prilagođeno pretraživanje po punom tekstu

ŠUMARSKI LIST 9-10/1969 str. 13     <-- 13 -->        PDF

tested, as well as the sampling for measuring the P^-radioactivity which was
carried out by means of a scintillation counter of the firm »EKCO«, type N664A.
On the surface of the soil sampling cylinder were added ca. 200 uC of resolution.

By means of metal prisms sized 1x5X30 cm. were taken the soil monoliths on
who´Se upper base (1x5 cm) representing the soil surface was added in the laboratory
a dose of ca. 1 uC of P!2. The activity of P32 in the soil monolith was measured
by means of a GM-counter »Acligraph II Nuclear Chicago«. To the surface
of the monolith a water deposit of 10, 20 and 60 m. m. of FLO/sq. m. was added.

P32-activities in samples, which were taken 3 times (1 hour, 15 and 30 days after
the application of P32) are presented in Tab. 2 and Graph. 1.
In Figs. 1—3 are given the skenograms of the penetration of P3´2 into the
monoliths of the soils investigated.

From the performed investigations of the penetration of radioactive phosphorus
(P32) into some soils of Croatia were obtained results on the basis of which
the following conslusions may be drawn:

1. Highest Reactivity was measured in the first 2 cm. in the lessive heather-
bracken soil from Zalija near Ogulin (Tab. 2), which had been expected, as the soil
is poorly provided with available phosphorus.
Phospohorus P32 penetrated into the first 2 cm. also in the monolith of the
lessive soil, and when adding the water deposit of 10, 20 and 60 m. m. HsO/sq. m.

— which corresponds approximately to the actual state of the rainfall during the
testing time — the penetration did not change much (Fig. 3., skenograms A, B,
and C).
2. The penetration of P32 in the alluvial soil from Jaždevec near Lučko was
greater (Tab. 2), but, if we consider the chemical properties of this soil (Tab. 1),
we see that the content of available phosphorus is relatievly high from which we
conclude that there came to no great exchanges of phosphate ions in the upper
layers of the soil. From skenogram (Fig. 1) we can see a greater penetration in the
monolith of the mentioned soil which coincides with the aforementioned results
obtained in samples taken in the field.
3. Longest penetration of P32 was measured in a pseudogley soil from Cerje
near Dugo Selo (in the natural — Tab. 2 — and the monolith treatment in_ the
laboratory — Fig. 2 —). In this soil was found the highest amount of available
phosphorus, viz. 4.6 mg. of P2O5/IOO g. of soil, wherefore also the penetration of

into the deeper layers of the soil is understandable.

4. Results of the. investigations in question demonstrate that through the
mentioned methods of application of P32 one may achieve rapid results of its penetration
into the rhizoSphere, which is very suitable for the indication of surface
soil manuring with phosphorus fertilizers. The value of the mentioned methods
reflects both in the non-destruction of natural soil composition and in the rapid
giving of results, i. e. 1 hours abready after adding the P32 do´se to the surface of
the soil.
Dr T. Filipan, Institut za stočarstvo i mljekarstvo
Poljoprivrednog fakulteta Zagreb, Maksimir 46
Dr B. Prpić, Katedra za uzgajanje šuma
Šumarskog fakulteta Zagreb, Šimunska 25