IMPROVEMENT OF MAIZE GROWING ON K-DEFICIENT SOIL
BY FERTILIZATION AND CHOICE OF HYBRID
Kovacevic V.
Faculty of Agriculture,University J. J. Strossmayer in Osijek, Croatia
Abstract
Potassium (K) nutritional problems (edge necrosis of leaves, stalk lodging inclination at maturity, low
yields) connected with high levels of magnesium (Mg) and strong K- fixation have been found on some
hydromorphic soils. Ameliorative KCl fertilization resulted by normalization of yields and improvement of
K and Mg status in maize. Also, by choice of tolerant genotypes could be acceptable solution. For example,
we found that maize hybrids contained Os1-48 inbred line as parent had higher yields and low percent of
stalk lodging in comparison with the hybrids of Os87-24 (means 5.64 and 4.16 t ha-1, 4.9 and 59.1%,
respectively).
Key words: ear-leaf at siking, magnesium oversupply, maize hybrids, potassium deficiency, grain yield
INTRODUCTION
Potassium (K) is an essential element for plants. Low K supplies for field crops have been found in some
hydromorphic soils of the Eastern Croatia. Overcoming this problem is possible by adequate K fertilization
and by choice of more tolerant genotypes. Importance of genetic aspects of plant mineral nutrition was
elaborated in numerous studies including Saric (1981, 1983), Saric and Kovacevic (1980). In this study was
reviewed response of maize to fertilization with potassium chloride and testing maize hybrids under
conditions of low K supplies in Eastern Croatia.
MATERIAL AND METHODS
Response of maize was tested under field conditions. The field trials were conducted in four replicates. In
general, maize was sown at end of April and it was harvested manually at end of September or at
beginning of October. Ameliorative fertilization was made on usual fertilization only in the first year of
testing, while for the next years usual fertilization was used. Ear-leaf was taken for chemical analysis at the
beginning of the silking stage. Grain yields were calculated on 14% grain moisture basis.
The field trials including response of maize hybrids to KCl fertilization
Residual effects of ameliorative fertilization with KCl (spring 1990) on maize yields and nutrtional status
of six maize hybrids (1993) on Mikanovci strong K-fixing soil was tested. The experimental plot measured
294 and 39 m2, for fertilization and hybrid, respectively (Kovacevic et al. 1996).
Five maize hybrids were grown on Gundinci K-deficient soil for three growing seasons (2001, 2002 and
2003) and their response to two levels of KCl (500 and 1250 kg K2O ha-1 applied before sowing (April 2,
2001) was tested. Experimental plots measured 165 m2 and 28 m2, for fertilization and hybrid, respectively.
Maize was sown on planned plant density (PPD) 58310 ha-1. Grain yields were calculated on 90% PPD
(2001 and 2002) and 70% PDD (2003). These investigations (the 2001 and 2002 growing seasons) were in
detail elaboreted by Kovacevic et. al. (2003).
Response of three maize hybrids to P and K fertilization (spring 2001) were tested Luzani hydromorphic
soils. The experimental plot measured 63 and 21 m2, for fertilization and hybrid, respectively (Kovacevic
et al. 2003). Monoammonium phosphate (MAP: 12% N + 52% P 2O5) and KCl were sources of P and K,
respectively. Calcium ammonium nitrate (CAN) was used for corrections of different N levels. Grain yields
were calculated on 90% PPD.
Testing ogf maize genotypes on soil stress induced by K-fixation
Two groups of maize hybrids (total 14) of same inbred line as a male parent (Os1-48 and Os 84-27, for the
A and B group, respectively) were grown on Mikanovci strong K-fixing soil (the 1990 growing season).
Experinmental plot of the hybrids measured 7 m2. Yields, stalk lodging and stalk base composition
elaborated by Kovacevic and Vujevic (1993).
Ten maize hybrids were grown on K-deficient Zupanja fluvisol for 1998 growing season. Experimental
plot of the hybrid measured 14 m2. Yields and ear-leaf nutrtional status were shown in detail by Kovacevic
et al. (2001).
RESULTS AND DISCUSSION
Low K and oversupplies of Mg in maize leaves in our investigations (Tables 1, 4 and 5) were found. Acute
K deficiency in maize is in close connection with K concentrations in dry matter of ear-leaf (silking stage)
less than 1.0 % K, while normal Mg concentrations are in range from 0.20 to 0.50% Mg (Bergmann, 1992;
Mengel and Kirkby, 2001). In general, considerable role of KCl fertilization and genotype on maize
properties on Mikanovci K-fixing soil was found. Fertilization with KCl resulted by eliminating unbalance
between K and Mg in maize. At the same time, considerably increased plant density realization and
decreased grain moisture and stalk lodging at maturity stage. Also, considerable role of heredity on tested
properties was found. For example, stalk lodging difference at maturity among the six hybrids were from
5.7 to 27.2% (Table 1).
Maize yield increases in the Gundinci experiment as affected by 1250 kg K 2O ha-1 application was 17%
(Table 2). Response of maize hybrids to KCl fertilization was specific. In 2001 yields of two hybrids
(OsSK444 and OsSK458) were higher (average 11.18 t ha-1) in comparison with remaining three tested
hybrids (average 10.70 t ha-1). Yield increases of individual maize hybrids under influences of applied
fertilization were in range from 5.4% (Florencia) to 28.3% (OsSK458). Similar findings were found in the
next year. Drought stress in the 2003 growing season was main reason for low maize yield. It was only
5.03 t ha-1 or for more than 50% lower in comparison to two previous years. However, residual effect of
KCl fertilization (yield increase for 10% in comparison with the control) was found, but only two hybrids
(Bc 5982 and Florencia) significantly increased yield as affected by KCl application three years ago.
Mean grain yields of maize in the Luzani experiment were moderate in comparison with the genetic
potential of these high-yielding maize hybrids and the weather characteristics during the growing seasons
(8.01 and 7.14 t ha-1, for the 2001 and 2002, respectively). Also, the yields are. In 2001, only the higher
rate of fertilizers resulted in significant yield differences as follows: yield increases for 18% (influences of
P) and 22% (influences P and K) and yield decreases for 10% (influences of K). We presume that the main
reason for this type of corn response to fertilization is affected by the ameliorative fertilization before
sowing and incorporation of the fertilizers in the surface layer until 10-15 cm by presowing soil tillage
treatments. In our investigation we found considerable influences of the hybrids on maize yields. In both
year of testing the hybrids OsSK444 and Bc5982 had similar yields. However, the yields of the OsSK552
were for 9% lower and for 10% higher in comparison to the remaining two hybrids for the 2001 and the
2002, respectively (Table 3).
Table 1. Residual influences of KCl fertilization (spring 1990) on maize (Kovacevic et al. 1996)
Factor
Fertilization
kg K2O ha-1
150
1000
1900
3250
Maize
hybrid
Maize properties (the 1993 growing season)*
Yield
The ear-leaf (% in DM)
t ha-1**
K
Mg
PDR
1.83
0.31
1.08
67.9
4.08
0.54
0.90
82.4
6.32
0.82
0.71
89.8
7.04
1.18
0.47
93.6
LSD A (fertilization) 5%
LSD A (fertilization) 1%
0.44
0.64
0.06
0.09
0.06
0.08
OsSK 377
OsSK382
OsSK 407
OsSK 552
OsSK 644
Bc 66-61
4.60
4.99
5.31
4.95
4.70
4.35
0.65
0.68
0.68
0.71
0.85
0.71
0.93
0.73
0.82
0.75
0.71
0.79
76.7
80.5
93.1
87.3
77.5
85.4
%
GM
34.1
27.4
25.2
25.0
SL
27.3
17.8
10.0
3.8
23.5
21.8
25.3
27.7
35.5
33.9
24.6
27.2
12.2
12.7
5.8
5.7
LSD B (hybrid) 5%
0.23
0.04
0.03
LSD B (hybrid) 1%
0.30
0.05
0.04
* DM = dry matter; PDR = plant density realization: 100% = 68027 (OsSK377); 63492 (OsSK382, OsSK407 and
OsSK552) and 54945 (OsSK644 and Bc66-61) plants ha-1: GM = grain moisture at harvest; SL = stalk lodging.
Typical example of heredity role on maize tolerance to soil stress is testing fourteen hybrids of two parents
(Os 1-48 and Os87-24, respectively) tested on usual fertilization on Mikanovci strong K-fixing soil (Table
4). These results indicated that Os1-48 inbred line could be used as source of property characterizing
resistance to stalk lodging at maturity stage under conditions of K deficiency (Kovacevic and Vujevic,
1993).
Table. 2. Response of maize to KCl fertilization for three growing seasons
Influences of fertilization (spring 2001) and hybrid on maize yields (t ha-1)*
K2O
The growing season
Mean Maize
The growing season
(kg ha-1) 2001
2002
2003
hybrid
2001
2002
2003
OsSK 444
11.02
9.74
5.06
Control
10.09
9.13
4.72
7.98
OsSK 458
11.34
10.18
5.51
500
11.04 10.63
5.28
8.98
OsSK 552
10.55
10.84
4.53
1250
11.54 11.28
5.12
9.31
Bc5982
10.66
10.44
4.12
Florencia
10.88
10.52
6.00
LSD 5%
0.84
0.45
0.29
LSD 5%
0.47
0.69
0.36
LSD 1%
1.27
0.69
n.s.
LSD 1%
0.62
0.91
0.47
Mean
8.61
9.01
8.64
8.41
9.13
* on 90% (for 2001 and 2002 ) and 70% (for 2003) of theoretical plant density (100% = 58310 plants ha -1)
Table 3. Grain yields of maize as affected by P and K fertilization (Kovacevic et al. 2003)
Maize hybrid
(the factor B)
OsSK 444
Bc5982
OsSK552
Mean (A)
LSD 5%
LSD 1%
OsSK 444
Bc5982
OsSK552
Mean (A)
LSD 5%
LSD 1%
Grain yield of maize (t ha-1) on 90%TPD* and 14% grain moisture basis
Ameliorative amounts (kg ha-1) on ordinary fertilization (the factor A)
a
b
c
d
e
f
P2O5
K2O
Mean
0
750
1500
750
1500
c+e
(B)
The 2001 growing season
7.14
7.40
9.39
7.35
6.45
9.18
7.82
7.45
8.02
8.55
6.72
6.82
8.87
7.74
8.29
8.40
8.97
7.77
7.45
9.97
8.48
7.63
7.94
8.97
7.28
6.91
9.34
8.01
A 0.51
B 0.28
AB 0.76
0.70
0.37
1.02
The 2002 growing season **
6.25
7.66
8.24
7.35
7.24
7.61
7.39
6.51
7.56
7.92
7.30
7.19
7.82
7.37
5.88
6.93
7.19
6.46
6.56
7.03
6.67
6.20
7.39
7.78
7.02
6.98
7.48
A 0.52
B n.s.
AB n.s.
0.73
* TPD = theoretical plant density: 58310 plants ha-1; 90% TS = 52479 plants ha-1
** residual influences of ameliorative fertilization (ordinary fertilization of the experiment)
Table 4. Response of maize hybrids on Mikanovci K-fixing soil (Kovacevic and Vujevic, 1993)
Yield
Stalk* (%)
Pedigree
(t ha-1) SL
K
Mg
P
Maize hybrids of Os1-48 inbred line (A)
as male parent (the A group)
Os87-44 x A 5.23 8.8
0.30 0.48 0.11
Os84-15 x A 6.30 4.8
0.30 0.55 0.07
Os84-25 x A 5.56 4.1
0.18 0.52 0.14
Os84-24 x A 5.89 4.6
0.17 0.48 0.08
Os86-39 x A 4.45 7.5
0.18 0.71 0.16
Os89-24 x A 7.20 4.1
0.30 0.45 0.07
B x A 4.83 0.7
0.21 0.52 0.27
Mean A
5.64 4.9
0.24 0.53 0.13
LSD 5%
0.53
0.04 0.09 0.03
LSD 1%
0.72
0.05 0.12 0.04
Yield
Stalk* (%)
Pedigree
(t ha-1) SL
K
Mg
P
Maize hybrids of Os87-24 inbred line (B)
as male parent (the B group)
Os87-61 x B
2.83 79.0 0.18 0.64 0.18
Os88-15 x B
4.71 83.3 0.21 0.88 0.29
Os86-92 x B
2.90 23.7 0.17 0.74 0.22
Os87-56 x B
3.52 52.1 0.21 0.74 0.21
Os84-24 x B
5.45 95.6 0.18 0.68 0.24
Os87-57 x B
4.28 74.1 0.19 0.68 0.22
AxB
5.40 5.3
0.18 0.69 0.19
Mean B
4.16 59.1 0.19 0.72 0.22
LSD 5%
0.53
0.04 0.09 0.03
LSD 1%
0.72
0.05 0.12 0.04
* K. Mg and P in three developed the lowest nodes of stalk at maturity (% in dry matter); SL=stalk lodging
Table 5. Influence of soil and genotype on maize yield and K and Mg status (Kovacevic et al. 2001)
Grain yield (t ha-1), and ear-leaf K and Mg status (% in dry matter at silking stage) of ten
maize hybrids on Zupanja K-deficient fluvisol (the 1998 growing season)
t ha-1
K
Mg
OsSK
OsSK
OsSK
OsSK
OsSK
OsSK
OsSK
OsSK
OsSK
OsSK
LSD
5%
1%
382
6.91
0.70
1.19
444
7.31
0.79
1.13
458e
7.14
0.53
1.24
497e
5.27
0.52
1.27
552
3.61
0.56
1.46
554
4.24
0.54
1.48
558
5.08
0.67
1.50
568e
9.59
0.75
1.00
602
8.01
0.73
1.26
617e
5.98
0.59
1.22
1.29
0.13
0.15
1.80
0.19
0.25
Acute K deficiency (mean 0.64 % K) and oversupply of Mg (mean 1.23% Mg) were found in the maize on
Zupanja fluvisol. Grain yield differences among the hybrids were from 3.61 (OsSK552) to 9.59
(OsSK568exp.) t ha-1. Their nutritional status were 0.56% K and 0.75% K, 1.46% Mg and 0.99% Mg, for
OsSK552 and OsSK568exp. respectively (Table 5). We presume that maize hybrids characterizing higher
K and lower Mg uptake could be better choice for K-deficient soils.
CONCLUSIONS
Ameliorative potassium application especially affected maize yields under K deficient conditions. For
practical purpose could be recommend combination of adequate fertilization and growing of more tolerant
genotypes.
ACKNOWLEDGEMENTS:
This study is dedicated to Academician Miloje R. Saric university professor and full member of the Serbian
Academy of Sciences and Arts (September 12, 1925 – December 6, 2002) as expression of author’s
gratitude for long-term successful scientific cooperation including leadership his PhD Thesis (June 2, 1980,
Faculty of Agriculture of University Novi Sad). Academician Saric was one of leading phytophysiologists
with high reputation among the members of world scientific community.
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