Soil samples were collected at alluvial sites of the Litavka River, which flows through the Beroun and Příbram cities in Central Bohemia Region of the Czech Republic in 2005 and 2006. Higher heavy metal content in soils (Cd, Pb, Zn, Cu) is due to composition of the parent rock, emissions from lead processing industry and the leak of toxic material from the steel works sludge ponds in the 1970s and 1980s. The samples were collected from six sites located at different distances from the contamination source (the former sludge ponds) and chemical and biological properties were determined. The ratio of the microbial biomass carbon to oxidisable carbon content dropped down significantly on more heavily contaminated sites. Basal respiration activity did not correlate with the content of heavy metals in soil, but there was certain declining tendency with increasing intensity of soil contamination. Respiration activities significantly correlated with the total carbon, oxidisable carbon and the total nitrogen content. The metabolic quotient showed higher values with increasing contamination. Dehydrogenases and arylsulphatase activities decreased with increasing contamination. Urease activity has also a declining tendency but its relation to different intensity of contamination was not unambiguous. Urease activity has shown a relationship with the content of total nitrogen in soil. No relationship was found between the total sulphur content and arylsulphatase activity. Dehydrogenases, arylsulfatase and urease activities significantly correlated with the microbial biomass carbon.

This study compares the effect of application of digestate, straw, cattle slurry and inorganic fertilizers on crop yield and soil organic matter content. Total organic carbon (C), total organic nitrogen (N), hot water soluble C, microbial biomass C and hydrophobic soil components were evaluated in soil from the field experiment in PragueRuzyně (Orthic Luvisol, clay loam) with winter wheat. All fertilized treatments significantly increased grain yield above the level of non-fertilized control (5.68 t/ha), and the sequence was as follows: digestate (9.88 t/ha) > NPK (9.80 t/ha) > cattle slurry (9.73 t/ha) > digestate + straw (9.35 t/ha). Average organic C content in the soil ranged from 1.668-1.704% and the effect of different fertilization was not significant. The highest increase of microbial biomass C was recorded in digestate + straw (43.2% increase compared to control). Highly significant correlations were found between hydrophobic soil components and hot water soluble C (r = 0.988; P ≥ 0.05) and microbial biomass C (r = 0.964; P ≥ 0.05). Total organic N content ranged from 0.157-0.160% and differences among treatments were insignificant. Fertilization with digestate itself brings an effect in increasing crop yield, but does not improve the level of soil organic matter significantly.

No abstract

Cambisols, luvisols and Stagnosols are main soil taxonomical units covering 78% of the total area of the Czech republic. in the period 2001-2008 soil samples from 13 arable and 2 grassed localities were collected and tested. Microbial biomass carbon (MBC) was determined using microwave irradiation method (MW), chloroform fumigation extraction method (FE) and re-hydration technique (rHD). Soil samples were moistened, according to the content of organic carbon (C org ), by deionized water addition (%C org × 0.19 ml/g DM -dry mass of soil) immediately before MBC determination. Microwave sterilization (800 J/g DM = 600 W, 2 × 67 s, 100 g DM (10 soil samples) and microwave soil extracts digestion (800 J/ml = 250 W, 77 s, 24 ml) give the lowest values of MBC (204 ± 67 mg/kg DM; 100%) in comparison with FE (236 ± 57 mg/kg DM; 116%) and rHD (478 ± 138 mg/kg DM; 235%), respectively. High significant correlation (r = 0.9713) was found between tC (total carbon; 1.36 ± 0.29%) and tn (total nitrogen; 0.15 ± 0.03%) determined by CnS analyzer. Furthermore, high significant correlations were found between MBC-MW and MBC-rHD (r = 0.8965) as well as MBC-FE and DHa (dehydrogenase activity; r = 0.8094), respectively. DHa in studied soils reached 147 ± 68 mg of triphenylformazan/kg DM/24 h. C org formed 96% of tC and total Kjeldahl nitrogen 97% of tn, respectively. according our results MW is fully acceptable for MBC determination.

Soils were sampled from the plots with four variants of fertilisation: Nil -without fertilisation, NPK -mineral fertilisation, FYM -farmyard manure, FYM + NPK -farmyard manure with mineral fertilisation, and two variants of crop rotation: field IV -classical 9-year crop rotation, field B -2-year rotation of alternative growing. Determination of urease, CFU of Azotobacter spp. and potential nitrogenase activity was conducted during the period 1999-2004. The urease activity was positively affected by manure fertilisation (FYM) and by the combination of FYM + NPK. The statistically significantly highest counts of Azotobacter spp. and the highest nitrogenase activity were determined on field B in variants FYM and FYM + NPK. The results show that there was a higher amount of accessible nitrogen present on field IV than on field B. This might explain the lower counts of Azotobacter spp. and therefore the lower nitrogenase activity. According to our results, activity of urease, CFU of Azotobacter spp. and potential nitrogenase activity are very closely connected with N inputs.