Joint International Conference on Long-term Experiments ...

For the conditions in from Western Romania, Colibaş I publishes in 1995 the first
partial results of researches regarding yield losses in millet, in the first year of
controlled pollution with different doses of petroleum. [2.]
MATERIALS AND METHOD
The researches carried out in Oradea wanted to establish the effects controlled pollution
with petroleum from Suplacu de Barcău had on agricultural yield and on the
biodegradation period, without any ameliorative measures.
The oil reserve in Suplacu de Barcău is located at relatively small depth, in a layer
of Pontian sands, and has a high content of asphaltines.
Almost half the soils in Romania (49,397%) which are affected by pollution with
oil are luvosoils, and that the soil from Suplacu de Barcău is also a luvosoil, the
experience carried out was placed also on a luvosoil. (Table 1.)
Table 1: Some physical and chemical properties of the luvosoil from Oradea
Horizont Depth Textural DA
(cm) Class (g/cm 3 pH V Humus N C/N
) (H2O) (%) (%) (%)
Ap 0-25 LP 1,35 5,51 64,3 2,40 0,116 13,0
El 25-44 LP 1,48 5,78 67,3 2,23 0,111 13,5
Bt1w 44-60 TT 1,56 6,24 77,9 1,91 0,096 13,5
Bt2 60-93 TT 1,58 6,46 83,4 1,73 0,087 13,4
BC 93-110 TT 1,62 6,51 86,6 0,70 0,036 13,3
C 110-152 TT 1,61 6,60 92,4 0,50 0,026 13,2
The soil is dusty and with a content of clay, in the worked layer and in the eluvial one,
and with medium clay in the layers underneath these ones. The values of the bulk
density are medium in the eluvial layer and becomes large in the layer where clay
gathers, and at the base of the profile, which indicates that the soil is poorly ploughed at
the surface and poorly settled from a 25 – 44 cm depth , and moderately settled on the
rest of the profile.[1.] The soil reaction is moderately acid in the first two horizons and
weak acid deeper. The total humus and N content is small in the ploughed layer, and the
values of the C/N index are high, which comes to prove a poor N supply in the soil.
The experimental field set out in 1993 is made out of parcels of 1m² set out in a
latin square, randomised, in four repetitions, which were willingly polluted with
petroleum from Suplacu de Barcău with 0, 3, 9, 15, and 30 l/m², thus resulting
concentrations of 0 in the ploughed layer (unpolluted witness) and 1, 3, 5, 10 %.
The field was cultivated in the first three years with millet (1993 – 1995) a plant
with a high tolerance to pollution, and afterwards for the next seven years with spring
wheat, Speranţa breed.
RESULTS AND DISCUSSIONS
1. The climate conditions, characterised by rainfall and by annual temperatures,
show that the period of the ten years observed had more rainfall than the average multi
annual with 26,2 m and was warmer with 0,5 ºC.
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