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B-HOI

LIBRAR!
DEB "/1970

Iexas A&M University

Phosphorus Fertilization
 0f
Direct Seeded Tomatoes

g/plul 0t 49 don

q/pmc a a6 4m

 rol Experiment Station
if Acting Director, College Station, Texas

July 1910
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Contents

Summary ...............................  .......................................... ._ 2
Introduction and Review of Literature ............................ .. 3
Materials and Methods .................................................... .. 4
Results and Discussion .................................................... .- 5

Influence of Phosphorus Rate and Placement

on Early Growth of Tomatoes ........................ .. 5
Influence of Phosphorus Rate and Placement
on Yield of Field Grown Tomatoes ....  ....... .. 6
Influence of Phosphorus Rate and Placement
on Nutrient Uptake by Tomatoes .................. .. 8
Influence of Temperature on Growth and
Phosphorus Response by Tomatoes ................ ..1O
Influence of Residual Phosphorus on
Growth and Yield of Tomatoes .................... -.11
Phosphorus Placement Requirements
for Tomatoes .................................................... ..11
Literature Cited ................................................................ .-14

Summary

   
  
  
 
 
   
   

Phosphorus fertilization of direct seeded tom
was studied in field, laboratory and greenhouse ex
ments over a 3-year period in the Lower Rio Gr
Valley of Texas. Results indicated that tomatoes
very sensitive to placement of phosphorus in that r
early growth and high yields were obtained with
phorus banded below the seed, but little benefit
obtained from broadcast phosphorus. Phosphorus u
by young plants was higher from banded than
broadcast phosphorus. Uptake of certain other nutr
was influenced by phosphorus rate and placemen

Phosphorus response was increased under cold
ditions of January and February, but phosphorus
tilization of fall tomatoes also increased yields.
benefit was obtained from phosphorus applied
previous year. For maximum response to phosp
by tomatoes, the phosphorus must be placed 2
inches below the seed. Other fertilizers such as nitr
should not be placed with the phosphorus becaus
decreased seed germination and damage to seedl

us Fertilization

ded Tomatoes

THE DIVERSITY OF FARMING PRACTICES in the Lower Rio

Grande Valley of Texas results in one of the most
complex agricultural areas found in the United States.
About 4O different kinds of crops on almost as many soil
types are grown in the area. The many soil types have a
wide range of chemical and physical properties. This soil
variation along with erratic rainfall patterns and intensive
irrigation gives rise to a variety of plant and soil relation-
ships that would be expected to influence the levels of
soil nutrients required for adequate nutrient absorption
by plants. The soils of the Rio Grande Valley are rela-
tively young compared with soils of other areas that have
been cropped for many years. Phosphorus (P) fertilizers
have been applied to many soils of the valley, but informa-
tion is lacking regarding how, when and how much
should be applied.

Many of the vegetable crops grown in the area
are winter crops. There is considerable evidence that
temperature influences the uptake of P by plants (14).
Mechanization has influenced the need for fertilization
in that time and uniformity of rate of maturity are of
utmost importance in crops adapted to maximum mech-
anization. The increasing need for further knowledge
about methods of using P fertilizers and their require-
ments by crops is evidenced by the increase in sales of
P fertilizer in Texas from 1959-1960 through 1967-1968
(5, 6). Decreased acreage and demands for increased
output have created a need for precision in diagnosing
fertility needs of crops to be grown on the limited acre-
age allocated to each crop.

In the Lower Rio Grande Valley of Texas, spring
tomatoes are direct seeded during january and February
when soil temperatures are still low. Phosphorus fer-
tilization is a common practice, butllittle attention is
directed to placement. Phosphorus deficient tomato
plants are a common sight, even in fields having had
applications of high rates of P. Phosphorus deficient
tomato-plants in the seedling stage can be recognized
easily by their dwarfed growth and purple coloration.
The underside of leaves becomes purple before the- re-
mainder of the plant, but in severe cases the entire plant,
including the stem, will be purple. The leaves are
generally small, and the plant does not appear to be
growing. As a result of the slow growth, length of time
to fruiting and maturity is increased, and yields are
decreased. Direct seeded tomatoes for fall production
are also susceptible to P deficiency, but the deficiency
is not as common as in spring tomatoes because of
higher temperatures at seeding.

Results from P experiments indicate that the same
rate or method of placement is not equally effective

*Associate professor, Texas A8zM University Agricultural Research
and Extension Center at Weslaco.

for all crops and soil types. Numerous P placement and
rate experiments have been conducted in greenhouse
pots. However, P placement and rate data from green-
houses are necessarily limited to short-term early growth
experiments. Because most of the P field experiments
with tomatoes have been conducted with transplanted
tomatoes, very little information is available regarding
the P requirements of direct seeded tomatoes.

Although research from other areas contributes to
the knowledge of P fertilization of tomatoes in the
Lower Rio Grande Valley of Texas, complete guidelines
cannot be established because of differences in soils and
environmental factors.

Rooting habits and high P requirements of tomato
seedlings are primary factors to consider in developing
a P fertilizer program for tomatoes. Locascio and Warren
(10) found that the growth of tomato plants was related
to the time required for their roots to reach applied
P and that the initial root growth was of the taproot
type. These findings suggest that distance of lateral
placement of P fertilizer would be of primary importance
in obtaining early growth and yield of tomatoes. In
other studies by Locascio, Warren and Wilcox (11),
good yields were obtained from low rates of P applied
as a seed treatment alone, but placement of P in a band
1 to 1.5 inches below the seed was the best method.
For transplanted tomatoes, deep placement of P was
found to be more efficient than shallow P placement (9).

In shallow rocky Florida soils, Orth (12) indicated
that it is difficult to place P in uniform bands, but
early P requirements of direct seeded tomatoes can be
satisfied by placing P with the seed. Results of studies
of the effect of soil temperature on P nutrition, reviewed
by Sutton (14), suggest that in certain cases adverse
effects of cold soils can be reduced by P fertilizers.

The influence of P fertilizers on the uptake of other
nutrients has been studied (1, 2). The primary effect
seems to be a reduction in zinc and iron uptake with
increasing amounts of P added. Recently, a magnesium-
phosphorus interaction in tomatoes was reported (8).
Occurrences of these interactions have been observed,
but their significance has not been fully evaluated.

Preliminary experiments with P placement methods
on Harlingen clay (c) soil (7) indicated that tomatoes
grown under Lower Rio Grande Valley conditions were
extremely sensitive to P rate and method of placement.
This led to a more complete investigation in which
field, greenhouse and laboratory experiments were con-
ducted at the Texas A&M University Agricultural Re-
search and Extension Center at Weslaco to gain addi-
tional information concerning the P requirements of
direct seeded tomatoes.

4

MATERIALS AND METHODS

Soils used in the study were Harlingen clay, Will

fine sandy loam (fsl) and Hidalgo sandy clay w»
(scl) all of which are common to the Rio Grande V

area of South Texas and Northern Mexico. Harling
is uniform in texture to a depth of several feet, 
due to its fine texture, waterpenetration is very sl.
Willacy and Hidalgo soils are medium textured ~

allow rapid water penetration. Harlingen and Hid
soils are calcareous throughout the soil profile. Wil:
soils are not calcareous in the surface but become p
careous below the topsoil. Soil test characteristics of
soils are shown in Table 1.

Field experiments were conducted on Harling‘ '

and Willacy fsl in spring 1967 to determine the influ

of P rate and placement on tomato growth, nutr a

uptake, maturity rate and yield. Phosphorus rates of
80, 120 and 200 pounds of P2O5 per acre were ap
by two methods (400 pounds of P205 per acre were

included on the Harlingen c). One method consi
of applying P as a band directly beneath the seed

(banded); the other method consisted of broadcas
the P over the entire plot area and then mixing it I

the surface 3 inches with a rolling cultivator. A r _.
without P was also included. The form of P 
was 0-46-0. ‘Chico’ tomatoes were seeded in 76-

rows and immediately watered to obtain a stand.
replications were included in the field experim’
Plant samples from all treatments were taken periodi
to gain information concerning nutrient uptake
growth rate. Normal cultural and irrigation pra
for the area were followed throughout the grog
season. Similar experiments were conducted on Hi
scl in 1969 except that the rates of P205 used
50, 100, 150 and 200 pounds per acre; the row spa
were 38 inches; and the variety of tomato grown
‘Chico III’.

An experiment to evaluate the influence of P a _

cation on fall-grown Chico tomatoes was conduct
Harlingen c in 1967. The rates of P205 were 0 and

pounds per acre applied in a band below the seeda .

Phosphorus treatments of O, 400, 800 and I
pounds of P205 per acre were broadcast on Harlin

TABLE ‘l. CHARACTERISTICS OF THE SOILS USED IN THE S

lb no.1

Ib Pzos/GCFGI
extracted with extracted‘-
sodium ammo
bicarbonate acet _
pH at pH 8.5 at pH
Harlingen c 8.2 I06 30 '
Willacy fsl 7.8 74 47
Hidalgo scl 8.2 28 

‘Based on 0 to 6-inch depth.

  
   
   
  
   
  
   
    
  
  
  
  
   
   
  
  
   
  
   
  
   
   
  
  
  
  
   
  
   
  

fOther treatments included placement of 14 and
i of P205 per acre in direct contact with the
p i60tand 120 pounds of P205 per acre in a band
1 below the seed. Chico tomatoes were grown.
; tomatoes were grown on the broadcast plots
to determine the residual effect of P applied
‘hl- year. Additional treatments were included
 the yield level with 200 pounds of P205
‘iapplied 3 inches below the seed and with the
 placed 3 inches below and 4 inches to the side
 d. Growth and P uptake were determined
A sample analysis.

‘F- experiments were conducted in 1968 and 1969
gen c and Hidalgo scl to evaluate the influence
gement on early growth of tomatoes. To evalu-
_ of placement on growth, trenches were
 in the center of the row and sloped from
we at one end to a depth of 12 inches at the
 of a 25-foot row. Phosphorus at the rate of
‘ids of P205 per acre was placed in the bottom
 ches; then the trenches were covered and the
piseeded directly over the trenches. To evaluate
i; ce of lateral placement of P, trenches were
 at a constant depth (2.5 inches) but started
 of the row at one end and gradually moved
=~ the row to a maximum distance of 8 inches
 row length. Phosphorus at the rate of 120
if P205 per acre was placed in the bottom of
 es, then covered, and the tomatoes were seeded
<  the center of the row. This resulted in
Ilateral placementof P from O to 8 inches from
 r line of the seed placement. The area was
to ensure germination. Plant samples were
 growth measurements and P analysis.

‘jT- ouse studies were conducted to determine
 nce of soil temperature on tomato response
il temperatures were thermostatically controlled
 culating water bath. Soil temperatures used
5y c were 60 i 4, 70 i 3 and 82 i- 4° F.
 es for Hidalgo scl were 65 i 3 and 84 i
Ltemperatures varied from about 74° F at night
‘during the day. Rates of P205 used were 0 and
 ~ per acre. Placement was in a band 2.5 inches
 seed. Temperature treatments were initiated
'nation. Plant data were taken to evaluate
"cc of P on growth at each soil temperature.

turbed cores __(5 inches in diameter by 3 inches
h taken fromiiwillacy fsl and Harlingen c and
1 a greenhouse. Tomatoes were seeded in the
 allowed to grow for 3O days. At the end of
w period, the plants were clipped at the soil
ried and weighed. The cores were then di-
the upper 1.5 inches and lower 1.5 inches.

The roots were removed from each half of the cores
and oven-dry root weights obtained.

Plant samples taken in these studies were dry ashed
according to the methods of Chapman and Pratt (3).
Phosphorus determinations were made by the molyb-
denum-blue method, and cation determinations were
made with an atomic absorption spectrophotometer.

RESULTS AND DISCUSSION

Influence of Phosphorus Rate and Placement
on Early Growth of Tomatoes

Growth of tomato plants at any given stage is a
function of several factors such as light, moisture, tem-
perature, variety and nutrient availability. Phosphorus
significantly influenced early growth of tomatoes on
Hidalgo scl (Figure 1). The Hidalgo scl used was very
low in P; consequently, there was a sharp increase in
plant growth with 5O pounds per acre of P205 placed
in a band below the seed. Increases in growth were not
obtained with 50 pounds of P205 broadcast. Maximum
early growth of tomatoes was obtained from a band
application of 100 pounds of P205. Broadcast applica-
tion of 200 pounds of P205 appeared to be equivalent
to about 30 pounds banded.

3'
0.7-

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t" O

3 ,

3 0.6- / y
m

g‘ 0.5‘ o Q o
‘O

3 0.4- /o

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° 0.3 - '

5 o

a O 2- BOhd
Q -—/O U Broadcast

0.! -
Hidalgo scl

50 I00 I50 200

P2 o5 Appma (lb/Al

Figure l. Influence of rate and placement of P on early growth
of tomatoes on Hidalgo scl.

5

TABLE 2. INFLUENCE OF P RATE AND PLACEMENT ON EARLY
GROWTH OF FIELD GROWN TOMATO PLANTS, SPRING 1967
Harlingen c _ Willacy fsl I
P105 applied 25 days 49 clays 25 days 49 clays
lb/acre mgm/plant’ g/plant mgm/plant g/plant

0 13.5’ 0.42 29.0 1.24
40 band 16.5 1.94 35.6 1.25
80 band 21.8 2.42 38.6 1.33
120 band 24.1 2.85 36.1 1.25
200 band 23.9 2.90 31.6 1.06
400 band 26.0 2.47

40 broadcast 14.0 0.69 32.7 1.28
8O broadcast 16.5 0.70 37.8 1.32
120 broadcast 17.1 0.63 33.3 1.01
200 broadcast 19.5 0.88 34.4 1.14
400 broadcast 20.0 1.03

LSD ‘(.051 y 5.1 0.41 5.2 N.S.
‘1 gram [g1 = 1,000 milligrams (mgm).

‘Weights are on oven dry basis.

Early growth response on Willacy fsl was not as
evident as on the Hidalgo scl (Table 2), but 25-day-olcl
plants grown on plots receiving 40, 8O and 120 pounds
banded and 8O and 200 pounds broadcast were signifi-
cantly larger than the control. At 49 days there were no
significant differences in size of plants due to rate or
placement of P.

Results obtained on Harlingen c soil indicated an
early growth response, but higher rates were required
by seedling tomatoes. Data in Table 2 indicate that at
25 days, rates greater than 80 pounds of P205 per acre
applied in a band resulted in significant early growth
differences, but the largest plants were grown on plots
that had received the 400 pounds of P205 band treat-
ment. Broadcast application of 200 pounds of P205 per
acre was required to significantly influence early growth
of tomatoes on this clay soil. Broadcast P application
was not as effective as placed P in promoting growth
during the first 25 days. Plant samples taken at 49 days
supplied additional evidence that broadcast P was not
effective in obtaining rapid early growth of tomatoes

TABLE 3. INFLUENCE OF P RATE AND METHOD OF APPLICATION
ON EARLY GROWTH OF FIELD GROWN CHICO TOMATOES ON
HARLINGEN C, SPRING 1968

Green wt
P105 applied 21 days after emergence
lb/acre g/plant‘
O 0.15
14 with seed 0.21
36 with seed 0.20
60 3 inches below seed 0.28
I20 3 inches below seed 0.35
400 broadcast 0.23
800 broadcast 0.30
1600 broadcast 0.35

‘Based on 70°C drying weight.
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46' Harlingen Clay

 
 
 
     
   
     
    
   
  
   
 
 

I00 20o 30o 4o

P205 Applied (lb /Al i‘

Figure 2. Influence of phosphorus rate and placement on »
required by tomato plants to reach bloom stage.

on Harlingen c soil. Plants receiving 400 pound
P205 per acre broadcast were much smaller than pl
receiving 4O pounds placed in a band below the I
Experiments in 1968 on Harlingen c indicated th
broadcast application of 1,600 pounds of P205 per
was equivalent to a placed application of 120 p0 =
(Table 3). There was a slight increase in plant
with each additional 400-pound-per-acre incremen
broadcast P205 up to 1,600 pounds per acre. The b i
cast rate required for maximum early growth would.
be economically feasible. Placement of low rates I
with the seed slightly increased early growth, butY
rates used (14 and 36 pounds of P205 per acre) did
promote early growth as well as treatments ba
below the seed. - ‘

Treatments that resulted in rapid early growt
tomatoes on Harlingen c also caused plants to bl
earlier (Figure 2). Tomato plants grown without
plied P bloomed in 63 days, whereas plants grown
40 and 400 pounds of P205 applied in a band b -
the seed bloomed in 52 and 49 days, respectively. »
broadcast P treatments were much less effective in
moting early bloom in that 400 pounds of P205 br
cast only reduced the days to bloom to 54. 

Influence of Phosphorus Rate and Placement
on Yield of Field Grown Tomatoes

Band application of P caused a large increas
yield at first harvest at all rates of P on Hidalgo

i Hidalgo scl

O

» e
l'z!,
I .
0 Bond
O Broadcast

so loo 15o. zoo

   
 
  
  
  
   
   
   
  
  
   
    
  

g o5 Applied (lb/A)

 luence of rote and placement of P on yield of toma-l
 Hidalgo scl. _2

 Highest yield was 11-.5 tons (T) per acre
pgapplications of 100 pounds of P205 per acre.
Qlmost a fivefold increase over the plots that
i ive P. .The greatest increase in yield occurred
'tial 50-pound increment applied in a band.
 of P205 per acre did not increase yields
 'cd as a broadcast treatment, but increased
 50 pounds slightly increased yields with each
if“ increment. Highest yield from broadcast P
i wasonly 4.5 T per acre and was obtained
Q-pound-per-acre rate of P205.

flgof tomatoes was not influenced by rate or
ref P on the Willacy fsl (Table 4). Data
 the concentration of available soil P in the
.  was sufficient for the yields obtained.

‘increases due to applied P on Harlingen c
 similar to those obtained on Hidalgo scl.
‘ds on the Harlingen c (Figure 4) were

 ' UENCE OF RATE AND PLACEMENT OF PHOSPHORUS
_ TOMATOES GROWN ON WlLLACY FSL, SPRlNG 1967

Tomato yield (T/ocre)

lewflflwvwflw
Pammmoooaw

obtained ‘with the 200-pound rate of P205 placed in a
band below the seed. Yields from the plots receiving
200 pounds of P205 placed were about two times greater
than those without applied .P. As on Hidalgo scl, _the
greatest yield increase was with the initial increment
of P. These yield increases with low rates of band P
indicate that correct placement of P is very important
in final yield as well as in early growth response. Very
little increase in yield of tomatoes was obtained with
broadcast P at any of therates used.

Yield data from. the_1968 experiments involving
extremely high rates of broadcast P. on Harlingen ‘c
were unavailable because of prolonged rain at harvest
time. Data from growth measurements in 1968___and
yield data from broadcast rates up to 400 pounds of
P205 per acre in 1967, however, indicate that broad-
casting P for tomatoes is not a feasible practice. A

Although most of the tomatoes are grown in the
spring in the Lower Rio Grande Valley, considerable‘
acreage is planted in. the fall. Response to applied P
would be expected ‘to be less in the fall than’! in the
spring because ‘of higher temperatures when tomatoes
are planted (July and August) for fall production.
Results from application of P to fall-grown tomatoes
(Table 5) ‘indicate that a substantial yield increase can
be expected. Yields were increased by about 5O ‘percent
as a result of band application of 1515 pounds of P205
per acre.

 

4

>

'2

I

‘i

2

O

5

- Horlingen c

25b 9 Band

{ . I Broadcast

I00 200 300 40.0

r505 Applied (lb/Al i

Figure 4. Influence of rote and placement of P on yield of tomci-
toes on Harlingen c. I - -

7

TABLE 5. INFLUENCE OF APPLIED P ON YIELD OF FALL~GROWN
TOMATOES ON HARLINGEN CLAY

P205 Oppliéd

lb / acre T / acre
0 6.1
I15 9.3

These data indicate that large yield increases can
be expected from the proper application of P fertilizer
to tomatoes. To obtain maximum results from applied
P, it must be placed in a band directly below the seed.
Although response to applied P appears to be less in
the fall, yield increases can be obtained from P applied
to fall tomatoes.

Influence of Phosphorus Rate and Placement
on Nutrient Uptake by Tomatoes

Hidalgo scl: Application of different P rates and place-
ment had a marked influence on P uptake by tomatoes.
Concentration of P in 36-day-old plants was significantly
higher from band treatments than from broadcast treatments
at all rates of P. Table 6 shows that P concentrations in
the whole plant were increased from 0.13 percent without
P applied to 0.58 percent with 50 pounds of P205 applied
in a band below the seed. The P content of plants was
increased to 0.69 percent with the 100-pound rate of P205.
Broadcast P slightly increased P concentrations in the plants,
but highest P concentration in the plants was only 0.35
percent with the 150 and 200-pound broadcast rates of
P205. For maximum plant size, the level of P needed
in whole tomato plants at this stage of growth appeared
to be between 0.6 and 0.7 percent. Potassium (K) concen-
trations in the plant at 36 days were also influenced by
P rate and placement. All treatments except the SO-pound
P205 broadcast rate resulted in significantly higher con-
centrations of K in the plants than in the check. These
data do not indicate whether there was a stimulation effect
by P or an accumulation of K due to rapid growth of the
plants. Magnesium (Mg) concentrations in the plants were

slightly decreased with additions of band P. This rea I
was previously reported (8). Even though Mg levels ~
reduced, they remained at a sufficient level for adeq i '
growth. Zinc (Zn) concentrations in the plants gene d
decreased with increasing rates of P, but the decr
were not consistent. Iron (Fe) and manganese (Mn) v
centrations in the plants were not significantly influen
by P treatment when sampled Qat 36 days. Analyses‘
plants 66 days after planting showed that P concentrati;
in plants from all band P treatments were signifi .»
higher than the control, but broadcast P did not signifi . y
increase the concentration of P in the 66-day-old p I
(Table 7). Band P treatments also resulted in décre
concentrations of Zn and Mg in the whole plants.

Willacy fsl: Phosphorus rate and placement definitely
fluenced P concentrations in ZS-day-old tomato p 2
grown on Willacy fsl (Table 8). The 40-pound rate
P205 in a band increased the P concentration from 0i

to 0.61 percent, but increasing the P205 rates above‘ _

pounds per acre did not result in further increase.
80, 120 and 200-pound-per-acre rates of broadcast P I
significantly increased P concentrations in the plants, g

P concentrations in plants from band treatments were u b

higher than those from broadcast treatments. Man r
and Zn concentrations were not influenced by P treating ‘
at the 25-day sampling. Magnesium and Fe concentra 
in the plants were decreased with high rates of 
but were not influenced by broadcast P. Potassium con
trations in the plants were increased over the check by
rates of band P.

When sampled at 49 days, plants from all trea .1

with band P contained higher concentrations of P

the check (Table 9). Concentrations of P in plants f A
broadcast treatments were slightly higher but not siyq
cantly higher than the check. Concentrations of Mn, 

K, Ca and Fe in the plants were not significantly '
fluenced by rate or placement of P. Zinc concentra ' i

in the plants were reduced with high rates of P regar
of application method.

TABLE 6. INFLUENCE OF P RATE AND PLACEMENT ON NUTRIENT UPTAKE BY FIELD GROWN TOMATOES ON HIDALGO SCL SOIL (W 

PLANT 36 DAYS AFTER PLANTING)

P105 applied % % % % PPM PPM
Ib / acre P‘ K Ca Mg Fe Mn
0 0.13 1.95 3.33 0.98 583 I35
50 band 0.58 3.13 3.61 0.87 463 I35
I00 band 0.69 3.30 3.85 0.77 563 I37
I50 band 0.68 3.26 4.24 0.82 586 I47
200 band 0.56 3.25 4.00 0.87 473 I10
50 broadcast 0.22 2.15 3.11 0.90 440 126
I00 broadcast 0.29 3.23 4.28 0.93 456 I32
150 broadcast 0.35 2.68 3.95 0.94 656 I34
200 broadcast 0.35 3.00 4.40 1.06 579 110
LSD (.05) 0.18 0.55 0.56 0.18 N.S. N.S.

‘All values based on 70°C drying weight.
8

    
     

,. mrwewce or P 1m: AND PLACEMENT on uurmem
' BY FIELD GROWN TOMATOES ON HIDALGO SCL SOIL
I PLANT 66 DAYS AFTER PLANTING)

Harlingen c: Application of P in a band below the seed
significantly increased the concentrations of P in the plant
when sampled 25 days after planting (Table 10). Rates of

I 16d ° . PPM PPM PPM -
 g’. Kg Fe M" Zn 200 and 400 pounds of P205 were required, however, to
significantly influence the concentration of P in the plants
0'24 0'96 482 98 52 when a lied as broadcast treatments. Concentrations of
0.33 0.72 426 75 33 PP _
0.44 0.76 426 98 28 M , Mn Ca and Fe in the lants were enerall decreased
0 41 0 a3 416 10a 29 g ’ P g y
 0:37 0'77 44o 95 36 with increasing rates of band applied P. Application of
 st 0.25 0.85 386 87 37 high rates of broadcast P resulted in reduced Mn and Fe
a  81% gig jgg  g: concentrations in the whole plants.
j -- 6.1 0.30 0.09 393 a6 4a
' 0.07 O. I2 N.S. N.S. I5

   

I s based on 70°C drying weight.

Concentrations of nutrients in tomato plants grown
on Harlingen c and sampled at 49 days are shown in

INFLUENCE OF P RATE AND PLACEMENT ON NUTRIENT UPTAKE BY FIELD GROWN TOMATOES ON WILLACY FSL SOIL (WHOLE

 

   
  

 iod ‘A. 7i. ‘l. 7t PPM PPM PPM
- P‘ K Cc Mg Fe Mn Zn
0.2a 3.64 3.75 1.00 31a 13a 26
0.61 4.29 3.50 0.91 297 96 25
0.56 4.05 3.49 0.a9 310 122 21
0.60 4.2a 3.34 0.37 25a 114 24
- 0.64 4.09 3.43 0.95 235 115 23
.1 0.30 3.65 3.55 0.95 310 123 24
A; - =1 0.36 4.0a 3.63 0.97 2a2 143 23
f " cost 0.34 3.39 3.65 0.9a 355 129 25
V. -- 6.1 0.35 4.06 3.50 0.94 312 126 22
1 0.06 0.32 0.25 0.1 1 61 us. N.S.

 s based on 70°C drying weight.

   

INFLUENCE OF P RATE AND PLACEMENT ON NUTRIENT UPTAKE BY FIELD GROWN TOMATOES
_ DAYS AFTER PLANTING)

ON WILLACY FSL SOIL (WHOLE

  

a Ied

 

 
  

  

   
 
   
 

°/o ‘l: 7o % PPM PPM PPM
P‘ K Ca Mg Fe Mn Zn
0.26 3J8 4.2 0.96 270 I98 28
0.32 3.I6 4.3 0.93 3I0 I85 24
0.36 2.98 4.4 0.99 283 I64 24
0.36 2.96 4.5 0.97 273 I64 20
0.34 3.06 4.5 I.03 305 2I0 23
SI 0.28 3.08 4.4 I.03 280 205 24
II 0.29 3.I0 4.2 0.95 263 I72 23
SI. 0.3I 3.06 4.4 0.99 295 I78 25
MI 0.29 3.35 4.5 0.99 288 I72 2I
p 0.06 N.S. N.S. N.S. N.S. N.S. 5
’ - based on 70°C drying weight.
_ INFLUENCE OF P RATE AND PLACEMENT ON NUTRIENT UPTAKE BY FIELD GROWN TOMATOES ON HARLINGEN C SOIL (WHOLE
f- DAYS AFTER PLANTING)
 6d % ‘Y. % 7. PPM PPM PPM
;. P‘ K Ca Mg Fe Mn Zn
0.II 2.62 5.0 I.I7 390 I88 I7
0.26 3.0I 4.7 I.08 282 I52 I6
0.30 3.35 4.6 I.I I 292 I45 I6
0.43 3.34 4.2 0.99 300 I I8 I6
0.42 3.20 4.5 I.07 305 I4I I6
' _ 0.46 3.44 4.4 I.I2 350 I32 I5
_y n ‘0.14 3.09 5.1 1.20 430 175 17
‘W 0.22 3.I4 4.8 I.I6 295 I54 I6
I OBI 0.I9 3.20 5.0 I.2I 328 I62 I3
I SI 0.26 3J9 4.4 I.I2 314 I4I I4
- SI 0.28 3.20 4.8 I.I3 288 I38 I3
0.I 2 0.23 0.4 0.07 80 36 N.S.

 

  

 based on 70°C drying weight.

TABLE 1l. INFLUENCE OF P RATE AND PLACEMENT ON NUTRIENT UPTAKE BY FIELD GROWN TOMATOES ON HARLINGEN C SOlL (WH _
PLANT 49 DAYS AFTER PLANTING) _ »

P105 applied ‘Y, 5% % p % PPM PPM _ v "
lb/acre P‘ K - Ca i Mg _ Fe Mn  '_ a

0 0.26 2.54 V4.39  1.16 343 178

40 band . 0.32 2.92 4.24 0.96 y _ 430 _» 55

80 band 0.36 p 2.83 , .4.52 0.98 525 ._ a 55

120 band 0.33 2.93 4.05 y 0.88 443 ._ 48

200 band . 0.36 3.01 4.20 0.91 460  57

400 band 10.34 2.79 I 4.32 0.94 ,. 510 4 g y 65

40 broadcast 0.28 2.27 4.57 1.02  536. 163

80 broadcast 0.28 - 2.76 4.55 . 1.16 _ 435 166

120 broadcast 0.28 2.39 4.76 __ (1.12 . 465i 165

200 broadcast A 0.25 2.59 4.69 1.12 _ 522 ~ 175

400 broadcast i 0.28 2.64 5.02 1.17 . 565 .. .168  _

LSD (.05) . i 0.03 N.S. 0.41 0.09 99 ‘22 , »‘-

‘All values based on 70°C drying weight. f

Table 11. Band application of P resulted in higher concen-
trations of P in the plants; broadcast P did not significantly
increase the P concentrations. Manganese, Zn, Mg and Ca
concentrations were decreased in plants receiving band P,
but concentrations of these elements were not affected by
broadcast P. This would indicate either a dilution effect
due to increased growth associated with high plant con-
centrations of P or an interaction between P and the uptake
of these nutrients.

Plants were also sampled for leaf analysis’ at 98 days,

The importance of ~ abundant ‘P in the early gr ‘z

_ stages of tomato plants grown on Harlingen c is "sh"

in Figure 5. A linear relationship with an r value ‘n

0.842 was obtained between percent P in the whole p ’

and green weight of ZS-day-old plants. This indicates q
high concentrations of plant P are required for rapid ~-
growth. Figure 6 shows that P concentration in plants- i
a function of rate of P application and age of plant 

i that to obtain the levels of plant P needed for early gro l *

the P must be" available at growth‘ initiation. At 25 --*

there were increases in P concentration up to 120 po i ' ‘

but, of the elements determined, only P concentration was

influenced by P rate or Placement of P205, but by 49 days the influence of P application

- P concentration was much less. By 98 days plants gr
on the check plots contained a slightly higher concentr p
of P in the leaves than those with P applied. These J

 

10,40. suggest that sidedress P would not be effective in st'
lating rapid early growth. ‘
0.35’ ,_ .
4 Influence of Temperature on Growth and
Phosphorus Response by Tomatoes
0'30’ Results of experiments with controlled soil tern‘
a, tures indicated that plant growth was a function of
i Q25. temperature and P application (Table 12). A defi
3 P-temperature interaction was evident on Harlingen c l
S’. Hidalgo scl. Plant growth increased with increasing M
E 020- perature from 60 to 82° F when no P was applied
U .
E _ . _ . .
\
5,, 015* a a '
_ TABLE 12. INFLUENCE OF SOIL TEMPERATURE AND P APPLICA
ON EARLY GROWTH OF TOMATOES
O
0'10 . "0842 Green wt Green
A ' ’ g/plant with g/plant
ygosnxlruoacm is Soil temperature °F 120 lb Pzos/GCTQ O 1
oas- ~ ' i
"mung." Clay Harlingen clay soil /
25 9°" G'°""' . e2 i 4 1.95 20.51 '
' ‘ ' ' " I 7O i 3 2.40 0.2
0| 0.2 0.3 0.4 0.5 0.6 60 i 4 0.62 0.1
of p I wh P Hidalgo sandy clay loam .'
° “ °" '°“'  a4 i s - y 2.21 o.6~
Figure 5. Relationship between P concentration in tomato plants 65 i 3 2.32 Q_3 '

and plant weight.
10

o‘ Harlingen clay
o.
; 0 o
0' 4 A
. 4A g-
° OM25 Doys
o. I 49 Days
A 98 Days

so 12o. ieo 24o aoo sso 42o

  
  
 
  
   
   
  
   
   
  
   
   
   
 
  
  
   
 
  

P205 Applied (lb/A)

Relationship between rate of P¢O5 applied in a band
t P in plants grown on Harlingen c. i

_,_ c soil. However, when 120 pounds of P205
‘were applied, plants grown at 70° were about
larger than those grown at 60°. Similarly,
as slightly increased on Hidalgo scl by increasing
iratures from 65 to 84° F without applied P.
 maximum growth response with? .~P applied
 the 65° F temperature.

p, of Residual Phosphorus on
‘(and Yield of Tomatoes

 indicate that tomatoes benefit very little from
 to Harlingen c the previous year (Table 1'3).
l“ in 33-day-old plants was not influenced by. P
 of 1,600 pounds P205 per acre the (previous
 fsize 6O days after emergence was slightly in-
-~ the residual effect of the previously applied
it However, the residual effect from 1,600 pounds
l- was not enough to stimulate maximum early
 fable 13). Plants grown in plots receiving 200
 P205 3 inches directly below the seed in 1969
 i; times larger than, those fromthe residual 1,600-
 ent and over-I three times larger than those
i- plots. Placement of 200 pounds of P205 in
_'ches._below and 4 inches to the side of the seed
resulted in much smaller plants at 60 days than
i rate placed directly below the seed. Phosphorus

.4

(‘on in 33-day-old plants was much higher‘ from

TABLE 13. INFLUENCE OF RESIDUAL SOIL P ON GROWTH AND
YIELD OF TOMATOES ON HARLlNGEN C SOIL

% P in g/plant
whole plant oven dry wt Yield of
33 days 60 days fruit,
P205 applied I after after T/acre,
lb/acre i‘ emergence emergence 1 969

0 0.15 0.27 3.9
400 broadcast, 1968 0.15 0.38 3.8
800 broadcast, 1968 0.15 0.33 4.5
1,600 broadcast, 1968 0.16 0.42 5.3
200 3 inches below seed,

1969 0.55 0.86 8.2
200 3 inches below seed

and 4 inches to , a

side, 1969 0.22 0.50 5.9

P placed directly below. the seed in 1969 than from the
residual P treatments and» the 1969 treatment placed 3
inches below and 4 inches to the side of the seed.

Yield response in 1969 was very similar in pattern
to early growth characteristics and P uptake by the plants.
Yields were increased only from 3.9 to 5.3 tons per acre
with the highest residual treatment, but the 200-pound
P205 rate placed below the seed in 1969 increased yields
to 8.2 tons ‘ per acre. Yields from the plots receiving P
3 inches below and 4 inches to the side of the seed were
considerably lower than from the same rate placed directly
below the seed. These data indicate further evidence of the
critical placement requirements of P for maximum yields
of tomatoes.

Phosphorus Placement Requirements for Tomatoes

Results of experiments with variable depth trenches
indicate depth-of-placement requirements on medium and
fine-textured soils (Figure 7). Depth of P placement is
extremely critical on the fine-textured soil but less so on
the medium-textured soil. Maximum early "growth of
tomatoes on the fine-textured soil was obtained when P
was placed at a depth of 2 inches. When placed closer
to the surface than 2 inches, drying and cracking of the
clay soil left the P in a dry zone near the surface. Because
root growth was below the dry zone containing the P,
little response to P was obtained. When P was placed
below a depth of 2 inches, there was less early growth
of the tomatoes possibly because of slow root growth in
the clay soil. -

A comparative study of root growth demonstrates the
slow root growth of tomatoes on Harlingen c soil (Table
14). In undisturbed cores from greenhouse studies, 88

TABLE 14. DISTRIBUTION OF TOMATO ROOTS lN UNDISTURBED
CORES OF WILLACY FSL AND HARLlNGEN C SOIL

‘Z. of roots
Soil in top 1.5 inches Top/root ratio
Harlingen c 88 6.5
Willacy fsl -  ' 56 - 2.2

11

Hidalgo scl

q/plant at 36 days

depth at P placement line.)

Figure 7. Influence of depth of phosphorus placement on early
growth of tomatoes.

and 56 percent of the tomato roots were contained in the
surface 1.5 inches when grown on Harlingen c and Willacy
fsl, respectively. These data indicate that roots grow down-
ward at a more rapid rate in the sandy loam soil than

 

6.0L -o.s
Harlingen c
i; -O.5
o
-u
q; ‘Q4 E
Q’ .2
o.
u "03 5
§ a.
Q 10.2 ‘Q
O
'0.l
l.O 2.0 3.0
l Distance that P was placed
from center of row line.)
Figure 8. Influence of lateral distance of placement on early

growth and P uptake by tomatoes grown on Harlingen c soil.

l2

in the clay soil. Furthermore, the larger top / root rati

obtained on the Harlingen c indicate that smaller amount

of roots must support the top growth on Harlingen c

on Willacy fsl. Robertson et al. (13) indicated simi 
results for root growth and P uptake by corn. Duncan M
Ohlrogge (4) obtained a close relationship between y
development and volume of fertilized soil. Similarly, r
P uptake by tomatoes on these sails appears to be clo l
related to volume of soil explored by tomato roots unl
P is placed in a concentrated band below the seed. I
mum depth of P placement on the clay soil would probabg
be influenced to a large extent by moisture conditi
prevailing during the early growth stages. As would i
expected from observations of the rooting habits, maxim 
P response on Hidalgo scl was obtained when P was pl --,
at a depth of 2 to 6 inches. Depth of placement was w
nearly so critical, however, on the medium-textured soil. l

The necessity for precise horizontal placement y‘
Harlingen c is shown in Figure 8. Plant size decre 
slightly with increase in lateral distance of placement f
to 1 inch but decreased sharply when P was placed 
than 1 inch away from the seed row. Phosphorus concen » a
tion in the plants followed essentially the same patt
as growth in that P concentration was seriously redu

when lateral placement was more than 1 inch. Late r .

placement on the Hidalgo soil was also critical in obtain —_

maximum early growth (Figure 9). The plant reaction’ p

P placement on Hidalgo scl was similar to that 
Harlingen c except that the critical lateral distance of pl i,
ment was 1.5 inches. ‘

 
   

l.2 "L2
q/plant .
;_ 1.0 11.0
U -
‘U
w 0.8 “(l8
N d
a 0.6 "05
‘E .
2 .
9- 0.4 '0.4
} . .
02' Hidalgo sci '0'?-
l.0 2.0 3.0
Distance that P was placed 
tram center of row line.) P
Figure 9. Influence of lateral distance of placement on 

growth and P uptake by tomatoes grown on Hidalgo scl soif _

 
  
     
  

 g data indicate that tomatoes are very
finutdtion and that large yield increases can
 soils of the Lower Rio Grande Valley
“ifie- 'cate requirements of placement are met.
_‘ requirements, P must be banded directly
if at planting time at a depth of 2 to 3
 best be accomplished with a combination
pit-planter that will band the P and plant
I operation.

possible damage to seed or seedlings,
p ’ types of. fertilizer should not be placed

LITERATURE cman

Boawn, L. C., F. G. Viets, jr. and C. L. Crawford. 1954.
Effect of phosphate fertilizers on zinc nutrition of field
beans. Soil Sci. 78:1-7.

Burleson, C. A., A. D. Dacus and C. j. Gerard. 1961. The
effect of phosphorus fertilization on the zinc nutrition of
several irrigated crops. Soil Sci. Soc. Am. Proc. 25:565-368.

Chapman, H. D. and Pratt, P. F. 1961. Methods of analysis
for soils, plants and waters. Univ. of Calif. Div. of Agri. Sci.
Duncan, W. G. and A. j. Ohlrogge. 1958. Principles of
nutrient uptake from fertilizer bands. II. Root development
in the band. Agron. j. 50:605-608.

Feed and Fertilizer Control Service Staff. 1965. Annual
Report 1964-65. Texas Agri. Expt. Sta. M.P. 740. j.
Feed and Fertilizer Control Service Staff. 1968. Annual
Report 1967-68. Texas Agri. Expt. Sta. M.P. 845-L.

Hipp, Billy W. 1968. Placement of phosphorus for tomatoes.
jour. Rio Grande Valley Hort. Proc. 22:49-52.

Hipp, Billy W. and C. j. Gerard.
phosphorus interrelationships in tomatoes.
61:403-405.

1969. Magnesium-
Agron. jour.

9.

10.

11.

12.

13.

14.

“and growth of direct-seeded tomatoes. Proc. Amer. Soc.-

jones, L. G. and. G. F.- Warren. 1954. The effici 
various methods of application. of phosphorus for to 1g
Proc.. Amer. Soc. Hort. Sci. 65:509-319. '

   
   
  
  
   
   

Locascio, S. j. and G.» F. Warren; 1959. vGrowth p 
of-the roots of tomato seedlings. 1-_Proc. Amer. Soc. Hort.
74:494-499. ’

Locascio,. s. 1., c. F. Warren and o. E. Wilcox. 1960. i
effect of“, phosphorus placement on uptake of phosp
Sci. 16605-514. ‘ 
Orth, Paul G. 1965. Response by tomato plants to phos?
placed with the seed. Soil and Crop Sci. Soc. of f,
25124-28. I

Robertson, W. K., P. M. Smith, A. j. Ohlrogge and U
Kinch. 1954. Phosphorus utilization by corn as affect‘
placement and nitrogen and potassium fertilization. 
77:219-226. l

Sutton, C. D. 1969. Effect of low soil temperature on 3
phate nutrition of plants — a review. j. Sci. Fd. Agric. 20,

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