Scientific Papers Series A. Agronomy

fertilizers,
outlined
during
thee past
35 years, is
the
expansion
and
diversification of the
range
of
liquid
fertilizers,
regardless
off
the
technologies
of f use
(Cioroianu
ett al.,
2009)
).
The
first “research”
on the posp
ssibility
to use
liquid
fert
tilizerss startedd about
1700 years
agoo
and
coincides
with
the
beginning
of
the
synthesis
of chemical
substancess based
onn
nitrogen
and
ammoniaa (Cioroianu et al., 2009)
).
The
liquid
fertilizers
have
special
advantages
due to thei
ir rapid and
d easy
application, as well
as to
their
higher
agrochemicall efficiencyy as
compared
to
the
clasc
ssical
solidd fert
tilizers
(Cioroianu
et al. , 2009).
elementss wass
obtained.
Under
continuouss
stirring conc
nditions, at a temperature of 25-30 o C, ,
a solution of
microelements (Fe,, Cu,
Zn, Mg, ,
Mn, B) wass chelated withh EDTE
TA disodiumm saltt
andd mixed with a solutionn of potassiumm humatee
(Sîrbu
ett al., 2010)
. The
scheme
to
obtain thee
NPK fertilizers is
presented
in Figure
1.
MATERIALS AND
METHODS
The experimental sch
heme comprised 9 variants
in 4 repetitions:
: V1-
Controll (Non-fertilized);
V2- AH-I
- 100
l/ha;
V3- AH-I - 150
l/ha; V4-
AH-U
- 100
l/ha;
V5- AH-UU - 150
l/ha; V6-
AH-N
- 100
l/ha;
V7- AH-NN - 150
l/ha; V8-
KH
- 100 l/ha; V9-
KHH - 150 l/hal
a.
For the experiment
organizedd onn the slag
g heapp
Figure 1. General sche
emee to obtain
thee NPK fertilizer
for
the corm
crop,
a basic
fertilization was
with humic substances
(accordingg to Pârvan
et al., 2012)
performed
before
sowing, witw
th solid
NPKN
K
15:15:155 - type fertilizers appliedd N – 90 kg/ha,
In
the
framework
of
the
experimentss
P 2 O 5 – 90
kg/ha,
K 2 O - 900 kg/ha,
and
the
performed,
the
potassium
humate
used
too
fertilizer physically
applied
per hectare was
obtain
the fertilizer
was extractedd from
thee coall
600 kg. Before the
sowing,
a basic
fertilizationn
mass,
lignite,
withh the
potassium
carbonatee
was
performed
with
N90PP 90 K 90 and
after
the
solution.
sowing
the
humate-based
liquidd fert
tilizers
Thee potassiumm humate extractedd fromm lignitee
AH-I, AH-U,
of
100-150
l fertilizer/
/ha inn
fertilizerr was thermallyy analyzed in the range
off
450-5000 l of water. The
weedingg operation was
ambient
temperature – 1000°C, inn the
air, withh
performed
60
days
afterr sowing. Soil
samples
a 10 K/mK
inute
heating
rate,
, simultaneouslyy
were
taken
150
days
after
the implementationn
drawing
the
TGA
(thermal
gravimetricc
of
the
experiment,
after
the
first trea
atment
analysis)
), DTG
(derivative
thermogravimetricc
applied
in threee stages,
the
second trea
atment
analysis)
), DTA
(differential thermal analysis)
)
AH-N
andd KH were
applied
in a andd
used
inn
obtaining
the
experimentall
concentration
was applied in three
stages, 2102
0 days
after
the
and
DSC
(calorimetric
analysis)
curves (Sîrbuu
first treatment and
soil samples
were
takenn 600
et
al.,
2010).
The measm
surements were
madee
days
after the
second treatment.
with
a Perkinn Elmerr thermoo balance whichh
The
procedure
to obtain
thee liquid
fertilizer
enabled
mass
determinations at an
error
of
1--
consisted
in
the
neutralizationn
off
the
2%
in thee temperaturee ranr
nge of:
ambientt
phosphoric
acidd con
ncentration
of f 85%
% withh
temperaturee – 1400°CC and
a heating
rate
of: :
potassium
carbonate
concentration
of 98%
%, 0.1-50
K/ /minute.
Thee
potp
tassium
humatee
resulting
in
a solutionn that containedd mono-
place
extraction
from
lignite
presented
four
mainn
under
a
continuous
stirringg at
a constant
decompositionn stages,
namely: up
to 85.3°
°C, ,
andd
obtainedd
in the
laboratoryy
by
alkalinee
dipotassium
phosphate. The
reactionn tookk temperature of 250-300 o C, gradually addingg ann
loss 10.4%,
which stage corresponded to dryingg
amidic,
nitrate and
ammoniumm nitrogen source,
by
an
ende
dothermall process with
a 57.
9 J/gg
and maintainingg the reaction
temperature,
andd
enthalpy; thee secondd
d process
was w
alsoo
as a result
a complexx
mixture
of
macro-
endothermal, in the
e range of o 85.3-267°C,
withh
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