8-1082
May 1969

 

production
and
management

 °*
SMALL GRAINS Fon FORAGE

   
 

TEXAS A&M UNIVERSITY
 Texas Agricultural Experiment Station
H. O. Kunkel, Acting Director, College Station, Texas

 

Summary

Small grains produce good yields of high
quality forage at a season when green grazing
is limited. Forage production generally is more
dependable and yields are higher than for any
other crop grown for Winter pasture. Acreage
of small grains grown for forage exceeds that of
any other winter grazing crop.

Small grains may be planted for forage pro-
duction from early September to late November.
Early plantings result in earlier forage produc-
tion while midseason plantings generally result
in maximum forage production. Early planting
increases the risks of insect and drouth damage
but is necessary if early forage production is
desired.

Seeding rates between 48 and 112 pounds

per acre appear to have little influence on total‘

forage production. Early production is favored
to some extent by the heavier seeding rates; for
this reason, seeding rates of 64-80 pounds per
acre are suggested.

Small grains respond to fertilization. Appli-
cation rates depend on soil type, rainfall and
desired production level and should be based on
soil test results. Studies have shown favorable
responses to nitrogen up to 120 pounds per acre.
A split application of nitrogen is definitely fav-
ored with part of the nitrogen applied at or prior
to planting and part applied as a top dressing in
midwinter.

Clipping management studies have shown
that forage yields may be reduced 20-80 percent
by early and frequent pasturing or clipping. Top
growth is reduced, and crown and root develop-
ment is retarded. Allowing the plant to become
well established, 6-8 inches high, before grazing
begins is particularly important if maximum
yields are to- be obtained. However, some sacri-
fice of total production may be necessary or
desirable to utilize some forage during critical
fall and early winter periods.

Growth. studies with oats have shown a
direct relationship between growth and temper-
ature. Winter temperatures generally are mild

2

enough south of College Station for c
growth, but north of this area, growth j
are likely to occur during cold period
the management program should allow '-
ual or accumulated growth for use du i;
periods. Otherwise, overgrazing may 
damage to the stands. Growth also is o
rainfall or available moisture during the,
season. Apparently about 20 inches 
from September through April is ad
most areas. Seasons with less than 20 a
rainfall occur frequently in most of t,
therefore, moisture often may be a lim'_
tor. Rainfall excessive for maximum
may occur, especially in the coastal -»-;f '

Reduced sunlight energy during t '
months apparently limits growth of w;
Planting rates and methods do not see ,
this response significantly. Prelimina 
tion of crops and varieties shows no i.
differences in adaptation to limited lig

Nitrate accumulation is known tofj
small grains and to induce toxicity inl
animals. Since many factors influeni
accumulation, seldom can it be attribu Q
single factor. Research has shown t 
tends to be higher in basal parts of the}
favored by overcast weather and dar"
is favored to some extent by use of 
an oxidized form of nitrogen. Ferti 
usually necessary for small grain produ,
the application of moderate amounts fl
lizer has not been associated with hi,
accumulation. “

Carrying capacity and total anima,
tion of small grain pastures are depe,
forage production level. Small gra”
quality is excellent, and average daily;
grazing animals are good. is:

Factors influencing choice of _
clude disease reaction, cold hardiness an
habit. Varieties change in disease
bility, and new, better adapted va"
being developed constantly. Current d,
should be determined when choosing ;~

   
  
 
 
  
  
 
  
  
  
  
 
 
  
  
 
  
   
 
  
 
 
  
  
 
 
  
  
 
 
  
   
 
  
 
 
  
  
  

production
 and
 management
 of
SMALL GRAINS

FOR FORAGE

   

4.‘

i. Holt, M. J. Norris and J. A. l.oncoster*

 

Contents

Summary .................................................................................... .. 2
Introduction ............................................................................... ._ 3
Date 0f Planting ..................................................................... _. 4
Seeding Rates and Methods .................................................. .. 4
Fertilization ............................................................................... _. 5
Time and Rate of Nitrogen Application ................... .. 5
Nitrogen and Phosphorus .............................................. .. 6
Management .............................................................................. .. 7
Growth Behavior ...................................................................... -. 9
Response to Management ............................... .; ............. _. 9
Response to Temperature .............................................. ..10
Response to Moisture ..................................................... ..11
Response to Cutting Height ......................................... ..1.3
Response to Light Intensity ......................................... __14
Nitrate Accumulation ............................................................. __16
Grazing ....................................................................................... __17
Varieties ..................................................................................... __18
Acknowledgments ..................................................................... __18

MALL GRAINS ARE SUITED to many uses, one of
the main ones ‘being forage for livestock. The
average annual acreage of small grains in Texas
is estimated to exceed 8 million acres. Of this,
more than 2 million are sown for livestock pas-
ture and are grazed during the Winter and spring
until the forage is exhausted and the crop killed
out. A considerable portion of the remaining
acreage is grazed during the winter, and then
the livestock are removed in time for a grain
crop to mature. "

In addition to grazing, some acreages, par-
ticularly of oats, are used for hay, silage or as
soiling crops. A larger percentage of the acre-
age in East Texas and on the Coast Prairie is
seeded exclusively for grazing than in the other
Texas areas. Oats and rye are the principal
small grain crops in East Texas, oats on the
Coast Prairie and Rio Grande Plain and wheat
and oats in Central and West Texas.

The small grains produce high quality for-
age at a season when green forage is limited.
The small grains generally are more reliable for
forage production and produce a larger volume
of forage than most other winter growing crops.
For these reasons, the acreage of small grains
used for winter pasture exceeds that of any other
winter crop. Because the costs of land prepara-
tion, fertilization, seed, seeding and other factors

*Respectively, professor, Soil and Crop Sciences Depart-
ment; associate professor, Texas A&M Agricultural
Research and Extension Center at McGregor; and asso-
ciate agronomist, Texas A&M Agricultural Research and
Extension Center at Overton.

3

make Winter forage from small grains expen-
sive, it is important to use adapted varieties and
follow good cultural and management practices
to obtain high yields and efficient production.

The results of studies of a number of fac-
tors influencing forage production are reported
in this bulletin.

DATE OF PLANTING

There is no fixed date for seeding small
grains for forage production. Planting may be
as early as late August or as late as late Novem-
ber. A 3-year study was conducted at College
Station to determine the effect of planting date
on forage production. Three varieties were
seeded at 15-day intervals from September 1 to
December 1.

The data in Table 1 show that date of
planting has a significant effect on early forage
production and also on total forage production.
Plantings made after October 1 had little or no
forage available by December 1. Peak harvested
forage yields were obtained with an October 15
seeding. Seedings prior to October 1 or after
November 1 generally produced less forage.

The number of clippings varied with the
date of seeding. Clipping generally reduces the
potential dry-matter production of small grains.
Thus, the study also included plots which were
harvested only at maturity to determine the in-
fluence of planting date in the absence of clip-
ping effects. The varieties did respond differ-
ently. Gator rye showed peak production with
November 1 seeding, Mustang oats with October

TABLE 1. FORAGE YIELD OF SMALL GRAIN VARIETIES WITH VARIOUS
DATES OF PLANTING, COLLEGE STATION (3-YEAR AVERAGE)

Total yield
Date Harvestable Total yield harvested
of Forage of 3 - 4 only at
planting Variety December 1 clippings maturity
Sept. 11 Gator rye2 360 1840
Mustang oats 790 1460
Suregrain oats?’ 960 1710
Sept. 15 Gator rye 700 2530 4260
Mustang oats 710 2050 3350
Suregrain oats 920 2210 3880
Oct. 1 Gator rye 590 2240 4100
Mustang oats 690 2120 3600
Suregrain oats 940 g 2160 4050
Oct. 15 Gator rye 230 2940 4680
Mustang oats 210 2610 4630
Suregrain oats 410 2900 4260
Nov. 1 Gator rye 0 2570 5370
Mustang oats 0 2310 3500
Suregrain oats 0 2180 4250
Nov. 15 Gator rye 0 2470 3840
Mustang oats 0 1980 3240
Suregrain oats 0 1830 2800
Dec. 1 Gator rye 0 1590 3490
Mustang oats 0 1850 2960
Suregrain oats 0 1330 2360

‘Yields are based on only 1 year and adjusted for year effects.
zCordova barley was used instead of Gator rye 1 year.
“Moregrain oats was used instead of Suregrain oats 1 year.

4

  
 
  
   
  
  
  
 
  
  
   
  
 
  
 
   
  
 
 
  
  
 
  
  

TABLE 2. FORAGE PRODUCTION WITH VARIOUS RATES’,
OATS AT CRYSTAL CITY r,

$2225 Pounds of air-dry forage per J
per acre January 3 February 10 March 18
48 31 l0 2380 4050
64 3060 2790 3480
80 3380 1740 3480
9s 4400 201a soao

15 seeding, and Suregrain oats differ
from October 1 to November 1. Late 
(after November 1) appeared to restric;
tial yield more than early seeding. .

Certain problems may be encounte“
early plantings which are less likely to It
later dates. The three major problems“
sects, drouth and Weeds. These are y;
eliminated with the advent of cool p‘
Early seeding is necessary for early fo i
duction. If the major need is for late ‘_
early winter forage, some sacrifice of t'l~‘
duction may be desirable in order 1:0,;
early forage. Similarly, the risks inv
early planting may not eliminate the desi
or necessity of early planting. i‘

,

SEEDING RATES AND METHODS

Seeding rate studies have been limi
in general they have shown that seedi '
between 48 and 112 pounds usually do not.
influence total forage production. The;
of a seeding-rate study with irriga
Crystal City are given in Table 2. Ea t;
duction was increased with the higher f
seeding, but total production with 96 p'

TABLE 3. THE INFLUENCE OF SEEDING RATE AND 
EARLY FORAGE PRODUCTION, COLLEGE STATION 

seeding Pcstggs Pounds dry forage per acre, 

method per acre Oats Rye I
Broadcast 50 1000 1260
100 1260 1480
Average 1130 1370
12-inch rows 50 870 1160
100 920 1380
Average 1015 1320

TABLE 4. INFLUENCE OF RATE OF SEEDING ON THE FO l‘
OF OATS AT KIRBYVILLE 

Pou nds 

Pounds seed
per acre forage p 
4s 63L .
64 602
80 6420
96 671 _;
1 l 2 b4 r31

l‘

   
  
  
  
  
  
  
  
  
   
   
    
    
    
  
   
   
 
 



A- YIELDS OF OATS WITH VARIOUS ROW SPACINGS
1;" TES AT BEEVILLE (4-YEAR AVERAGE)

Pounds of
Pounds of air-dry forage
seed per acre per acre
32 1440
48 T680
64 1550
48 T540
24 1290
36 1430
48 I330

,nly 500 pounds above that with 48
 ailable forage on December 1 in a
llege Station, Table 3, was increased
cum of 260 pounds due to a heavy
' Similar results were obtained at
where yields varied less than 700
,. seed rates from 48 to 112 pounds
gble 4. Because of the need for early
gand the slight advantage of increased
ji- both in producing early forage
g a satisfactory stand, it probably is
,1 use 64-80 pounds of seed per acre.

Small grains are drill-seeded with the
Qches apart. Experimental plantings
12111005 were in 12-inch rows or drills
'_ence in handling the small plots. In
j College Station involving broadcast
 ch row seedings, there were no sig-
ferences in early forage production,

acing and seeding-rate studies have
pfcted at Beeville for 4 years. The
"f presented in Table 5. It is apparent
 - row spacing nor seeding rate influ-
5e production significantly. Yields
h row plantings tended to be slightly
jwith 12 and 18-inch rows. These
 conducted in a dry area. Where
5 adequate, there might be a greater
 yield from Wide rows. However,

these results do indicate that the tillering char-
acteristic of small grains tends to compensate
for lower plant populations whether from lower
seeding rates or wider row spacings.

FERTILIZATION

The growth of winter-growing crops is lim-
ited by two main factors: temperature and light.
Growth of small grains essentially stops at 40°
F. While less work has been published on light
effects, it is known that light energy during the
winter months amounts to only a fraction of
peak summer light levels. Probably anything
that limits growth also limits responses to other
factors. Thus, it would ‘be expected that yield
response to applied nutrients would be less than
in warm-season grasses and that smaller amounts
of nutrients would be necessary for maximum
production. Fertilizer management might be-
come quite important under such conditions.

Time and Rate of Nitrogen Application

Studies were conducted at College Station
and Mt. Pleasant to determine the effect of time
of nitrogen application as well as total amount
of nitrogen application on forage yield of small
grains. Studies involving rates of nitrogen have
been conducted at Temple. The College Station
and Mt. Pleasant studies were on fine sandy soil
and the Temple studies on Houston black clay.
In all cases the crops were fall planted, usually
in mid-October, in rows 12 inches apart. Phos-
phorus and potassium were applied prior to
planting. Fall nitrogen applications were made
prior to planting; other dates of application are
shown in Tables 6 and 7. The plots generally
were clipped 3-5 times each year or when 12-15
inches of growth had occurred. Yields are pre-
sented as totals approximately to February 1,
from February 1 to March 15 and after March
15.

The study at College Station indicates that
seasonal production and total yield of both oats

IIIGE YIELD OF OATS AND RYE AS INFLUENCED BY TIME AND AMOUNT OF NITROGEN, COLLEGE STATION (2-YEAR AVERAGE]

 

Pounds of dry forage per acre

Oats Rye
Date of nitrogen application Early Late Early Late
October December January March winter winter Spring Total winter winter Spring Total

40 1130 580 1055 2765 ° 1415 1090 425 2930 d
80 1210 570 990 2770 ° 1660 1175 420 3255 “I
40 4o 1050 970 1050 3090"" 1330 1545 430 3355 b"
40 40 1370 1040 1095 3505“ 1495 1660 445 3600"”
120 _ 1835 655 1135 3625" 2095 1275 330 3700"”
60 60 1450 850 1150 3450*‘ 1855 1515 505 3875“
60 I 60 1260 1060 1050 3370*‘ 1920 1730 400 4050“
4O 40 40 1210 1140 970 3320*‘ 1695 1595 440 3730"“
40 40 40 1340 1170 1100 3610" 1880 1730 460 4070"
40 40 40 1280 860 1250 3390“ 1755 1435 550 3740*“
40 40 40 1230 1100 1160 3490“ 1580 1555 535 3670"”
30 30 30 30 1120 1045 1035 3200"" 1520 1575 540 3735"”

   

 in a column with a common letter designation do not differ significantly.

TABLE 7. INFLUENCEIOF APPLICATION TIME AND NITROGEN RATE ON FORAGE PRODUCTION OF OATS, MT. PLEASANT (4-Y 

 

Nitrogen applications
Pounds per acre

 

Pounds of air-dry forage per acre

v4. =1»; . x.’

October l February l5 March l5 Total Early winter Late winter Spring f
0 0 343 10o 573 =1
30 30 710 213 733 
50 50 1055 34o 923 2 f
90 90 1155 390 1093 -_
120 120 1130 453 1253 i,
3o 30 50 720 393 1515 
45 45 90 393 573 1550 1»
5o 50 12o 1055 735 1740 ¥
30 30 30 9o 733 433 1930 3t
45 45 45 120 335 595 1933

w
T '~ 1 T‘ ha‘.

Yields wih a common letter designation do not differ significantly.

and rye were affected by time and rate of appli-
cation. The study did not include a 0 nitrogen
level. The 80-pound nitrogen level increased
yield over the 40-pound level, 0n the average,
165 and 375 pounds, respectively, for oats and
rye. The 120-pound rate gave a further average
increase of 480 pounds. Neither the level of
production nor the response to fertilization above
a minimum level was great. There was an in-
crease of 300 to 400 pounds of forage with the
120-80-80 treatment with three nitrogen appli-
cations over the 120-40-40 applied in a similar
manner. However, the yield was no greater
than with 120-40-40 when the nitrogen was split
into only two applications.

Early winter forage production was encour-
aged by a heavy pre-planting nitrogen applica-
tion or a combination of pre-planting and Decem-
ber application. Late winter production was
greater when some of the nitrogen was applied
in January.

Yields generally were favored by splitting
the nitrogen into a pre-plant and a post-plant
application. There was no advantage to more
than one top dressing. The post-plant applica-
tion can be made in either December or Janu-
ary with little effect on total production.

The study at College Station was continued
a third year with fertilizer rates up to 200-160-
160. This treatment produced 400 pounds more
forage than the 120-40-40 treatment. Intermed-
iate treatment levels produced from 150 to
200 pounds more forage than 120-40-40. Thus,
while some responses were obtained above 120
pounds of nitrogen, they were not of practical
significance.

In the study at Mt. Pleasant, presented in
Table 7, yield responses to» nitrogen were greater
than at College Station. It is apparent that 120
pounds of nitrogen produced 1200 to 1500
pounds more foragethan 60 pounds of nitrogen.
Fall and early Winter growth increased as the
pre-plant nitrogen increased from 30 to 120
pounds. Nitrogen applied in February increased
late-winter growth slightly. A split application,

6

.3

   
   
 
 
 
  
  
     
 
  
 
  
  
  
  
    
  

especially of the high rate, increased yi'
a single pre-plant (October) applicatiof
ever, more than two applications (one
and one postplant) did not further incr ~’
but did alter distribution of growth 
extent. 

Similar results have been obtained;
grass in the Coastal Prairie (unpublish
Thus, it appears that 40-60 pounds of 
at the time of or prior to planting a
pounds in December, January or Feb "
vide the best combination for small g ,
winter annual grasses for forage p vi»
Phosphorus and potash should be applied.
ing to soil test indications-probabl
pounds of each on light-textured soils in»
and East Texas. l

Nitrogen and Phosphorus

1
a

A 5-year study of fertility practices»
production of oats for forage in the b I
was conducted at Temple. The data 
8 indicate both a nitrogen and a ph
response. That more forage production;
from nitrogen and phosphorus in c0 
than from the additive effects of the tw;
independently indicated a favorable in =17
The maximum yield was produced with
but this was only 220 pounds higher t‘
produced with a 30-30-0. A 60-60-60 
was included in the test, but its produc
no higher than that from a 60-60-0. ”

TABLE 3. THE INFLUENCE OF COMBINATIONS o1= NI 
PHOSPHORUS ON FORAGE AYIELDS OF oATs AT 
AVERAGE) _,

Pounds of air-dry forage per acre

P338? Pounds N per acre g
per acre O l5 30 60 90' 
0 2700 3040 3550 3520 3790i

30 2920 3515 3950 3910 4050

50 3055 3530 3990 4040 4130
Average 2395 3395 3330 3320 4010 if

    
  
  
   
  
  
   
 
  
  
 
  
   
   
   
   
   
  
   
  
  
   
  
   

MANAGEMENT

 clipping or other harvest of small
' for forage should strive for maxi-
fned forage production Without dam-
fds of the. crop. The management
 ld be economical and practical, tak-
nsideration total production and the
distribution of the forage produced,
 pasture or silage.

A ouse and field-clipping studies on
oats were conducted at Crystal City
e the importance of stage of growth
pping and the frequency of clipping
 in forage yields. These results are
 Table 9.

both field and greenhouse conditions,
id that oats produced more than twice
y; 1 forage for the season when allowed
11a height of 14-16 inches than when
soon as they reached 3-4 inches or 8-
 height. Clipping at 3-4 inches was
'5 ental than clipping at 8-10 inches.
jWGPG reduced more than those of bar-
"r field conditions, barley yields from
 clippings were 10-percent less than
65' 16-inch clippings, while the yields
gere reduced 59 percent with the same
 The effects of clipping were more
he greenhouse than under field condi-
ping effects probably are more severe
a1 livestock grazing effects because
“moves all the forage at one time.

lvious greenhouse study at the same
  ‘d shown that the oat yield was reduced

 When the plants were clipped each
gglfeached a height of 3-4 inches. Clip-
“lants one time at 3-4 inches high fol-
_ gular clipping at 10-12 inches reduced
‘ f? percent, as compared with regular
,X;10-12 inches.

We studies, the best root development
id barley occurred when they attained

c1 OF CLIPPING ON THE FORAGE PRODUCTION or
 VEY, CRYSTAL ClTY

 Height Yield in Percent

at which Number oven-dry reduction in
 clipped, of grams of yield due
 inches clippings forage to clipping
Oats
3 4 8 7 83
8 l0 5 l5 63
l4-l6 2 40
3- 4 9 4l4 75
  8-10 5 669 59
p; 4-16 3 1637
 Barley
 - 4 8 6 76
 -10 5 15 4o
 -16 3 25
 3- 4 ll 518 5l
 s-1o 6 95a 1o
3:14-16, 4 1061

Figure l. Growth of oat varieties in clipping management study.
College Station, February.

a height of 14-16 inches before clipping. Plants
clipped at 3-4 inches showed poor root develop-
ment, and those at 8-10 inches showed moderate
development. This points out the importance
of allowing small grains to become well estab-
lished before pasturing livestock on them.

Studies carried out at College Station, Table
10, further emphasize the importance of proper
management of small grains used for winter
pasture. Oats, clipped each time the plants
reached a height of 4-6 inches, produced only
1550 pounds of forage. When clipped each time
the plants attained a height of 10-12 inches, yield
amounted to 3170 pounds or twice as much. Fig-
uredl shows the growth of plants in this clipping
stu y.

The plants in this study had reached a
height of 4-6 inches on November 13 and did
not reach a height of 10-12 inches until January
3, or 6 weeks later. The grower must decide
whether the production during this period is
more important than greater total production
for the season. However, the value of allowing
oat plants to become well established before graz-
ing starts is evident, and if frequent close utiliza-
tion reduced production by as much as 1500

TABLE lO. AVERAGE FORAGE YIELD, POUNDS PER ACRE, OF TWO
OAT VARIETIES CLIPPED AT TWO STAGES OF GROWTH, COLLEGE
STATION

Season of ha rvestl

Height of
cutting, Early Mid- Early
inches winter winter spring Total
4- 6 485 450 6l5 T550
l0-l2 985 T005 1180 3170

lDates of Clipping: EARLY WlNTER——(4-6 inches) November l8,
December l, December l7, January 3; (l0 to l2 inches) January 3.
MlD-W|NTER——(4-6 inches) January 20, February 9, February 24;
(l0-l2 inches) February 24. EARLY SPRlNG—(4-6 inches) March 7,
April l5; (lO-l2 inches) March 7, April l5; (l0-l2 inches) April l5.

7

TABLE ll. FORAGE PRODUCTION OF OATS OF DIFFERENT GROWTH HABITS AND WITH VARIOUS CLIPPING FREQUENCIES, COLLEGE;

Figure 2. Mid-winter
College Station of a '
variety (left) and a y,
variety of small grain f

"
‘

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Pounds of air-dry forage per acre 

Early Harvest
growth frequency, November l0 December 2O February I March l4
habit days to December 20 to February l to March l4 to May 3

Erect l0 220 350 290 l00
2O 420 780 630 200

4O 390 790 620 240

Maturity 2550

Average 340 640 5l0 770

Prostrate l0 210 450 490 I30
2O 230 560 (>80 310

4O 320 680 960 340

Maturity 2370

Average 250 560 7l 0 770

pounds per acre, the value of production at this
level might be questionable.

The influence of clipping practices on root
and crown development as well as on forage pro-
duction has been studied at College Station. An
erect and a prostrate variety of oats, Figure 2,
were clipped at 10, 20 and 40-dayintervals and
at maturity. Supplemental irrigation was used
to prevent’ growth stoppagefrom drouth and to
permit regularity of clipping. Air-dry forage
produced with these treatments is shown in
Table 11. By December 20, a greater tonnage
of dry matter was produced on plants unclipped
t0 that time (40-day interval) than on plots that
had been clipped two or four times. Clipping
at a 10-day interval reduced production of the
erect variety 48 percent when compared with
the 40-day clipping and 58 percent when com-
pared with clipping only at maturity. The reduc-
tion in the prostrate variety yield due to fre-
quent clipping was slightly less than for the
erect variety.

3

Crown and root development was p.
frequently and followed the same pattern
production. Average root and crown We
the end of the growing season are given i1
12. Apparently, more frequent clipping 
tillering and resulted in a smaller crow

'1

TABLE t2. TOP AND ROOT GROWTH OF OATS OF If,
GROWTH HABITS AND WITH VARIOUS CLIPPINGFR
LUFKIN FINE SANDY LOAM SOIL, COLLEGE STATION 

gligil/lr/h frlgggléiily Pounds of air-dry matters’.

habit days Forage Crowns 
Erect I0 I060 490
20 2030 8T0
40 2040 ll40
Maturity 2550 2720
Prostrate l0 I280 760
20 I780 I600
40 2300 2190
Maturity 2370 3170

  
 
  
   
  

Plots unclipped

1
’ — - - — - . 
a

   
   
 
 
  
 
  
  
  
 
 
  
  
  
 
  
  
  
 
 
  
 
  
 
 
  
 
 
  
 
  
 
  
  
 
  
  

fl’ 1 | 1 n | n 1 n I l
Hi9 1/2 1/16 1/30 2/13 2/27 3/13 3/27 4/10 4/24 s/e

Dates

jverage cumulative growth of three oat varieties on
‘Andy loam, College Station.

expected to reduce top growth. Crowns
fmost frequently clipped plots weighed
 rcent as much as those from plots
p," 40-day intervals. Approximately half
Ave-ground development was in the
‘tllllfit it was below the mower blade
-18 -

production in the top foot of soil was
 frequent clipping, ‘but to a lesser
n top and crown development. Roots
fuently clipped plots weighed 30 per-
 an roots from 40-day clipping. That
 ction was poor this particular season
unt for theopoor growth obtained in

a t lative growth of three oat varieties
‘ithout the effects of clipping has been
fgure 3. Two sets of plots were estab-
fe set of plots was unclipped and the
ped at regular intervals. Due to in-
eather, clipping was delayed until late
hen more than 2,000 pounds of forage
Qproduced. Total cumulative growth
 o treatments is shown in Figure 3.
following clipping was extremely poor
f'cates that utilization may be delayed
especially if all the top growth is to be
nd if regrowth is expected. Any de-
pfoliation of small grains is somewhat
i}: to total development of the plant.
f these studies, maximum total produc-
obtained with a single harvest at the
 growing season.

tion in root development from fre-
ping could result in reduced ability of
l to take up moisture and nutrients.
to cause it to suffer from drouth earlier
if‘?- with extensive root development.
¥i.¢rown development reduces the area
 growth takes place and leaves more
 exposed to evaporation and water loss
?-0ff. All of these factors and others

.- ‘$-
Ll.
4.:

r in clipping studies.

are important in developing a grazing manage-
ment program. The available data indicate the
desirability of delaying the first grazing until
the plants are well established. Subsequent
grazing or utilization should provide for either
adequate residual leaf area or an adequate recov-
ery period between grazings or utilization.

GROWTH BEHAVIOR

The growth of small grain varieties depends
on light, soil and air temperatures and soil mois-
ture and nutrients. Varieties may differ in their
response to management practices and environ-
mental factors. In establishing a forage pro-
gram, it would be valuable to know the response
to reduced light, the minimum and ,maximum
temperatures at which small grains stop growth
and whether varieties respond alike to these
conditions. Should growth stop below certain
minimum temperatures, accumulated growth
must be depended on for grazing during such
periods.

Response to Management

The growth-behavior pattern of oat varie-
ties has been studied at College Station and Iowa
Park for 2 years. Three varieties differing in
growth habit and cold-hardiness were used at
each location. The varieties were seeded in 12-
inch rows and sampled for above-ground growth
at weekly intervals. Since the plants were re-
moved at ground level, the data presented in the
figures that follow include the weight of crowns
and are higher than those normally obtained
Forage harvesting was im-
posed on one set of plots at College Station.
Water and fertilizer were applied at levels to pre-
vent there being limiting factors in plant growth.
A continuous record of air temperature was
made.

Accumulated growth on plots harvested three

times during the growing season is presented in
Figure 4. With all above-ground parts har-

vested, the rate of growth of the three varieties

    
   

6 ' _ --- Erect non-winter hardy j
---- -- Prostrate hardy j
-'— - Erect hardy

—§1§_;¢

Forage harvested
Jan. 3
Feb. 15
Apr. 1

Tons of dry matter per acre
4>
I

l l l l l l l l I l l l l l l l l I l l j 1 l l
12 19 25 3 10 17 24 31 7 14 21 28 4 11 18 25 4 ll 18 25 1 8 15 22 29 6

Nov. Dec . Jan . Feb . Mar . Apr .
Dates of sampling

Figure 4. Cumulative growth of three oat varieties grown on Lufkin
fine sandy loam.

9

Was very similar. Their growth habits normally
are different, and it would not be expected that
the yields would be equal using normal harvesting
procedures. However, when all above-ground
growth was measured, the three varieties pro-
duced about the same until the first date of
harvest. The erect nonwinter-hardy type failed
to recover and produce as much after the first
clipping. After the second clipping, its produc-
tion dropped even further below that of the
other two varieties.

All three varieties were slow in their recov-
ery following each clipping. As much as 4-5
weeks were required for recovery and any appre-
ciable growth. During this period, there was
some shoot growth but little change in total plant
weight. Apparently food reserves in the crown
were being transferred to develop new shoot
growth, resulting in little change in the accumu-
lation of above-ground dry weight. When the
first clipping was delayed until late January,
Figure 3, reco-very was never satisfactory. These
results indicate that clipping may be delayed too
long as well as be too- frequent, and the effects
may be much the same. These results also show
that a longer rest period than is usually pro-
vided between grazings would be desirable if
rotation grazing is practiced.

Response to Temperature

To study the growth response of plants to
temperature, plots were clipped throughout the
season. Growth to each date was determined
by sampling an unclipped 2-foot section of row.
Average accumulative growth of the three va-
rieties by weekly periods is shown in Figure 5.
Growth was more uniform at College Station
than at I-owa Park. This is to be expected since
winter temperatures at College Station are more
suitable for continuous growth. The only major
break in growth at College Station during the
first year came in March. The temperature
dropped below freezing for a short period, im-
pairing growth and evidently producing some
top kill since accumulated growth was reduced
during this time. Growth was almost uniformly

6 , ‘ College Station
Year 1

    
  
 
  

 

College Stati?
Year 2 ‘ £)

Iowa Park

Tons of dry matter per acre

l I l l l l l l l l l l I l I l l l I I l l I I I l l‘
2T4 1118 25 l 8 15222951219265 12 19262 9 1623 3071A 2128
Dec. Jan. Feb. Mar. Apr. May
Date of sampling

Figure 5. Average cumulative growth of small grain varieties at two
locations in Texas.

l0

>1

  
 
  
 
 
  
  
 
 
 
  
 
 
  
 
 
 
  
 
 
  
 
  
 
  
  
   
 
 
  
 
   
  
  
  
 
 
 
 
  
  
 
 
  
  
  
 
 
  
 
  
  
  
  
  
 
 
  

av

continuous at College Station during the
year. ..

Growth was more irregular at 10W.
probably because conditions unfavorable I,
growth occurred more frequently. Th
breaks in growth occurred in mid-J
early March and early April. During
15 days of January, the temperature 
below 20° F. on several occasions, and i;
age temperature for the “entire period "
363° F. In early March and early Ap '1
temperatures probably would be more
because of the more advanced stages of
of the plants, the temperature dropped J
ing on 1 or more days. Growth stopp
actual loss of dry matter during those;
are apparent in Figure 5. Less than 50:
of the total growth at Iowa Park had Q
duced by March 26, whereas 75-100 pe j
the growth had been produced at College;
by this date. One to 2 tons more fo i
been produced at College Station than f?
Park by March 26. Although growth "
duced at Iowa Park during the winter, 
tion was less reliable from the grazin-
point than at College Station. These
point up the need for more critical j
management in the Texas areas having?
xvinters. i"

Although growth behavior of the i"
rieties without clipping is not presente
interactions at Iowa Park may be poin
In the early part of the season, all thr
ties behaved about alike. Even during 
cold period in January, there was no di‘
in the growth of the three varieties even
they differed in winter-hardiness. D A
freezing period in early March, the er
winter hardy oat produced no growth
weeks, the erect winter hardy varie 
slight growth and the prostrate type ma
growth. Evidently the stage of gro -=
major factor in determining the influence?
temperature on growth. The erect typ
in a critical stage of growth in earlyf
while the prostrate, being later in matu ’
not reach this critical stage until early f

The relationship of oat growth to m ‘p,
perature was calculated. Temperatures V
every 3 hours were averaged in computi
temperatures. The regression of growth f
temperature, shown in Figure 6, was 1.-
nificant. The correlation coefficient W
with 37 degrees of freedom indicating
relationship between the two variable;
regression of growth on temperature -<'
as a straight line relationship gave a Q ,
64 and indicates little or no growth r
average daily temperature of 40° F. Q
average with each 1° change in tem.‘
biweekly growth changed 64 poundsfwi
temperature limits of these studies. It i‘, a
ent from the regression figure, which 
on 3 years of data at College Station an}
at Iowa Park, that other factors also in

  
  
   
  
   
  
   
   
  
  
  
   
  
   
   
   
 
   
  

45 50

g f? It is difficult t0 maintain moisture at

um level, and this was a contributing
"$1 variability in growth rate. Sunlight
* ‘fried and may well have contributed to
tion in plant growth. Some o-f the vari-
uld have been due to sampling error
 a 2-foot sample was taken from each
jthe stands were not completely uniform.

_-’ regression line shown is ‘based on a
 atio-n. Growth probably would not be
lpecially at the lower and upper limits.
fession line would indicate no growth
 average temperature of 4O to 42° F.
wth was measured at Iowa Park at tem-
 below this level, indicating that the
not linear. The data indicate that when
irature drops below a mean of 45° F.,
 h may be expected.

 high temperatures under field condi-
encountered only at or near the end of
 growth cycle of oats, it was not pos-
“determine at what point or level high
 res could becbme a limiting factor in
pwth. It is evident, however, that high
g res seldom limit oats grown for forage

e studies indicate that residual or sur-
 h rather than continuous growth must
g» on for continuous grazing 1n areas

55 60 65 70
Average weighted temperature (°F)

iifiegression of oat growth on weighted air temperaturefiollege Station and Iowa Park.

in which average temperatures may be below
45° F. for periods of several days.

Response to Moisture

Yield in response to moisture was not studied
under controlled conditions, but some informa-
tio-n can be gained from the data obtained at
several locations over a period of years. Rain-
fall varied by location and from season to sea-
son at a given location. Figure 7 shows the
total rainfall for the growing season, September
through April, for a 6-year period at six loca-
tions in Texas. Average forage yield of all
varieties grown at each location during the entire
6-year period also is shown.

Yield data are not available fo-r all years
at Angleton. The available data indicate a nega-
tive relationship between yield and total rain-
fall. The lowest rainfall during the growing
season was about 17 inches, which apparently
is adequate for good production. This is an
area where drainage is a problem in periods of
high rainfall. Apparently, poorer performance
in high rainfall years is related to the drainage
problem.

Results at Temple indicate a good relation-
ship between yield and rainfall below 20 inches.
Above this amount of rainfall, the yield levels
off at about 11/2 tons of air-dry forage per acre.

ll

   
  
  
 
 

Rainfall apparently was adequate during all fall. Thus, the yield level remained r,
years of the test at Kirbyville. The studies were same through the test Deriod- l",
located on a deep sandy soil which apparently Rainfall at Gilmer, which was th
had no drainage problems in years of high rain- location to Mount Pleasant, varied from y

..;.

—-- — Forage

   

   

Rainfall
3 I. Beeville ‘T "
\ \
\ /
/ \
\\ I \
" \
d I \" § fl
| I I I

H \
$ . . *5
>3 - P Klrbyvll 1e 
H l
G) :_
Cu 
m 
54 ;
g c n ( i i 
o. f

a "
o0 
cu 
H .
o I — _
U-l ‘-
l-H i“
0 .¢_
m i;
a , 
H I | n n a
Nacogdoches .‘

- . i

\ i

\ \ a

n I 1 n | I n n j a 1 1 

52-3 53-4 54-5 55-6 56-7 57-8 52-3 53-4 54-5 55-6 56-7 57-
Year 5

Figure 7. Average forage yield of small grain varieties and total seasonal rainfall, Beeville, Angleton, Temple, Kirbyville, g
and Nacogdoches. .~Y

12

  
 
  
  
 
  
 
  
  
 
  
  
  
 
  
  
  
  
 
  
 
 
  
 
 
  
 
  
 
 
 
 
 
 
  
 
  
 
  
 
 
  
 
  
 
  
 
 
  
 
  
 
 
 
  

n 40 inches. Yield was related to
wy in the years of lower rainfall. The
low yields in 1956-57 and 1957-58 are
_ derstood. The test plots were located
If? sand which should have been well
_t is possible that rainfall in excess of
resulted in some leaching of nutrients,
‘fing yields.

 ainfall and yield varied considerably
voches, but the relationship between
gariables was not close. This was a
gtion, and the test area was moved
 period. It is possible that soil effects
Vere the more important since rainfall
‘f’ inches except for 1 year.

all is important in determining ex-
‘ds of small grains grown for forage.
y be insufficient for maximum pro-
 many areas of Texas. The Coast
less likely to experience a deficiency,
fr: of the flat topography and heavy
isive moisture for optimum growth
f» countered. Failure to obtain better
ps between growth and moisture in
l: may have been due in part to rain-
yution patterns, inadequate nutrition
gement effects. The incidence of dis-
 related to humidity and general mois-
;'tions. Several outbreaks of disease
sir the yield-rainfall relationships.

 Cutting Height

 production and total above-ground
 growth of a prostrate oat variety, an
ariety and annual ryegrass were deter-
gthree cutting (stubble) heights. The
 planted in mid-October and harvested
lif intervals at stubble heights of 2, 4
‘hes beginning December 21. Total
nd growth including harvested ma-
f determined at weekly intervals begin-
l- second cutting. Leaf area index also
y, ined weekly.

fforage yield was not significantly in-
A, height of clipping, Table 13. Winter
I yields of oats and ryegrass were very
l. 4 and 6-inch stubble heights. Over
f» of forage had been harvested from
1 2 inches by the end of January while
unds had been harvested with the 6
g height, Figure 8. The short heights
as much total yield only because the

‘ l’! FORAGE YIELD OF OATS, RYE AND RYEGRASS CUT
vi HTS AND TWO FRlfiQUENClES, COLLEGE STATION

Pounds of dry forage per acre

Rye Ryegrass Average
1764 3008 2317
2460 2550 2427
1848 2750 2364

Clipping height
2-inch

3000 '

2000

1000 I

3000 '

2000

Pounds of harvested dry forage per acre

1000

 

Dates of harvest

Figure 8. Cumulative yield of rye and oats clipped at 28-day
intervals, College Station.

final clipping was made at a uniform 2-inch
height. Rye which was more upright in growth
produced more winter forage with the 4-inch
height.

Total above-ground cumulative growth of
oats and rye was favored by the 6-inch clipping
height, Figure 9. Most of this growth was
apparently below the 4 to 6-inch height. Since
midwinter is a more critical period for available
green forage than early spring, the improved
growth of the plant with mild clipping during
this period is of less significance than the utiliza-
tion of the growth.

Since total cumulative growth is favored by
mild defoliation, it might be assumed that growth
was more uniform with the less severe defolia-
tion. However, this was not found to be the

Clipping height
2-inch _
3000 ,- --— 4- inch
------ 6-inch

2000 5

 

1000 -

4
00o - A
.

3000

Pounds of dry matter per acre

2000

 

1000 P

l l l I I | l l
1-18 1-25 2-1 2-8 2-16 2-23 3-8 3-15 3-23 3-29

Dates of sampling

Figure 9. Cumulative growth of rye and oats clipped at 28-day
intervals, College Station.

13

case. Clippingfregardless of the clipping height,
resulted in a decrease during the following weeklil
or weeks in accumulated Weight of the plants. '
These weight losses were more severe with
greater stubble heights than with the lesser.
Even though the weight losses were more severe,
recovery was more rapid. These results suggest
that initial regrowth is made at the expense of
reserves stored in the crown. The less severe
defoliation would favor a greater storage and
more potential for weight change. Greater
reserves would result in more rapid recovery.
Frequent close utilization would restrict the
building up of stored carbohydrates and thus the
potential for weight loss would be limited.

Height of cutting resulted in significantly
different leaf-area patterns. The relationship of
leaf area to growth during the succeeding week
had a correlation coefficient of 0.243 which is
highly significant. Even though this relation-
ship was significant, it was not high and sug-
gests that many other factors than the amount
of leaves influence regrowth of these plants.

The winter of 1959-60 had extended periods
of overcast when limited light retarded growth.
Under these conditions the effect of differences
in leaf area might be reduced. The growth be-
havior of the plant suggests that initial regrowth
following clipping is made from stored reserves
rather than from new photosynthetic products.
Since significant differences in leaf area existed,
this growth behavior might suggest that the old
or basal leaves are inefficient or ineffective and
that new leaves produced from stored reserves
are necessary for photosynthesis. Leaf area
actually decreased further during the week fol-
lowing clipping with most treatments indicating
that many of the basal leaves died and that this
leaf loss exceeded new leaf growth.

If it is assumed that the old leaves are in-
efficient in photosynthesis, a better correlation
of leaf area with growth might be obtained by
omitting the week following clipping when only
old leaves were present. The correlation coeffi-
cient for leaf area and growth using an average
of the leaf area in the second and third week
following harvest and total growth in the third
and fourth weeks was significant, r : 0.520.
This was based on the periods following the Jan-
uary 18 and February 16 harvests.

The results of these studies suggest that
prostrate varieties of oats and ryegrass may have
to be utilized at fairly short heights in midwinter
if forage is to be available at critical periods.
These practices do» not favor maximum plant
development, but a compromise seems necessary.
Greater clipping heights favor total plant devel-
opment but not necessarily uniformity of growth.
Winter annual plants respond to clipping with a
loss in total accumulated dry weight. With
greater clipping heights, recovery is more rapid,
probably because of more stored reserves and
greater residual leaf area to promote recovery
growth.

14

 
 
 
 
 
 
  
  
  
 
 
 
 
 
 
  
  
  
  
  
  
 
 
 
   
  
 
 
 
  
  
  
 
  
 
 
 
 
 
 
   
  
 
  
 
 
  
 
 
  
 
  
 
 
  
 
  

Response to Light Intensify

One of the major environmental
probably limiting growth of winter crops 1
Relatively little information is available,
response of agronomic crops to- light or f‘
available crops differ in their response to
light. One method of increasing produ
winter crops would ‘be using or developi
suited to growth under low light conditio
eral crops have been evaliiated under or
trolled environment and field conditions;
assumption that if reduced light does nf
growth, light is not a major factor in theT
tion of that crop. f

Five cool-season forage crops (ryegr‘
barley, oats and wheat) were planted in‘
Norwood fine sandy loam soil. Followil
gence the plants were thinned to 25 pl‘
pot, trimmed to a uniform 2-inch height 
formly watered with a liquid complete f {Q
The pots were placed in two growth ci
operating at alternating day-night temp
of 72 and 60° F. Maximum light inten
maintained in one chamber, and light
other chamber was reduced approxim
pertclent. The day and night periods were i
eac . ‘

When the plants reached an appr
height of 6 inches, they were cut to w.
stubble height, and the clippings were d .
weighed. The stubble from one-half the
each chamber was removed at the soil 
dried and weighed, and the pots were
tinued. Pots of two of the five remainin
in each chamber were switched to balan f
ous light effects. The pots were again ,
with a complete nutrient solution, and ~43
were allowed to grow to a height of 6;
followed by a second harvest. ‘

Three winter annual crops (ryegrj,
and oats) were seeded on Lufkin fine san
soil October 24 in 12 and 24-inch rows?
rate of 75 pounds of seed per acre. Li
reduced 25 percent beginning December",
28 days and again January 31 for 28 1;;
treatments including shading were repli =3
times. 

In the field test, plant samples were
at weekly intervals and separated into 
stems. Air temperature was recorded Y
Dixon recording thermograph, and lig
recorded with a Pyrheliometer. .1

' .1

Winter-annual Crops (Growth c u
Rye and ryegrass showed the least effect §
level on yield in the growth chamber. 
regrowth, wheat showed the least effec
duced light followed by ryegrass. Howev
differences were not great, Table 14. _,
was definitely less with reduced light, :-
reduction of stubble weight caused by p}
light in all cases indicated a lack of carbo
storage in the presence of limited light. 

Previous light level also influenced r
following cutting. Maximum yields W.

 
   

‘RAGE EFFECTS OF LIGHT LEVELS ON GROWTH
ANNUAL CROPS IN A GROWTH CHAMBER

irst cutting Second cuttingz

Stubble Previous

weight light Yield

0.1323 High 0.1840
Low 0.1586

0.0911 High 0.1541
Low 0.1252

   
  
    
 
  
   
  
   
   
 
  
   
    
  
    
  
   
  

I approximately 4O percent in the low light chamber.
jot dry matter per pot.

.2

 plants maintained throughout at
; educed light had approximately the
;on regrowth whether the reduced
,1! the initial growth or the regrowth.
[he effect of reduced carbohydrate
j e stubble with reduced light was
h» t as the direct effect of reduced
 Wth. Regrowth from plants main-
yuced light throughout was approxi-
lcent as great as from plants main-
'hout at high light.

ta do not suggest any major differ-
{the varieties in response to limited
barley and oat varieties may have
.,more sensitive than Wheat, rye and
egrass showed slightly fewer over-

P!
5

nnual Crops (Field): Plant devel-
6' her expressed as total plant weight
Tmponents, was less on a unit-area
ye rows than in narrow rows; the
from 30 to 50 percent, Table 15.
nexpected since plant growth at the
 measurements was inadequate to
 ire area between 24-inch rows.

juction reduced growth approxi-
‘rcent in late December and early
I e trend started out the same in
[it the pattern was reversed the last
"urement. In every instance shaded

a

Average Temperature (°F)

57 55 52 57 48 55 58 61 54 59 S5
| n I

I l l l I

30

    
  

12" row

Grams per square foot
N
c
I

 
  

Full sunlight
iF-X-X- 757.. sunl ight

I l l I I l I l I |
12/13 12/20 12/27 1/3 1/10 1/17 1/24 l/31 2/7 2/14 2/21
Date of sampling

Figure 10. Cumulative growth of winter annual crops and response
to reduced light. -

plants exceeded unshaded plants at the final sam-
pling date.

The growth patterns are shown in Figure
10 along with average maximum temperature
for each measurement period. That the two row
spacings showed the same pattern of response to
shading would suggest no major difference in
light utilization efficiency due to row spacing.
The reversal of the shading effect at the final
sampling period is assumed to be associated with
temperature and a generally very poor light situ-
ation. A below freezing temperature occurred
on February 17, and there were only two days
of sunshine during the period. Covered frames
were used to reduce the light. Even tho-ugh they
were elevated at least 12 inches to allow air
circulation, they no doubt offered some protec-
tion from the low temperature. The lack of light
would have prevented recovery in the exposed
plots, whereas the protected plots likely con-
tinued to make some growth (elongation) from
stored reserves in the stubble.

These studies indicate that major winter
annual crops do not differ greatly in sensitivity
to limited light. The data also indicate that the
crops are restricted in growth by limited light as
well as by low temperatures.

ERESPONSE OF WINTER ANNUAL CROPS‘ TO REDUCED LIGHT UNDER FIELD CONDITIONS

  

Date of sampling

    

    
  
  
   
  

 Light December January February

treatment 1 3 2o 27 3 31 7 14 21
if Plant weight (grams per square foot)

‘unlight 8.3 12.7 18.6 18.7 23.6 27.7 28.2 27.3
_. ent sunlight 8.3 12.8 15.0 17.0 23.6 25.8 25.8 31.1
unlight 6.8 8.4 13.5 11.9 16.2 22.9 19.8 18.8
 ent sunlight 6.8 8.2 12.5 9.8 16.2 20.4 17.8 20.6
  Leaf weight (grams per square foot)

lsunlight * 6.4 9.6 13.7 13.9 17.1 20.3 21.7 21.4
i- ent sunlight 6.4 9.9 11.2 12.7 17.1 19.2 20.2 22.3
‘sunlight 5.3 8.3 10.8 8.8 11.4 16.8 17.8 14.4
 ent sunlight 5.3 5.9 9.7 7.1 11.4 15.0 13.3 14.9

 perature (°F.) s7 ss s2 47 s1 s4 s9 ss

 

   

‘rass, rye and oats.

15

NITRATE ACCUMULATION

Nitrate accumulation sometimes occurs in
small grains, and animal toxicity may result from
grazing small grains high in nitrate. Many fac-
tors, both internal and external, influence nitrate
accumulation. A few of these factors have been
studied with oats grown under field conditions
on fine sandy loam soil at College Station. These
factors have included time and rate of nitrogen
application, form of nitrogen, plant parts and
day-night fluctuations in nitrate content of plant
tissue.

A plot was seeded to oats in mid-October
and fertilized with 40-40-40 at time of seeding.
On February 1, two sources of nitrogen were
applied at the rate of 100 pounds of N per acre
onplots 5 by 10 feet in three replications. Be-
ginning February 14, plant samples were col-
lected from each plot at 3-hour intervals for a
period of 48 hours. The plants were cut at the
ground level and dried immediately at 180° F.
Following drying, each sample was separated
into leaves versus sheath and stem tissue. The
samples were then ground to pass a 40-mesh
screen and were analyzed for nitrate.

The data in Figure 11 indicate a source of
nitrogen effect. a diurnal cycle in nitrate content
and a morphological difference in nitrate accum-
ulation. Obviously sheath and stem tissue was
higher in nitrate than leaf tissue. With few
exceptions this occurred with all treatments and
times of collection. Source of nitrogen effect is
most apparent in the stem tissue, the oxidized
form resulting in the greatest accumulation. A
level of approximately 1.0 is considered to be
approaching or in the area of potential toxicity.
This level was exceeded or even approached only
in stem tissue with an oxidized form o-f nitrogen.
Nitrate accumulation with nitrate fertilization
was greater during dark periods than light
periods. but no diurnal cycle is evident with
ammonia fertilization. The sampling period was
characterized largely by mild temperatures, com-

TABLE 16.

NITRATE CONTENT (PERCENT NITRATE) OF OATS WITH VARIOUS FERTILIZATION TREATMENTS, COLLEGE STATION

  
   
  
   
  
 
    
  
  
  
 
   
  
   
   
 
 

""4

Percent Nitrate

N03
Stem
 __ Leaf
I 

9 12 3 6 Q,
Day "

 

9 12 3 6
Day

9 12 3 6
Night

Time of day or night

Figure 11. The influence of source of nitrogen, plant ~-
of day on nitrate content of oat tissue. 

plete cloud cover and periodic light rail
for some clearing during the final 3-6 h.’

Following the initial sampling, t,
were harvested, but no additional nitr
applied. A second set of samples was i.
14 days after the initial sampling. 
trends in nitrate content were eviden
second sampling — two weeks had elaps,
a greater time interval between fertiliza
sampling, the period was characterized 
rather than cloudy weather, and new;
was involved. Any or all of these facto
have caused the difference in results. i
est nitrate levels encountered were w,
the suspected toxicity level. Obviouslyzf
accumulation does not always occur even“
or in stem and vascular tissue or with .
fertilization. ‘

To determine whether either time or}
of nitrogen fertilization is important in:
accumulation in winter forage, oats wer
in October and fertilized with phosph

r

Pounds of N and date Part

Date of sample

of Gpplicotiorfi of December January - February

October December January plant 22 29 5 13 26 1 9 18
40 Leaves .45 .32 .75 .96 .39 .32 .41 .16
Stems .97 .88 .98 .92 .76 .79 .42 .10

120 Leaves .52 .55 .69 1.05 .44 .35 .43 .29
Stems 1.38 1.35 .95 .95 .57 .46 .36 .43

60 6O Leaves .69 .65 .78 .93 .51 .40 .54 .37
Stems 1.63 .77 .87 .60 .57 .76 .54 .62

4O 40 4O Leaves .22 .36 .61 .46 .58 .29 .33 .56
Stems .56 .88 .91 .97 .72 .50 .62 .37

Leaves .47 .47 .71 .85 .48 .34 .43 .34

Date average3 Stems 1.14 .97 .97 .86 .66 .63 .49 .38

‘All plots received 0-40-40 prior to planting.

“On the average, stems were significantly higher in nitrate than leaves.

“Dates differed significantly.
16

  
 
  
  
  
 
 
 
  
  
  
  
  
 
 
  
  
 
  
 
  
  
 
  
  
  
 
 
  
 
  
 
 
  
 
 
 
 
  
 
 
 
  
  
 
  
  
 
 
 
 
 
 
  
 
  
 
  
  
  

_ lanting. Nitrogen in the form of
f» nitrate was applied at the times and
 - shown in Table 16. Nitrate deter-
[were made on samples taken at inter-
3 December 22 to February 18. The
jere divided into those portions above
Lmower cutting height and labeled as
stems, respectively. Stem tissue or
.-,, rt 0f the plant was higher in nitrate
tissue. Stem tissue from plots receiv-
' e heavy nitrogen application in Octo-
fher in nitrate in late December than
e from plots receiving smaller incre-
ft consistent trends or differences seem
ciated with December or January
 of N up to 60 pounds per acre. These
jicate some effects of nitrogen fertiliza-
1Q» one of these levels would be considered
;_ a toxicity standpoint.

e accumulation is influenced by many
id may change greatly within a few
ihese samples were taken during late
ours except as indicated in Table 15,
 not necessarily the peak period. Thus,
ffound in these studies do not neces-
esent maximum or even average levels
7give a fairly good indication of treat-
Vts. The results suggest that an oxi-
 of nitrogen may favor nitrate accum-
gpecially in mid-winter. Heavy rates
e application might influence nitrate
on under favorable conditions. There
dication that nitrogen application in
samounts or increments is a major fac-
I fate accumulation in small grains.

GRAZING1

 zing research was started at the
i311 University Research Center at Mc-
}fall 1958. Experimental pastures, 10
 , were located on gently sloping land,
{class II, medium depth Houston clay
V; 1959-62, a fertilizer treatment of
_' acre was applied at planting time
pdressing of 20 pounds of nitrogen
 January. During the 1963-65 period,
per rate was increased to 50-40-0 at
lime without topdressing in January.

Eng variety of oats was used in 1959
" Suregrain oats were used in 1961.
" New Nortex and Bronco oats were
12. Alamo-X, new Nortex and Bronco
"es were used during 1963-65. The
fsown at the rate of 96 pounds of seed
and planting dates varied from October
 20 during 1959-62. During 1963-
vnting dates ivaried from September 15
' 10. "l

“teers weighing about 400 pounds, rang-
1350 to 500 pounds, were purchased in

Tported in this section was taken from Texas
 Experiment Station Progress Report 2473,
y M. J. Norris and W. E. Kruse, Texas A&M
>_Research Center at McGregor.

the fall and used on the pastures. The animals
were weighed at 28-day intervals except during
rainy weather. Stocking rate adjustments were
made on weigh day using the put-and-take system
to adjust the animal numbers for the forage
available. Stocking rate adjustments were made
to maintain a visual surplus of forage on 25-30
percent of the pasture. Grazing was continu-
ous. Animals were not taken off pastures dur-
ing wet weather, and no supplemental feed was
given livestock.

Summaries of animal performance on oat
pastures for 1959-65 are shown in Table 17. The
year column in this table designates the year the
oat crop matured. The grazing period included
the spring of the year listed and the fall of the
previous year. The calendar grazing period var-
ied from 141 days in 1964 to 219 days in 1960.
Grazing was started as early as November 10
and as late as January 23 and ended as early as
May 5 and as late as June 8.

Rainfall, temperatures and other forage
crop growing factors during this 7-year period
were erratic but provided a reasonable sample
of conditions that are normally expected at this
location.

Oat grazing results with beef cattle steers
during a 7-year period furnished realistic esti-
mates of stocking rates, animal grazing days

TABLE 17. SUMMARY OF OAT GRAZING WITH BEEF STEERS,
McGREGOR, 1959-65

Sfgjlfiierg Animal Livestock gains, pounds
acres per days Per Daily,
Year animal per acre acre per head
Winter grazing‘ 3.3 26.1 40.4 1.5
1959 Spring grazingz 2.6 39.9 100.7 2.5
Season total 2.9 66.0 141.7 2.2
Winter grazing 2.6 43.0 45.0 1.0
1960 Spring grazing 2.5 44.8 121.6 2.7
Season total 2.5 87.8 166.6 1.9
Winter grazing 2.0 49.0 97.5 2.0
1961 Spring grazing 1.1 85.8 214.2 2.5
Season total 1.4 134.8 311.7 2.3
Winter grazing 3.3 19.5 36.4 1.9
1962 Spring grazinga 2.3 44.9 96.5 2.4
Season total 2.6 64.4 132.9 2.1
Winter grazing 2.9 26.6 74.1 2.8
1963 Spring grazing 2.1 44.3 109.5 2.5
Season total 2.4 70.9 183.6 2.6
Winter grazing 2.3 16.6 14.6 0.9
1964 Spring grazinga 1.7 62.2 130.0 2.1
Season total 1.8 78.8 144.6 1.8
Winter grazing 2.2 37.6 62.2 1.7
1965 Spring grazing 0.8 98.1 193.1 2.0
Season total 1.2 135.7 255.3 1.9
Aver- Winter grazing 2.7 31.2 52.9 1.7
age Spring grazing 1.9 65.4 137.9 2.4
Season total 2.1 96.6 190.8 2.1

‘Winter grazing includes grazing to March 1.
zSpring grazing includes grazing from March 1 to end of season-
about June 1-15.

“Stocking rates were not high enough to fully use forage available in
the spring.

17

per acre, individual livestock gains and acre live-
stock gains. Under average weather conditions,
2.7 acres per steer were required for satisfactory
gains during the winter and 1.9 acres from
March 1 to about June. Livestock gains per
acre averaged 190.8 pounds per season, with 96.6
animal grazing days per acre at an average daily
gain of about 2 pounds per steer. During a more
favorable growing season, such as 1961, the
stocking rate was increased to 2 acres per ani-
mal during the winter and 1 acre per animal
after March 1, with a production of 312 pounds
animal gains per acre on 135 animal-grazing days
per acre.

VARIETIES

Small grains are the most important crops
grown for late fall, winter and early spring graz-
ing in Texas. Many varieties which give satis-
factory performance are available. Over much
of the State the crop is grown primarily for
grain but is grazed during a part of its grow-
ing season. Therefore, one of the factors in-
fluencing choice of variety is its grain produc-
tion. Practically all of the varieties that are
grown extensively are commercial grain varie-
ties. Experimental lines that show promise for
grain production are tested for forage produc-
tion. Thus, information on the forage producing
ability is available when the variety is released
for commercial production.

Oats are the predominant cereal crop used
for grazing in the central, eastern and southern
sections of the State. Other cereal crops are
included in tests in these areas, but research
work has been concerned primarily with oat
varieties. Descriptions of these varieties are
available in other publications. Varieties differ
in total production and in the distribution of
production during the growing season. Oats are
classified as spring, winter and intermediate
types. The so-called “spring types” are not true
spring types, such as are grown in the Corn Belt,
but are erect-growing winter oats of low hardi-
ness which produce early forage when fall-
seeded. Winter-type oats have a prostrate
growth habit in the fall and winter and are late
in forage production, but are cold-hardy. The
intermediate types are intermediate between
spring and winter types in these characteristics.
Wheat, barley and rye varieties also differ in
cold-tolerance and type of early growth.

Because of the major disease problems on
small grains, varieties change rapidly. Disease
is less a problem in forage production than in
grain production because disease seldom becomes
serious until early spring when the major forage
needs have been met. However, disease suscepti-

18

TABLE l8. LIST OF VARIETIES CURRENTLY ADAPTED 

PRODUCTION
Area Oats Wheat Rye
North and Ora Knox 62 Bonel
Northeast Nora Riley 67 Elbon
Texas Norwin Caddo
Alamo-X Sturdy
Moregrain -_
New Nortex 
Central and Coronado Caddo Bonel
Southeast New Nortex Sturdy Elbon
Texas Ora Knox
Alamo-X Milam
Florida 500 Atlas 66
Suregrain
Coast Prairie Coronado Milam Bonel
Cortez Atlas 66 Elbon
Florida 500
Ora
Suregrain
Rio Grande Florida 500 Milam Bonel
Plains Coronado Atlas 66 Elbon
Cortez
Ora
Suregrain
West Texas Cimarron Caddo Bonel
Norwin Tascosa Elbon
Alamo-X Concho
New Nortex Wichita
Scout
Northwest Cimarron Caddo Bonel
Texas Norwin Sturdy Elbon
Wintok Concho
Arkwin Tascosa
Wichita
Scout

      
   
   
   
  
  
  
    

bility would probably reduce forage pr,
and certainly influences availability l"
Since varieties do change relatively rapi
cific variety performance data will not,
ported in this publication. Currently, V]
which give the most consistent perform
various sections of the State are incl’
Table 18. Other varieties not named =’
satisfactory, and new ones are in the pr
being developed.

ACKNOWLEDGMENTS

Some of the data in this bulletin 
plied by Lucas Reyes, Texas A&M Un_
Agricultural Research Station at Beeville
Cook, Blackland Research Center, Temx
J. R. Wood, Texas A&M Agricultural '{
and Extension Center at Beaumont. _Y_

Seed for many of the studies were 
by I. M. Atkins and associates, Depart
Soil and Crop Sciences, College Station,
independent small grain breeders. A

[Blank Page in Original Bulletin]

Texas Agricultural Experiment Station

Texas A8cM University 

College Station, Texas 7784s 
H. O. Kunkel, Acting Director- Publication
' P05
Unind Sum