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ŠUMARSKI LIST 9-10/1962 str. 22     <-- 22 -->        PDF

in the forest enterprise Pančevo, locality »Hugin put«, in the age of 8 years
282 cu. m./ha. or a mean annual increment of 35 cu. m./ha.
The best results in forest plantations were achieved with cv. »robusta« and

cv. »marilandica«. The cultivar »serotina« was given up because of its low yield
capacity and weak resistence against diseases.
The Yugoslav Advisory Centre for Agriculture and Forestry has elaborated an
up-to-date technique of intensive establishment and tending of Poplar plantations
combined with field crops. According to this technique there were laid out 27 large-
scale trial plots, each one on an area averaging 10 ha., in order to demonstrate new
solutions and to follow up the biological, technical and economic indices.

The main characteristics of the adopted modern method of growing Poplars
with the agricultural intercrops are as follows:

Deep soil working (depending on soil structure and underground-water level)
ranging from 50 to 80 cm. (In places the soil is worked deeper when it is
necessary to shatter the impervious gleyized subsoil layer in order to enable
water to percolate).

Fertilizing is carried out compulsorily on the basis of soil analyses and planned
level of the yield. The amount of mineral fertilizers ranges from 800 to
1500 kg./ha. for plantations where Poplars and field crops are cultivated.

Planting stock production is carried out by the »rooting bed — transplant
bed« method. For the establishment of plantations are used strong and well-
developed 2/3 or 2/2 plants.

Among the cultivars and clones of Poplars (Populus x euroamericana) the
following are cultivated: cv. »robusta«, cv. »marilandica«, cv. »angulata«, cv.
»regenerata«, and cvs. »1-214«, »1-154«, »1-455«, »CBD«, »Jacometti«, as well
as some other clones, but in a less degree because they are still being tested.
In the Mediterranean zone is also cultivated P. nigra var. thevestina. The
best result was achieved with clones cv. »1-214«, and cv. »robusta«.

Spacing of the plants in the plantations is most frequently from 6 to 7 m.,
wich is dictated by the width of auxiliary agricultural machines.

Pruning of the lower branches is performed successively and in time, ordinarily
in the 4th, 6th and 8th years.

Protection of the nurseries and plantations is an important moment which
should be continuosly taken into account. Preventive services should play a
´, major role in this respect. Considering the large areas of Poplar plantations,
the protection should be still better organized and technically equipped.

The first experimental plots were laid out in 1959. The best results for the
present are presented by clone cv. »1-214«, and cv. »robusta«.

Among the field crops the highest yields were given by maize (max. 10,800
kg./ha. and on an average 8,300 kg./ha. in 1960. and 5,300 kg./ha. in 1961.).

As to the field intercrops the following facts are interesting:

As an intercrop, maize gave the best biological and economical results in
relation to the growth of Poplar.

Soy exercised a very favourable influence on the growth of Poplars but
itself gave poor yields.
— In the second year wheat gave an undiminished financial effect.
— Sugar beet achieved a high yield but influenced the growth of Poplars in a
very negative manner.
Poor natural and financial yields were manifested where besides the soil working
was not applied also a proper quantity of mineral fertilizers, which leads to
the conclusion that incomplete agrotechnics is the most expensive.