRGWN EN COMBENATION

mg; Em 9%» Dear» cf Ph. D.
MEfiWGA?! STATE {JNNERSITY
éasagh Eéeai Pratt
W61

 

This is to certify that the
thesis entitled

The Effect of Phosphorus and Potassium on the Botanical
and Chemical Composition, Yield, and Persistence of
Alfalfa and Certain Grasses Grown in Combination

presented by

Joseph Neal Pratt

has been accepted towards fulfillment
of the requirements for

_2L..D.._deqree in_S°.. 11 Science

/

’ . _ 7 ‘ z
./ [7’ ’ I /l/ (7-1/
( M [{l/ 1/: ' ;.l"“l
f J l I 'L ' 4' " jg ' ‘
/ C
Major professor

Date January 30; 1961

0-169

LIBRARY

Michigan State
University

 

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By

Jose?” Neal Pratt

1- ‘_._;(m a 71 '1 ‘ 7123"“‘(1‘ “I
ad aroihnCL Or A inhalb

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Soil Science

1961

I
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T335 MF' CT OF PhOSEK HUS -133 POTASSIUL ON T31 BOTAHILLL
111135.1- 10-11- co: cs :11::o , 11-11-17», 111-111 PARSISTLJCIS
OF (lil‘jiltlalfigl [54D CARI 1.1 LI: W thiisudt Q (3'3!) ("l-I

IN COl‘n-B 11.41; 11: 0'14

by Joseph Neal Pratt

The effect of phosphorus and pots ss i1m on the
botan al and chemical corposition, yield, and persistence
of alfalfa when grown in association with certain grasses
was studied under field and greenhouse conditions. Field
plots established in lQSt were used to study the persistence
of unfertilized alfalfa.

The botanical composition, yield, and chemical com-
position of forage for the fourth harvest year, 1958, were
determined. hive soil profiles were sampled and analyzed
for reserve phos horus and potassium by horizo-s.

Fertilizer subtreatments resulted in 51 ield differences
which were highly significant for all eight cuttings over
a four year period from l95t to 1958. The highest amount
of alfalfa in the forage occurred in the treatment and
subtreatment receiving no fertilization at the tine of
establishment or as a tOpdressing. A significant negative
correlation existed between the percentage of alfalfa in
the forage and the amount of phosphorus in the soil.

Increased phosphate applications increas

\D

d the amount of

 

Joseph Neal Pratt

phosphorus extracted from soil samples, but increased
potash applications resulted in little influence on the
amounts of potassium extracted from soil samples.

In the 1959 field experiment, significant differ-
ences in yield existed as a result of five fertilizer
treatments applied in the fall of 1958. Only treatments
receiving the potash yielded significantly higher amounts
of forage than the original check plots established in
195h and which were check plots in 1959.

A tendency for decreased yield with phosphorus fer-
tilization and increased yield with potash fertilization
was shown by alfalfa with a reverse tendency shown by
bromegrass. No radical change in the percentage of
alfalfa in the forage during one growing season was
noticed as a result of fertilizer treatment.

Phosphate fertilization increased the phosphorus
content while decreasing the potassium content of both
alfalfa and bromegrass tissue.

Potash fertilization increased the yields of both
alfalfa and bromegrass. It caused little to no change
in the phosphorus content while increasing the potassium
content of both alfalfa and bromegrass.

Removal of soil phosphorus was increased as a result
of both phosphate and potash fertilization. Removal of
soil potassium was increased by potash fertilization and

unchanged by phosphate fertilization.

In all three greenhouse experiments, striking
similarities of yield resulted from phosphate and potash
fertilization. High levels of phosphate fertilization
increased the yields of grasses and had little influence
on the yields of alfalfa. High levels of potash fertiliza-
tion resulted in higher yields of alfalfa and lower yields
of grasses.

fhe botanical composition of the alfalfa-bromegrass
association showed significant differences as a result of
both phosphate and potash fertilization. The lowest
amount of applied phosphate produced the highest percentage
of alfalfa in the forage, with the highest amount of phos-
phate producing the lowest percentage of alfalfa in the
forage. Potash fertilization increased the percentage
of alfalfa at low levels of added phosphate, but not at
high levels of added phosphate.

The percentage of phosphorus and potassium in the
tissue of alfalfa and the associated grass was increased
as the applications of these nutrients were increased.

In all three greenhouse experiments, alfalfa con-
tained a higher percentage of phosphorus in the tissue
than the grass grown in association. the phosphorus con—
tent of bromegrass was higher than the phosphorus content
of timothy and ryegrass.

Negative associations were found in all three green-
house eXperiments between the percentage of alfalfa in the

forage and the phOSphorus content of the soil.

 

The persistence of alfalfa when grown with an
associated grass without phosphorus or gotassium fertili—

zation was attributed to the subsoil furnishino phosphorus

Q
in sufficient arouht to enable alfalfa to compete with a
shallow rooted grass plant. The restricted growth of
grass, in turn, enabled the soil to sugply sufficient

potassium to maintain the alfalfa in association with a

(“’1

Irass. The pH of the surface and subsurface horiions may
have proved a disadvantage in phosphorus uptake by the

grass.

17:22; arrow 03 P‘IOSPL—LORUS AND rornssrn: 0;: TEE sermon.
yarn 0&1:an COE»-‘DOSITIO;\I, '[I......""TD, 2;: PJZSI“1‘LLTCE

or minim A‘s-1D can u: 21 c Passis 320m»;

IN C 013 IIL‘L‘I‘I OBI
BY

Joseph Neal Pratt

r, 1"“! (3'?

Submitted to
Lichigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PEI OSOPni

Department of Soil Science

1961

5; an)?
36/:13/25/

A»! LI 0: .124: :‘&-d—4. . .s.

The author wishes to express his sincere appreciation
to Dr. K. D. Eoth for his unselfish and continuous guid-
ance throughout the course of this study.

nrJreClcthQ.lS also expressed to Dr. E. L. Cook,

Dr. J. F. Davis, Dr. A. i. Erichson, Dr. W. D. Eaten, and
Dr. 2. S. Enndurski for their assistance and suggestions
during the study.

The financial assistance provided through the Lichi—
gen Agricultural hxperirent Station is hereby acknow—

ledged.

its aut hor is forever in debted to his devoted wife,
Larjorie, whose interest, understanding, encouragenent,
and assistance with every phase of the study from initia-
tion of the experiments to completion and typing of the

manuscript has enabled him to complete the study.

‘4.
H

Joseph Neal Pratt
candidate for the degree of

Doctor of PhilOSOpb"

“J

FINAL EXALINATION: January 30, 1961

The Lffect of Phosphorus and Potassium on the

Botanical and Chemical Conposition, Yield, and

Persistence of Alfalfa and Certain Grasses Crown
in Combination

OUTLIIA OF SBUDIAO:

Major subject: Soil Science
hinor subjects: Statistics
Botany

B' OGRAPHIGAL ITMmS:

Born: April lb, 1932, Dallas, Texas
Undergraduate studies:
Southwest Texas State College,

Texas, l9h9-53
Graduate studies:

Southwest Texas State College, 1953-54
hichigan state University, 1957-61

San Marcos,

Secondary public school teacher, Vanderbilt,
Texas, l95h-55

hember United States Army, 1955-57

Graduate Research Assistant, Department of Soil
Science, Iichigan State University,

1957 60

Area Agronomist, Texas Agricultural Extension

Service, College Station, Texas, 1900

1»---.L.- 314R:

American Society of Agronomy

Soil Science Society of America
International Society of Soil Science
Society of the Sigma Xi

F.
H
H.

A
.

TABLE or conrsnrs

Chapter B

I. IHTRODUCTION . . .

O O O O O O 0 Q 0 O O O O O O l

I I o RAVIJJ‘H OF LI 15.1.5 III-i. ITLTFJ

o o o o o o o o o o o o o o 3
7- *" .311: -~. "\. ‘ ‘ “- Z“ A» “'
.LII o LIA-Lil LIIOUS ALLI‘JL - -ZILA-IJLLIJ‘LIJD o o o o o o o a o o o o o 2 0

Field BXperiments . . . . . . . . . . . . . . . 20
Greenhouse nxperinents . . . . . . . . . . . . . 2h
Laboratory Techniques . . . . . . . . . . . . . 26

Soils . . . . . . .

O O C D C O D O O O O C 26
Plant Samples . . . . . . . . . . . . . . . 26
COIHLDthatiO-n C O . O . . O C C O O O O O O O O . 2%

IV. RESULTS AND DISCUSSION

0
O
O
O
O
0
O
M
\O

1958 Field Bxperiments . .
Yield . . . . . . . . . . . . . . . . . .
Botanical Composition .
Tissue Analyses . .
Soil Analyses . . .

MN“)

1959 Field BXperiments
Yield . . . . .

Botanical Composition

Tissue Analyses .
Soil Analyses . .

wan-own)
5,-5ij (nO\\n1=*\O\O\O

Greenhouse iXperiments . .
Yield . . . . . . . . . . . . . . . . . . .
Botanical Composition .
Tissue Analyses . . . .
Soil Analyses . . . .

o
o
o
o
o
o
o
o
o
o
o
'3‘

(5

o
o
o
o
o
o
o
o
.
\fl 1."
O\\n

O\O\
\nO

V. SULRARY AND CONCLUSIONS

\1
H

1958 Field Experiments
1959 Field Bxperiments .
Greenhouse nXperiments .

. . .
. . .
. . .
. . .
. . .
. . .
. . .
o O 0
—\}\1\)
J;-I\H~'

VI. LITLRAI RB CITED

\3
O\

O O O O O O O O O O O O O 0

iv

11-3 is 1‘

l. Broadcast fertilizer treatments applied to the
established field experiments in the fall of
1.958 0 o o c o O o o o o o o o o o o o o o o O 22

2. Grasses associated with alfalfa, and rates of

phosphorus and potassium applied in three
greenhouse experiments . . . . . . . . . . . . 25

3. The effect of fertilizer treatment on the yield
of alfalfa—bromegrass hay for the fourth
harvest year, 1958 . . . . . . . . . . . . . . 30

A. Botanical composition of alfalfa~bromegrass
forage at the time of the first cutting of the
fourth harvest year, 1958 . . . . . . . . . . 31

5. Soil phosphorus and potassium of selected
treatments, 1958 . . . . . . . . . . . . . . . 33

o. The phosphorus and potassium.content of alfalfa
and bromegrass as influenced by selected
fertilizer treatments, 1958 . . . . . . . . . 34

7. Soil pH, phosphorus and potassium content by
horizons of five profiles taken at selected
locations on experimental plots, 1958 . . . . 37

8. The effect of fertilizer treatment on the yield
and botanical composition of the first cutting
of alfalfa-bromegrass hay, 1959 . . . . . . . 38

9. The phosphorus and potassium content of alfalfa
and bronegrass as influenced by fertilizer
treatment in the 1959 field experiment . . . . no

10. The amount of phosphorus and potassium removed

from the soil by alfalfa and bromegrass in the
field, 1959 . . . . .

o o o o o o o o o o o 0 1+2

11. The reserve phosphorus and potassium content of

the soil as influenced by alfalfa—bromegrass
under different fertilizer treatments, 1959. . Ah

V

LIES].I OF TABLLS - Continued

12. The effect of fertilizer treatment on the yie
of alfalfa when grown with bromegrass in the
greenhouse . . . . . . . . . . . . . . . . . to

13. The effect of fertilizer treatment on the yi
of bromegrass when grown with alfalfa in the
greenhouse . . . . . . . . . . . . . . . . . 47

1h. The effect of fertilizer treatment on the yield
of alfalfa when grown with perennial ryegrass
in the greenhouse. . . . . . . . . . . . . . A9

15. The effect of fertilizer treatment on the yield
of perennial ryegrass when grown with alfalfa
in the greenhouse. . . . . . . . . . . . . . 50

lb. The effect of fertilizer treatment on the yield
of alfalfa when grown with timothy in the
greenhouse . . . . . . . . . . . . . . . . . 52

17. The effect of fertilizer treatment on the yield
of timothy when grown with alfalfa in the
greenhouse . . . . . . . . . . . . . . . . . 53

18. A summary table of the yield of alfalfa and
grass of three greenhouse experiments at
different levels of phosphorus and potassium
fertilization. . . . . . . . . . . . . . . . Eh

19. 1he effect of fertilizer treatment on the
average botanical composition of eight out-
tings of alfalfa-bromegrass mixture grown in
the greenhouse . . . . . . . . . . . . . . .

‘».fi
0\

20. The effect of fertilizer treatment on the
average botanical composition of eight cut-
tings of an alfalfa—ryegrass mixture grown in
thegreenbouse............... 57

21. The effect of fertilizer treatment on the
average botanical couposition of eight out—
tings of en alfalfa—timothy mixture grown in

the greenhouse . . . . . . . . . . . . . . . 57

22. Summary table of the botanical composition of
three greenhouse experiments at different
levels of phosphorus and potassium fertili-
zation . . . . . . . . . . . . . . . . . . . 59

vi

2h.

26.

27.

28.

29.

30.

Page
The effect of fertilizer treatxent on :hosghorus
and potassium contents of alfalfa and bro e
grass grown in the greenhouse . . . . . . . . 61
The effect of fertilizer tleatrent on the phos-
phorus and pota ssiuh content of alfalfa and
ryegrass grown in the greenhouse . . . . . . a?

1he effect of fertilizer tree tn eat on the phos—

phorus and potassium content 0
greenhous

timothy arown in the

alfalfa and

f
e . . . . . . . 63

Summary table of the chemical composition of
alfalfa and grass of three greenhouse experi~
nents at different levels of phosphorus and
potassium fertilization . . . . ”/

D41

o......00

The ellect of alfalfa-bronegrass on the phos-
phorus and potassium.contenf of the soil when
crown under different fertilizer treatments in

the greenhouse . . .

O O O O O O O O O O O 07

lhe effect of alfalfa-ryegrass on the phOSphorus
and potassium content of the soil when grown
under different fertilizer treatments in the

greenhouse . . . . .

. . . . . . . . . . . 68

The effect of alfa lfa- timothy on th e phosphorus
and potassium.content of the soil. when grown
under different fertilizer treatments in the

greenhouse . . . . .

O O O O O O O O O O O 69

Available soil phosphorus and potassium at the
completion of the greenhouse experiments. . . 70

I.“

I. INTRODUCTION

Alfalfa-grass mixtures (especially bromegrass) have
been grown on considerable acreage in.Michigan for several
years. As early as l9h3, alfalfa and smooth bromegrass had
proved their value in a mixture for both pasturage and hay
purposes. Although there have been exceptions, the general
reports have indicated that compatible mixtures of grasses
and legumes are higher yielding than any single component
grown in a pure stand. IMixtures are more efficient than
pure legumes in the control of soil erosion and in the
prevention of bloat in cattle.

maintenance of the desired portion of alfalfa growing
in association with bromegrass has been a major problem in
Michigan as well as many other regions. Increased compe~
tition from bromegrass, resulting from insufficient potash
fertilization, has often been cited as the cause for de-
creased alfalfa percentages in stands with time.

A study of the establishment and fertilization of
'legume-bromegrass hey at the University Farm showed that
plots receiving no fertilization contained a higher per-
centage of alfalfa at the end of a four year experiment

than plots fertilized with phosphorus and potassium (26).

The purpose of this study was to determine how phosphorus
and potassium fertilization affected the growth of the
alfalfa and bromegrass to provide an explanation for the
persistence of alfalfa in the alfalfaugrass association.

It was hoped that the information obtained would make
possible a more efficient fertilization program for alfalfa-

bromegrass hay fields and pastures.

II. REVIEW OF LITERATURE

The growing of legumes and non—legumes together has
been an important factor in agriculture from the earliest
days, and an interesting historical review has been made
by Wilson (7k).

Frequently the treatment that would be best for any
one of the component species of a mixture is not best for
the.mixture as a whole. There is less basic information
on the responses of various forage species to management
when two or more are grown in association than on the
responses of individual species in pure stands.

One of the earliest workers to study the effect of
fertilizers on maintaining stands of alfalfa was Brown (7)
in Connecticut. He reported that: (a) nitrogenous fer-
tilizers increased yields” but tended to increase the
grasses and weeds and reduce the percentage of alfalfa in
the stands, (b) carriers of phosphoric acid gave slightly
better stands of alfalfa than no fertilizer treatment, and
(c) potash was very beneficial in maintaining stands of
alfalfa. The experiment was conducted on a Gloucester
fine sandy loam, and all of the plots received lime.

Rich and Odland (53), studying the effect of various
fertilizers on the botanical composition and yield of

4

grass-legume hay, used a standard application of 20 pounds
of nitrogen, 80 pounds of phosphate, and 100 pounds of
potash per acre. Reducing the nitrogen or phosphorus had
no significant effect on either the yield or percentage of
legumes in the hay. Reducing potash applications from 100
to 50 pounds per acre lowered the proportion of legumes
from 50 to 39 per cent and the hay yield from.3.08 to 1.63
tons per acre. A.further reduction in potash to 25 pounds
resulted in less than two per cent legumes and a hay yield
of only 1.17 tons per acre.

Chiasson (13) found in Canada that applications of
nitrogen, phosphorus, and potassium to an area grazed and
unfertilized for over 30 years resulted in some immediate
and marked improvements in yield and botanical composition.
Phosphorus at rates up to 80 pounds per acre brought about
the most.marked improvement, being responsible for highly
significant increases in yield. Phosphorus increased wild
white clover and useful grasses, and decreased weeds and
bare ground. Potassium.up to 60 pounds per acre also gave
highly significant increases in yield. Potassium had
little effect on the prevalence of species at first, but
by the fourth year had maintained white clover better than
phosphorus. The effect of nitrogen on botanical composition
was largely to decrease the percentage of white clover
with a corresponding increase in grasses.

Haskell (33) and Beaumont gt 3;. (2) in Massachusetts

reported that the clover and grass plots which received

high amounts of potassium showed a superior type of vegan
tation with respect to clovers.

Jackson 22 21. (3h) found that on well limed and
phosphated soils in Wisconsin 500 pounds of muriate of
potash increased the total legumes from practically none
to 50 to 70 per cent. Originally, 250 pounds of muriate
of potash maintained alfalfa at only 10 per cent of the
forage.

Parsons‘gg‘gl. (#9) conducted field studies on Ladino
clover, orchardgrass, smooth bromegrass and timothy in
Ohio. Each specie was planted in a pure stand. By the
third crop year, Ladino clover comprised less than five
per cent of the vegetation on the plots receiving low
amounts of potash.

Stivers and Ohlrogge (61) found that the stand.main-
tenance of alfalfa was closely related to both potassium
fertilization and potassium content of alfalfa on two soil
types in Indiana. The higher rates of potassium fertili-
zation maintained stands better than the lower rates.
There was no relationship between stand maintainence and
phosphorus fertilization or phosphorus content.

Dodd (18) reported that lime, phosphate, and weather
were the major factors responsible for the fluctuation in
the white clover content of permanent sod areas in Ohio.

Sears (56) in New Zealand found that without dung

and urine, grass-clover.mixtures were dominated by clovers,

but where dung and urine were returned to the soil, the
grasses were dominant. He also found that superphosphate
gave responses in growth only on the mixture not receiving
dung and urine.

‘Wang 23,51. (71) obtained results which they said
left no question but that high levels of lime and available
phosphorus and potassium.markedly promote winter-survival
of alfalfa in Wisconsin.

Determining the effect of different fertilizer
levels on the yield, persistence, and chemical composition
of alfalfa, Gerwig and Ahlgren (30) found in Wisconsin
that potassium.was the most important factor in maintaining
high yields and persistence of an alfalfa stand. Potassium
deficiency decreased the stand by as much as 80 per cent
on the plots not receiving potassium. They found that
nitrogen applications resulted in lower yields, reduced
stands, and increased weeds. Phosphorus fertilization
was found to have no significant beneficial effect.

Brown and Mhnsell (9) made a study in Connecticut of
clovers in permanent grasslands as influenced by fertili-
zation. They found that 30 to 40 pounds of nitrogen
annually, even with lime, phosphorus, and potassium, in-
creased the growth of grasses and depressed clover stands,
and that omdssion, as well as large applications of phos-
phorus, depressed clover first.

In a study of the influence of association upon the
forage yield of legume-grass mixtures, McCloud and Mett (L2)

found that bromegrass was higher yielding for the first
two years, but that alfalfa led in the third year. The
shift was apparently caused by a depletion of soil nitrogen
favoring legume production.

In grass-legume associations, interspecific comp
petition for nutrients is apparently a considerable factor
in determining legume production. Blackman (5) showed
that nitrogen fertilizers added to grass-clover associa-
tions may lead to marked suppression of the clover, due
to the effects on nodule formation and increased competition
from the grasses which are greatly stimulated.

The available nitrogen has a remarkable effect on
the grass-clover balance. Although frequently explained
by increased competition for light by nitrogen treated
grasses, there is evidence to suggest a direct increase
in nutrient competition. Mouat and walker (4h) studied
the competition for nutrients between three grass species
and white clover for phosphorus and potassium. Nitrogen
application was shown to increase competition for nutrients
by grasses in clover association without postulating an
indirect mechanism acting through competition for light.

'Willoughby (73) determined earlier that under apprOp-
riate conditions, grass development may be considerably
reduced by competition for nitrogen by the associated
clover.

walker 22.3l0 (69) reported that grasses take up 95

per cent of the mdneral nitrogen utilized by a grass-

clover association. Hence, an increase in the supply of
combined nitrogen will thus automatically intensify the
competition offered by grasses for other nutrients.

McLean (43) found that plants grown under variable
nitrogen levels produced increased top growth with higher
nitrogen levels than plants with low nitrogen levels.
However, root growth did not increase in proportion to
top growth. Contents of phosphorus and potassium were
generally decreased with greater nitrogen content of the
medium.

The use of nitrogen fertilizer on grass-legume
meadows and pastures has received considerable attention
from research workers in recent years. There have been
several studies of the effect of fertilizer nitrogen on
the botanical composition using clover as the legume.
Ridgman at 31. (5A) in England obtained increases in the
grass portion of an alfalfa-orchardgrass association using
as much as 60 pounds of nitrogen per acre with no change
in the alfalfa portion of the matter. Lewis (A0) ob-
tained total forage increases with nitrogen, but grasses
increased at the expense of legumes. Rouse gg‘gl, (55)
in Colorado found an increase in grass and a reduction of
clovers. In a study by Sprague and Garber (59), nitrogen
fertilization stimulated the grass to such an extent that
Ladino clover was almost entirely crowded out.

Inca study of nitrogen fertilization of alfalfa-

grass mixtures on a Wooster silt loam soil in Ohio,

Parsons (L8) found that nitrogen fertilizer of an alfalfaa
orchardgrass sod produced more hay but increased the grass
at the expense of the alfalfa. However, the yields and
botanical compositions of alfalfa-bromegrass and alfalfa—
timothy sods were not affected by nitrogen.

Carter and Foth (12) found that nitrogen fertiliza—
tion increased yields of alfalfa in the greenhouse, but
did not increase yields of alfalfa in the field when
applied either at time of establishment or to established
stands in Michigan.

How atmospheric nitrogen, symbiotically fixed by
legumes, becomes available to associated plants has been
investigated. It is remarkable how few experiments have
demonstrated any increase in nitrogen uptake by the non~
legumes during the period of vegetative growth of the
legumes. A remarkable exception has been Virtanen's and
von.Hausen's (68) pot-culture trials. Virtanen and von
Hausen (67) attributed this benefit from.1egumes to the
excretion of nitrogenous compounds from the legume roots.
Wilson and Burton (75), and Wilson and wyss (76) have
confirmed Virtanen's and von Hansen’s (68) findings that
direct excretion of nitrogen by legumes does occur, with
a consequent increase in nitrogen uptake by the non-
legumes. Subsequently, these workers (75, 76) confirmed
that temperature, shade, and length of day affected

excretion of nitrogen, and Strong and Trumble (62) also

10

found that shading may induce nitrogen excretion by
legumes. Wilson (7A) advanced a hypothesis that the
beneficial effect is due to the sloughing-off of the
roots and nodules. Black (4) concluded that the grasses
may obtain nitrogen from legumes by both processes,
namely, the excretion and sloughing-off. Walker and
associates (70) held the opinion that the transference of
nitrogen from.the legumes to the grasses should probably
increase as the proportion of legumes in the mixture
increases. They concluded that: (a) in some cases,
clovers seemed to transfer to grasses half the nitrogen
fixed, in a form readily absorbed by grasses, (b) in a
high producing association, almost all of the nitrogen
under certain conditions could be contributed by the
clovers, and (0) management should be directed toward a
high production from clovers, which in turn should lead
to high production from.grasses if given the correct
species and management.

Ramage (51) concluded that alfalfa-grass mixtures
grown on Duchess and associated soil types in New Jersey
without added nitrogen and adequately fertilized with)
phosphorus and potassium.will produce yields of forage
about equivalent to the yields of pure grass fertilized
with 150 to 200 pounds of nitrogen per acre.

Blaser and Brady (6) conducted experiments in New

York to ascertain the effects of nitrogen and potassium

ll

fertilization on the productivity and botanical and
chemical compositions of Ladino clover and non-legumes
when grown in a mixture. They found that potassium
fertilization stimulated the growth of Ladino clover,

but did not directly affect the productivity of the non-
leguminous plants in the association, and that nitrogen
fertilization increased the growth of grasses and decreased
the growth of the leguminous plants in a mixed associa-
tion.

Vandecaveye and Baker (66) reported that the general
effect of mixed phosphorus and potassium fertilizer was
to increase the amount of clover in mixed grass hay. The
chemical composition of alfalfa at harvest stage was less
influenced by fertilization than was the chemical com-
position of grasses.

Forage yields of alfalfa and legume-grass mixtures
were higher the first year after heavy initial broadcast
application of phosphorus than after smaller broadcast or
topdress applications according to Terman‘gg'gl. (63) in
Kentucky. In the following years, yields after the
initial application only became progressively poorer, as
compared to yields after smaller annual topdressings.

Time of application affected yields much more than method
of application or source of phosphorus.

Brown (8) found that smaller, frequent applications

of.muriate of potash were much more effective in maintaining

12

the stands and yields of a Ladino clover-orchardgrass
seeding than larger, less frequent applications.

Doll‘gg El. (19) reported a yield response from
phosphorus, but not from.potassium. Also, there was no
movement of phosphorus below three inches, nor potassium
below six inches in the soil.

In an alfalfa-bromegrass meadow where the fertilizer
was broadcasted, the bromegrass obtained a greater per-
centage of its phosphorus from the fertilizer than did
the alfalfa, according to Lawton 33,31. (39). However,
at three and six inch depths, the alfalfa absorbed two
to three times as much phosphorus as did the bromegrass.

Hanway 23 El. (32) topdressed alfalfa-timothy
meadows with phosphorus and potassium fertilizers on a
soil very low in these nutrients. They found competition
between these species for both phosphorus and potassium,
with alfalfa being the more dominant competitor for
phosphorus and timothy more dominant for potassium. There
was very efficient recovery of phosphorus and as much as
100 per cent recovery of potassium from several treat-
ments.

Differences in ability of plant species to use
potassium.from the soil have long been observed. Drake
‘22,21. (21) contributed this ability largely to the
cationpexchange capacity of the plant root and the valence

of the cation. Cation-exchange capacity of roots of the

13

dicotyledonous plants investigated were roughly double
the value for monocotyledons. Hence, they claimed that
in grass-legume associations at low levels of soil potas-
sium, because of the lower exchange capacity of the root
surface, grasses were able to obtain much more potassium
than legumes, which eventually reduce the yields and
longevity of legume stands.

Gray et al. (31) in hassachusetts studied the
competition for potassium when Ladino clover was grown
alone and in association with each of three grasses.

-

Their objective was to explain the disappearance of legumes

0

from pasture mixes as a result f plant comoetition for

potassium. Tie relative competibility for potassium was

,3

smooth bromegrass (best), Kentucky bluegrass (i-termediete),
and bentgrass (poorest). They found that maintaining an
adequate potassium supply for Ladino clover When in
association with bentgrass was almost impossible.

Through greenhouse and laboratory investigation,
Brown and House (l0) determined that the persistence of
clover in white clover—:allisgrass associations on Sumter
clay in Alabama was highly dependent on potash and minor
element fertilization. They reported that Dallisgrass
had a greater ability than white clover to absorb potas-
sium from the soil, either as a result of greater soil
coverage by its fibrous root system or because it is able
to absorb potassiun from sources that are less available

to clover.

1h

Gray 33 El. (31) studied the relative uptake of
potassium by Ladino clover, smooth bromegrass, Kbntucky
bluegrass, and bentgrass when grown separately. They
found that potassium uptake by plant species at low
levels of soil potassium.was closely correlated with root
cation-exchange capacity.

Fried (27) compared certain plant species as to
their feeding power for both monocalcium phosphate and
rock phosphate. The Species differed in their ability to
absorb phosphorus from basic calcium phosphates. The
phosphorus of rock phosphate was more available to legumes
than to grasses. He suggested that the differences among
species in their capacity to absorb phosphorus from basic
calcium phosphate were due not only to differences in
root size and extensiveness but also to differences in
species-source interactions.

Seay and Weeks (58) reported that topdressed phos-
phorus was taken up by alfalfa even in the winter or
dormant season.

Chin gt El. (14) reported that the uptake of phos—
phorus by alfalfa from.monocalcium phosphate on Minnesota
soils in greenhouse studies was increased by lime appli-
cation.

Finn 22,2$° (24) found that rock phosphate resulted
in higher yields of alfalfa hay and roots on three pod-

zolized soils of eastern Canada than did superphosphate.

15

Lime did not greatly reduce the effect of rock phOSphate

except on one soil when the pH was raised to 8.0.
macLean and Cook (hi) reported that the greatest

uptake of phosphorus and highest phosphorus content of

alfalfa plants occurred at a pH of about 7.5. Also,

the yields were either similar to or higher than at any

lower pH.

Thorp and Hobbs (65) applied lime to some acid
soils from the south~central part of Kansas. Both phos~
phorus and potassium uptake were increased by lime appli-
cations.

.A linear relation was found by Seay 33 El. (57) to
exist between the percentage of potassium contained in
alfalfa and the logarithm of the number of pounds or
exchangeable potassium.per acre in the soil on which the
crop was grown. Lawton and Tesar (38) found that potas-
siwm absorption by both alfalfa and bromegrass was sig-
nificantly increased as applied potassium increased in
greenhouse treatments.

Attoe and Truog (l) in Wisconsin found the yields
of alfalfa and clover hay to be significantly correlated
with the levels of available phosphorus and potassium in
the soil.

A.prediction when legume hays will respond to added
fertilizer, according to Lawton ggpgl. (37), can be

benefited by rapid soil tests. They found general relation

16

between response to fertilizers and the amount of phos~
phorus and potassium extracted by the rapid tests.

Nelson and MacGregor (#5) reported that significant
yield increases of alfalfa were associated with high
potassium content and to a lesser degree with high phos—
phorus content of the plant. Soil samples from the top
six inches showed almost no correlation between the
phosphorus and potassium in the soil and that found in the
alfalfa plants.

Cutting management is an important factor influencing
productivity and maintenance of stands of grasses and
legumes. The ultimate in management assures the continued
survival of the seeded species in desirable proportion
and the most effective production possible.

Gervais (29) studied the chemical composition of
Ladino clover grown alone and in mixture with grasses as
influenced by cutting treatments. He found that: (a)
bromegrass had a higher content of phosphorus and potassium
than timothy, (b) the height at cutting failed to modify
the chemical composition of the grasses, and (c) in both
forage fractions, the phosphorus and potassium content
were higher with four or six cuttings than with two
cuttings.

As early as 1897. Crozier (16) showed that hay cut

every seven days yielded much less than hay out only once

during the season. Ellett and Carrier (23) reported that

17

the total yield of hay varied inversely with the number
of times it was cut. This has been reported by Nowosad
and Stevenson (47).

In a study of the stage of cutting of grasses, using
pure species alone, Bird (3) found that bromegrass was
the highest yielding of the group of four grasses which
included bromegrass, timothy, red-tOp and Kentucky blue-
grass.

. Burger 32 El. (11) reported that smooth bromegrass
was less persistent than tall fescue when in mixture with
legumes and there was a higher percentage of legumes and
.more weed encroachment in the bromegrass-legume mixture.

Kalton and Wilsie (35) studied the effect of six
bromegrass varieties sown broadcast with ranger alfalfa.
They evaluated the forage yield and mixture composition
for a four year period and found no difference in the
yield of two cuttings per year among the varieties. They
also found no difference in yield or composition due to
the rate of alfalfa seeded.

In a study of the productivity and botanical com-
position of Ladino clover grown alone and in mixture with
timothy and smooth bromegrass, Gervais (28) found that:
(a) the mixtures yielded more clover but less grass and
total production when out four times than when out twice,
and (b) the mixed awards contained the.most clover when

out four times and the least when out only twice. Because

18

of the slow establishment of bromegrass, it produced a
small amount of grass the first year in comparison with
timothy, but outyielded timothy the second year.

Comstock and Law (15) reported that grass species
were better able to compete with alfalfa when frequently
clipped than when the clipping was less severe.

In a study of the effect of cutting treatments on
the yield, botanical composition and chemical constituents
of an alfalfa-bromegrass mixture, Dotzenko and Ahlgren (20)
reported that weed growth was generally greater under the
treatments receiving earlier cuttings.

The results of Sprague and Garber (59) indicate
that the time of removal of the first crop in the spring
was an important factor in determining the persistence of
Ladino clover. Removal of the first and subsequent crops
when eight to ten inches in height provided good yields
and maintained the clover better than later cuttings.

Nowosad and Stevenson (47), Newell and KBim (46),
Keonce (36), and Rather and Harrison (52) have reported
that.more frequent cutting of alfalfa-grass mixtures
favors the grass component as compared to cutting at the
hay stage. Tesar and Ahlgren (6h) conducted an experiment
to determine the effect of two heights and three frequen-
cies of cutting on the production and continued survival
of Ladino clover grown alone and with smooth bromegrass,

tbmothy, or orchardgrass. They reported that the percentage

19

of surface area of soil occupied by Ladino clover was
higher on the plots given the less severe cutting treat-
ments than on plots given the more severe cutting treat-
ments.

In a study of growth responses of alfalfa and Sudan-
grass in relation to cutting practice and soil moisture,
Dennis 23,3l. (17) found that the yield was associated
directly with the cutting interval. The more frequently

plants were cut, the less productive they were.

III. .METHODS ANDIMATERIALS

Field Experiments

 

Established field plots on the University Farm were
used in an.experiment to study the persistence of unfer-
tilized alfalfa. The experiment was established in 1954
to study the effect of phosphate and potash fertilizer on
the yield and stand maintenance of alfalfa-bromegrass hay
(26).

A.split-plot randomized block experimental design of
the original experiment consisted of seven fertilizer
treatments applied when the alfalfa-bromegrass was seeded,
and six fertilizer subtreatments applied to the established
stands. Eight pounds of Montana Grimm alfalfa and three
pounds of Canadian bromegrass per acre were seeded with a
standard grain drill without presswheels. The plots had
been limed according to soil test. Oats was used as the
companion crop.

In the spring of 1958, a definite change in the
botanical composition of the forage was noticed. The
plots which received no fertilizer at the time of estab-
lishment contained a larger percentage of alfalfa than
the plots which received fertilizer. The same tendency

had been observed at the end of a four year harvest period

20

21

in another experiment adjacently located. As a result of
these observations, this study was initiated to try to
explain the effect of phosphorus and potassium on the
growth of alfalfa and bromegrass when grown in association.

Just prior to harvest in June 1958, field estimates
were made of the percentage of alfalfa. Forage samples,
weighing approximately 1,000 grams, were collected for
hand separation and determination of the botanical com-
position in the laboratory. They were sub-divided into
four subsamples and the components in each were estimated.
At first, the components were weighed, but as skill in
estimating the percentages was obtained, only an occasional
sample was weighed to check accuracy. Later the samples
were ground in a Wiley mill in preparation for chemical
analysis. Total forage yields were taken from areas of
7 by 40 feet and samples weighing approximately 1,000
grams were taken for determining the moisture content of
the hay.

Samples of the top eight inches of soil were taken
from all plots of main treatments 1, 6, and 7, and analyzed
for reserve phosphorus and potassium and pH. These treat-
ments represented the range of the percentage of alfalfa
in the forage.

It was believed that information of the levels and
location of nutrients in the soil might indicate a reason

why alfalfa persisted without fertilization. Therefore,

22

five soil profiles were sam led and analyzed for reserve

phOSphorus and potassium by horizons.
In the fall of 1958, the fourth harvest year, the
original experimental design was altered. The split-plot

design consisting of seven main treatments and ix sub-

U)

treatments was changed to a randomized block design
consisting of seven main treatments. The plots which had
received subtreatment fertilization prior to 1958 received
the fertilization of the main treatments in the fall of
1958. The fertilizers were applied as a topdressing in
the fall. The treatments are given in Table l.

TLBLH l.-Eroadcast fertilizer treatments applied to the
established field experiment in the fall of 1958

 

 

 

Pounds P205 Pounds K?
Original treatmenta per acre per acre
1. 0-0-0 Check Check
2. 40-120-60 4O 0
3. 20-120~60 200 0
4. 0-120-o0 O 30
5. 40—120~60 0 150
6. 00-120-60 120 90
7. 60-240—120 Check Check

 

a '7 1
Pounds of U, 3205 and £20 per acre, respectively.

23

Just prior to harvest in 1959, field estimates were
made of the percentage of alfalfa in the forage. The
total forage yields were taken for each plot, and samples
of approximately 1,000 grams were collected to determine
the air-dry moisture content of the hay. The samples
were later ground in a Wiley mill, oven dried, and analyzed
for phosphorus and potassium.

A composite sample of the top eight inches of surface
soil was taken from each plot at harvest time, 1959. The
pH was determined with a glass electrode and reserve
phosphorus and potassium were determined using 0.13 N HCl
as the extracting solution.

The eXperiment was located on the University Farm
at Forest and Harrison Roads in East Lansing, Michigan.
The area includes a wide range of soil types from a well
drained Brant loamy sand to a poorly drained Brookston
clay loam.

Brant loamy sand is a light-colored, medium to
slightly acid, well to moderately—well drained soil which
developed on calcareous sands, gravels, and loamy sands,
over calcareous loam to silty clay loam materials.

Dryden sandy loam is a moderately-well drained,
fairly light colored, Gray-Brown Podzolic soil developed
on a calcareous sandy loam till. The subsoil texture
ranges from sandy clay loam to loam. Dryden is the

moderately-well drained member of the catena which includes

24

the imperfectly drained Locke and poorly drained Barry
series.

Conover loam is an imperfectly drained, moderately
dark-colored Gray-Brown Podzolic soil which developed on
highly calcareous loam till. It is slightly to medium
acid throughout the solum and has a mottled clay loam
subsoil.

Macomb fine sandy loam is an imperfectly drained
soil which developed on gravelly loam and sandy loam
materials overlying loam to clay loam calcareous till.
The subsoil is a mottled sandy clay loam.

Barry sandy loam is a slightly acid to neutral,
naturally poorly to very poorly drained soil developed
on calcareous sandy loam till.

Brookston clay loam is a naturally poorly drained,
dark-colored Humic Gley soil which developed on calcareous
loam till. Brookston is the poorly drained member of the
catena which includes the well drained Miami, the mod-
erately-well drained Celina, and the imperfectly drained

Conover.

Greenhouse Experiments
Three greenhouse experiments were initiated in the
fall of 1958 to determine the influence of phosphorus and
potassium fertilizer on the persistence of alfalfa when

grown with different grasses.

25'

The soil used for all three experiments was a
Conover loam with a pH of 7.0, which was collected from
an area adjacent to the field experiment. A brief
description of this soil has been given earlier. The
soil was dried, screened, weighed, mixed with fertilizer,
and placed into four-gallon containers which had been
lined with polyethylene bags. Grass and alfalfa seeds
were planted in alternating semicircles near the outer
edge of the pot.

The grass in association with alfalfa and the levels
of phosphorus and potassium for the respective experiments
are given in Table 2. Each pot received both phosphorus
and potassium fertilization.

TABLE 2.-Grasses associated with alfalfa, and rates of
phosphorus and potassium applied in three greenhouse

 

 

 

experiments
Exp. 1 Exp. 2 Exp. 3

Grass associated Perennial

with alfalfa Bromegrass ryegrass Timothy
Levels of phosphorus 50, 100, 50, 400, 50, 400,

(pounds per acre) 200, 400 800 800
Levels of potassium 25, 50, 25, 200, 25, 200,

(pounds per acre) 100, 200 400 400
Number of treatments 16 9 9
Replications 4 4 3

 

A few days after emerging, the plants were thinned

to twelve alfalfa and twelve grass plants per pot. During

26

the course of the experiment the pots were weighed period-
ically and water was added to bring the soils to a uniform
moisture content.

The forage was harvested when one-tenth to one-
fourth of the alfalfa plants began to flower. A total of
eight harvestings were made. The forage from each con-
tainer was separated by hand immediately after cutting
into the alfalfa and grass components. These components
were dried in an oven at 700 C. and weighed. Due to
insufficient weight of dry material for chemical analyses,
replications for each treatment were combined. The
combined samples of each treatment were ground in a Wiley
mill and each cutting was analyzed separately for phos-

phorus and potassium.

Laboratory Techniques
Soils
Soil reaction was determined by a glass electrode
using a 1:4 soil to water ratio. Available phosphorus and
potassium were determined by the Spurway method (60)

(0.13 N H01, soil to acid dilution 1:4).

Plant Samples
The plant samples were wet-ashed by the perchloric
acid method of Piper (50).
One gram sample was placed in a 180 m1. tall form

beaker and 15 ml. of concentrated nitric acid were added.

27

The sample was digested on an electric hot plate until
almost all of the organic matter was destroyed and a
clear solution was obtained. After cooling, 6 m1. of

70 per cent perchloric acid were added to the solution
and the digestion continued until the oxidation was
complete and a clear, colorless solution was obtained.
The solution was then evaporated almost to dryness,
cooled, and the volume made up to 100 ml. with 0.1 N HCl.
The solution was filtered through Whatman No. 2 filter
paper.

The phosphorus in solution was determined by a
molybdenum blue reduction method. One ml. of the
solution was diluted to 10 ml. and 6 drops of ammonium
molybdate-sulfuric acid reagent were added, followed by
the same amount of Fiske-Subbarrow (25) reagent. The
solution was shaken, and after fifteen minutes the ab-
sorbance of blue color develOped was measured in a Coleman
spectrophotometer using a red filter (650 mu).

The potassium in solution was determined using
the Coleman.MOde1 21 Flame Photometer. The source of
fuel for the flame was natural gas burned in the presence
of oxygen. TWO m1. of the solution were diluted to 10
m1., shaken, and transferred to a 10 ml. beaker. The

solution was vaporized and emission was measured using a

red filter (771 mu).

28

Computation

 

Analysis of variance and Duncan's Significant
Studentized Range Test (22) were used to determine
statistical significance. Any difference less than

the L. S. D. value was considered not significant.

IV. RESULTS AND DISCUSSION

lgégpgigld Experiments
Yield

Table 3 shows the effect of fertilizer treatments
and subtreatments on the yield of alfalfa-bromegrass hay
in 1958 as reported by Foth 23 31. (26). There was no
significant difference between the treatments, but there
were highly significant differences between the subtreat-
ments. The latter showed that by the fourth harvest year,
plots receiving 60 pounds of potassium per acre annually
were yielding significantly more forage than those receiv-
ing 30 pounds of potassium per acre. They also reported
that fertilizer applications at the time of establishment
caused significant yield differences for the first three
cuttings, but not in the later cuttings. Also, fertilizer
subtreatments resulted in highly significant yield dif-
ferences for all eight cuttings over a four year period.
Attention is directed to the fact that the check plots
yielded approximately 85 per cent as much hay as the
fertilizer plots.

Botanical Composition
The botanical composition of alfalfa-bromegrass
forage at the time of the first cutting is presented in
Table 4.

29

30

TABLE 3.-The effect of fertilizer treatment on the yield of
alfalfa-bromegrass hay for the fourth harvest year, 1958

 

 

Tons per acre

 

 

 

 

 

 

Treatments*
at establishment
(1954) lst cutting 2nd cutting
1. 0-0-0 1.54 .97
2. 40-120e60 1.66 .97
3. 20~120-60 1.72 .86
he 0-120“60 loéh 1005
5. 40-120-60 1.54 .82
6. 60-120-60 1.56 .83
7. 60-240-120 1.90 1.06
Mean 1 065 0914»
L. S. D. N.S. N.S.
Subtreatments
topdressed
after establishment
(1955-1953l
A. o-o-c 1.23d** .75d
B. 0-60-30 spring of b b
each year 1.70 .998
C. 10-60-30 spring of
each year 1.72b .89bc
D. 0-120-60 spring of
second harvest year 1.420 .780
E. 0-60-60 spring of
each year 1.95a 1.088
F. 0-60~60 after first
cutting each year 1.92a 1.13a
Lean 1.66 .94
L. s. D. 1% 1%

 

*
Pounds of N, P205 and K20 per acre, respectively.

**Any two means that do not have the same letter are
significantly different and any two means having the same
letter are not significantly different as calculated by
Duncan's shortest significant range test.

31

TABLE 4.-Botanical composition of alfalfa-bromegrass forage
at the time of the first cutting of the fourth harvest
year, 1958

 

 

Per cent of components

 

 

 

 

 

Treatmentsa
at establishment —
(1954) Field estimate Laboratory inspection
Alfalfa Alfalfa Bromegrass Weeds
1. 0-0-0 87 63 26 ll
2. 40-120-60 71 47 47 6
3. 20-120-60 77 56 39 5
4. 0-120~60 80 51 44 5
5. 40-120-60 81 45 48 7
6. 60-120-60 68 46 48 6
7. 60-240-120 81 53 39 8
Subtreatments
topdressed
after establishment
(1955-1958)
A. 0-0-0 83 61 33 6
B. 0-60-30 Spring
of each year 76 47 45 8
C. 10-60-30 spring
of each year 77 48 42 10
D. 0-120-60 spring
of second harvest
year I 76 53 43 u
B. 0-60-60 spring
of each year 78 50 43 7
F. 0-60-60 after
first cutting
each year 76 50 43 7

 

a
Pounds of N, P205 and K20 per acre respectively.

The highest percentage of alfalfa in the forage was
observed in the treatment and subtreatments receiving no
fertilization at the time of establishment or later as a

topdressing. The botanical composition as determined both

32

by field estimate and by laboratory inspection showed the
same trend, even though the percentages of the latter were
consistently smaller.

Yields of the alfalfa and bromegrass components, as
calculated from the laboratory inspection data, reveal that
the fertilizers increased the yield of grass much more than
the yield of alfalfa, relatively speaking, and is con—
sistent with the finding that the highest percentage of
alfalfa existed on unfertilized plots in 1958.

Foth 22 31. (26) reported similar findings in an-
other adjacently located bromegrass experiment for the
first cutting of the fourth harvest year, 1956. The
unfertilized forage contained 58 per cent alfalfa while
the average for three fertilizer treatments, each con-
taining phosphorus and potassium, was 35 per cent.

From the range of the percentage of alfalfa in the
forage, fertilizer treatments 1, 6, and 7 were selected
to determine if a relationship existed between soil
nutrients and the percentage of alfalfa in the forage.

The results of soil analyses for reserve phosphorus
and potassium in the top eight inches of soil of the
selected treatments are shown in Table 5.

Correlation analysis of all plots of treatments 1,
6, and 7 revealed a significant negative correlation be-
tween the percentage of alfalfa in the forage and the

amount of phosphorus in the soil.

33

TABLE 5.-Soil phosphorus and potassium of selected treat—
ments, 1958

 

 

 

 

 

 

Treatmentsa Pounds per acre
at establishment Per cent
(1954) Phosphorus Potassium alfalfa
1. 0-0-0 32 47 63
6. 60-120~60 109 62 46
7. 60-240-120 55 56 53
Subtreatments
topdressed after
establishment
(1955-1958)
A. 0-0-0 52 55 61
B. 0-60-30 spring
of each year 65 55 47
C. lO-60-30 spring
of each year 72 55 48

D. 0-120-60 spring
of second harvest

year 64 52 53
E. 0-60-60 spring
of each year 67 56 50

F. 0-60-60 after
first cutting
each year 72 56 50

 

aPounds of N, P205 and K20 per acre, respectively.

There was no significant correlation found between
the percentage of alfalfa in the forage and the amount of
potassium in the soil. However, the trend was similar to
that for the phosphorus.

For the subtreatments, the highest percentage of
alfalfa was again associated with the lowest soil test for
phosphorus. No association existed between the percent-

age of alfalfa in the forage and the potassium revealed by

soil test of the subtreatments.

34

Tissue Analyses
The percentages of phosphorus and potassium in
alfalfa and bromegrass tissue as determined by chemical
analyses of selected treatments are shown in Table 6.
TABLE 6.-The phosphorus and potassium content of alfalfa

and bromegrass as influenced by selected fertilizer treat-
ments, 1958

 

 

 

 

 

 

 

 

 

Alfalfa Bromegrass
Treatmentsa —

at establishment Per cent Per cent Per cent Per cent

(1954) P K P K
1. 0-0~0 .21 1.02 .20 1.66
6. 60-120-60 .22 .89 .23 1.73
7. 60-240-120 .24 1.06 .23 1.64
L. s. D. 57% N.S. N.S. N.S. N.S.

Subtreatments

topdressed
after establishment

(1955-1958)
.A. 0-0-0 .18 .89 .18 1.49
B. 0-60-30 spring

of each year .21 .94 .23 1.72
0. 10-60-30 spring

of each year .25 1.03 .24 1.61
D. 0-120-60 spring

of second harvest

year .17 .78 .19 1.75
E. 0-60-60 spring

of each year .25 1.13 .25 1.66

first cutting

each year .24 1.00 .20 1.69
L. S. D. 5% .03 N.S. .03 N.S.

.17; .04 N.SO .01)» N.S.

 

a
Pounds of N, P205 and K20 per acre, respectively.

35

.Analysis of variance revealed no significant dif-
ferences between the main treatments in the percentage
of phosphorus and potassium.

The subtreatments, however, showed highly significant
differences between the percentages of phosphorus in both
alfalfa and bromegrass tissue. The subtreatments receiving
phosphorus each year contained significantly greater
amounts of phosphorus in the tissue than the subtreatments
receiving no phosphorus and those receiving phosphorus in
the second harvest year. This condition existed for both
alfalfa and bromegrass tissue.

There were no significant differences between the
subtreatments with respect to the percentages of potassium
in either alfalfa or bromegrass tissue. The subtreatment
receiving potash only in the second harvest year contained
the lowest percentage of potassium in alfalfa tissue and
the highest percentage in bromegrass tissue.

Highly significant correlations were found between
the phosphorus in alfalfa and bromegrass tissue and the
phosphorus revealed by soil test. A.similar association
was not present between the potassium in plant tissue and

the potassium revealed by soil test.

Soil Analyses of Profile Samples

The pH, phosphorus and potassium content by soil

horizons of five soil profiles taken in 1958 are shown in

36

Table 7. The table shows that the lower soil horizons
tended to have more phosphorus than the upper soil
horizons. The reverse tendency is shown for soil potas—
sium. Average values for all five soils revealed an
increasing amount of phosphorus and a decreasing amount
of potassium with soil depth.

These findings are in agreement with Whiteside (72).
He grouped some Michigan soils with similar profile charac-
teristics, similar management requirements, and similar
potential productivities. The groups of soils that
included the soils in this experiment contained more
available phosphorus in the subsurface horizons than in
the surface horizons. ,Available potassium was less in
the subsurface horizons than in the surface horizons.

The pH appears satisfactory for the growth of alf-

alfa in all cases.

iggg‘ggggg Experiments

As was.mentioned earlier, the experimental design
was altered in the fall of 1958. The subtreatments were
grouped into one treatment, making seven treatments, each
consisting of six plots of the original experiment. The
fertilizer treatments applied in the fall of 1958 were
given in Table l.

Drainage tile was installed in part of the experi—
ment in the spring of 1959. Therefore, only two of the
original four replications were harvested for a total of

84 plots.

37

TABLE 7.-Soil pH, phosphorus and potassium content by
horizons of five profiles taken at selected locations on
experimental plots, 1958

Wi—

 

Tt

Pounds per acre

 

 

 

 

 

 

 

Depth

in
Horizon inches PhOSphorus Potassium pH

Celina sandy loam
AP 0-6 11 55 6.4
12 9-15 10 55 6.2
Cl 28-32 6 34 8.3

Celina sandy loam
AP Duo 10 27 7.3
B2 18-22 24 34 6.9

Brookston clay loam
AP 0’6 .121 82 700
A2 9-15 198 21 7.4
Locke fine sandy loam
Ap 0~6 19 62 7.2
A2 9-15 84 41 7.1
B2 18-24 55 41 6.4
Cl 26-30 198 41 7.8
Conover loam

AP 0-6 11 62 7.3
A2 9-15 27 76 6.8
B2 18-22 42 34 7.0
Cl 23-26 10 21 8.3

 

38

J

Yield
Table 8 shows the yield in tons per acre of alfalfa-
bromegrass hay as influenced by fertilizer treatments.
TABLE 8.-The effect of fertilizer treatment on the yield

and botanical composition of the first cutting of alfalfa-
bromegrass hay, 1959

 

 

Tons per acre

 

 

 

_ a Per cent
Treatment Tons of hay alfalfa Yield b
per acre in forage Alfalfa Grass
1. 0-0-0 1.51 64 .97 .54
20 0"LOHO 1055 60 .93 .62
3. 0-200—0 1.60 48 .77 .83
4. 0-0u30 1.77 56 .99 .78
5. 0-0-150 2.03 66 1.34 .69
6. 0-120-90 1.83 64 1.17 .66
7. 0-0-0 1.69 62 1.05 .64
L. S. D. 5} .21

 

a
Pounds of N, P205 and K20 per acre, respectively.

bAll forage other than alfalfa.

Analysis of variance showed a significant difference
between fertilizer treatments.

The lowest yielding treatment was one of the checks
(treatment number 1), while the highest yielding treatment
was the one receiving the highest amount of potash (treat-
ment number 5).

Only treatments receiving potash yielded signifi-
cantly higher amounts of forage than the original check
plots established in 1954, and which were check plots

(treatment number 1) in 1959.

39

The calculated yield of alfalfa (Table 8) showed
a tendency for decreased yield with phosphorus fertili-
zation and increased yield with potash fertilization. The
yield of grass showed a reverse trend. As was the case in
the 1958 data, fertilization increased the production of
grass more than the production of alfalfa.

The results of Rich and Odland (53) were similar.
They found that reducing the amount of potassium applied
to grass-legume stands from 100 to 50 pounds per acre
reduced the total hay yield from 3.08 to 1.63 tons per
acre.

Comparison of the total yields of hay in 1959 with
the yields of bay of subtreatments B, C, E and F in 1958
reveals striking similarity of the effect of potash

fertilization.

Botanical Composition

The estimated percentage of alfalfa in the forage
at the time of cutting in 1959 is shown in Table 8.
Although there was no significant difference, treatment
number 3 (high phosphate) contained the lowest percentage
of alfalfa. The treatments receiving potash and the
treatments receiving no fertilization showed very similar
trends in their composition.

The works of Haskell (33) and Beaumont 23 al. (2)

might be considered at this point. They reported that

#0

clover and grass plots in Massachusetts which received
high amounts of potassium showed a superior type of
vegetation with respect to clovers. Rich and Odland_(53)
reported that reducing potassium applications from 100 to
50 pounds per acre reduced the prOportion of legumes from
50 to 39 per cent.

The omission of fertilizer in 1958 from the original
check plots did not cause these plots to have a smaller
percentage of alfalfa in 1959 than those fertilized each

year for five years with phosphorus and potassium.

Tissue Analyses
The-results of chemical analyses for phosphorus and
potassium in plant tissues are given in Table 9.
TABLE 9.-The phosphorus and potassium content of alfalfa

and bromegrass as influenced by fertilizer treatment in
the 1959 field experiment

 

 

 

 

 

 

Alfalfa Bromegrass
Per cent Per cent Per cent Per cent

Treatmenta P K P K
10 0-0-0 .19 071+ .18 1.36
2. 0-40-0 .23 . .68 .24 1.13
3. 0-200-0 .24 .67 .27 1.14
it. 0-0'30 020 1002 019 1.066
5. 0~0~150 .19 1.22 .16 1.94
6. 0-120-90 .23 1.06 .24 1.71
7. O-O-O .24 .79 .23 1.17
L. S. D. 5% .03 .17 .03 035

1% .05 .26 .05 .52

 

a
Pounds of N,-P205 and K20 per acre, respectively.

41

Phosphate fertilization increased significantly the
amount of phosphorus in alfalfa tissue over the treatments
which received potash fertilization. Similarly, treat-
ments receiving potash fertilization contained significantly
higher amounts of potassium in the tissue than the check
treatments and treatments receiving phosphorus fertilization.

There is a striking similarity of results obtained
from chemical analyses of bromegrass tissue. The tenden-
cies are the same, although the percentages of these two
nutrients are somewhat different. Bromegrass contained
a higher percentage of potassium in the tissue than did
alfalfa.

It might be mentioned at this point that the results
from treatment number 7 (check) were similar to treatments
receiving phosphate fertilization. Possibly there was
some carry-over of phosphorus from the original experiment.

The removal of phosphorus and potassium from the
soil by alfalfa and bromegrass is shown in Table 10.

Phosphorus fertilization increased the percentage of
phosphorus while decreasing the percentage of potassium
in both alfalfa and bromegrass tissue. The yield of
alfalfa was decreased and the yield of bromegrass increased
as a result of added phosphorus. At the same time, re~
moval of potassium from the soil was decreased by alfalfa

and increased by bromegrass.

 

 

42

 

.maopfluowmmmn .msow you 0mm was momm

.Z M0 meadow

 

 

 

 

 

was wwawhaw mp Hfiom map Scam cm>o8mm Ssfimmmpom one manonmmoam mo pcdoad 059:

w
©.Hw mo.n 0 ma 4m.m 0.0H 4o.m 01010 .n
4.54 4m.m @.mm 0H.m m.4m mm.m omaomaxo .6
4.0m omob moawN ONoN .0on OH.“ OmHOOIO om
w.m4 No.0 m.mm om.m m.om om.m Omcouo .4
4.0m mH.m o.oa w4.4 4.0a os.m o-oomuo .m
0.0N mm.m 0.4a om.m o.ma om.4 oao4no .m
o.mm mo.m 6.4H 4m.a 4.4a wo.m ououo .H

adwmmmpom menonmwonm asflmmmpom manommwosm adwmmwpom manommmozm
mmmmmmaomm mewMHw mucoepmoaa

mmow mom meadow deuce an nopoamn onom mom mvcdom
. m. c mm Hmmeon

mama as we map H a n .oa gummy

I.—
\

Potash fertilization caused no Change in the per—
centage of Lhosphorus in alfalfa and a all ht decrease in

. ' L -..-. -..' . F7“ ' .
rus 14 bfemeglaes. 1013 V88

4“
o

the percentage of phos .

‘

.o

i

accompanied by an increase in tse percentage of potassium
in both alfalfa and brOuegrass tissues. rotassium increased
the yield of alfalfa. Removal of phOSphorus from the soil
by both alfalfa and bromegrass was slightly increased,
whereas removal of potassium from the soil was
increased as a result of adding potash.
PhOSphorus removal from the soil by alfalfa and
bromegrass increased as a result of both phosphate and

potash fertilization. Removal of potassium from the soil

P-

O

., but

P-

was unchanged as a result of phOSphate fartil zat

;

increased by potash fertilization.

Soil Analyses
The results of analyses for reserve phosphorus and
potassium of the soil samples taken after harvest are
shown in table 11.

The treatments receiving phosnbate fertilization

:‘~

A

contained more phosphorus in the soil sample than the
treatments not receiving phosphate fertilization. Similar

results were obtained from treatments receiving potash

fertilization.

44

TABLE 11.-The reserve phosphorus and potassium content of
the soil as influenced by alfalfa-bromegrass under different
fertilizer treatments, 1959

 

 

Pounds per acre

 

 

Treatmenta Phosphorus Potassium
l. 0-0~0 22 37
2. 0-40-0 31 36
3. 0-200-0 56 31
4. 0-0-30 19 50
5. 0-0-150 26 57
6. 0-120-90 38 44
7. 0-0—0 47 37

 

8Pounds of N, P205 and K20 per acre, respectively.

The results of soil analyses in 1958 and 1959 differ.
Increased potash application showed little influence on
the amount of potassium extracted from soil samples in
1958, while in 1959 soil samples from the treatments
receiving potash fertilization showed a marked increase in
the amount of potassium extracted, but the amount extrac-
ted was still low.

There was no significant correlation found between
the percentage of alfalfa in the forage and the phosphorus
or potassium extracted from the soil samples. This is in
contrast with the findings in 1958 when a significant
negative correlation existed between the percentage of
alfalfa in the forage and the amount of phosphorus in the

soil. However, treatment 3 had the highest rate of

45

phOSphorus applied, the highest soil test for phosphorus
after harvest and the lowest percentage of alfalfa in the
forage.

There was a significant correlation found, however,
between the percentage of phosphorus in both alfalfa and
bromegrass tissue and the phosphorus content of the soil.
In addition, there was a highly significant correlation
between the percentage of potassium in both alfalfa and
bromegrass tissue and the potassium content of the soil.

Blaser and Brady (6) found that potassium fertili-
zation stimulated the growth of Ladino clover, but did
not directly affect the productivity of the non-leguminous

plants in the association.

Greenhouse Experiments

 

Attention is directed to Table 2 which lists the
grasses grown in association with alfalfa, the rates of
phosphorus and potassium fertilization, and the number
of replications for each of the three greenhouse experi—
ments. It might be recalled at this point that treatments
1 and 2 contained four replications, while treatment 3

contained three replications.

Yield
The effect of fertilizer treatments on the total
yields of alfalfa and bromegrass when grown in association

is shown in Tables 12 and 13.

46

TABLE 12.—The effect of fertilizer treatment on the yield
of alfalfa when grown with bromegrass in the greenhousea

 

 

 

 

 

Treat- Cutting
ment
1 3 4 6 8 Av.

PlKi 15.3 40.3 47.4 29.6 20.2 33.0
PlKQ 13.9 42.2 51.5 32.2 20.6 34.4
P185 17.6 47.8 51.9 40.6 24.0 38.1
Pix, 21.8 54.6 64.4 48.4 25.8 44.0
P2K1 11.1 34.8 42.2 33.4 12.0 27.6
222. 3.6 25.2 26.6 19.4 8.6 18.2
£2K3 14.2 38.6 52.0 34.0 22.8 33.5
228% 19.6 49.6 57.0 43.8 25.4 39.1
93K1 12.9 37.8 44.4 32.0 12.0 29.5
23K? 12.3 37.2 39.3 28.0 12.0 27.5
P3K3 16.3 38.8 40.5 34.2 20.8 32.1
P3KL 16.1 42.4 47.3 34.4 22.6 33.5
PAKi 15.4 33.0 39.0 34.2 15.8 29.2
Pth 17.0 40.6 42.9 31.6 15.6 30.6
aux, 18.4 45.4 55.2 39.6 21.6 37.7
P4K4 10.2 42.2 51.7 33.6 17.6 32.5
L.s.D.

5@ N.S. 2.7 3.1 3.4 2.0

16 N.S. 3.6 4.1 4.6 2.6
P x K N.S. N.S. 56 N.S. N.S.

aTotal yield in grams of

four replications.

47

TABLE 13.-The effect of fertilizer treatment on the yield
of bromegrass when grown with alfalfa in the greenhousea

 

 

 

 

 

Treat- Cutting

ment

1 2 3 4 5 6 7 8 Av.

PlKl 3.7 4.7 4.6 7.6 7.5 10.4 7.6 2.0 6.1
Ple 3.6 3.1 3.8 7.2 6.9 10.2 6.8 1.6 5.4
P1K3 5.9 3.2 3.4 4.6 5.5 7.4 3.6 .6 4.3
PlKfi 4.0 2.8 3.4 5.6 6.6 9.0 6.6 .6 4.8
P2K1 5.9 7.3 7.4 13.8 8.1 12.8 8.6 5.2 8.6
PZKQ 4.9 8.0 8.0 10.6 9.3 11.8 10.8 6.4 8.7
P2K3 4.1 4.2 4.2 7.8 7.9 10.2 6.8 2.2 5.9
P2K4 2.8 4.1 4.2 6.4 6.8 9.0 6.0 1.0 5.0
P3K1 3.4 4.7 4.0 6.2 6.0 9.2 5.6 1.0 5.0
P3K2 5.7 5.5 5.6 10.0 7.9 11.8 8.6 4.0 7.4
P3K3 3.4 7.2 4.8 10.6 7.7 9.8 8.0 1.4 6.6
PBKL 4.3 7.1 5.2 9.8 7.5 10.2 7.4 1.2 6.6
P4K1 6.7 10.7 9.0 11.2 8.7 12.2 8.0 1.6 8.5
PAKQ 4.0 7.3 6.2 9.8 8.6 12.2 6.2 2.0 7.0
P4K3 4.2 6.8 5.2 10.2 10.2 11.6 5.6 1.8 7.0
PAK£ 4.0 4.9 5.4 9.8 9.4 10.8 7.8 3.8 7.0
1.S.D.

5p N.S. .3 .1 1.3 .1 N.S. N.S. .9

1% N.S. .4 .1 1.8 .1 N.S. N.S. 1.1
P X.K N.S. N.S. N.S. N.S. N.S. N.S. N.S. N.S.

 

aTotal yield in grams of four replications.

 

48

0
1?—
*u

The differences between cuttings were highly

U)

nificant for both species, probably due to varied climatic
conditions.

Analyses of Variances also show highly significant
differences due to both phosphate and potash fertilizations,
with one significant phosphorus-potassium interaction.

Generally speaking, the higher rates of phosphate
fertilization decreased the yields of alfalfa and increased
the yields of bromegrass.

With one exception, the highest level of potash
application gave significantly higher yields of alfalfa
and significantly lower yields of bromegrass over the
lowest level of potash fertilization.

When each cutting of alfalfa was analyzed separately,
there were significant differences due to phosphorus in
six of the eight cuttings; significant differences due to
potassium in seven of the eight cuttings; but only one
significant phosphorus-potassium interaction of the eight
cuttings. Separate analyses for the cuttings of brome-
grass, however, showed significant differences due to
phosphorus in five of the eight cuttings, and a difference
due to potassium in only one of the eight cuttings.

Tables 14 and 15 show the effect of fertilizer
treatments on the yield of alfalfa and perennial ryegrass

when grown in association.

49

TABLE l4.-The effect of fertilizer treatment on the yield
of alfalfa when grown with perennial ryegrass in the

 

 

 

greenhousea
Treat- Cutting
ment
1 2 3 4 5 6 7 8 Av.

 

PlKi 10.3 53.7 38.8 56.1 32.6 67.4 35.4 29.8 40.5
Ple 15.5 65.5 43.8 61.4 37.2 62.4 33.2 32.4 43.9
9185 18.6 57.8 47.2 64.9 43.9 67.2 40.2 34.6 46.8
8281 17.7 61.3 41.8 52.9 44.4 69.6 36.0 35.0 44.8
PZKQ 20.6 66.6 41.0 55.6 42.9 63.6 28.2 32.8 43.9
P2K3 20.9 55.5 47.0 60.1 46.3 83.6 49.8 35.4 49.8
PBKi 13.5 59.4 41.8 51.4 43.4 65.2 30.0 24.0 41.1
P3K2 24.6 66.3 42.2 60.1 45.9 73.6 50.0 34.0 49.6
P3K3 22.6 73.7 48.8 62.2 50.9 76.0 47.2 36.8 53.4

 

L. SC. D.
5/9 100 209 1.6 207 106 2.7 2.5 102
170 20]. [+00 201 307 202 306 301+ 1.06
P x KI N.S. N.S. N.S. N.S. N.S. 56 1% 1%

 

aTotal yield in grams of four replications.

Analysis of variance of alfalfa yields revealed sig-
nificant differences due to cuttings, phosphorus and potash
fertilization, and phosphorus—potassium interaction.
Analysis of variance of ryegrass yields, however, showed

differences due only to cuttings and phosphorus fertili-

zation.

 

 

50

TABLE 15.—The effect of fertilizer treatment on the yield
of perennial ryegrass when grown with alfalfa in the

 

 

 

 

 

greenhousea
Cutting
Treat-
ment
1 2 3 4 6 7 8 Av.
PlKi 15.6 14.2 2.2 4.0 . . 3.0 1.2 6.7
P1K2 14.2 12.1 3.8 3.6 . . 7.0 2.0 7.1
PlK3 13.6 10.0 3.2 2.6 . . 2.6 1.2 5.5
PZKl 1205 1301+ 306 [+02 0 o 666 2014' 701
P2K2 13.7 12.3 6.4 7.8 . 11.2 4.4 9.3
P2K3 12.3 10.9 4.6 4.4 . . 3.4 .6 6.0
PBKl 1803 1805 306 501+ o 0 13.14. 9.8 1101+
PBKQ 12.8 13.2 4.2 4.2 . . 10.4 4.2 8.2
PBKB 15.9 1.502 500 502 o o 0 80h 308 8.9
L.S.D.
5p N.S. .6 .5 .6 . . . . .9 .5
170 l\IOSO .8 07 .8 o o o o 1.3 .7
P x K N.S. N.S. N.S. N.S. . . . . 596 1:6

 

aTotal yield in grams of four replications.

The higher rates of phosphate fertilization increased
the yields of ryegrass, relatively speaking, more than
the yields of alfalfa. In experiment 1, the yields of
alfalfa were decreased with increased phosphate fertili-
zation.

As in experiment 1, the yields of alfalfa were

increased with increased potash fertilization, whereas the

51

yields of ryegrass were decreased with increased potash
fertilization.

Analyses of individual cuttings of alfalfa revealed
significant differences due to phosphorus fertilization
in six of the eight cuttings; significant differences due
to potash fertilization in all eight cuttings; and phos-
phorus-potassium interactions in three of the eight
cuttings.

Growth of the grass in two of the eight cuttings was
insufficient to be measured. The significant differences
in the individual cuttings of ryegrass were due to phos-
phorus fertilization in five of the six cuttings, to
potassium fertilization in four of the six cuttings, and
to phosphorus—potassium interaction in only two of the
six cuttings.

The yields of alfalfa and timothy in experiment 3
are reported in Tables 16 and 17.

There were highly significant differences in the
yields of alfalfa due to cuttings, and phosphorus and
potassium fertilization, while only cuttings showed
differences in the grass yields.

Analysis of each cutting of alfalfa separately re-
vealed differences in six of the eight cuttings due to
phosphate fertilization and in four of the eight cuttings
due to potash fertilization. One of the eight cuttings

had significant phosphorus-potassium interaction.

52

TABLE l6.-The effect of fertilizer treatment on the yield
of alfalfa when grown with timothy in the greenhousea

 

 

 

 

 

Treat,- Cutting
ment ,
1 2 3 4 5 6. 7 8 Av.
PlKi 19.7 41.9 30.2 36.9 21.6 44.2 32.2 24.0 31.3
PlKZ 21.2 47.4 36.6 32.8 33.4 47.4 43.2 27.4 36.1
PlK3 19.1 51.9 39.2 37.4 36.0 48.6 48.0 28.0 38.5
P2K1 18.2 47.4 38.2 48.2 34.8 59.6 40.6 25.6 39.1
P2K2 20.9 52.7 35.6 50.6 35.8 59.0 53.4 26.8 41.8
P2K3 23.9 55.6 41.4 44.2 38.1 62.6 63.0 26.4 44.4
P3K1 20.2 53.7 38.6 52.0 29.6 49.4 37.0 19.8 37.5
P3x2 20.7 52.5 39.6 53.2 33.7 54.2 53.4 25.6 41.6
P3K3 21.4 59.6 41.4 52.0 34.2 57.8 48.0 30.8 43.2
L.S.D.
54 N.S. 2.9 1.6 2.1 1.7 2.8 3.1 1.8
14 N.S. 4.0 2.1 2.8 2.4 3.8 4.2 2.5
P x.K N.S. N.S. N.S. N.S. 5i N.S. N.S. N.S.

 

aTotal yield in grams of three replications.

Immeasurable amounts of grass were produced for the

fourth, fifth, sixth, and eighth cuttings. Only one of
the four cuttings showed any significant difference due
to phosphorus and potassium fertilization.

As in experiments 1 and 2, increased potash appli-

cations increased the yields of alfalfa and decreased the

yields of the grass.

53

TABLE 17.-The effect of fertilizer treatment on the yield

of timothy when grown with alfalfa in the greenhouse8

 

 

 

 

 

Treat- Cutting
ment
1 2 3 4 5 6 7 8 Av.
PlKl [+08 1100 lot} 0 o o o o o 300 o o 5.1
Plli2 606 996 100 o o o o o o 290 o o [4.8
PlK3 [#05 [4.8 10,-} o o o o o o 202 o o 302
PZKl 703 14.0 201} o o o o o o [4.2-2 e o 700
P2K2 [+0.]. 1101. 06 o o o o o o 2.8 o 0 he?
P2K3 309 8.? lot} 0 o o o o 0 301+ o 0 [+014
PBKl 6.2 13.9 102 o o o o e [+02 0 0 601+
P31{2 [+02 1201+ 01+ 0 o o o o o 3.2 o o 501
PBKB 502 1206 1011» o o O o o 0 [+02 0 o 509
143.40.
5;“ N.S. 102 IIOSO o o o o o o NOS. 0 o N.S.
l/b IqOSo lob I103. o o o o o 0 Nos. 0 o Iqoso
P X K N.S. N.S. N.S. . . . . . . N.S. . . N.S.

 

aTotal yield in grams of three replications.

Increased phosphate fertilization increased the

yields of timothy, but had little effect on the yields of

alfalfa. A similar tendency was observed in experiment

2.

The yields of alfalfa and the associated grass for

all three greenhouse experiments have been summarized in
Table 18. The higher rates of phosphate fertilization

increased the yield of grasses in all three experiments,

54

 

 

 

 

 

 

.m peossnmaxm Hoe mpom awaaoaammn means to waste as e 6 a
.N was A mummaflnomwo now muom oopwowammn 930% Mo madam ma camaw wprMprwWWMMo>m one
a
.1. N.ms a.m m.sm 44::
m.os m.am m.aa m.4 m.o m.m o.ma o.ma 4.mm mm
p.44 0.4m m.am m.a m.w H.s m.mm m.ms n.s~ mm
H.ma m.om 0.0m m.o ¢.m a.u m.mm H.ma w.m~ HM
8.8m 4.4 “.mm am
«.64 n.4m 6.4m a.“ m.8 4.6 4.04 o.ss 6.6m mm
«.54 m.mm 5.6m s.m 5.5 H.s m.as H.64 o.mm mm
8.0m H.0m o.ms 4.4 4.6 ~.m m.mm s.ms a.em Hm
m N H m N H m N H
q no a q
pamaano NM 9 as 6 am pdmaaamqsm wdoansz
no
H8905 mmmno whawhdw. Hopcq

 

 

 

muofipwufiaapnow adammwpoq was menoammonm mo mam>oa pcmnmhufio as muses

ufinmmxm omsondcmnw manna no macaw can suawwas ho cams» can no mans» mamaadm dr.wa quaa

55

while the yield of alfalfa was slightly decreased in one
and increased in two of the experiments. Increasing potash
resulted in increased yields of alfalfa and decreased
yields of grasses in all three experiments.

These results are supported by the findings of
several workers. Rich and Odland (53) found that phOSphorus
had no significant effect on the yield or percentage of
legumes in grass-legume combinations. Reducing potassium
applications from 100 to 50 pounds per acre reduced the
hay yield from 3.08 to 1.63 tons per acre. Gerwig and
Ahlgren (30) in‘Wisconsin.found that potassium was the
most important factor in maintaining high yields of alf-
alfa. Phosphorus fertilization was found to have no .
beneficial effect. Blaser and Brady (6) also found that
potassium fertilization stimulated the growth of Ladino
clover, but did not directly affect the productivity of
the non-leguminous plants in the association.

Other factors beside phosphorus and potassium fer-
tilization have definite influences on the yield of legume—
grass mixtures. Cutting management is an important factor
influencing the productivity of stands of grasses and
legumes.

Several workers (17, 23, 28, 36, 46, 47. 52, 64)
have reported that the total yield of hay varied inversely

with the number of times it was cut during the season.

56

Botanical Composition

The effect of fertilizer treatments on the botanical
composition of the forage is shown in Tables 19, 20, and
21. The percentages of alfalfa shown in the tables are
the averages of all eight cuttings. when the growth of
grass was immeasurable in certain cuttings, the forage
was considered to consist entirely of alfalfa.
TABLB 19.-The effect of fertilizer treatment on the average

botanical composition of eight cuttings of alfalfa-brome—
grass mixture grown in the greenhouse

Per cent

Treatment alfalfa

in forage
P141111 0 o o o o o o o o o o o o o o o 85
Pl:{2 o o o o o o o o o o o o o o o o 86
leLCB o o o o o o o o o o o o o o o o 89
I‘ll-K4 o o o o o o o o o o o o o o o o 90
J. 2K1 o o o o o o o o o o o o o 80
P2132 o o o o o o o o o o o o o o o a 7L!
P2K3 . . . . . . . . . . . . . 85
PZKL; o o o o o o o o o o o o o o o o 89
P311]. 0 o o e o o o a o o o o o o o o 85
P3fi2 o o o o o o o o o o o o o o o o 80
533;:3 o o o o o o a o o o o o o o o o 85
o a 0 8L}-

. . . . . . . . . . . . . 75

PAIIZ o o o o o o e o o o o o o o o o 77
£14,113 a o o o o o o o o o o o o o 82
FAQ 0 o o o o o o o o a o o o o o o 76

L0 30 Do 57; o o A

1/0 c o o o o o o o o o o o o o o 5

57

TABLE 20.-The effect of fertilizer treatment on the average
botanical composition of eight cuttings of an alfalfa-
ryegrass mixture grown in the greenhouse

Treatment Per cent

alfalfa
in forage

PlKi . . . . . . . . . . . . . . . . 88
PlKQ . . . . . . . . . . . . . . . . 90
P1K3 . . . . . . . . . . . . . . . . 92
P2K1 . . . . . . . . . . . . . . . . 89
P2K2 . . . . . . . . . . . . . . . . 87
F2K3 . . . . . . . . . . . . . . . . 91
.3h1 . . . . . . . . . . . . . . . . 81
PBKQ . . . . . . . . . . . . . . . . 88
P3K3 . . . . . . . . . . . . . . . . 88

L. s. D. 5% N.S.

TABLE 21.-The effect of fertilizer treatment on the average
botanical composition of eight cuttings of an alfalfa—
timothy mixture grown in the greenhouse

Per cent
Treatment alfalfa
in forage
PlKl o o o o o o o o o e o o o e o 0 91+
PlIC2 o o o o o o o o o o o o o o o 0 91!-

Li S- D. 5% o o o o o o o o o o o o o o o N.S.

58

Analysis of variance of the percentage of alfalfa
in the forage in experiment 1 revealed significant dif-
ferences due to both phosphate and potash fertilization.
The lowest amount of applied phosphate produced the highest
percentage of alfalfa in the forage, and the highest
amount of phosphate produced the lowest percentage of alf-
alfa in the forage. The percentage of alfalfa in the
forage was increased by potash fertilization at low levels
of phosphate fertilization, but was not affected to such
an extent at high levels of phosphate fertilization.

Analysis of variance of the percentage of alfalfa
in the forage in experiments 2 and 3 reveal no significant
differences in the percentages of alfalfa in the forage
due to either phosphate or potash fertilization.

All three experiments (Table 22) indicated a trend
of decreased alfalfa percentage as a result of high rates
of phosphate, and increased alfalfa percentage with high
rates of potash fertilization.

These results agree with the findings of several
workers. Brown and Munsell (9) reported that omission,
as well as large applications of phosphorus depressed
clovers first in permanent grasslands in Connecticut.
Rich and Odland (53) found, when using 80 pounds per acre

of phosphate, that reducing potash reduced the proportion

of legumes. Stivers and Ohlrogge (61) reported that stand

maintenance of alfalfa was closely related to potash

 

 

59

fertilization, especially at high rates. They found no
relationship between stand maintenance and phosphate
fertilization. Brown (7) reported that potash was very

beneficial in maintaining stands of alfalfa. Chiasson

(13), on the other hand, reported that phosphorus increased

clover and useful grasses at the beginning of the exper—
iment, but that potash had maintained clover better by
the fourth year than phosphorus.

TABLE 22.—Summary table of the botanical composition of

three greenhouse experiments at different levels of
phosphorus and potassium fertilization

 

 

 

 

Per cent alfalfa Per cent grass
ngel in forage in forage
Nutrient Experiment Experiment
1 2 3 l 2 3
P1 88 9O 94 12 10 6
P2 82 89 94 18 11 6
P3 84 86 93 16 14 7
P4 78 22
K1 81 86 93 19 14 7
K2 79 88 95 21 12 5
K3 85 90 95 15 10 5
Kg 85 15

 

Cutting management affects the botanical composition,

as well as the yield, of grass—legume associations. Inves-

tigators (36, 46, 47, 52) have reported that more frequent

 

 

6O

cutting of alfalfa-grass mixtures favors the grass com-
ponent as compared to cutting at the hay stage. However,
it should be recalled that the forage in these experiments
was cut at what would be considered the hay stage.

The botanical composition of the greenhouse experi—
ments compared favorably with those of the field experi—
ments. In both instances, the treatments receiving the
highest rate of phosphate fertilization contained the

least amount of alfalfa.

Tissue Analyses

lhe effect of fertilizer treatments on the phosphorus
and potassium contents of plant tissue is shown in Tables
23, 24, and 25.

Table 23 reveals that treatment effects reflected
significant differences in the percentages of phosphorus
and potassium in both alfalfa and bromegrass tissue.
Increases in phosphute applications increased the content
of phosphorus in the tissue of both the alfalfa and
bromegrass, but to a greater extent in the bromegrass.
Increased amounts of potash added to the soil increased
the percentage of potassium in the tissues of alfalfa and
bromegrass in comparable amounts.

There seemed to be a tendency for the higher amounts
of potash fertilization to reduce the phosphorus content
of alfalfa. This trend was not noticed in the bromegrass

tissue.

61

TABLE 23.-Ihe effect of fertilizer treatment on phosphorus
and potassium contents of alfalfa and bromegrass grown in
the greenhouse

 

 

 

 

 

 

Alfalfaa_ Bromegrassb

Treatment . ‘_

Per cent Per cent Per cent Per cent
P K P K
PlKi .37 .78 .26 1.05
P1K2 .38 .88 .23 1.10
P1K3 .38 1.06 .25 1.28
P1K4 .38 1.40 .25 1.46
PzKl .45 .89 .25 .91
P2K2 .42 .85 .28 .97
P2X; .38 1.11 .25 1.20
P2K4 .32 1.51 .27 1.44
P3K1 .48 .86 .29 .95
P3K2 .48 .94 .33 1.07
P3K3 .46 1.14 .31 1.23
P3K£ .45 1.55 .29 1.52
PhKl .46 .98 .29 1.05
FAX? .43 .98 .33 1.13
PAKB .43 1.16 .33 1.30
PLKL .42 1.57 .33 1.49
L. S. D. 5% .06 .22 .04 .11
1p .07 .29 .05 .15

8Average of eight cuttings.

bAverage of six cuttings.

62

TABLE 24.-The effect of fertilizer treatment on the
phosphorus and potassium content of alfalfa and ryegrass
grown in the greenhouse

 

 

 

 

 

Treatment Alfalfaa Ryegrassb
Per cent Per cent Per cent Per cent

P K P K
PlKl .27 .89 .13 .96
9132 .23 1.68 .12 1.45
91KB .22 2.06 .12 1.64
P2K1 .45 .79 .20 1.01
P2K2 .38 1.39 .23 1.41
P2K3 .37 2.09 .20 1.77
P3K1 .52 .88 .29 1.09
P3K2 .46 1.41 .27 1.46
P3K3 .39 2.28 .24 1.81
L. S. D. 55 .23 .28 .04 .17
16 .30 .38 .05 .23

 

aAverage of eight cuttings.

bAverage of five cuttings.

l.

Different levels of phosphate fertilization showed
no noticeable effect on the percentage of potassium in
either alfalfa or bromegrass tissue.

As in experiment 1, Table 24 shows that increased
amounts of phosphate and potash added to the pots in-

creased the respective percentages in the tissue of both

63

alfalfa and ryegrass. Increasing potash fertilization
reduced the percentage of phosphorus in alfalfa, while
holding constant or slightly retarding the phosphorus
content of ryegrass. This tendency is decidedly more
pronounced in experiment 2 than in experiment 1.

TABLJ 25.-1he effect of fertilizer treatment on the

phosphorus and potassium content of alfalfa and timothy
grown in the greenhouse

 

 

 

 

 

 

 

Treatment Alfalfaa Timo thyb
Per cent Per cent Per cent Per cent
P K P K
FlKl .26 .85 .11 .98
PlKé .22 1.67 .11 1.39
. PlK3 .22 2.38 .10 1.62
Pzfil .46 .91 .20 1.19
P2K2 .34 1.51 .19 1.49
P2K3 .35 2.22 . .19 1.67
P3K1 .54 .83 .19 1.18
P3K2 .45 1.39 .19 1.44
P3K3 .42 2.17 .20 1.62
L. S. D. 55 .09 .23 .02 .12
1p .11 .30 .02 .17
a

Average of eight cuttings.

bAverage of three cuttings.

64

Increasing the amount of phosphate application,
however, seemed to have very little, if any,effect on
the phOSphorus content of either alfalfa or ryegrass.
w Table 25 reveals similar results for experiment 3
as Table 24 does for experiment 2. That is, increased
phosphate and potash fertilizations increased the
respective contents in both alfalfa and timothy. Also,
as in Table 24, increasing the amount of potash application
reduced the percentage of phosphorus in the tissue of
alfalfa but not in timothy. Increasing the amount of
phosphate had no effect on the percentage of potassium in
either alfalfa or timothy.

In all three experiments, phosphorus and potassium
in the tissue of both alfalfa and the associated grass
were increased as the amount of the nutrient applied was
increased. Lawton and Tesar (38) also obtained results
from greenhouse experiments to the effect that potassium
absorption by both alfalfa and bromegrass was significantly
increased as applied potassium increased.

The results of chemical analyses of plant tissues
of all three greenhouse experiments are outstandingly
similar. Increasing the potash application at a constant
level of phosphate reduced the phosphorus in alfalfa
tissue, but not in the grass tissue. Conversely, increasing
the phosphate application at a constant level of potash
showed no effect on the potassium content of either the

alfalfa or the grass tissue.

 

 

65

The phosphorus content of bromegrass was higher
than the phosphorus content of timothy and ryegrass as
shown in Table 26, which was basically the result ob-
tained by Gervais (29). However, the potassium content
of bromegrass was not higher than ryegrass or timothy,
which is contrary to findings of Gervais (29). In all
three experiments, the phosphorus content of alfalfa was
higher than the phosphorus content of the grass grown in
association.

Vandecaveye and Baker (66) reported that the chemical
composition of alfalfa at harvest stage was less influenced
by phosphate and potash fertilizations than was the chemi-

cal composition of grasses.

Soil Analyses

The results of soil analyses for phosphorus and
potassium are given in Tables 27, 28, and 29.

Analysis of variance of each experiment revealed
significant differences due to treatments. Generally,
as the amount of each nutrient applied was increased, the
amount of the respective nutrient extracted was increased.

Correlation analyses of the phosphorus in the soil
and the percentage of phosphorus in plant tissue revealed
a positive association in all three experiments. A
highly significant correlation existed for both the alfalfa
and the associated grass in experiments 2 and 3, and for

bromegrass in experiment 1.

 

TnBLE 26.-Summary table of the chemical composition of
alfalfa and grass of three greenhouse experiments at
different levels of phosphorus and potassium fertilization

 

 

 

 

 

 

 

Level Per cent phosphorus Per cent potassium
Of
nutrient Experiment Experiment
1 2 3 l 2 3
.lfalfa

P1 .38 .24 .23 1.03 1.53 1.63
32 .39 .40 .38 1.09 1.09 1.55
P3 .47 .48 .47 1.12 1.19 1.46
P4 .44 1.17

:{l 014.14- ohl 011.2 088 .85 .86
K2 01-43 036 o 37 09]. l [1.0 1.52
x3 .41 .33 .33 1.12 2.14 2.26
K4 .39 1.51

Grass

Pl 025 012 all 1022 1035 1033
P2 .26 .21 .19 1.13 1.39 1.45
P3 026 .27 .19 1019 101.45 101+].
1:1 026 .21 .17 .99 1.02 1012
Iiz 029 021.16 1907 1014—1} 101?}1'
:I3 .28 019 016 1025 1071+ 1061+

67

TABLE 27.-The effect of alfalfa-bromegrass on the phosphorus
and potassium content of the soil when grown under different
fertilizer treatments in the greenhouse

 

Pounds per acre

 

 

 

Treatment phosphorus Potassium
PlKl 52 91
Ple 1.5 7"
PlK3 “5 86
P1K£ “2 87
P2Kl 03 7O
PZKZ 52 52
P2K3 59 81
PZKA 56 96
PBKl 95 73
P3K2 95 67
P3K3 9O ' 90
PBKA 75 89
PhKl 19“ 99
Pth 191 89
PLK3 212 115
PAK£ 18“ 92

L. s. D. 53 28 22

1w 37 3O

68

TABLE 28.-Ehe effect of alfalfa-ryegrass on the ohosphorus
and potassium content of the soil when grown under different
fertilizer treatments in the greenhouse

 

Pounds per acre

 

 

 

Treatment
Phosphorus Potassium

PlKl 45 35
911:2 1.5 88
PlK3 . 37 78
szl 337 46
P2112 303 62
P2K3 337 102
P3X]. (306 80
P3312 622 79
P3K3 647 117
L. S. D. 5,0 87 30
1;; 118 1+0

 

Correlation analyses of the potassium in the soil
and the percentage of potassium in plant tissue revealed
also a positive association in all three experiments.
Highly significant correlations existed for alfalfa in
eXperiments 2 and 3, and for grass in experiments 1 and 2.

Negative associations were found in all three
eXperiments from correlation analyses of the percentage
of alfalfa in the forage and the phosphorus in the soil.
A highly significant correlation existed for experiment 1,

but not for experiments 2 and 3.

69

TABLE 29.-The effect of alfalfa-timothy on the phosphorus
and potassium content of the soil when grown under different
fertilizer treatments in the greenhouse.

 

 

Pounds per acre

 

 

 

Treatment
Phosphorus Potassium

PlKl 37 61
PlKQ 33 84
121K3 33 122
"92151 305 1.7
P2X? 277 AB
P2K3 » 230 73
P331 644 71
P3Ké 579 80
P3K3 588 112
L. s. D. 57; 73 30
1% 100 43

 

No significant correlation was found between the
potassium in-the soil and the percentage of alfalfa in
the forage. Table 30 combines the results of soil
analyses for all three greenhouse experiments.

This is in contrast to the findings of Stivers and
Ohlrogge (61). They found that stand maintenance of
alfalfa was closely related to potash fertilization and
potassium content of alfalfa.

Nelson and hacGregor (45) reported that soil samples
showed almost no correlation between the phosphorus and

potassium in the soil and that found in the alfalfa plants.

7O

TABLA 30.-Available soil phosphorus and potassium at the
completion of the greenhouse experiments

 

 

Pounds per acre

 

 

 

Level Phosphorus in soil Potassium in soil
of
nutrient Experiment Experiment
1 2 3 l 2 3
P1 46 42 34 85 67 89
P2 58 326 271 75 70 56
P3 89 625 604 80 92 88
P4 195 99
K1 101 329 329 83 54 60
K2 9b 323 29a 71 76 71
.K3 102 340 283 93 99 102

K14, 89 91

 

V. SUMMARY AND CONCLUSIONS

1958 Field mxperiments

Fertilizer subtreatments resulted in yield differences
which were highly significant for all eight cuttings over
a four year period. Phosphate fertilization increased
the yield of forage over the check treatments, with phos~
phate and potash fertilization yielding the highest amount
of forage.

The highest proportion of alfalfa in the forage
occurred in the treatment and subtreatment receiving no
fertilization at the time of establishment or as a tOp-
dressing.

The subtreatments receiving phosphorus each year
contained significantly greater amounts of phosphorus in
both alfalfa and bromegrass tissue than the subtreatments
receiving no phosphorus as a topdressing and those receiving
phosphorus in the second harvest year. There were no
significant differences, however, between the subtreat-
ments with respect to the content of potassium in either
alfalfa or bromegrass tissue.

Increased phosphate applications resulted in
increased amounts of phosphorus extracted from soil samples,

but increased potash application resulted in little

71

72

influence on the amounts of potassium extracted from soil
samples.

A significant negative correlation existed between
the percentage of alfalfa in the forage and the amount of
phosphorus in the soil.

Highly significant positive correlations existed
between the percentage of phosphorus in alfalfa and brome-
grass tissue and the phosphorus extracted from soil
samples. Such was not the case for potassium.

Chemical analyses of soil profiles revealed that
phOSphorus content increased with depth while potassium

content decreased with depth.

1959 Field Experiments
Significant differences in yield existed between
fertilizer treatments. The lowest yielding treatment
was one receiving no fertilization, while the highest
yielding treatment was the one receiving the highest
amount of potash. Only treatments receiving potash yielded
significantly higher amounts of forage than the original

check plots established in 1954, and which were check plots

in 1959.

[Jo

Alfalfa showed a tendency for decreased yield w th

phosphorus fertilization and increased yield with potash
fertilization. bromegrass showed a reverse tendency.
No radical change in the percentage of alfalfa in

the forage during one growing season was noticed as a

73

result of fertilizer treatment, although the treatments
receiving potash and the treatments receiving no ferti-
lization showed very similar trends.

An increase in the amount of a nutrient applied to
the soil increased significantly the percentage of that
nutrient in the plant tissue. Bromegrass contained a
higher percentage of potassium in the tissue than did
alfalfa.

Significant positive correlations existed between
the amount of a nutrient in the soil and the percentage
of the respective nutrient in the plant tissue of both
alfalfa and bromegrass.

Phosphorus fertilization decreased the yield of alf-
alfa and increased the yield of bromegrass; increased the
phosphorus and decreased the potassium contents of both

alfalfa and brOmegrass tissue; and decreased the removal

of soil potassium by alfalfa while increasing the removal

p

01 soil potassium by bromegrass.

Potash fertilization increased the yields of both
alfalfa and bromegrass, caused little or no change in
the phosphorus content while increasing the potassium
content of both alfalfa and bromegrass, and increased
slightly the removal of soil phosphorus while greatly
increasing the removal of soil potassium.

Phosphorus removal from the soil was increased as

a result of both phosphate and potash fertilization.

74

Removal of soil potassium was increased by potash ferti-

lization, and unchanged by phosphate fertilization.

Greenhouse Experiments

Striking similarities of yield results of all three
greenhouse experiments were noticed as influenced by phos-
phate and potash fertilization.

The higher rates of phosphate fertilization increased
the yields of the grasses, while having little influence
on the alfalfa yields. The higher rates of potash
fertilization resulted in higher yields of alfalfa and
lower yields of grasses.

Significant differences due to both phoSphate and
potash fertilization were found in the botanical composi-
tion of the alfalfa~bromegrass association. The lowest
amount of applied phosphate produced the highest percentage
of alfalfa, while the highest amount of applied phosphate
produced the lowest percentage of alfalfa in the forage.
The percentage of alfalfa in the forage was increased by
potash fertilization at low levels of phosphate fertili-
zation, but less affected at high levels of phosphate
fertilization.

The percentages of phosphorus and potassium in the
tissue of alfalfa and the associated grass were increased
as the amount of the nutrient applied was increased.

Increasing the amount of potash at a constant level

of phosphate reduced the percentage of phosphorus in

75

alfalfa tissue but not in grass tissue. Increasing the
amount of phosphate at a constant level of potash showed
no effect on the potassium content of either alfalfa or
grass tissue.

The phOSphorus content of bromegrass was higher than
the phosphorus content of timothy and ryegrass. In all
three experiments, alfalfa contained a higher percentage
of phosphorus in the tissue than the grass grown in
association.

Positive correlations were found in all three exper-
iment between the amount of a nutrient in the soil and
the percentage of the respective nutrient in plant tissue.

Negative associations were found in all three exper-
iments between the percentage of alfalfa in the forage and
the phosphorus content of the soil.

The explanation given for the persistence of alfalfa
when grown with an associated grass in the field without
phosphorus or potassium fertilization is that subsoil
pnOSphorus is furnished in sufficient amount to the deep
rooted alfalfa plant so that alfalfa is enabled to compete
advantageously when grown in association with a shallow
rooted grass plant. The restricted growth of the grass
made it possible for the soil to supply sufficient
potassium to maintain the alfalfa in association with
bromegrass. In addition, the pH of the surface and sub-

surface horizons may have proved a disadvantage in phos-

phorus uptake by the grass.

 

LITERATURE CITED

 

 

1.

2o

3.

h.

5.

6.

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