Joint International Conference on Long-term Experiments ...

exactly known due to the size of the pot and the roots of the plant interwove the whole
pot. Perennial ryegrass (Lolium perenne L.) was used as a test plant. The advantage of
this plant is that it endures well the conditions of the greenhouse and it can be cut
several times during the vegetation period, therefore, the dynamics of the processes can
be concluded too.
The effect of four factors (soil, nitrogen supply, calcium carbonate application and
nickel loading) on plants was studied.
As it is already known, the basic soil characteristics such as soil type, humus
content, pH etc. have a major effect on plant development. Accordingly, the experiment
was carried out on two extremely different soils. One of the soils was calcareous
chernozem with high fertility and buffering capacity from Debrecen-Látókép, while the
other was an acidic sandy soil with weak fertility from Újfehértó.
The basic parameters of the untreated soils used in the greenhouse experiment are
included in Table 1. Calculated for air-dry state, 1.0 kg of each soil was put separately
into the vegetation pots.
Table 1: Parameters of untreated soils
Soil site Debrecen-Látókép Újfehértó
Soil type Calcareous chernozem Shifting sand
Soil texture Loam Sand
Hygroscopicity acc. to Arany (KA) 39 26
pH-H2O 6.05 5.01
pH-KCl 5.41 3.98
pH-CaCl2 5.73 4.19
Hydrolytic acidity (y1) 9.07 7.06
Total C content (%) 1.89 0.27
Mass volume (kg dm -3 ) 1.19 1.49
Calculated lime requirement (t ha -1 ) 6.16 3.19
Calculated lime requirement (g kg -1 ) 2.07 0.86
The initial total carbon content of soils was measured by Nagy, P. T. (2000). The
standard treatment of pots was a joint solution of 100 mg kg -1 P and 160 mg kg -1 K, in
10 cm 3 KH2PO4 and K2SO4. The combinations of treatments applied on the soils are
shown in Table 2.
Nitrogen and nickel were added to the soils as NH4NO3 and NiSO4 solution,
respectively. Lime requirement of the soils was calculated according to the method of
Filep (1988) as
CaCO3 (kg ha -1 ) = 17.4 * KA * y1
then was added to the soil as fine powder. Each treatment was carried out in four
replications.
The water supply was ensured by daily irrigation to a specific weight. The
transpirated and evaporated water was supplemented by irrigating the chernozem and
sandy soil with distilled water to 75% and 60% of the field water capacity, respectively.
At high vegetative mass, plants were irrigated in the afternoon also on hot days to avoid
wilting.
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