State of the Environment
Bulgaria 2003
Soil
Soil degradation
Soil acidity
The soil analyses data shows that the total area of the soils with pH 5-5.6 occupies about 630 ha. A significant part of lands are covered with high vulnerable to acidification soils (pH<5.0). Soil acidification is strongly depending on agriculture intensification level. Therefore numbers and kinds of cultivation as well as numbers and kinds of fertilizer used, specially these ones with ammonium content, are very important (fig. 24-27)
Fig. 24 Distribution of soils which are violated by acidification
Fig. 25 Percentage distribution of violated by acidification soils towards cultivated country territory
The nitric fertilizers are the most often used mineral fertilizers in Bulgaria. During the last years, the usage of mineral fertilizers (nitric, phosphoric and potassim based) as the active substance was strongly reduced. Fig. 26 shows that the consumption of the nitrc fertilizers in agriculture decreases from 165 258 t in 1996 to 127 451 t in 2000.
Fig. 26 Fertilizer use as an active substance
/Sourse: National Statistic Institute/
Fig. 27 Fertilizer use kg/100ha
/Sourse: National Statistic Institute/
Very important indexes of soil acidification are the critical loads of sulphur and nitrogen depositions (fig. 28 - 29). In 2000, there was the same tendency in Clmax(S) /Maximal Critical Loads of Sulphur/, as this in 1999. But in 2000 there was a decrease in levels of Clmax(S) towards the levels in 1999.
In 1999 33.4% or 1/3 of the research territory are determined to have the Minimum Critical Loads of nitrogen /Clmin(N)/ below 500 eq/ha/yr. This situation is nearly the same in 2000 as Clmin(N) is quite lower. In 1999 66.6% of the research territory have Clmin(N) up to 500 eq/ha/yr while in 2000 these levels are 72.5 eq/ha/yr.
Fig. 29 Percentage cells participation with levels of Clmin(N) below and above 500 eq/ha/yr for deciduous receptors
Last update on March 2003