© Acta hydrotechnica 19/31 (2001), Ljubljana
ISSN 1581-0267
117
UDK / UDC: 504.4:546.17:546.39:556.34 Prejeto / Received: 30.7.2001
Izvirni znanstveni prispevek / Original scientific paper Sprejeto / Accepted: 27.12.2001
VPLIV AGREGACIJE POROZNEGA MEDIJA NA PRENOS NITRATA IN
AMONIJA V ZEMELJSKIH KOLONAH
THE INFLUENCE OF POROUS MEDIA AGGREGATION ON THE
NITRATE AND AMMONIUM TRANSPORT IN SOIL COLUMNS
Vesna ZUPANC, Miran VESELIČ, Peter CEPUDER
V enodimenzionalnih kolonah smo preučevali prenos tekočine z drugo mešajočo tekočino v
nasičenih pogojih. Kot sledilo za opazovanje obnašanja dušika v procesih prenosa, smo uporabili
dušično gnojilo (mešanica amonijske (NH4+) in nitratne (NO3-) oblike dušika). Za premikajočo
tekočino smo uporabili destilirano vodo. Med izvajanjem poskusov so se pogoji v kolonah,
napolnjenih z medijem frakcije tal < 2 mm spremenili. Izbrana velikost agregatnih delcev je imela
vpliv na obnašanje sledila. Krivulje prehoda NO3
- so bile v primerjavi s krivuljami prehoda NH4
+
simetrične oblike pri vseh velikostih agregatnih delcev. Krivulje prehoda NH4+ so dobile simetrično
obliko pri večjih delcih od 0.63 do 2 mm in od 2 do 4 mm. Največji vpliv na prenos NH4+ je imela
sposobnost fiksacije NH4
+ na negativne površine delcev.
Ključne besede: kolonski poskusi, porozen medij, velikost delcev, nitrat, amonij
The displacement of one fluid by another miscible fluid under saturated conditions and at different
average flow velocities in one – dimensional soil columns was studied. For the tracer solute,
nitrogen fertilizer (combination of ammonium (NH4
+) and nitrate (NO3
-) form of nitrogen) was used
to observe the behavior of the nitrogen in the transport processes. For the displacing fluid, distilled
water was used. In the course of the experiments, conditions in soil columns with < 2 mm soil
fraction were altered. The size of the chosen aggregates influenced the behavior of the tracer.
Breakthrough curves of NO3
- were compared to the NH4
+ breakthrough curves symmetrical with all
aggregate sizes. The BTC of the NH4
+ obtained a clear shape with the larger aggregate sizes 0.63–
2 mm and 2–4 mm. The greatest influence on the NH4
+ transport had the ability of the NH4
+ to
fixate on the negatively charged particle surfaces.
Key words: column experiments, porous media, aggregate size, nitrate, ammonium
1. UVOD
Kakovost podtalnice je lahko ogrožena
zaradi različnih onesnažil, zatorej je
poznavanje in razumevanje procesov prenosa,
kot so sorpcija, disperzija in difuzija nujno in
pomembno. Prisotnost nitratov (NO3
-) v
podzemnih vodah je posledica številnih
dejavnikov. Eden glavnih dejavnikov
onesnaževanja je neprimeren način
kmetovanja.
Dušik je bistvena sestavina rastlinskih
gnojil in igra pomembno vlogo pri
povečevanju količine in kakovosti pridelka
1. INTRODUCTION
Groundwater quality can be compromised
by many different contaminants; therefore, it is
imperative to understand the importance of
transport mechanisms such as sorption,
dispersion, and diffusion. The widespread
appearance of nitrate (NO3
-) in ground water is
a consequence of a number of factors.
Unsuitable agricultural practices are one of the
main pollution sources.
Nitrogen is an integral component of many
essential plant nutrients and plays important
roles in increasing crop yields and crop quality
(Brady, 1998). The human mediated
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
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(Brady, 1998). Vnos reaktivnega dušika v
nitratni (NO3
-) in amonijski obliki (NH4
+) z
gnojenjem je najbolj učinkovita metoda za
povečanje rastlinske proizvodnje. Vendar ima
odvečni dušik, uporabljen za gnojenje,
nedvomno okoljevarstvene posledice na
globalni, regionalni in lokalni ravni, kot npr.
onesnaženje površinskih in podzemnih voda z
NO3
- (Brady, 1998).
Kationska narava NH4
+ omogoča retenzijo
NH4
+ - N na talnih koloidih v izmenljivi obliki,
tako so ioni v tej obliki učinkovito zaščiteni
pred izpiranjem s pronicujočo vodo (Nommik
& Vahtras, 1982). Med talne koloide uvrščamo
glinene minerale, organske snovi ali okside
mangana in železa ter so večinoma negativno
nabiti.V nasprotju z NH4
+ ioni, se NO3
- ioni ne
vežejo na negativno nabite koloide, ki
prevladujejo v večini tal. Zatorej se NO3- ioni
prosto gibljejo navzdol z odtekajočo vodo in
so tako zlahka sprani iz tal. Te izgube NO3
-
povzročijo širše resne okoljske težave in hkrati
zmanjšajo produktivnost ekosistema (Brady,
1998). V svetovnem merilu izpiranje NO3
- iz
tal še vedno predstavlja izgubo okrog
19 odstotkov celotnega dušika, ki se uporabi
za gnojenje (Lin et al., 2001). Kljub
pomembnosti problematike pa je razumevanje
izpiranja NO3
- iz različnih tipov tal še vedno
pomanjkljivo (Hansen et al., 2000).
Pri študiju spiranja NO3
- iz tal in procesov v
tleh se pogosto uporabljajo kolonski poskusi.
Iz praktičnih razlogov je težko izpeljati poljske
poskuse na regionalni ravni pod normalnimi
pogoji toka, mogoče pa je oceniti relativni
transport reaktivnih in nereaktivnih snovi v
laboratorijskih poskusih. V Sloveniji smo jih
uporabili pri raziskavah vpliva vrste gnojila in
tipa tal na koncentracijo in izotopsko sestavo
NO3
- v perkolatu z 15N (Pintar et al., 1998;
Lojen et al., 1999; Pintar, 2001), ki so sledile
študijam izvora onesnaženja podtalnice z NO3-
na Apaškem polju, s pomočjo stabilnih
izotopov. Poskus izpiranja je potrdil, da za
izluževanje NO3- iz tal ni pomembna le vrsta
gnojila, pač pa tudi substrata. Podatki, ki jih
pridobimo iz takih poskusov, lahko v praksi
pojasnijo pretekla gibanja onesnažil v
podtalnici ter so v pomoč pri napovedi prenosa
snovi.
introduction of reactive nitrogen such as
nitrate (NO3
-) and ammonium (NH4
+) for
fertilization, has been recognized as the most
effective method for increasing food
production. However, excess nitrogen used in
fertilization has undoubtedly resulted in
various global, regional and local
environmental problems such as the NO3
-
pollution of ground and surface waters (Brady,
1998).
The cationic nature of NH4
+ permits the
retention of NH4
+ - N by soil colloids in
exchangeable form, and in this form, the ions
are effectively protected against leaching by
percolating waters (Nommik & Vahtras,
1982). Soil colloids are clay minerals, organic
substances or manganese or iron oxides and
are mostly negatively charged. In contrast to
NH4
+ ions, NO3
- ions are not adsorbed by the
negatively charged colloids that dominate
most soils. Therefore, NO3
- ions move
downward freely with percolating water, and
are thus readily leached from the soil. Such
NO3
- leaching losses not only cause several
serious environmental problems, but also
reduce ecosystem productivity (Brady, 1998).
Of the total amount of applied fertilizers
worldwide, 19% is lost to NO3
- leaching (Lin
et al., 2001). In spite of the importance of the
issue, a major deficiency in our understanding
of NO3
- leaching form various soil types
persists (Hansen et al., 2000).
For the NO3
- leaching and transport
processes, research column experiments are
often used. Due to practical constraints, it is
difficult to conduct field tests at regional
scales under normal flow conditions; however,
it is feasible to gauge the relative transport of
reactive and non-reactive solutes at the
laboratory scale. Column experiments have
been used for he research of the influence of
different fertilizer and soil types on NO3
-
concentration and isotopic composition in
effluent with 15N (Pintar et al., 1998; Lojen et
al., 1999; Pintar, 2001), which followed the
research on the source of NO3
- groundwater
pollution in the Apače valley using stable
isotopes. The experiment showed that for NO3
-
leaching, not only the type of fertilizer applied,
but that substrate type was also important. On
a practical level, data obtained from such tests
can elucidate past contaminant movement in
groundwater, and may also assist in transport
prediction.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
119
Z uporabo mešanih sledil različnih
fizikalnih in kemičnih lastnosti lahko ločimo
različne parametre prenosa snovi in tako
zagotovimo edino mogočo rešitev za uporabne
enačbe. Kemična in fizikalna sredstva prenosa
snovi so pod vplivom porozne narave medija.
Večina zemljin je strukturiranih, vsebujejo
agregate ali pore različnih velikosti. V tem
primeru se gibanje vode ne more opisati s
posamezno povprečno hitrostjo toka, ker voda
znotraj večjih por teče znatno hitreje kot v
manjših porah. Vodo, ki se nahaja v majhnih
porah znotraj gostih agregatov, lahko
označimo kot efektivno stoječo. Snovi bodo
skozi večje pore migrirale s premikanjem vode
(konvekcija), medtem ko difuzija snovi v
stagnirajočo raztopino povzroči zaostanek.
Ta fenomen pripisujemo fizikalnemu
neravnovesju ali neravnovesju prenosa
(Brusseau & Rao, 1990). Ta povzroči
asimetrično krivuljo prehoda za nereaktivne
kemikalije: do začetnega prehoda snovi pride
hitreje, celoten prehod snovi pa traja precej
dalj, kot bi pričakovali v primeru homogenih
tal. Ta pojav, ki se lahko označi kot razvlečen
prehod, je bil opažen v študijah prenosa snovi
v različnih tipih strukturiranih medijev, kot so
agregirane in razpoklinske zemljine, zemljine
z makroporami, kanali korenin in kanali
zemeljskih črvov ter v zemljinah s
prostorskimi razlikami v hidravlični
prevodnosti tal (Brusseau & Rao, 1990).
Razvlečeni prehodi krivulj prehoda so
posledica nihanj hitrosti fluida porozne snovi,
povzročene zaradi zamašenih por. Blokada
ustij por povzroči visoke hitrosti v
preferenčnih poteh, kar vodi v zgodnji prehod
snovi. Območja s slabo prepustnostjo
zakasnijo prehod snovi, kar poveča nagib
krivulj prehoda (Bouhroum & Civan, 1994).
By using multiple tracers of differing
physical and chemical characteristics, the
various transport parameters can be separated,
and thus provide a unique solution of the
applicable governing equations. The chemical
and physical means of transport are influenced
by the porous nature of the media. Most soils
are structured; they contain aggregates or
pores with a range of sizes. The water
movement cannot be described by one average
flow velocity because soil water flows
significantly faster in larger pores than in
smaller pores. The soil water that is located in
the small pores inside aggregates might even
be considered effectively stagnant. The solute
will migrate along with the movement of the
water through the large pores (convection),
while diffusion into the stagnant solution
causes retardation.
This phenomenon is referred to as physical
non-equilibrium or transport non-equilibrium
(Brusseau & Rao, 1990). It causes an
asymmetrical breakthrough curve for non-
reacting chemicals: initial breakthrough occurs
faster, and complete breakthrough takes much
longer. That would be expected in the case of a
homogeneous soil. This effect, also named
‘tailing’, has been observed in transport
studies with different types of structured
media, such as aggregated and fractured soils;
soils with macropores, root channels or earth
worm channels and soils with spatial variation
in hydraulic conductivity (Brusseau & Rao,
1990).
Long tails in BTCs are a result of the
velocity fluctuations induced by particle
clogging. The blockage of pore necks, which
induces higher velocity in preferential flow
pathways, leads to early solute penetration;
whereas the low permeability zones which
delay the rate of the solute transport increase
the skewness of the BTCs (Bouhroum &
Civan, 1994).
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
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2. MATERIALI IN METODA DELA
V enodimenzionalnih kolonah smo
preučevali prenos tekočine z drugo mešajočo
tekočino v nasičenih pogojih. Kot sledilo za
opazovanje obnašanja dušika v procesih
prenosa je bilo uporabljeno dušično gnojilo
(mešanica amonijske NH4
+ in nitratne NO3
-
oblike dušika) v ekvivalentu 100 kg N/ha. Za
premikajočo tekočino smo uporabili
destilirano vodo (ISO 3696:1987).
Krivulje prehoda za sledilno raztopino (Co)
so izmerjene za dve hitrosti vode porozne
snovi. Dve hitrosti sta določeni z različnima
ravnema vodnih tankov. Na podlagi teksturne
klasifikacije, dostopne na Inštitutu za
hidravliko in upravljanje z vodami v
kmetijstvu, sta bili določeni dve lokaciji za
zbiranje vzorcev tal (preglednica 1). Vzorec tal
s poskusnega polja Univerze za agronomske
znanosti na Dunaju pri Gross–Enzersdorfu
(GE), v bližini Dunaja, je bil vzet iz globine 0
do 25 cm, vzorec tal s poskusnega polja
Univerze za agronomske znanosti na Dunaju
pri Pyhra (P) pa iz globine 15 cm.
2. MATERIALS AND METHOD
The displacement of one fluid by another
miscible fluid under saturated conditions in
one – dimensional soil columns was studied.
For the tracer nitrate, fertiliser in the
equivalent of 100 kg N/ha (combination of
ammonium NH4
+ and the nitrate form NO3
- of
nitrogen) was used to observe the behavior of
the nitrogen in the transport processes, and for
displacing the fluid distilled water.
The breakthrough curves for the tracer
solute Co) were measured for two pore water
velocities. The two water velocities were
determined by the different water tank levels.
Based upon the textural classification available
at the Institute for Hydraulics and Rural Water
Management, two locations were identified for
soil sample collection (Table 1). Soil from the
experimental station of the University of
Agricultural Sciences, Vienna, at Gross –
Enzersdorf (GE), near Vienna, was collected
from a depth of 0 – 25 cm, and soil from the
experimental site of the University of
Agricultural Sciences, Vienna, at Pyhra (P),
was collected up to a depth of 15 cm.
Preglednica 1. Teksturna klasifikacija vzorcev tal P < 2 mm in GE < 2 mm.
Table 1. Textural classification of P < 2 mm and GE < 2 mm samples.
Prod
Gravel
>2 mm
Pesek
Sand
2–0,06 mm
Melj
Silt
0,06–0,002 mm
Glina
Clay
>2 µm
Teksturni razred (Slika 1)
Textural classification
(Figure 1)
P < 2 mm 0 34 45 21 Ilovica / Loam
GE < 2 mm 0 20 55 25 Meljasta ilovica / Silty loam
Vzorci tal so bili v laboratoriju posušeni s
pomočjo električnih ventilatorjev. Večje grude
tal smo previdno ločili in odstranili gramoz.
Prav tako smo odstranili kamne in korenine.
Preostali vzorec smo presejali skozi sita
velikosti 4 mm, 2 mm, 1 mm in 0.63 mm.
Drug material (npr. manjši ostanki korenin), ki
je prodrl skozi sita, smo izločili. Na presejanih
talnih vzorcih so bile narejene analize za
teksturo tal (slika 1), pH tal, električno
prevodnost kot tudi za organski ogljik, humus
in celokupen dušik (preglednica 2).
The soil was dried, carefully disintegrated
and the gravel, stones and roots were removed.
The remaining soil was sieved through 4 mm,
2 mm, 1 mm and 0.63 mm sieves, and all the
material passing through was collected
separately (i.e. smaller root residues) and
removed. For the sieved soil sample particle
size analysis (Figure 1), soil pH and electrical
conductivity were determined, as well as
organic carbon, humus and the total nitrogen
composition (Table 2).
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
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Slika 1. Teksturni trikotnik po USDA klasifikaciji (Vrščaj, 2001)
Figure 1. Texture triangle after USDA classification (Vrščaj, 2001)
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
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Preglednica 2. Kemične lastnosti in mineraloška struktura celokupnih vzorcev.
Table 2. Chemical properties and mineralogical structure of bulk samples.
P < 2 mm GE 0,63–2 mm GE 2–4 mm
MINERALOŠKA STRUKTURA CELOKUPNIH VZORCEV
MINERALOGICAL STRUCTURE OF BULK SAMPLES
% Kremen / % Quartz 60 59 55
% Silikatni sloji / % Silicate layers 31 0 0
% Sljud / % Feldspars 9 5 2
% Kalcit / % Calcite 0 19 17
% Dolomit / % Dolomite 0 17 25
KEMIJSKE LASTNOSTI / CHEMICAL PROPERTIES
pH 6.4 8.27 8.89
Električna prevodnost (µS/cm)
Electrical conductivity (µS/cm)
0.3 0.32
Organski ogljik / Organic carbon 1.24 0.777 0.456
Humus 2.138 1.34 0.785
Skupni dušik / Total nitrogen 15 10 5
TEKSTURA (po USDA klasifikaciji) Ilovica Pesek Prod
TEXTURE (after USDA classification) Loam Sand Gravel
Kot sledilo je bilo uporabljeno mešano
dušično gnojilo amonij nitrat (komercialno
ime Nitramoncal/NAC, proizvaja AgroLinz,
Avstrija, 27% N-NO3, 27% N-NH4), ki je v
vodi zelo topen. Z agronomskega stališča je
odlično gnojilo. Zagotavlja enake količine
NH4
+ in NO3
- oblike dušika, kar je fiziološka
prednost pri prehrani rastlin (Follet, 1989).
Za kemično analizo perkolata je bila za
določitev NH4+ uporabljena metoda z
indofenolom. NH4
+ oksidira s pomočjo
aktivnega klora v kloramin. Reakcija se pojavi
ob oksidaciji fenola v chinonchloramin, ki se v
alkalnih snoveh veže z drugimi fenoli v
zeleno obarvan indofenol. Koncentracijo
indofenola lahko fotometrično ugotovimo pri
660 nm.
Za določitev NO3- je bila uporabljena
metoda po Navonnu. NO3
- adsorbira UV-
svetlobo v kislem mediju. Valovna dolžina
svetlobe, uporabljene pri tej metodi je 210 nm.
Ker pa pride do adsorpcije nekaterih drugih
organskih substanc, kot npr. huminske kisline
As a tracer, ammonium nitrate (commercial
name Nitramoncal/NAC, produced by
AgroLinz, Austria, 27% N-NO3, 27% N-NH4)
was used. It is highly soluble in water. From
an agronomic standpoint it is an excellent
fertilizer. It provides equal amounts of NH4
+
and the NO3
- form of N, which may be a
physiological advantage in the nutrition of
crops (Follet, 1989).
For the chemical determination of NH4
+ in
the effluent, the indophenol method was used.
NH4
+ oxidizes through active chlor to
chloramin. The reaction occurs in the presence
of phenol under the oxidation to
chinonchloramin, which, in an alkaline media,
bonds with other phenol to a green colored
indophenol. The concentration of indophenol
can be photometrically determined at 660 nm.
For NO3
- determination, the method
belonging to Navonne was used. NO3
- adsorbs
UV light in an acidic medium. The wavelength
used with this method is 210 nm. Because
some of the organic substances, such as the
humic acids, also adsorb at the same
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
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pri isti valovni dolžini, moramo izvesti dve
meritvi. Pri drugem merjenju izmerimo
količino motečih substanc. Zaznavo
koncentracije NO3
- ovirajo bakreni svinčeni
delci, ki jih pred drugo meritvijo čez noč
dodamo vzorcu. Perkolat je bil vzorčen z
avtomatičim vzorčevalnikom.
wavelength, two measurements were needed.
The second time, only the disturbing
substances were measured. The registration of
the NO3
- concentration was hampered by
adding coppered zinc granulates to the probe
overnight. The effluent solution was collected
with an automatic sample changer.
Spodnji del kolone je bil zaprt z zamaškom
iz pleksi stekla. Kolono smo pazljivo napolnili
s posameznimi vnosi po 100 g vzorca tal.
Vzorec tal znotraj kolone smo enakomerno
porazdelili, s fino paličico smo ga premešali,
da bi odstranili sloje, ki bi se lahko oblikovali
ob posameznih vnosih v kolono. Kolone smo
nato udarili po vseh štirih smereh na zunanji
strani, da bi zagotovili homogenost posamezne
kolone. Kolono smo zaprli s čepom iz pleksi
stekla. Na vsakem koncu kolone iz pleksi
stekla smo namestili fin najlonski filter, ki je
preprečeval izgubo vzorca tal med poskusom
(slika 2).
Težo dela iz pleksi stekla, težo in volumen
suhega in nasičenega vzorca tal smo določili
gravimetrično za vsako kolono, da bi lahko
izračunali poroznost, suhi obseg gostote in
vsebnost vlage v tleh (preglednica 3).
Kolono z vzorcem tal smo počasi od spodaj
nasičili z destilirano vodo v času 24 ur.
Najprej smo dovolili, da se je voda znotraj
kolone dvignila s pomočjo kapilarnega dviga,
nato pa smo pri vstopu počasi dvigovali
pritisk, dokler ni pričela pritekati tekočina pri
izhodni cevki. V tistem trenutku smo kolono
stehtali, da bi ugotovili volumen vode v
koloni.
One end of the column was enclosed with a
Plexiglas end cap. The column was carefully
packed by dropping 100 g of soil into the
column each time. The soil inside the column
was spread uniformly and stirred with a very
fine rod to remove any layers which might
have formed each time the soil was dropped
inside the column. To ensure that media inside
the column remained homogenous, the column
was also tapped from all four directions on the
outer side. The column was closed by a
Plexiglas end cap, and a fine nylon filter was
placed to prevent soil sample loss during the
experiment (Figure 2).
The weight of the Plexiglas assembly, and
dry and saturated soil weight and volume were
determined gravimetrically for each column, in
order to calculate porosity, dry bulk density
and the moisture content of the soil (Table 3).
The soil column was slowly saturated from
the bottom with distilled water for 24 hours.
Initially the water was allowed to rise inside
the column by capillary rise, and later the head
at the inlet was slowly raised until the solution
started appearing from the outlet. At this
moment the soil column was weighed to
determine the water content of the column.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
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(b)
(c)
(d)
Slika 2. (a) Oprema in postavitev poskusa. (b) Stranski ris valjaste prozorne kolone iz pleksi stekla
(10 cm dolžine, 9 cm zunanji premer, 8 cm notranji premer), tloris pokrova pri vtoku (d)
in iztoku (c), (e) menjalna točka.
Figure 2. (a) Experiment equipment and installation. (b) Side plan of the cylindrical transparent
Plexiglas column (10 cm length, 9 cm outer diameter; 8 cm inner diameter), (c) ground plan
of the inlet and (d) outlet cover; (e) switching point.
(c)
(d)
(e)
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
125
Po doseženem ravnotežju smo poskuse
pričeli z nižjo hitrostjo vode porozne snovi. Po
določitvi pritiska za dano hitrost vode porozne
snovi smo vhodno cev preusmerili (t = 0) v
rezervoar s tekočino za premeščanje, tj.
destilirano vodo (slika 2, e). Iz rezervoarja na
vstopnem koncu smo koloni dodali 100 ml
vodne raztopine dušičnega gnojila (NAC) in
nato to raztopino spodrinili z destilirano vodo.
Avtomatični izmenjalec vzorcev je zbiral
perkolat ob določenih časovnih intervalih v
majhne plastične lonce (max 80 ml). Vse
poskuse smo izvajali pri stalni temperaturi 20°
C ± 1° C.
The experiments started with the lowest
pore water velocity after reached equilibrium.
After establishing the head for a given pore
water velocity, the input line was changed
(t = 0) to the reservoir containing the
displacing solute, i.e. distilled water (Figure 2,
e). From a reservoir at the input end, a volume
of 100 ml of an aqueous solution of nitrogen
fertilizer (NAC) was added to the column, and
then the solution was displaced by distilled
water. The automatic sample changer collected
the effluent at fixed time intervals in small
plastic bottles (max 80 ml). All the
experiments were conducted at a constant
temperature of 20°C ± 1°C.
Preglednica 3. Podatki za zemeljske kolone.
Table 3. Soil column data.
Specifična
gostota tal
(g/cm3)
Bulk density
(g/cm3)
Poroznost
%
Porosity %
Volumska
vsebnost
vode θ
Volume
Wetness θ
Povprečni
tok (ml/h)
Average
flow
(ml/h)
Hitrost
vode
porozne
snovi
(cm/h)
Pore water
velocity
(cm/h)
Darcy-
jeva
hitrost
(cm)
Darcy’
s
velocity
(cm)
Re
število
Re
number
K
(začetni)
(cm/sec)
K (start)
(cm/sec)
x 10-5
K
(končni)
(cm/sec)
K (end)
(cm/sec)
x 10-5
< 2 mm
15.66 0.74 0.3 0.2 1.15 1.04
1 1.49 0.44 0.42
19.26 0.91 0.4 0.2 1.28 1.17
20.1 1.03 0.4 0.2 1.59 1.41
2 1.48 0.44 0.39
30.1 1.54 0.6 0.3 2.03 1.77
0.63–2 mm
36.5 1.74 0.7 0.4 5.93
1 1.55 0.41 0.42
46.73 2.20 0.9 0.5 4.69
36.5 1.75 0.7 0.4 5.76
2 1.55 0.42 0.41
54 2.62 1.1 0.5 6.78
2–4 mm
175.4 5.87 3.5 1.7 74.6
2 1.57 0.44 0.39
186.8 6.30 3.7 1.9 73.7
Da bi preverili veljavnost Darcyevega
zakona, na podlagi katerega smo izračunali
hitrosti vode porozne snovi in hidravlično
prevodnost vzorca v zemeljski koloni, smo
določili tudi Reynoldsovo število (Re). Re za
porozen medij smo izračunali po formuli:
Pore water velocity and hydraulic
conductivity were calculated based on Darcy’s
law. To gauge the Darcy’s law validity for this
experiment, Reynolds number for flow
through porous media was determined:
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
126
ν
dq ⋅=Re (1)
kjer je q specifični pretok (cm/sek), d
reprezentativna dimenzija zrn (cm) ter ν
kinematična vsiskoznost tekočine (cm2/sek)
(preglednica 3).
Tako rekoč v vseh primerih, kjer je Re,
izračunano na podlagi povrečnega premera zrn
med 1 in 10, je Darcyev zakon veljaven. Pri
večjih Re pride do tranzicijske cone. Na
spodnjem delu je prehod iz laminarnega
režima, kjer prevladujejo sile viskoznosti, do
drugega območja laminarnega režima, kjer
prevladujejo sile inercije. V zgornjem koncu
tranzicijske cone je postopen prehod do
območja turbulentega toka. Nekateri avtorji
navajajo kot zgornjo mejo za laminarni tok
vrednost Re 100 (Bear, 1988).
where q is the specific discharge (cm/sec), d,
the representative dimension of the grains
(cm), and ν, the kinematic viscosity of the
fluid (cm2/sec) (Table 3).
In practically all cases, Darcy’s law is valid
as long as the Re based on the average grain
diameter does not exceed some value between
1 and 10. As Re increases, we observe the
transition zone. At the lower end of this zone
we have the passage from the laminar regime,
where viscous forces are predominant, to
another laminar regime, where inertial forces
govern the flow. At the upper end of the
transition zone we have a gradual passage to
the turbulent flow. Some authors suggest Re
100 for the upper limit of the laminar flow
regime (Bear, 1988).
3. REZULTATI Z DISKUSIJO
Predmet te raziskave so bili laboratorijski
sledilni poskusi, pod nasičenimi pogoji v
kolonah (dolžine 10 cm), s tremi različnimi
frakcijami talnih delcev (vzorec tal P < 2 mm,
vzorec tal GE 0.63–2 mm in 2–4 mm). Kot
sledilo je bilo uporabljeno mešano dušično
gnojilo Nitratamoncal (NAC), v količini,
ekvivalentni nanosu 100 kg N/ha. Namen
laboratorijskega eksperimentalnega dela je bil
ugotoviti obnašanje dušika v obliki nitratnega
(NO3
-) in amonijevega iona (NH4
+), v
odvisnosti od teksture tal.
3. RESULTS AND DISCUSSION
The subject of this study were laboratory
trace experiments under saturated conditions
in soil columns (length 10 cm) with three
various soil aggregates (soil sample P < 2 mm,
and soil sample GE 0.63–2 mm and 2–4 mm).
As a tracer, mixed nitrogen fertilizer
Nitratamoncal (NAC) in the equivalent of 100
kg N/ha was used. The purpose of the
laboratory experimental work on the soil
columns with various soil fractions was to
determine the behavior of nitrogen in the form
of the nitrate ion (NO3
-), and the ammonium
ion (NH4
+), in relationship to the soil texture.
3.1 PREPUSTNOST
Pred začetkom poskusa so bili določeni
poroznost, specifična gostota tal in hidravlična
prevodnost (Preglednica 3). Med poskusom so
se v kolonah z vzorcem tal P < 2 mm po vnosu
sledilne raztopine pogoji spremenili, zato smo
po končanem poskusu vnovič določili
hidravlično prevodnost (Slika 3). Sprememba
je nastala kot posledica nenamernega
stranskega učinka, ob odprtju vtoka na
atmosferski pritisk (to je bilo opazno tudi pri
poskusih na večjih talnih frakcijah) in kot
posledica spremembe prepustnosti kolone
zaradi rabe sledila.
3.1 PERMEABILITY
Before the experiment, porosity, bulk
density and hydraulic conductivity were
determined (Table 3). In the course of the
experiments, column conditions with the P < 2
mm sample were altered after the tracer solute
application; therefore, hydraulic conductivity
was determined again after the experiment
(Figure 3). The change occurred, firstly, due to
the unintentional side effect of opening the
inlet to the atmospheric pressure (as well noted
with coarser fractions), and, secondly, due to
the changes in column permeability caused by
the use of the tracer.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
127
Nepredviden učinek spiranja sledila z
destilirano vodo je bila občutno zmanjšana
prepustnost kolone. Za prvotno izbrani tip tal
se sledilni poskusi niso posrečili, ker se je
prepustnost v kolonah z vzorcem tal GE
frakcije < 2 mm zmanjšala, preden je kolono
prešel NO3
- del sledila. Zmanjšana prepustnost
je lahko posledica interakcije med NH4
+
kationi sledila ter glinene frakcije tal. Vnos
sledila v kolono lahko povzroči zmanjšano
debelino difuznega dvojnega sloja okoli
glinenih delcev (Luckner & Schestakow,
1991), kar koloidne agregate stabilizira.
Vendar se zaradi spiranja sledila z destilirano
vodo koncentracija kationov hitro zmanjša. To
povzroči nenaden obrat v debelini difuznega
dvojnega sloja. Povečan dvojni sloj lahko
zmanjša permeabilnost zaradi dveh pojavov:
− nabrekanja frakcije glinenih mineralov,
− destabilizacije koloidnih agregatov.
Prvi pojav pomeni povečano razdaljo med
prilegajočimi glinenimi delci zaradi povečanih
elekričnih odbojnih sil in je torej reverzibilen
pojav.
Drugi pojav pomeni razpad koloidnih
glinenih agregatov zaradi povečanih odbojnih
sil. Stabilnejši koloidni glineni delci postanejo
mobilni in migrirajo skozi pore tal, dokler ne
zaprejo mejnih por oziroma so izprani iz
kolone. Ta proces je ireverzibilen. Do
premeščanja delcev pa je verjetno prišlo tudi
zaradi neprimerno izbranih hidravličnih
gradientov za izbran tip tal.
The unintentional side effect of the flushing
with distilled water was a significant reduction
in column permeability. Experiments on the
originally chosen GE < 2 mm soil samples
failed because the permeability was reduced
before the NO3
- part of the tracer came through
the column. The reduced permeability may
have been due to interactions between the
NH4
+ cations of the tracer and the clay fraction
of the soil. The introduction of the tracer to the
column may cause a decrease in the thickness
of the diffuse double layer around the clay
particles (Luckner & Schestakow, 1991),
stabilizing the colloidal aggregates. However,
when fresh water is used to flush the column,
the cation concentration is suddenly reduced.
This causes an abrupt reversal of the change in
the thickness of the diffuse double layer. And
the increasing double layer reduces the
permeability via two mechanisms:
− swelling of the clay fraction,
− destabilization of the colloidal aggregates.
The first mechanism involves an increased
distance between adjacent clay particles due to
the increased electrical repulsive forces, and is,
therefore, reversible.
The second mechanism involves colloidal
clay aggregates breaking up due to the
increased repulsive forces. The more stable
colloidal clay particles become mobile and
migrate through the soil pores until they clog
pore restrictions or are washed out of the
column. This process is irreversible. It is
possible that the particle transport also
occurred due to the inappropriate hydraulic
gradients.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
128


Prva kolona / First Column
K 2
K 1
K 2K 1
0.
0E
+0
0
5.
0E
-0
6
1.
0E
-0
5
1.
5E
-0
5
2.
0E
-0
5
2.
5E
-0
5
0 1 2
1. Nanos / 1. Application 2. Nanos / 2. Application



Druga kolona / Second Column
K 2
K 1
K 2
K 1
0.
0E
+0
0
5.
0E
-0
6
1.
0E
-0
5
1.
5E
-0
5
2.
0E
-0
5
2.
5E
-0
5
0 1 2

1. Nanos / 1. Applicat ion 2. Nanos / 2. Applicat ion
Slika 3. Sprememba koeficienta hidravlične prevodnosti pri poskusih na kolonah P < 2 mm.
Vrednosti koeficienta hidravlične prevodnosti so se spremenile
pri drugem poskusu na talnih kolonah P < 2 mm.
Figure 3. Hydraulic conductivity coefficient values of P < 2 mm soil column experiments
Coefficient of hydraulic conductivity values changed
with the second tracer experiment on the P < 2 mm soil columns.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
129
3.2 VPLIV MIKROORGANIZMOV
Pojavi se vprašanje, ali je bil vpliv
mikroorganizmov pri opisani nastavitvi
poskusa odločilen na obliko dobljenih krivulj
prehoda pri NO3
- in NH4
+. Poskus je bil
izvajan pod nasičenimi pogoji, zatorej
predvidevamo, da anoksičnih con ni bilo.
Vzorec tal, uporabljen v poskusu, je bil pred
pakiranjem toplotno tretiran (sušen na 105ºC
za 24 ur), pri katerem je prišlo verjetno do
uničenja mikroorganizmov skoraj v celoti.
Predvidevamo lahko, da je bil vpliv
mirkoorganizmov na obliko krivulj prehoda
minimalen.
3.3 INFLUENCE OF
MICROORGANISMS
The question was what was the influence of
microorganisms on the shape of the obtained
breakthrough curves for NO3
- and NH4
+ from
the described experiment. The experiment was
conducted under saturated conditions;
therefore, the presence of anoxic zones was
highly unlikely. The soil sample used in the
experiment was dried at 105ºC for 24 hours;
during this time, the extermination of
microrganisms occurred. It can be presumed
that the influence of microrganisms on the
shape of the breakthrough curves is minimal.
3.3 VPLIV VELIKOSTI DELCEV
Krivulje prehoda pri NO3
- so bile v
primerjavi s krivuljami prehoda pri NH4
+ pri
vseh velikostih agregatnih delcev simetrične
(slike 4 – 9).
3.3 INFLUENCE OF AGGREGATE SIZE
Breakthrough curves of NO3
- were
symmetrical with all aggregate sizes; the NH4
+
breakthrough curves were not (Figures 4 – 9).
NO3
- 
< 2 mm
0
0.5
1
0 0.5 1 1.5 2 2.5 3V/Vo
C
/C
o
0.73 cm/h
0.91 cm/h
0.65 cm/h
0.91 cm/h
Slika 4. Krivulja prehoda za nitratni ion (NO3
-) pri hipnem nanosu sledila na medij velikosti P < 2
mm.
Figure 4. Nitrate ion (NO3
-) BTCs for pulse tracer application on P < 2 mm media
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
130
V primeru večjih frakcij (večje hitrosti
toka) je prišlo do premika krivulj prehoda proti
manjši vrednosti relativnega volumna
perkolata porozne snovi (V/Vo). Vpliv na
obliko krivulje ima hitrost, s katero potuje
sledilo skozi porozni prostor. Vrednosti Re
števila (preglednica 3) kažejo na to, da je bil
med poskusom v kolonah laminarni režim
toka. Mogoč je tudi delni vpliv prejšnjega
poskusa in spremenjene strukture znotraj
kolon, vendar menimo, da pri frakcijah 0.63 do
2 in 2 do 4 mm ta vpliv ni bil velik.
In the case of larger fractions (higher flow
velocities), the shift of the BTC toward a
smaller relative pore water volume (V/Vo)
occurred. The velocity with which the tracer
traveled through porous media had some
influence on the shape of the curve. Re number
values (Table 3) support the laminar flow
regime during the soil column experiment. A
partial influence of the previous experiment
was also possible, due to the changed structure
inside the column, but it is our opinion that
this influence was not significant.
Pri večjih hitrostih je postal jasen rep –
razvlečen desni del krivulj prehoda (sliki 5 in
6). Oblika krivulj prehoda NO3
- grobih frakcij
(sliki 5 in 6) odraža vpliv nihanja hitrosti
tekočine v poroznem prostoru, nastalih zaradi
preferenčnih poti skozi makropore.
With higher pore water velocities, the
tailing became clear (Figures 5 and 6). The
shape of the NO3
- BTCs of the coarser
aggregates (Figure 5 and 6) reflects velocity
fluctuations in the porous media due to the
preferential flowpaths forming from the
macropores.
Razvlečena oblika krivulj prehoda se pojavi
pri debelo zrnatih tleh (prisotnost makropor)
ali tleh, spiranih v zasičenih pogojih (van
Genuchten, 1981; Bouhroum & Civan, 1994).
Ta pojav je opisal Selim s sod. (1987) za Mg+
in Ca2+ na 1 do 2 in 4 do 5 mm velikih
agregatih, pri hitrosti vode porozne snovi 2
cm/h. Li & Ghodrati (1997) sta pri študiju
modelov za preferenčne poti pri kontrolni
krivulji prehoda za NO3
- dobila še bolj ostro
obliko krivulje prehoda na silikatnem pesku
pri hitrosti vode porozne snovi 17 cm/h (max
C/Co = 0.35).
Extreme tailing is expected when cracked
soils or soils containing macropores are
leached under saturated conditions (van
Genuchten, 1981, Bouhroum & Civan, 1994).
The phenomena was described by Selim et al.,
(1987), with Mg+ and Ca2+ BTCs on 1–2 and
4–5 mm aggregate sizes of pore water velocity
2 cm/h. Li & Ghodrati (1997) studied
preferential flow paths and obtained an even
sharper shape of the BTC for NO3
- on silica
sand with a pore water velocity of 17 cm/h
(max C/Co = 0.35).
Pri prehodu NH4
+ je imela največji vpliv
sposobnost fiksacije NH4
+ na negativno nabit
difuzni sloj vode okoli glinenih mineralov
agregatnega medija, kar je imelo tudi učinek
na permeabilnost vzorca v koloni (Poglavje
3.1). Nejasna oblika krivulj prehoda na vzorcu
tal do 2 mm je posledica fiksacije NH4
+ na
mineralne delce (slika 7). Krivulje prehoda pri
NH4
+ so dobile jasno obliko pri večjih
agregatnih delcih, velikosti GE 0.63 do 2 in
2 do 4 mm (sliki 8 in 9).
Pri predstavljenih poskusih smo uporabili
prodne in peščeno ilovnate frakcije.
Predvidevamo, da je uporabljeni vzorec, kljub
odstranitvi frakcije < 0.063 mm, vseboval zelo
majhno količino frakcije, ki vsebuje glinene
minerale.
The ability of NH4
+ to fixate onto the
negative charged diffuse water layer had the
greatest influence on the breakthrough of
NH4
+, which also affected the permeability of
the soil sample in the column (Chapter 3.1).
The unclear shape of the NH4
+ BTCs on the P
< 2 mm soil samples is due to the NH4
+
fixation on the clay minerals (Figure 7). The
BTC of NH obtained a clear shape with larger
aggregate sizes GE 0.63–2 and 2–4 mm
(Figures 8 and 9).
In the presented experiments, the gravel
fraction of the loamy sand type of soil was
used. We presume that the coarse soil samples,
in spite of removal of the < 0.063 fraction, still
contained a small part of the fraction which
includes clay minerals.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
131
NO3
-
0.63 - 2 mm
0
0.5
1
0 0.5 1 1.5 2 2.5 3V/Vo
C
/C
o
1.75 cm/h
2.62 cm/h
1.93 cm/h
2.75 cm/h
Slika 5. Krivulja prehoda za nitratni ion (NO3
-) pri hipnem nanosu sledila na medij velikosti GE
0.63 do 2 mm.
Figure 5. Nitrate ion (NO3
-) BTCs for pulse tracer application on GE 0.63–2 mm media.
NO3
- 
2 - 4 mm
0
0.5
1
0 1 2 3 4 5 6V/Vo
C
/C
o
5.87 cm/h
6.29 cm/h
Slika 6. Krivulja prehoda za nitratni ion (NO3
-) pri hipnem nanosu sledila
na medij velikosti GE 2 do 4 mm.
Figure 6. Nitrate ion (NO3
-) BTCs for pulse tracer application on GE 2–4 mm media.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
132
NH4
+ 
< 2 mm
0
0.01
0.02
0 0.5 1 1.5V/Vo
C
/C
o
0.73 cm/h
0.91 cm/h
1.03 cm/h
1.53 cm/h
Slika 7. Krivulja prehoda za amonijev ion (NH4
+) za hipni nanos sledila na medij P < 2 mm.
Figure 7. Ammonium ion (NH4
+) BTCs for pulse tracer application on P < 2 mm media.
NH4
+ 
0.63 - 2 mm
0.00
0.05
0.0 1.0 2.0 3.0 V/Vo
C
/C
o
1.93 cm/h
2.75 cm/h
1.73 cm/h
2.2 cm/h
Slika 8. Krivulja prehoda za amonijev ion (NH4
+) za hipni nanos sledila na medij GE 0.63–2 mm.
Figure 8. Ammonium ion (NH4
+) BTCs for pulse tracer application on GE 0.63–2 mm media.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
133
NH4
+ 
 2 - 4 mm
0.00
0.05
0.10
0.0 1.0 2.0 3.0 4.0 5.0 6.0
V/Vo
C
/C
o
3.47 cm/h
6.29 cm/h
Slika 9. Krivulja prehoda za amonijev ion (NH4
+) za hipni nanos sledila na medij GE 2–4 mm.
Figure 9. Ammonium ion (NH4
+) BTCs for pulse tracer application on GE 2–4 mm media.
Glineni minerali močno vplivajo na prenos
kationov, še posebej NH4
+ iona. Ta ima visoko
sposobnost adsorpcije na trdne površine
prodnatih delcev. Zatorej bi bilo zanimivo
videti stopnjo zadržanega NH4+ na predhodno
z NH4
+ zasičenem mediju, da bi videli stopnjo
prehoda NH4
+ pri prevelikih vložkih NH4+ - N.
Zadrževanje – fiksacija NH4+ in imobilizacija
sta zelo kompleksna problema. Kolonski
poskusi, predstavljeni v tem delu, niso pokrili
vseh vidikov, ki vplivajo na prenos NH4
+.
Clay minerals strongly influence cation
transport, especially NH4
+, the latter having
the capacity to adsorb on the surface of gravel
parts. It would be interesting to compare NH4
+
mass recovery from previously NH4
+ saturated
media in order to observe the NH4
+
breakthrough with excess NH4
+ - N input. The
detention – fixation of NH4
+ and
immobilization is a very complex problem.
Soil column experiments do not cover all the
aspects that influence the transport of NH4
+.
4. ZAKLJUČKI
Med poskusom so se v kolonah z vzorcem
tal < 2 mm pogoji spremenili. Vzroki so
nenameren stranski učinek ob odprtju vtoka
na atmosferski pritisk, sprememba
prepustnosti kolone zaradi uporabe NH4
+
sledila in spiranja z destilirano vodo. Pogoji v
< 2 mm koloni so se med poskusom spremenili
tudi zaradi nepravilno izbranih hidravličnih
gradientov.
4. CONCLUSIONS
In the course of the experiments, the
conditions in < 2 mm soil columns were
altered. The causes were the unintentional side
effect of opening the inlet section to
atmospheric pressure, changes in the column
permeability caused by the use of the NH4
+
tracer, and rinsing with distilled water.
Conditions in the < 2 mm soil columns were
also changed during the experiment due to
improper hydraulic gradients.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
134
Velikost talnih delcev je imela vpliv na
obnašanje sledila. Krivulje prehoda pri NO3
-
so bile v primerjavi s krivuljami prehoda pri
NH4
+ pri vseh velikostih agregatnih delcev
simetrične. V primeru večjih frakcij in večje
hitrosti toka je prišlo do premika krivulj
prehoda proti manjši vrednosti relativnega
volumna perkolata porozne snovi (V/Vo),
razvlečen desni del krivulj prehoda je postal
jasen. Pri večjih agregatnih delcih, velikosti
0.63 do 2 in 2 do 4 mm so pri NH4
+ krivulje
prehoda dobile jasno obliko.
The size of the chosen aggregates
influenced the behavior of the tracer.
Breakthrough curves of NO3
- were compared
to the NH4
+ breakthrough curves and were
symmetrical with all aggregate sizes. In the
case of larger fractions (higher flow
velocities), the shift of the BTC toward smaller
relative pore water volume (V/Vo) occurred.
The BTC of the NH4
+ achieved a clear shape
with the larger aggregate sizes of 0.63–2 and
2–4 mm.
VIRI – REFERENCES
Bear, J. (1988). Dynamics of Fluids in Porous Media. Dover Publ. inc., revised ed. 764 p.
Bouhroum, A., Civan, F., (1994). A study of particulates migration in gravel-pack. SPE 27346, Int.
Symp. On Formation Damage Control, Lafayette, La., p. 75 – 91.
Brady, N.C. (1998). Nitrogen and sulfur economy of soil. In: The Nature and Properties of Soils,
12th ed., eds. Brady, N.C. and Weil, R.P., p. 492 – 522, Elsevier, New York
Brusseau, M.L., Rao, P.S.C. (1990). Modeling solute transport in structured soils – A review.
Goederma 46, 169–192.
Follet, R.F. (1989): Nitrogen management and groundwater protection. Elsevier Science Publishers
B.V., Amsterdam, The Netherlands. 395 pp.
Hansen, B., Kristensen, E.S., Grant, R., Høgh-Jensen, H., Simmelsgaard, S.E., Olesen, J.E. (2000).
Nitrogen leaching from conventional versus organic farming systems – a systems modelling
approach. European Journal of Agronomy 13(1), 65-82.
ISO 3696:1978 Water for analytical laboratory use; Specialized and test method.
Li, Y., Ghodrati, M. (1997). Preferential Transport of solute through soil columns containing
constructed macropores. Soil Sci. Soc. Am. J. 61, 1308–1317.
Lin, B L; Sakoda, A; Shibasaki, R; Suzuki, M. (2001). A modelling approach to global nitrate
leaching caused by anthropogenic fertilisation. Water Research 35(8), 1961-1968.
Lojen, S., Pintar, M., Lobnik, F. (1999). (15)N in soil leachate: incubation experiments with
different fertilisers. In: International Symposium on Isotope Techniques in Water Resources
Development and Management, Vienna, Austria, 10-14 May 1999. Book of extended synopses.
Vienna: IAEA, 242-243.
Luckner, L., Schestakow, W. M. (1991). Migration Processes in the Soil and Groundwater Zone.
Deutcher Verlag für Grundstoffindustrie, Leipzig: 485 p.
Nommik, H., Vahtras, K. (1982). Retention and Fixation of Ammonium and Ammonia in Soils. In:
Stevenson, F.J. (ed.): Nitrogen in Agricultural Soils, Agronomy Monograph No. 22, ASA, CSSA
in SSSA, Madison, Wisconsin, p. 123–171.
Pintar, M. (2001). Nitrogen isotope ratio as an indicator of nitrate reduction in the dystric brown
soil. Unpublished Doctoral Thesis, University of Ljubljana, Ljubljana, 173 pp.
Pintar, M., Lojen, S., Lobnik, F. (1998). Nitrogen isotope changes in different type fertilizers
application, IV. Isotope Workshop, Portorož, 1998. Rud.-metal. zb., special issue, No. 1/2, Vol.
45, p. 158-162
Selim, H. M., Schulin, R., Flueher, H. (1987). Transport and ion exchange of calcium and
magnesium in an aggregated soil. Soil Sci. Soc. Am. J. 51, 876–884
van Genuchten, M.Th. (1981). Non-equilibrium transport parameters from miscible displacement
experiments, Research Report no. 119, USSL, Riverside, 88 p.
Vrščaj, B. (2001). Teksturni trikotnik po USDA klasifikaciji. Center za pedologijo in varstvo tal,
BF, Ljubljana.
Zupanc V., Veselič M., Cepuder P.: Vpliv agregacije poroznega medija na prenos nitrata in amonija v zemeljskih
kolonah - The Influence of Porous Media Aggregation on the Nitrate and Ammonium Transport in Soil Columns
© Acta hydrotechnica 19/31 (2001), 117-135, Ljubljana
135
Naslov avtorjev - Authors' addresses
Mag. Vesna Zupanc
Univerza v Ljubljani - University of Ljubljana
Biotehniška fakulteta - Biotechnical Faculty
Jamnikarjeva 101, SI -1000 Ljubljana
Prof. dr. Miran Veselič
 IRGO
Slovenčeva 93, SI-1000 Ljubljana
Prof. dr. Peter Cepuder
Institut für Hydraulik und Landeskulturellewasserwirtschaft
Universität für Bodenkultur
Muthgasse 19, A-1180 Wien
OZNAKE - SYMBOLS
C (mg/l) Koncentracija raztopine Solution concentration
C0 (mg/l) Začetna koncentracija Initial concentration
V (cm3) Volumen pretečeni Volume
Vo (cm3) Celotni volumen perkolata porozne
snovi v eksperimentalni koloni
Total pore volume of the
experimental column
q (cm/sek) Specifični pretok Specific discharge
d (cm) Reprezentativna dimenzija zrn Representative dimension of the
grains
ν (cm2/sek) Kinematična viskoznost tekočine Kinematic viscosity of the fluid
USDA Urad za agronomijo Združenih držav United States Department of
Agriculture