J. Balík

Retention of copper originating from different fungicides in contrasting soil types

This work described the retention of Cu from two different commonly used pesticides, the Bordeaux mixture (CuSO(4)+Ca(OH)(2)) and Cu-oxychloride (3Cu(OH)(2).CuCl(2)), and from Cu(NO(3))(2) in contrasting soil types (Leptosol, Chernozem, Cambisol). Thermodynamic modeling showed that Cu speciation was similar in all fungicide solutions. However, the retention of Cu differed with the fungicide used (maximum retention from the Bordeaux mixture) which indicates that different retention processes occurred in the studied soils. The suggested mechanisms include: specific and non-specific adsorption (especially on soil organic matter), precipitation of newly formed phases, such as CuO, Cu(OH)(2), Cu(2)(OH)(3)NO(3), CuCO(3)/Cu(2)(OH)(2)CO(3) and in the case of the Bordeaux mixture, precipitation of various Cu-hydroxysulfates. These phases were identified by the speciation model. The retention of fungicide-derived Cu in the studied soil types followed well the Freundlich isotherm and was directly controlled by the chemical form of Cu. This fact should be taken into account for both environmental and practical applications.

Interactions of EDDS with Fe- and Al-(hydr)oxides.

The efficiency of EDDS ([S,S]-ethylenediaminedisuccinate) in metal (phyto) extraction has been discussed in many recent papers. This study demonstrated that the presence of Fe- and Al-(hydr)oxides in soils influences the speciation of EDDS and thus can decrease the extraction of the targeted metallic contaminants (e.g., Pb, Cu, Zn). Above all, amorphous and poorly crystalline oxides (e.g., ferrihydrite) seem to significantly control dissolved Fe and Al concentrations in soils in the presence of metal-EDDS complexes and especially uncomplexed EDDS. Metals released from these minerals compete for the chelating agent and the extraction efficiency of the targeted metals is lowered. The formation of stable Cu-EDDS complexes, which are preferentially formed in soils with high Cu concentrations, results into a lower dissolution of ferrihydrite and goethite compared to free EDDS and Al-EDDS. Information about the contents of amorphous and poorly crystalline oxides in the treated soils would thus be beneficial for choosing efficient EDDS dosages.

The Variability of Arsenic and Other Risk Element Uptake by Individual Plant Species Growing on Contaminated Soil

Surrounding Kutná Hora (Czech Republic) are areas characterized by former silver mining activity. Therefore, a high level of risk elements was reported in soil close to the historical mines. The Aqua Regia extractable (i.e. “pseudo-total”) element values in soils exceeded the Czech threshold values representing 30 mg kg−1 As, 1.0 mg kg−1 Cd, 200 mg kg−1 Cr, 80 mg kg−1 Ni, 140 mg kg−1 Pb and 200 mg kg−1 Zn, by up to 15-fold for zinc, 30-fold for cadmium, and even 80-fold for arsenic. Mobile portions of elements determined in 0.11 mol L−1 CH3COOH solution did not exceed 1% of the “pseudo-total” element content for As, Cr, and Pb. Diversity of vegetation cover growing at the contaminated soil close to the former mine, as well as element uptake by aboveground biomass of individual plant species, was investigated. Plant species growing in these soils represented an ordinary ruderal plant community of 29 species without occurence of metallophytes. Moreover, the element concentrations in above-ground biomass of plants were low. Transferfactors, given as a ratio of element content in plant and its “pseudo-total” content in soil, varied from 0.0003 to 0.003 for As, from 0.001 to 0.174 for Cd, and from 0.016 to 0.169 for Zn. Evidently, the analyzed plant species are characterized by low ability to take up the risk elements and translocate them to above-ground biomass and the potential risk for animals consuming this biomass is negligible.

Soil pH changes in long-term field experiments with different fertilizing systems.

Vasak F., Cerný J., Buraňova S., Kulhanek M., Balik J. (2015): Soil pH changes in long-term field experiments with different fertilizing systems. Soil & Water Res., 10: 19–23. The changes of soil pH in long-term 14-year field experiments with different fertilizing systems are described. The field experiments were located at four sites of the Czech Republic with different soil and climatic conditions (Cervený Ujezd, Hněvceves, Lukavec, and Prague-Suchdol). At each site, the same fertilizing systems and crop rotation (potatoes – winter wheat – spring barley) were established. Six experimental treatments were applied to crop rotation: (1) unfertilized treatments (control); treatments with organic fertilization: (2) farmyard manure (FYM), (3) sewage sludge (SS); treatments with mineral fertilizers: (4) nitrogen (N), (5) nitrogen with straw application (N + straw), and (6) nitrogen with phosphorus and potassium (NPK). The long-term effect of fertilizers significantly depends on soil conditions. At the site Prague-Suchdol minimal differences in the soil pH were observed by all treatments. This is caused by the high buffering capacity of Chernozems against the soil acidification. At Cervený Ujezd (Haplic Luvisol), Hněvceves (Haplic Luvisol), and Lukavec (Stagnic Cambisol) sites, soil pH decreased by all treatments. Only at Hněvceves site the soil pH did not change with N treatment. The highest soil pH decrease in the treatment with NPK (ΔpH –0.89) and N + straw (ΔpH –0.70) was observed at Hněvceves site. By the treatments FYM and SS the highest decrease was registered at Cervený Ujezd (ΔpH of about –0.30 and –0.63, respectively). The highest decrease in control treatment (ΔpH of about –0.63) was observed at Lukavec site. The results showed that to evaluate long-term soil pH changes a whole complex of factors must be examined.

A comparison of arsenic mobility in Phaseolus vulgaris, Mentha aquatica, and Pteris cretica rhizosphere

The ability of Phaseolus vulgaris, Mentha aquatica, and Pteris cretica to release arsenic (As) species from contaminated soil was tested in rhizobox experiments in three soils differing in their physicochemical parameters and total and mobile As concentration. Relatively low uptake of arsenic by P. vulgaris and M. aquatica resulted in very low and ambiguous changes in rhizosphere soil compared to bulk soil. However, there were observed differences in the distribution of the mobile As portion in soil to individual As species as affected by plant species and/or plantation conditions of these plants. Higher percentage of mobile arsenite in mint rhizosphere seems to be related to more reducing conditions during cultivation of these wetland plants. P. cretica planted in the soils containing between 36 and 1436 mg As kg−1 was able to accumulate between 80 and 500 mg As kg−1 in aboveground biomass. The extractable concentrations of As compounds in rhizosphere soil of P. cretica showed a clear depletion of arsenate (representing more than 90% of extractable arsenic) with the distance from plant roots. However, the As uptake mechanisms, as well as As transformation within hyperaccumulating fern plants, differ substantially from those in higher plants. Therefore the finding of suitable higher plant tolerant to the As soil contamination with good ability to accumulate As in aboveground biomass remains for the further research.

The response of tomato (Lycopersicon esculentum) to different concentrations of inorganic and organic compounds of arsenic

Tomato plants were cultivated in greenhouse and water solutions of arsenite (As(III)), arsenate (As(V)), methylarsonic acid (MA) and dimethylarsinic acid (DMA) were applied individually into cultivation substrate at two As levels, 5 and 15 mg kg−1 of the substrate. Comparing the availability of arsenic compounds increased in order arsenite = arsenate < MA < DMA where the arsenic contents in plants decreased during vegetation period. Within a single plant, the highest arsenic concentration was found in roots followed in decreasing order by leaves, stems, and fruits regardless of arsenic compound applied. Arsenic toxicity symptoms reflected in suppressed growth of plants and a lower number and size of fruits were most significant with DMA treatment. However, the highest accumulation of arsenic by plants growing in the soil containing DMA was caused by higher mobility of this compound in the soil due to its lower sorption affinity. Our results confirmed substantial role of transformation processes of arsenic compounds in soil in uptake and accumulation of arsenic by plants.

Growth and Metal Uptake by Plants Grown in Mono- and Dual Culture in Metal-contaminated Soils

Plants are able to affect the mobility of heavy metals in the rhizosphere due to root exudates and other mechanisms resulting in a change in their phytoextraction ability. We tested separate (monoculture) and intercropping (dual culture) systems of hyperaccumulator Thlaspi caerulescens and accumulator tree Salix dasyclados in two soils with different levels of contamination. Intercropping did not significantly affect accumulation and removal of Cd, Pb, and Zn in moderately contaminated soil. Separately cropped S. dasyclados continuously died due to phytotoxicity of the highly contaminated soil. We indicated an important positive effect of intercropping in this soil. Intensive uptake of heavy metals by Thlaspi roots decreased relatively toxic concentrations in soil and improved the growth of S. dasyclados. The maximum limit of the phytoextraction potential of T. caerulescens was not reached at the extremely contaminated soil but the efficiency of the intercropping at the extremely contaminated soil still remains limited and alternative remediation techniques can be considered at this particular contaminated site.

Influence of precipitation amount during grain filling on nitrogen uptake and grain yield of spring barley fertilized by ammonium injection

The aim of this study was to observe the influence of the amount of precipitation during the grain filling period on nitrogen uptake and grain yield of spring barley fertilized by ammonium injection. Conventional nitrogen fertilization before sowing and CULTAN (Controlled Uptake Long Term Ammonium Nutrition) injection fertilization were compared during a 5-year small-plot field experiment under the conditions of Central Europe. In contrast to conventional nitrogen fertilization, with the CULTAN treatment there was observed no significantly negative effect of below-average precipitation during the grain filling period on post-heading (BBCH 51) nitrogen uptake from the soil with applications of 80 and 130 kg N.ha−1, grain yield, nitrogen uptake efficiency (NUpE) and thousand-grain weight with an application of 80 kg N.ha−1, nor there was a significantly positive effect on the contribution of nitrogen translocation to total nitrogen in the grain with an application of 130 kg N.ha−1. CULTANtreated plants achi...

Winter wheat fertilizing using nitrogen–sulphur fertilizer

Precise field experiments were established on two sites with winter wheat under different soil-climatic conditions in the Czech Republic. Four treatments were fertilized with same dose of nitrogen (200 kg N ha−1) and increasing dose of sulphur (0, 10, 20 and 40 kg S ha−1) using nitrogen–sulphur (N–S) fertilizer with calcium sulphate form. Soil and plant aboveground biomass samples were taken in the stages of development BBCH 26–28; 30–32; 37–39; 49–51. The winter wheat grain yield ranged between 7.20 and 10.86 t ha−1 and had an increasing trend with increasing sulphur dose. Although the differences were usually not statistically significant, there were found increasing tendencies of bioavailable sulphur content in soil with increasing S split doses. Soil S content decreased with time probably due to plant uptake. Sulphur dose did not influence the S content in plant aboveground biomass. The total S contents in grain after harvest ranged between 0.09% and 0.14% and were not significantly influenced with the fertilizing treatment. The same statement is valid for the S content in straw, which ranged between 0.03% and 0.11%. Both, S content in winter wheat seeds and straw were strongly influenced by the site conditions.

Nitrogen uptake by winter wheat (Triticum aestivum L.) depending on fertilizer application

The influence of the injection of nitrogen fertilizers with the CULTAN system (Controlled Uptake Long Term Ammonium Nutrition) on nitrogen uptake by winter wheat (Triticum aestivum L.) was observed at small-plot field experiments under conditions of the Czech Republic (central Europe) during 2007–2013. The CULTAN system consisting in the injection of all the nitrogen in one dose was compared with conventional broadcast surface fertilization which is carried out in three partial nitrogen doses. The total nitrogen dosage was 150 kg N.ha−1. If the CULTAN fertilization was carried out at the beginning of tillering of winter wheat (BBCH 22) instead of at the end of tillering (BBCH 29), the CULTAN-treated winter wheat did not suffer from nitrogen deficiency at the BBCH 45 (boot stage) and BBCH 51 (beginning of heading) growth stages. Nitrogen utilization efficiency and biomass production efficiency were significantly higher with the CULTAN treatment compared to the conventional fertilization whereas nitrogen up...