the field experiments carried out in 2000 and 2001 at the Nagyhörcsök Experimental
Station on calcareous chernozem soil contaminated with heavy metals the results
show that the application of 40 t/ha Balinka brown coal did not decrease the uptake
of essential elements by the maize, barley and rape test plants, and did not
decrease the fertility of soil. There was no change or sometimes a slight
increase in the investigated tissues of the plants due to the effect of coal application.
This is advantageous in Zn deficient soils, but on similar soils strongly
polluted with Zn the Balinka brown coal cannot be used as an effective
remediator. The coal treatment drastically decreased the Se toxicity of the soil,
the maxi-mum yield could even be obtained on the strongly Se-polluted plots. The
development of plant stands in the coal treated plots improved considerably,
perhaps due to the better moisture regime conditions of the soil. The Sr and Cd
content in plant tissues decreased in several cases due to brown coal application.
The most dangerous contaminant, the Cd concentration in the plants dropped to
half or even 1/3, as a result of coal treatment. The results of the two-year experiments showed
that the 40 t/ha rate of Balinka brown coal can be used successfully and
economically in the
remediation of Cd, Se and Sr contaminated
soils. This rate does not influence the original fertility parameters of the
soil, but can be applied with advantages both in extremely light- or heavy
textured soils in case of moderate contamination. However, further investigations
are needed to find out the effects of Balinka-type brown coal application on
other soil types, plants and other polluting elements.