10 15 20 25
3.5
4.0
4.5
5.0
10 15 20 255 15 25
10
20
30
40
50
5 10 15 20 25
Introduction
Polyhalite has potential to be a multi-nutrient fertilizer for maize
production. However, little information is available for the
response of maize to polyhalite. This study was conducted for
two consecutive seasons (2013 and 2014) to compare effects of
polyhalite (POLY), to muriate of potash (MOP), sulfate of
potash (SOP) and sulfate of potash magnesia (SOPM), on maize
grown in a sandy soil in greenhouse and in open field excluding
SOPM.
Materials and Methods
For both studies, treatments were arranged in a complete
randomized design with three and four replicates for the
greenhouse and the open field respectively. Fertilizers were
applied at the rates of 50, 100, 200, and 300 K2O Kg ha-1, for the
greenhouse and 50, 100, 150, and 250 K2O Kg ha-1 for the open
field. Soil used in both studies was the Ankona sandy soil
(Sandy, siliceous, hyperthermic, ortstein Arenic Ultic Alaquods).
All treatments received 200 N kg ha-1 as urea and 125 P2O5 kg
ha-1 as triple super phosphate (TSP). POLY was provided by
Sirius Minerals Plc, Scarborough, UK and MOP, SOP, SOP-M,
urea and TSP were acquired from a local fertilizer dealer.
Evaluated variables
Soil analysis before planting and after harvest, plants height,
plants basal stem diameter, kernel size, grain yields, leaves
greenness, elemental concentration in leaves and in grains at 30
and 100 days after planting respectively were analyzed for both
studies. For the greenhouse study, the germination rate and
number of leaves were also assessed. Treatments effects over
variables were quantified using analysis of variance (α >0.05)
and marginal means were separated using Student’s LSD or
Tukey’s HSD.
Results
Germination rate from seeds in pots receiving MOP at 300 K2O
kg ha-1 was 33% and 42% for the 2013 and 2014 season,
respectively while other treatments had 75%-100% germination
rates. MOP effect over seeds germination was not observed in
the open field study at the rate of 250 K2O kg ha-1, the highest
rate used in that study. Maize responded well to polyhalite
under greenhouse and field conditions. POLY does not affect
maize seed germination nor kernel size.
Using Polyhalite As a Multi-Nutritional Fertilizer for Corn
Number of leaves and basal stem diameter for plants receiving POLY were similar to those receiving MOP, SOP and SOPM. Plants receiving POLY were taller than those receiving SOPM
and MOP. Leaves were greener for plants receiving SOP and POLY than those receiving SOPM and MOP. Total fresh and dry weight from those plants receiving POLY were similar to
those receiving SOP, but greater than the ones receiving SOPM and MOP. K uptake by leaves from those plants receiving POLY was similar to SOP but greater than SOPM and MOP. Ca
uptake by leaves from those plants receiving POLY was greater than those receiving MOP, SOP or SOPM. Mg uptake by leaves and grains from those plants receiving POLY was similar
to those receiving SOPM, but greater than those receiving SOP or MOP. K and Ca uptake by grains from those plants receiving POLY was greater than SOP, SOPM and MOP. After
harvest, more available Ca and SO4 were found in the soil treated with POLY than those treated with MOP and SOP.
SOP-M SOP POLY MOPGreenhouse in g plant-1 Open field in Mg ha-1
Ca
in soil
after
harvest
Correlation
between
Grain yield
and
K concentration
in leaves
Marcel Barbier, Yuncong Li, Guodong Liu, Zhenli He, Rao Mylavarapu, Shouan Zhang
Tropical Research and Education Center & Indian River Research and Education Center
Conclusions:
This study demonstrated that POLY is an alternative source of K, Ca, Mg and S and can meet the nutritional
requirements of maize plants for healthy growth and production.
Acknowledgements:
We want to thank Sirius Minerals Plc. for the
support and sponsor of this study.
Gra
ins
g p
lan
t-1
2013 2014
Mg
ha-1
2013 2014
K mgleaves g-1
K mgleaves g-1
Grain
yield
24
31
41
31 3
4
45
26
34
45
20
34 3
8
50K2O ha-1
2013
100 K2O ha-1
200 K2O ha-1
19
26
46
26 3
2
42
24
31 3
6
12
31
39
50K2O ha-1
2014
100 K2O ha-1
200 K2O ha-1
3.9 4
.4 4.5 4.7
3.9 4.2 4
.6
4.6
3.9 4
.4
4.4
4.2
50K2O ha-1
2014
100K2O ha-1
150K2O ha-1
250K2O ha-1
ab
ab
ab
ab
ab
ab
ab
ab
ab
ab
a a ab
ab
ab b
ab
ab
ab
ab
a ab
a ab
3.9 4
.4 4.5 4.7
3.9 4.2 4
.6
4.6
3.9 4
.4
4.4
4.2
50K2O ha-1
2013
100K2O ha-1
150K2O ha-1
250K2O ha-1
a a a a a a a a a a a a a a a a a a a a a a a a
SO4
in soil
after
harvest
12
3
11
6
10
5
10
6 12
0 13
3
83
12
1
12
7
13
4
10
6 13
6
50K2O ha-1
2013
100 K2O ha-1
200 K2O ha-1
12
3
12
1
10
2
10
7
11
6 13
3
81
12
1
12
8
58
10
1
14
8
50K2O ha-1
2014
100 K2O ha-1
200 K2O ha-1
57
8
57
1
58
7 73
884
4
72
6
96
3
1,2
47
46
3 61
1
60
6
61
2
50K2O ha-1
2014
100K2O ha-1
150K2O ha-1
250K2O ha-1
ab
abc
bc
ab
ab
ab
ab
abc
abc
ab
ab
ab
ab
abc
bc c
ab
ab
ab
abc
abc
aab
ab
41
4
28
5
28
3 38
149
8
53
0
36
7
36
2
23
0 34
6 43
1
43
9
50K2O ha-1
2013
100K2O ha-1
150K2O ha-1
250K2O ha-1
b
14
6
29
0
18
9
78
2
1,4
93 2
,27
8
38
2
44
6
44
9
25
5
15
2
24
5
50K2O ha-1
2013
100 K2O ha-1
200 K2O ha-1
14
1
29
9
19
8
76
6
1,5
42 2
,28
5
32
6
45
8
48
3
22
6
16
1
27
2
50K2O ha-1
2014
100 K2O ha-1
200 K2O ha-1
15
1
14
7
14
2
13
8
16
3
15
6
39
8
70
6
13
1
13
4
17
2
14
2
50K2O ha-1
2014
100K2O ha-1
150K2O ha-1
250K2O ha-1
92
78
67
471
12
14
1
37
9 52
9
48 77
49 50
50K2O ha-1
2013
100K2O ha-1
150K2O ha-1
250K2O ha-1
aab
ab
ab
ab
ab
ab
ab
ab
ab
ab
ab
abb b b b bb b b b b
Greenhouse Open field
Greenhouse Open fieldCa mg soil kg-1 Ca mg soil kg-1
c
b
a
cd
cde
a
b
cde
cde
cde
de
e e e e e e ee e e e e e
a
ab
abc
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bc
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cc
c c c c c c cc c c c