xt7ffb4wjp67 https://nyx.uky.edu/dips/xt7ffb4wjp67/data/mets.xml   Kentucky Agricultural Experiment Station. 1962 journals 118 English Lexington : Agricultural Experiment Station, University of Kentucky Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Progress report (Kentucky Agricultural Experiment Station) n.118 text Progress report (Kentucky Agricultural Experiment Station) n.118 1962 2014 true xt7ffb4wjp67 section xt7ffb4wjp67 FERTILIZER EXPERIMENTS WITH CORN
‘ IN KENTUCKY
‘ By E. C. DOLL
· Progress Report 118
(Filing Code: 1-1)
UNIVERSITY OF KENTUCKY
AGRICULTURAL EXPERIMENT STATION
Department of Agronomy
Lexington

 i .
. FERTILIZER EXPERIMENTS WITH CORN IN KENTUCKY F
By E. C. Doll
This report gives the results of a number of fertilizer experiments conducted with .
corn in Kentucky. Although the results are not discussed in detail, brief interpretations
of the various experiments are given. Fertilizer recommendations for corn, given in _
other publications of the Agronomy Department, were in part derived from the results
of the experiments presented in this report.
PHOSPHORUS
Fertilizer phosphorus is required for efficient corn production on practically all
Kentucky soils with the exception of the high-phosphate soils of the Inner Bluegrass and
certain alluvial soils along the Ohio and Mississippi rivers. Soil where corn is grown
in rotation with a sod crop is frequently more deficient in phosphorus than in other
elements.
Corn was grown in a three-year rotation whith wheat and red clover from 1946 to
1959 at the Greenville, Ky. , soil field. Starting in 1957, allplots were divided and l
phosphorus applications were continued at the original rate on half of each plot with
no phosphorus applied to the other half. The yields obtained with and without phosphorus
at pH 6. 1 and pH 6. 5, together with the soil test values, are given in Table 1. Differences
in yield between the two pH levels (pH 6. 1 and 6. 5) were greater on plots which received
lower rates of phosphorus; the phosphate fertilizer was apparently more effective at the
higher pH level.
TABLE 1. - EFFECT OF PI-IOSPHORUS ON AVERAGE YIELD OF CORN GROWN IN ROTATION WITH WHEAT AND
RED CLOVER FROM 1957 TO 1959 ON TILSIT SILT LOAM (THE. EXPERIMENT WAS STARTED IN _
1946, ALL PLOTS WERE DIVIDED IN 1957; PHOSPHORUS WAS APPLIED AT ORIGINAL RATE ON
HALF OF EACH PLOT, AND NO PHOSPI-IORUS WAS APPLIED TO TI-IE OTHER HALF, RESIDUAL.)
 
Yield per Acre (bushels) \
Pounds P205 Limed to pl-I 6. 1 Limed to pH 6. 5
per Acre P No P Soil P No P Soil
gr Rotation Applied Applied Test Applied Applied Test
Bu/A Bu/A Bu/A Bu/A
20 41. 2 34.9 9 48. 3 39. 3 6
40 55. 1 42. 4 10 60. 2 46. S 7
60 60. 5 45. 9 13 64. 6 56. 5 10
80 67.2 57.3 11 71.1 51.9 9
100 66.7 65.4 14 74.8 62.7 16
160 75. 8 77. 7 22 78. 6 77. 2 27
240 76.0 81.6 43 81.9 79.7 45
320 82. 0 78. 6 79 80,1 78. 8 71
Average 65. 6 60. 5 70. O 61. 6
 

 -3-
Since phosphorus was applied to respective plots at the given rates once during each
_ ` rotation, all yields represent at least some element of response to residual phosphorus.
The soil test results show that various levels of phosphorus have been established. Gen-
erally, yields increased very little, if at all, when more than 160 pounds of PZO5 were
applied per rotation. When phosphorus applications were discontinued, yields tended to
be lower on the halves of the plots which did not receive phosphorus when less than 160
I pounds of P205 per acre per rotation (or 53 pounds per year) had been applied.
The results of a number of phosphorus experiments conducted on soils which tested
very low or moderately low in available phosphorus are given in table 2. Past fertilization
history on these fields indicated that very little or no phosphorus had been applied previously. `
Consequently, yield increases obtained are more marked than usually would be expected.
' For all of these soils except Russellville, recommendations on the basis of the soil test
. would be 100-120 pounds P205 per acre, and for the Russellville soil the recommendations
would be 50-60 pounds. The present recommendations agree quite well with the results
of these experiments.
_ TABLE 2. - EFFECTS OF PHOSPHORUS FERTILIZATION ON YIELD OF CORN
Y
2.
3 J? 3 S ..  
·-= o .*3 +—· ~ .*3 9* m
E :3 E ¤ .5 .5 ¤ 5 M
5 ~ ‘€ E iz i: E 8 2
Soil Series E-. In "
Year 1949 1953 1953 1954 1954 1955 1955 1956 1956
pl-I 5.,5 6,3 5.,8 5.4 5.0 ‘ 5.2 5.6 5.3 6.1
Soil Test 3 6 3 3 9 3 3 3 12
Lb P2O5
ESI 21C1`€
Bu/Acre
None 22.4 42.3 41.7 7.3 13.3 13.3 23.7 38.6 65.8
Row:
" 20 27. 8 43. 9
30 50. 8 32. 2 24. 9 65. 4
40 35. 8 54. 0
60 80. 2
80 37. 2 61. 7
90 83. 2
Broadcast:
30 46. 7 43. 7 50. 6
40 77. 2
60 59.1 51.5
80 80.0
90 58. 3
120 78.9
' 200 53. 9 37.1 82. 0 104. 5

 Of p:1:·1ieula;3 interest are the experinieiits 0n Maniteu seil in 1955 and Celyer seil '
in 1956. When all ef the ph·;·sphe1‘i,v.s was applied in the rew, yields appeared te be leveling _
eft at a leweté level than was ebtained with heavy breadcast applieatiens. These results
are in agteeeinent with these <)l>1,&i1‘:<:¤C] in other states where highest yields were ebtained
when part ef the pnesphcirzis was brr.»ade;:.st and part applied in the rew 0n seils very lew
in pliespheiiiis.
POTASSEUM V
Most Kentne1<§,¤ seils eeintained adequate amounts ef available petassium befere they
were cropped. However, with crciitiinied Fenievfil Of b.3.1‘VeSted <:r0ps, nearly all Seils in
the state (with the exception ni certain seils in the Eden Shale area and everflew seils
along the Ohie and Mississippi) require frequent applications ef petash fertilizers,
The results of a nninbtrwr ef entl ying cxperiinents with petassium are given in Table 31
In general. yield responses te petassinin app`1ie:1tiens were net s0 marked as these ebtained
with [)ll()S[)l?O`fT.lS zipplicritiens Generally, Seine respense was Obtained On upland Seils
shewing petaissinm tests in the very lew 01* lew eategeries. The seil test dees net seein
its uetzizrztte {Yi? p1‘<>dic:tingj petassium needs on bottem seils as On upland Seils.
TABLE 3, »- EE·`E*EC'l' OF POT/\SSi'.I]~/1 FERTUJZ/\'[`lO}E ON YIELD OF CORN
:2 17 *2 @ : > E gi jg > :>
is V; ii g ui] rd · _ -3 ni L15
.>; 1·· A in   g ri r·: M 6 M M 3 N7 3
§2;Q11—L.-.......-...- --...-... ....-.--. --._...-..-.-..--.....-..__..........-.._...._.......
13:52.Va*<1;_.}*'§tL-J§5..i .@§.-1?.‘§i..l€@....i2§5 -19.§§.--l?.§_}2EQ_i?§.6- 1.9.56.- .19.56..1.9§§..i2§_.1§Q.
Li L-------.- .i1§.-.§.Q..-&¤9 ....;.·..-i.3...-- .i—.2.--Q~.L._.§.c9_£;L..é:.?3__.`E·_§._j·Iu_.L.?...“1;;....§)...
§§lli§;..l§.}..-iL._ -.E-.--M.-_L- .... L- --.l_. j}._.& .._Vi...J‘4__`1?L_.__T*/L.£_..TVL-.L-
lb Kg0 Pur I
_/x;?_...-._--.._.-- .... -----.-_-------#,-,-_____--________..__..__._- _,- A
B·i/ Aer;
0 63.,1 38, is 89,2 64.7 7:3. 2 04,7 s0 S 63.9 7407 IOOO 3 90. 3 91¤6 84.,1 1071,9 64.,4
40 771, 5 75,, 3 76,, 8
50 6*, 7 37, 0 S3 , 6 \
(10 101. 6
220 77, 0 71 , 5 68,1
100 6;*. 2 39.6 $4,4 76.1 $4,,6 64., 3 10109 100.2 102..7 10719 7312
120 T2, 5 7I%, it VS, 9 99,, 8
160 73,1 1~»2,2
200
l VL, vert, low; L, 1on_.~~1, 1»n.~1.{C1ix:1
7 .
" All K,0 .i1~;»}i·:tl l~r1¤,1dc;1s;
J 7`vl·;·.1i11n~ ·1.~ x·.·:1‘-t1i21i;;u.1 .`;‘;cl— buitniti soils

 -5-
The effects of various rates of potassium (and nitrogen) on the yield of corn grown in
_ ' a two-year rotation with wheat on Tilsit silt loam at the Greenville soil field (Table 4) show
a very marked response from rates of potassium up to 160 pounds of KZO per acre per two-
year rotation (80 pounds per year).
NITROGEN
_ I
The proper use of fertilizer nitrogen is one of the most important factors in efficient
corn production. Since no suitable nitrogen soil test has been developed for Kentucky,
nitrogen needs are estimated on the basis of past fertilization and cropping history. `
The effects of nitrogen (together with various rates of potassium) on yields of corn
` grown in rotation, following a sweet clover—lespedeza cover crop, are shown in Table 4. ,
Yield responses to nitrogen were not marked, although a consistent yield increase was
obtained for the first 25—pound increment of nitrogen when adequate potassium was applied.
The residues of the preceding legume crop apparently contained nearly enough nitrogen
for maximum yields under these conditions.
TABLE 4. - EFFECTS OF VARIOUS RATES AND COMBINATIONS OF NITROGEN AND POTASSIUM ON AVERAGE
YIELD OF CORN GROWN IN TWO-YEAR ROTATION WITH WHEAT (LESPEDEZA-SWEET CLOVER COVER
CROP) FROM 1952 TO 1959, INCLUSIVE, ON TILSIT S]].T LOAM
 
Pounds N Pounds K20 per acrel
p€I` 3.CI'€
for corn O 40 80 160 320 Av
Bu/Acre
0 36. 0 40. 6 50. 3 58. 2 60. 4 49.1
25 24. 4 41. 4 54.. 5 64. 6 64.1 49, 8
50 22.8 47.5 55.,5 64.7 65.7 51..2
75 18..1 47,0 58.1 63., 3 58.2 48.9
 
A Av 25. 3 44. 1 54. 6 62. 7 62.1 -
· $611 54 59 70 130 273
Test VL VL VL M I-I
A 1Rates refer to total K 0 applied per two·=year rotation.
The results of a number of outlying experiments with corn are given in Table 5.
Three of these experiments were on newly—cleared land, and in every instance a marked
response to nitrogen was obtained. In eight of these experiments, where sod was plowed
for corn, a mathematical evaluation of the response curves indicated that the average
maximum profitable nitrogen application was approximately 80 pounds N per acre.
When corn followed legumes (red clover or lespedeza), maximum yields were usually
obtained with lower rates of nitrogen than when corn followed grass sods.

 -6-
TABLE 5. - EFFECT OF NITROGEN ON YIELD OF CORN '
2
Q va U5 SZ > > "’ "*" vz
tu gg E ni rc ni cd ”‘ *3 3 T; _
_ ' _ 2 l-• ::0 Z E cu cu 3 N $ 8 raf. na E-··
Soil Series _
Year 1954 1954 1954 1955 1955 1956 1956 1956 1956 1956 1956 1956-9 1956—9
Stalks per acre —
(1000) 10.5 10. 5 14.0 14.0 10.5 9.5 10.0 8.0 10.5 10.0 14.0 14.0 10.5 10.5
Erecedinq eropl R R S S S S L S C S R S L L ___
Lb N per acre
Bu/Acre
0 12.9 22.4 72.6 67.6 60.6 87.0 71.3 45.9 102.0 71.0 59.2 74.8 74.3 63.7
30 75.8
40 68. 3 82. 6
50 93.4
60 86.1 102.2 79.6 112.1 71.0 83.7 75.3 68.5
80 76. 0 82. 8
100 53.9 37.1 82.0 104.5
120 74. 0 93. 9 100. 2 110. 8 78.1 107. 9 69. 5 78. 9
160 69,9 84.0
180 101.9 100.2 102.7 73.2
200 63.1 38.8 72.9 82.7 99.8 V
IS —~ sod, C - corn, L - legume, R — cleared land
2Medium-to·well-drained creek bottom soils.
In Table 6, yields are given of corn grown following a mixture of red and Ladino
clover at Princeton for 6 years. A mathematical evaluation of the average response
curve indicated that the maximum profitable rate of nitrogen was about 45 pounds N per
acre. However. the stalk population was low in these experiments.
TABLE 6. — EFFECT OF NITROGEN ON CORN YIELDS FOLLOWING RED AND LADINO CLOVER ON PEMBROKE SILT l
LOAM AT PRINCETON 10, 500 STALKS PER ACRE)
Pountls N
per acre 1954 1955 1956 1957 1958 1959 Av \
bu/acre
0 37. 2 44. 7 77. 3 99. 2 77. 0 85. 7 70. 2
30 39. 8 60. 0 84. 3 103. 8 81.1 92. 3 76. 9
60 38.1 60.2 90.6 101.1 83.5 91.6 77,,5
120 39. 0 64. 0 90. 0 107.1 88. 6 93. 6 80. 4
Table 7 gives the corn yields obtained at Greenville following various legumes. Profit-
able increases were obtained for as much as 50 e ounds of nitrogen er acre following les edeza.
P e P e P .
red elover. or sweet clover. In 1959. higher yields were obtained when corn followed sweet
clover than when it followed red clover.

 -7-
I TABLE 7, - EFFECT OF NITROGEN ON CORN YIELDS FOLLOWING VARIOUS LEGUMES ON TILSIT SILT LOAM AT
, GREENVILLE (10, 500 STALKS PER ACRE)
 
Pounds N Lespedeza Red Clover Sweet Clover
per Acre 1956 1957 1958 Av 1959 1959
i
Bu/A Bu/A Eu/A Bu/A Bu/A Bu/A
0 71,1 64,1 101.,8 79.0 61,1 77,6
30 81,7 69, 1 109,0 86.6 67,4 79,6
60 87. 4 74.. 6 110, 9 91. 0 80.1 86, 5
Table 8 shows the effect of nitrogen on the yield of corn grown following corn (second-
year corn). In general, a more marked response to nitrogen was obtained than when corn
I was grown following a legume (Table 7), Profitable increases were obtained at least, for
~ 60 pounds of nitrogen per acre, and the type of response obtained indicates that higher rates
_ than were used in the experiments would have been profitable. Yields of second-year corn
(Table 8) were considerably lower than yields of corn following legumes (Table 7). Whether
this is the result of nitrogen deficiency or deterioration of soil structure is not known, but
additional work is being conducted at this location.
TABLE 8. - EFFECT OF NITROGEN ON YIELD OF CORN ON TILSIT SILT LOAM AT GREENVILLE WI-I-EN PRECEDING
CROP WAS ALSO CORN (10, SOO STALKS PER ACRE)
 
Pounds N
per acre 1957 1958 1959 Average
Bu/Acre
O ,, 40, 9 25, 3 53, 1 39, 8
· 30 45., 7 70, 0 68. 8 61, 5
60 47, 7 75, 1 74, S 65, 8
 
Table 9 gives the effects of various rates of nitrogen at different stalk populations
for five experiments. Several effects of nitrogen fertilization and stalk population are
clearly shown by these experiments:
1. When no nitrogen or 50 pounds of nitrogen was applied, yields were generally
not increased or were depressed when the stalk population was increased.
2. When 100 or 200 pounds of nitrogen was applied, higher yields were obtained
` with higher stalk populations,
3. Although the data are not given, considerable stalk breakage occurred when 200
pounds of nitrogen was applied, particularly at a population of 21, 000 stalks per
acrer
4, For high yields. nitrogen applications of 150 to 180 pounds per acre may be profitable

 -8..
TAPE! 9. — EFFECT OF NITROGEN AND RATE OF PLANTING ON YIELD OF CORN _
"·;;;:;   
Powd; N Stal}/s pe-: WDB1 PDB2 WDB WDB Grenada Av
;B;ig;e_______a.cre 1958 1959 1959 1959 1959
0 10, 500 64.4 24.4 61.7 84.0 56.7 58.2 _ .
14, 000 52. 7 21. 7 54. 1 98. 2 66. 3 58. 6 l
21, 000 46.7 24. 8 53.8 85.7 53.2 52.9
____/i;______ 54. 6 23. 6 56. 5 89. 3 58. 8 56. 6
50 10, 500 75. 6 64.1 81.9 95. 2 72. 5 77. 8 A
14, 000 91. 4 54. 3 87. 5 108.9 62. 8 81. 0
21, 000 83.8 53.4 80.7 114.4 53.9 77.2
____Ay_______ 83. 6 57. 3 83. 4 106. 2 63. 1 78. 7
100 10, 500 83. 2 72. 6 79. 3 98. 9 66, 3 80. 1 ,
14, 000 94.7 77.6 98.1 111.0 66.4 89.6
21, 000 106.2 72.5 103. 3 129.5 69.8 96.3
  94. 7 74. 2 93. 6 113. 2 67. 5 88. 6 ·
200 10, 500 78. 7 71. 4 84. 8 108. 6 80. 0 84. 7
14, 000 106.0 97. 3 100.2 122.2 81.8 101.5 .
21,000 104.6 95.1 98.5 140.0 79.6 103.5
___ _A};_____ 96.4 87.9 94.5 123.5 80.5 96.6
iiiottom roll, well drained.
°8ov.1om so‘l, poorly drained.
Th cse data show that heavier rates of nitrogen must be combined with higher stalk
populations, ii` high corn yields are to be obtained. When the types of response obtained _
in the experiments shown in Table 9 are compared with those obtained in the preceding
i-xperimcnts, it seems probable that stalk population may have limited yields in many
nl` the preceding experiments. Field observations, together with results of other experi-
inents, indicate that 21, OOO stalks per acre is probably too high for optimum production
and that a population of about 16, OOO is probably most desirable when yield, ease of
ha west., and possibility of drouth periods are considered. When the planting rate is \
incveasccl, additional potassium may help reduce stalk breakage.
1. 8M-9-62