ON THE AMOUNTS OF MINOR ELEMENTS IN FINNISH SOILS

Jouko Vuorinen

Agricultural Research Centre Department of Soil Science, Helsinki

Received December 12, 1957

In agricultural development one of the most certain increasers of productivity
is the intensifying of fertilization. By the help of field and laboratory investigations,
the nutrient condition of the cultivated field has been brought towards the correct
balance in the best cases with regard to both the amounts of the different nutrients
and the relation between them (7). In Finland we can already say that this is soin
the case of the major nutrients in practical cultivation (8). From the point of view
of the minor elements the situation is, on the contrary, still uncertain in many ways.
A long »robbery» cultivation towards minor elements is a fact in agriculture nowa-
days. Besides this, the more intensive the cultivation is in other respects, the greater
the »robbery» effect. The consequences are already to be seen in many places both
in extensive and intensive plant husbandry, especially in sugar-beet cultivations
and in gardens. The farmers are even overinterested in the minor element problem,
and the blame for poor growth is often laid on the minor elements, although ameliora-
tion with lime or with the main nutrients has not been done.

Investigations to solve the minor element problems of the Finnish soils are being
carried out in many ways. From fertilizing experiments in field conditions, the defic-
iency of copper and boron, for example, has already been proved and on using the
corresponding fertilizers big increases in yield have been obtained (5, 6,3). The
amounts of minor elements in the soil have been investigated spectrographically
(4, 10), but questions such as the solubility of the minor elements in Finnish soils and
the need for or the poisonous qualities of the minor elements still require much in-
vestigation.

Material

In the following a summary is given of the minor elements in Finnish soils,
based on the results of analyses received up to the present. The material of the in-
vestigation consists of samples of surface soils, taken from the experiment fields used
in minor element fertilization investigations, from experimental and school farms,
and from fields belonging to private farmers. The analysis figures show the total
concentrations of the minor elements. The determination has been done spectro-
graphically (4).



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Samples Finnish soils (9)
in this investigation in general

Number of samples % Number of samples %

Moraine 248 6.8 5 385 4.8
Sand 38 1.1 1 590 1.4
Finesand 1 030 28.9 29 391 26.3
Silt 320 9.0 9 164 8.2
Clay 723 20.3 38 670 34.6
Gyttja clay 157 4.4 4 270 3.8
Mould 511 14.4 12 592 11.3
Carexpeat 471 13.2 9 396 8.4
Sphagnum peat 66 1.9 1 373 1.2

The amounts of the minor elements vary considerably in the different soil
types in Finland. However the distribution of the material (about 3500 samples)
between the different soil types represents Finnish soils well (9), as the table above
shows.

Results

The following average values (ppm metal in air-dry sample) have been obtained
for the concentrations of the minor elements in Finnish field soils:

Minor In Finland In the ground In cultivated soil in
element on an average (1) Scotland, (2)

on granitic on gneiss-
ground granite ground

Cu 21 70 <lO 25
Ga 24 15 25 70
Pb 16 16 20 70
Z n 36 80
Co 12 40 <2 10
Cr 87 200 5 200
Mn 617 1 000 700 1 000
Mo 4.5 2.3 <1 <1
Ni 23 100 10 40
V 183 150 20 250

The average minor element content of the Finnish soil does not greatly differ
from the minor element content of the earth's shell (1). Compared withScottish
cultivation soils (2), one can notice that in our field soils the concentrations of minor
elements are of very much the same magnitude. The concentrations of some minor
elements (Ga, Pb, Mn, Ni) correspond more with figures from the fields in the granite



32

HtMr = loamy moraine HtS = loamy clay
HHk = sand LjS = gyttja clay
KHt = coarser fine sand Mm = mould
HHt = finer fine sand Ct = Carex peat
Hs = silt LCt = Ligno Carex peat
AS = heavy clay CSt = Carex Sphagnum peat

districts of Scotland, while the concentrations of others (Cu, Co, Cr, V) correspond
better with concentrations in the soils in the gneiss-granite districts.

However, in the total amounts of the minor elements investigated there are
very big differences to be seen between the soil series (Fig. 1 and 2).

Discussion

Scrutiny according to soil type shows that grain size and humus content are
decisive factors in the total amounts of the minor elements (Fig. 1 and 2).

In sorted mineral soils especially the consequences of grain size can be noticed.
All the minor elements investigated increase very clearly from the coarse soil types
to the finer ones (HHk-AS,— sand-heavy clay, Fig. 1 and 2). Thus the amounts
of the minor elements in heavy clay are multiples of the corresponding amounts in

Fig. 1 Piirros 1

Fig. 2 Piirros 2



33

sand-soils. For molybdenum and cobalt this difference is 4—5-fold, for zinc more
than threefold, for vanadium about threefold, for chromium and manganese it is
more than twofold and for copper and nickel it is twofold. Accordingly, a heavy
increase of minor elements in these sorted soils can be noticed as the soil becomes
finer. It cannot be seen that the grade of fineness has the same effect in moraine
soils.

The minor element content of the peat soils (Gt-CSt, Carex-Carex Sphagnum
peat, Figures 1 and 2) is very low and on the same level as in sand soil. Bog peat
soils generally have a lower minor element content than Carex peat soils.

The youngest soils in our country, loamy clay (HtS), gyttja clay (LjS), gyttja
(Lj), mud (Jm) and mould (Mm) lie between glacial clay and peat soils as regards
concentrations of the minor elements. On an average the amounts of the minor
elements decrease in the order of the soil types mentioned above, from loamy clay to
mould, which is also the main direction of increase in humus content. In this group
the copper content is the highest ( >26 ppm) and is fairly uniform. Only heavy clay
contains more copper (35 ppm) than these young soils on an average. Mud has the
highest copper content (37 ppm).

Fig. 4 Piirros 4

Fig 3 Piirros 3



34

As a rule the amounts of the minor elements decrease (Fig. 3 and 4) as the humus
content of the soil increases. In the beginning, when the ignition loss rises from
o—lo0—10 % to 10—20 % the amounts of all minor elements increase, because a consider-
able part of the loss consists of water, and actually the coarse mineral soils undergo
a change, becoming finer. In the greater ignition losses (organic soils), on the con-
trary, the amounts of the minor elements decrease more or less regularly. For nickel
this increase goes up to a 20—30 % ignition loss and for copper up to a 40 —50 %
ignition loss, which shows that humus evidently acts as a store for these substances.

When comparing the relations of the amounts of different minor elements with
each other, it has been calculated how many °/00 each of the ten investigated minor
elements are out of their total amount. Manganese forms the main part (600 °/ 00 )
of these and its proportion is highest in moraine and lowest in gyttja clay. The pro-
portion of vanadium is about 180 °/ 00 and its amount proportions in different soils
are opposite to those of manganese. The proportion of chromium is about 80 °/oo
rather equally in all soils. Only gyttja clay and mould contain comparatively more
chromium. The proportional amount of zinc is 40 °/ 00 on an average. It is highest in
heavy clay (50 °/ 00 ) and lowest in coarse soils and moraine (25— 30 °/00). The average
proportion of copper and nickel among the minor elements investigated is about
20 °/„o and it is highest in heavy clay, mould and peat soils. In moraine and coarse
mineral soils the proportion of copper and nickel is distinctly the lowest. The pro-
portion of cobalt is above 10 °/00 and that of molydenum below 10 °/ 00 . Moraine and
coarse mineral soils have the lowest contents with regard to these elements also.

The total amount of the ten investigated substances is highest in silt and silty
clay soils (about 1600 ppm); in heavy and loamy clay it is about 85 % of the above
value, in fine sandy and loamy soils and in gyttja clay about 2/3, in moraine and
mould soils about 1/2 and in peat soils about 1/3 of the amounts contained by silt
soils. The big store of the minor elements, as well as that of the main nutrients con-
tained in silt soils, is certainly partly due to the bad physical conditions of the soils.
Thus growth and yield are so poor that the nutrients stay in the soil unused.

The use of the important minor nutrients for fertilizing in different conditions,
however, demands above all elucidation of the solubility questions with regard to
these substances, which again is a comprehensive field in itself.

REFERENCES

(1) Goldschmidt, V. M. 1954 (ed, Muir, A.) Geochemistry. Oxford.
(2) Chemistry of the Soil 1955 (ed. Bear, F. E.) I—X, 1—373. New York.
(3) Hänninen, P. 1956. Observationer over inverkan av bor pä rödklöverns fröavkastning i mellersta

Finland. Ref. J. Vuorinen. Nord. jordbr. forskn. 38: 199—209.
(4) Lappi, L. & Mäkitie, O. 1954. Quantitative spectrographic determination of minor elements

soil samples. Acta agric, scand. 5: 69 —75.
(5) Tainio, A. 1951. De hittillsvarande resultaten av undersökningar rörande mikroelementen i Fir

land. Nord, jordbr. forskn. 33; 287—291.



35

(6) —»—- 1956. Koppargödslingens inverkan pä timotejvallarnas avkastning i Finland. Ref, J. Vuo-
rinen. Ibid. 38: 199—209.

(7) Vuorinen, J. 1952, Koetilojen peltojen viljavuudesta. Summary: On the fertility of soils on ex-
perimental farms in Finland. Agrogeol. julk. 59; 1—59.

(8) —» — & Kurki, M. 1955. Viljavuustutkimustulosten tarkennettu tulkintaohje. Maatalous-
koelaitos, maatutkimusosasto, 4 pp. Helsinki.

(9) —■»— 1955 Nurmien viljavuudesta. Summary: On the fertility of grassland soils in Finland.
Maatal. ja koet. 9: 23—37.

(Id) - D— 1956. Finska undersökningar rörande M, Cu och B. Nord. jordbr. forskn. 38; 199—209.

SELOSTUS:

SUOMEN MAALAJIEN HIVENAINEMÄÄRISTÄ

Jouko Vuorinen

Maatalouden tutkimuskeskus, Maantutkimuslaitos, Helsinki

Hivenravinteiden puutoksia on Suomessa todettu (5.6. 3) lannoituskokeilla kenttäolosuhteissa.
Toisaalta on hivenaineiden esiintymistä maaperässämme tutkittu spektraalianalyyttisesti (4. 10), mutta
esim. hiventen liukoisuus Suomen maaperässä, hivenravinteiden tarve tai myrkyllisyys kasville on vielä
monien selvitysten tarpeessa.

Tässä tutkimuksessa on esitetty tuloksia Maantutkimuslaitoksen aineiston spektrograafisista
analyyseistä (n. 3500 näytteestä) tärkeimmistä maalajeista, joiden osuus tutkimuksessa on esitetty
taulukossa. Eri hivenaineiden (10 kpl) kokonaismäärät miljoonasosina (ppm = mg/kg) on esitetty
Suomen maaperää kuvaavina keskiarvoina. Toisaalta on näiden hiventen määrät eri maalajeissa esitetty
piirroksissa 1 ja 2.

Tulokset osoittavat kivennäismaiden raesuuruuden hyvin ratkaisevasti vaikuttavan
hivenaineiden kokonaismääriin niin, että mitä hienommasta maasta on kysymys sitä suurempi on yleensä
sen hivenainepitoisuus. Tämä suhde on esim. hienon hiekan ja aitosaven välillä kahdesta viiteen kertai-
nen ja eri hivenaineilla erilainen.

Maan humuspitoisuudella on ilmeisesti huomattava merkitys hivenainevarastona.
Tämä näkyy erityisesti piirroksissa 3 ja 4, joissa on esitetty maan hehkutuskevennyksen ja hivenaine-
määrän suhde.

Hivenaineiden keskinäisissä suhteissa todetaan mangaani päätekijäksi (60 %) kun taas
muiden osuus tutkitun kymmenen aineen yhteismäärästä on esim. sinkin kohdalla 4 %, kuparin 2 % ja
koboltin ja molybdenin n. 1 %. Hiesu- ja hiesusavimaissa tämä yhteismäärä on kaikkein suurin (n.
1600 ppm), aito- ja hietasavessa n. 85 % siitä, hietamaissa ja liejusavessa n. 2/3, moreeni-ja multa-
maissa n. 1/2 ja turvemaissa n. 1/3 hiesumaiden sisältämistä määristä. Hiesumaiden runsaat hiven-
ravinnevarat johtunevat, samoin kuin myös niiden runsaat pääravinnevarat näiden maiden yleensä
heikosta kasvusta.