/

B-1564
April 1987

Influence of Planting Date
on Response of Winter

Wheat to Phosphorus

Billy w. Hipp*

  
  
 
 
  

.,  TTI-‘EFWT’ 

 
 
 
 
 
 
 
 
 
 
 
  
  
  
  

l
l

 

Abstract

Wheat is grown extensively in the Texas Blacklands,
and even though phosphorus (P) fertilization is a
common practice, factors that influence the magnitude
of response have not been ascertained. Field studies
were conducted over a 4-year period to determine
the influence of planting date on winter wheat
response to P. Plantings were generally made in
September, November, and December on soils that
ranged from 6 to 19 ppm NaHCO3 extractable P.
Yield response to P under cold conditions (December
planting) on soils with 6 and 8 ppm P was 86 and 60
percent, respectively, when compared to yields from
untreated plantings. Response to P was influenced
slightly by planting date on soils with 13 ppm and not
at all on soils containing 19 ppm P.

 

Keywords: Triticum aesfivum L., Blackland soil,
vertisol, temperature, fertilizer.

 

*Professor, Texas Agricultural Experiment Station at Dallas,
17360 Coit Road, Dallas, Texas 75252

    

 

THE TEXAS AGRICULTURAL EXPERIMENT STATION! Neville P. Clarke, Director! The Texas A8iM University System! College Station, Texas

Introduction

Wheat (Triticum aestivum L.) is the major crop
grown in the northern portion of the Blackland Prairie
of Texas. It is planted in the fall or early winter and
harvested the following June. Applications of P
fertilizer are generally made but response has been
erratic. Research conducted in the area has shown
that P fertilizer is required for optimum yields (3, 4),
but all factors influencing the magnitude of P response
have not been determined. ln Montana (1), P response
by spring wheat was influenced by soil moisture and
planting date. The importance of adequate P during
early growth stages has been demonstrated for several
crops. Boatwright and Viets (2) found that adequate P
supplied during the first 5 weeks of wheat growth was

enough for maximum yield. Spinks and Barber (5)

indicated that applied P was more important in
nutrition during the first 4 weeks of growth but
indigenous soil P was the most important source after
4weeks.

Field studies were conducted at four locations from
September 1977 to June 1981 at the Texas Agricultural
Experiment Station at Dallas to obtain information
regarding factors influencing P response by wheat
grown on soils of the Texas Blacklands.

Materials and Methods

Soil at the experimental sites was Austin silty clay
(Entic Haplustolls), except in 1979 when the studies
were conducted on Dalco clay (Udic Pellusterts).
Sodium bicarbonate extractable P at the Austin silty
clay sites was 6, 8, and 19 ppm in 1977, 1978, and
1980, respectively. The Dalco clay site in 1979 con-
tained 13 ppm P.

Wheat (cultivar ‘Sturdy’) was planted with a grain
drill at three dates during each year of the study. The
dates of planting were September 20, November 15,
and December 15, 1977; September 20, November
15, and December 18, 1978; September 18, November
6, and December 10, 1979; and October 5, November
11, and December 4, 1980. These planting dates
allowed a wide range of temperatures during the
early stages of plant growth. Average air temperatures
for the 5-week period following each planting date
are given in Table 1.

Phosphorus treatments of O, 25, and 5O kg/ ha (as
0-46-0 or 0-20-0) were applied with the seed in the
furrow at each planting. Plots were 3 x 6 m with rows
20 cm apart. Each treatment was replicated four times
in ‘a randomized block design. Each plot received 8O
kg N/ ha as NH4NO3. All other nutrient levels were
deemed adequate for wheat production by standard
testing procedures for the area.

Yield estimates (based on 14 percent moisture)
were made by cutting 2 m2 (1.3 m? in 1978) from the
center of each plot, threshing with a plot thresher,
and weighing grain. No yield data were obtained from
the November 1978 planting because of poor stands.

2

Table 1. Air temperature for the 5-week period follov
each date of planting (average of maximum and minimum;

Planting date °C
September 20, 1977 f1 21.9
November 15, 1977 ‘ 11.2 ,
December 15, 1977 4.3 v
September 20, 1978 21.1
December 18, 1978 3.4
September 18, 1979 21.3
November 6, 1979 9.6
December 10, 1979 6.7
October 5, 1980 17.6
November 11 , 1980 9.3
December 4, 1980 7.2

Results and Discussion

Yields of December planted wheat treated with 0,
25, and 50 kg P/ha were 1216, 2224, and 2330 kg/ ha,
respectively, when grown on soil containing 6 ppm
NaHCO3 extractable P (Figure 1). Wheat planted in
November responded slightly to P application but
wheat planted in September showed no response to
application of P. Generally, delaying the time of
planting caused reduction in wheat yields. The
average yields for September-October, November,
and December planted wheat were 2900, 2747, and
2392 kg/ ha, respectively. Wheat response to P appli-
cation on soil with 8 ppm P was similar to that of soil
with 6 ppm P in that the yield of December planted

3500
m 9/20
a Q A
x A 11/15
g 2500;?
“- f0
j O 12/15 v
(U
O .-
‘3: 2000 I LSD 0.05
6 ppm P
1500-
L)
25 50
kg P/ha ‘J

Figure 1. Influence of P application on wheat yields
from three planting dates (Austin silty clay soil 1978).

3500~

9/20

D
j‘.
2500 12/18

>- l o
I LSD 005
2000-
8 ppm P
1500

1
25 50
kg P/ha

kg/ha

wheat weld

Figure 2. Influence of P application on wheat yields
 from two planting dates (Austin silty clay 1979).

O A
j A 
I

u: 300° / Q 
c

\

0

X

B 2500

0

'; LSD Q05

3 20o

0

2

¥ 13 DDm P

1500
1
25 50

kg P/ha

g igure 3. Influence of P application on wheat yields
‘ om three planting dates (Dalco clay 1980).

Lwheat was 1670 kg/ha with no P applied but in-
creased to 2610 ._kg/ ha with 50 kg Pl ha (Figure 2).
i-Wheat produced labout 3000 kgl ha when planted in
‘September with or without P application.

. When planted late, wheat grown on soil containing
‘13 ppm NaHCO3 extractable P produced higher
 ‘ds with applications of P (Figure 3), but response
(i, wheat to P was less evident with earlier plantings.
1 ields decreased with later plantings at all P levels,
j» P fertilization partially offset yield loss due to late
fplanting.

 

ascor-
3000-
E 12/4
\ . '
U!
x. ,i 11/1113
‘o 2500 A? g_____o
g, 32"" 10/5
l
g 2000-
l:
z
1500- 19 ppm P
a
I
25 50

kg P/ha

Figure 4. Influence of P application on wheat yield:
from three planting dates (Austin silty clay 1981).

   
   

 

(U

E 10o ~

Q.

D O

Z §=2s7.47e‘°-‘83‘
U‘)

g 75 12/4-19 R099
O

D

° o

3 so -

(U

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O

5 9=-1.1sx+2e.4

2 25 ' O

2 11/6-15 A r2095

>  

A
a 9/18-10/15
_|  l . L L
5 1o 1s 20
soil PUJDm)

Figure 5. Relationship between soil P level and wheat
yield increase at the 50 kg P/ha rate and various
planting dates.

The study conducted in 1980-81 on 19 ppm P soil
was the only one in which early planted wheat did not
produce higher yields than late plantings (Figure 4).
Yield increase due to P application was not significant
(0.05 level) at any of the planting dates on soil with 19
ppm P. Yield of all wheat grown throughout the area
in 1980-81 was decreased because of lodging caused
by prolonged spring rains.

The relationship between soil P and percent yield
increase (over no P) from 50 kg P/ha (Figure 5)
indicates that date of planting is an important factor in

3

the response of wheat to P. Wheat planted December
4-18 showed a much greater response to P on soil
with 6 or 8 ppm P than wheat planted in September
and November. When extractable soil P was 13 ppm,
the percent increase in wheat yields from application
of 50 kg P/ ha was about 5, 10, and 20 percent for
September-October, November, and December plant-
ings, respectively. Regardless of planting date, little or
no response to P by wheat was obtained when soil P
levels were 19 ppm.

Yield response (%) from 5O kg P/ha applied to
December pla/nted wheat could be descAribed by the
decay curve y = 257.47e'°-"°X where y is % yield
increase and X is soil P level (Figure 5). The r? value
for the relationship was 0.99. The relationship between
percent yield increase caused by 5O kg P/ha and soil
P was linear at the November plantings, showing
about a 2O percent increse at 6 ppm P and 5 percent
increase at 19 ppm P. The percent yield increase
resulting from applied P at all soil P levels was about
5 percent when date of planting was September 18 to
October 15. Similar relationships were obtained when
25 kg P/ha was applied (Fig. 6), but the magnitude of
the P response was less than with 50 kg P/ ha. The
yield increases from 25 kg P/ha in November and
December were 13 and 78 percent, respectively, on
soils with 6 ppm P. Phosphorus response was slightly
greater with later date of planting if soil P was 13 ppm,
but P response was less than 8 percent at all planting

(U

C

\

°- 100 -

G

X

3 o

2 75 P Q: 2o3e'0.173X
3 r2098
° 12/4-18

3 5o ' o

(U

O

O

.5 25

B Q:-0.61x+15.4

E’, 11/545,; r2073‘;

as 9/18-10/ 5

5 10 15 2o
soil P (ppm)

Figure 6. Relationship between soil P level and wheat
yield increase at the 25 kg P/ha rate and various
planting dates.

Mention of a trademark or a proprietary product does not con

dates if soil P was 19 ppm. The percent yield increse.

due to applications of 25 kg P/ha for December
plantings could be described by an exponential
equation with soil P the independent variable, but the
relationship to application of 25 kg P/ ha was linear at
the November planting date. The r2 values obtained

were 0.98 and 0.73 for the December "and November  
plantings, respectively. The yield increase attributed ‘ '

to P at the September-October plantings was not
statistically significant (0.05 level) at any soil P con-
centrations in these studies.

These data indicate an interaction between soil P
level required for wheat production and planting date.
Early planting (September-October) resulted in warm
temperatures during the 5-week period of early growth
that has been determined to be critical in soil P
uptake by wheat (2). Later plantings resulted in much
colder temperatures during the critical 5-week period.
The average temperature during the 5-week period
following each date of planting is given in Table 1.
Temperatures for 5 weeks after the September
plantings ranged from 21.9 to 17.6 °C; in contrast,
temperatures after the late plantings (December) ranged
from 3.4 to 7.2 °C. These data indicate a need for
higher amounts of available P for wheat under cold
conditions. Six ppm NaHCO3 extractable P were
adequate for the yields obtained if temperatures were
about 20 °C for the first 5 weeks after planting, but
soil P levels of about 19 ppm P were required to
preclude an influence by planting date (temperature).

Literature Cited

1. Black, A. L. and F. H. Siddoway. 1977. Hard red
and durum spring wheat responds to seeding date
and NP-fertilization on fallow. Agron. J. 69: 885-
888.

2. Boatwright, G. O. and F. G. Viets, Jr. 1966. Phos-
phorus absorption during various growth stages of

spring wheat and intermediate wheatgrass. Agron.

  .1. 5a; 185-188.

3. Longnecker, T. C. and W. H Longstaff. 1955.
Fertilizing winter grains in the Blacklands.
Hoblitzelle Agric. Lab. Bull. 5. Texas Research
Foundation, Renner (Dallas), Texas.

4. Spence, C. O. and C. D. Welch. 1977. Phosphorus
fertilization for wheat production on Blackland and
Grand Prairie Soils, Texas Agri. Ext. Serv. L-1530.

5. Spinks, J. W. T. and S. A. Barber. 1947. Studygot
fertilizer uptake using radioactive P. Sci. Agric.
27: 145-155.

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