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Experiments were used to determine the potassium release from the non-exchangeable K (Kne) forms that are involved in plant nutrition and which replenish the pool of available K. Long-term stationary field experiments with different fertilisation systems (organic: farmyard manure, sewage sludge, straw; mineral: NPK, N) were carried out to study the potassium balance and the K content changes in the topsoil (0-30 cm) and subsoil (30-60 cm). The trials were located at three sites with different soil-climatic conditions. The following crops were rotated within the trial: potatoes (maize) - winter wheat - spring barley. All three crops were grown each year over 21 years. Positive correlations between the contents of the available K in the topsoil and the potassium balance (K inputs - K outputs) were observed. There were no statistically significant differences among the treatments. Depending on the soil properties, the ratio of non-exchangeable K (Kne) was 12-37% of the values obtained via the aqua regia extraction. Depending on the site, the amount released from the Kne forms to the available K form was 46-69 kg K/ha/ year. The use of K from the farmyard manure varied from 7.4% up to 25%. Due to the low K content in the sewage sludge, the long-term fertilisation with sludge may only lead to the depletion of the available K in the soil, similar to the sole N mineral fertilisation.

Soil aggregate structure and soil organic matter are closely interrelated and commonly considered as key indicators of soil quality. The aim of this study was to evaluate the effects of different fallow durations on indices of soil structure and humus status indicators. Studies were conducted on abandoned agricultural fields (15, 20 and, 35 years after abandonment). As a reference site, we used a cultivated field in the area. The experimental soil fields are classified as Gleyic Cambisols. Soil macroaggregates were separated with the sieve (dry sieve) to seven aggregate size fractions, i.e.> 10, 10-5, 5-2, 2-1, 1-0.5, 0.5-0.25 and < 0.25 mm. The humus status parameters of soils included the following indicators: soil organic carbon (C_org), humus reserves (Q_H), the degree of humification of organic matter (SOM_dh), fractions of humic acids (HA) (free and bound with monovalent cations and Al₂O₃, Fe₂O₃, bound with Cа²⁺ which forms humates, bound with clay minerals), fulvic acids (FA) (free aggressive) and ratio of HA to FA (C_HA : C_FA). After a fallow period of more than 20 years on the surface formation of a sod layer. A long-term fallow period had an impact on the mean weight diameter of the aggregates (MWD) and agronomically valuable aggregates (AVA). Fallow soils have a significantly better structure than soils under a cultivated field. Long-term cultivation leads to the deterioration of soil structure and the formation of large aggregates (>10 mm). The C_org content remains at the level of the background content when the soils are left fallow for less than 15 years and increases over time. The C_org in the upper 0-20 cm soil layer has been shown to increase from 3.55 to 8.74% on arable land that has been fallow for 35 years and has been largely associated with significant accumulation of organic matter within the plant root mass. Mature sites are characterized by an increase of fulvic acids in the humus composition in comparison with their arable analogues. The abandonment of soil agricultural use and the cessation of mechanical tillage results in the restoration of the natural structure of soils and the improvement of their agrophysical properties. Such studies have not been previously conducted in the Primorsky region of the Russian Far East.

The effects of tillage and crop rotation on the soil carbon, the soil bulk density, the porosity and the soil water content were evaluated during the 6^th season of an on-going field trial at the University of Fort Hare Farm (UFH), South Africa. Two tillage systems; conventional tillage (CT) and no-till and crop rotations; maize (Zea mays L.)-fallow-maize (MFM), maize-fallow-soybean (Glycine max L.) (MFS); maize-wheat (Triticum aestivum L.)-maize (MWM) and maize-wheat-soybean (MWS) were evaluated. The field experiment was a 2 × 4 factorial, laid out in a randomised complete design. The crop residues were retained for the no-till plots and incorporated for the CT plots, after each cropping season. No significant effects (P > 0.05) of the tillage and crop rotation on the bulk density were observed. However, the values ranged from 1.32 to1.37 g/cm³. Significant interaction effects of the tillage and crop rotation were observed on the soil porosity (P < 0.01) and the soil water content (P < 0.05). The porosity for the MFM and the MWS, was higher under the CT whereas for the MWM and the MWS, it was higher under the no-till. However, the greatest porosity was under the MWS. Whilst the no-till significantly increased (P < 0.05) the soil water content compared to the CT; the greatest soil water content was observed when the no-till was combined with the MWM rotations. The soil organic carbon (SOC) was increased more (P < 0.05) by the no-till than the CT, and the MFM consistently had the least SOC compared with the rest of the crop rotations, at all the sampling depths (0-5, 5-10 and 10-20 cm). The soil bulk density negatively correlated with the soil porosity and the soil water content, whereas the porosity positively correlated with the soil water content. The study concluded that the crop rotations, the MWM and the MWS under the no-till coupled with the residue retention improved the soil porosity and the soil water content levels the most.

To study the effects of straw return and aeration of the water layer on oxygen and redox status in the water column and at different depths in paddy field soil, a short-term incubation experiment was conducted with four treatments: (1) no straw return (NS); (2) straw return without aeration (S); (3) straw return and 30 minutes of aeration per day (SO30); and (4) straw return and 90 minutes of aeration per day (SO90). Compared to NS, S decreased dissolved oxygen (DO) and redox potential (ORP) by 23-58% and 47-53 mV, respectively, and increased active reducing substance (ARS) by 21-46% in the water and soil layers. The aeration treatments increased DO and ORP by 25-120% and 11-86 mV, respectively, and reduced ARS by 5-16% compared to S. The results indicated that straw return to paddy fields exacerbated hypoxia and reducing conditions in the soil. SO90 achieved better effects than SO30 in alleviating the negative impact of straw return by supplying more oxygen, but the effects weakened over time and with soil depth.

Climate change has increased attention paid in the research to forest soils and tree species composition, in respect to the potential for carbon sequestration. It is known that forest stands are able to store soil organic carbon (SOC), but little is known about the effect of forest naturalness on SOC content. This is important in relation of dying of unnatural spruce stands. It is necessary to determine a suitable composition of tree species which will replace them. This research is based on 248 plots with oak, beech, and spruce stands and mixtures of these species, with measured values of SOC. Our results show that autochthonous and mixed stands, in terms of tree species composition, in the study area had a higher SOC content than allochthonous and pure stands. In addition, it was found that autochthonous oak and beech stands, especially in mixtures, had a higher SOC content than allochthonous spruce stands (monocultures). On the basis of the presented results, it is possible to optimize the future tree species composition of stands in the study area, which currently have an allochthonous representation of spruce, to provide better function of carbon sequestration and resistance to climate change.

The aim of this study is to describe the changes of bioavailable phosphorus content in soil in long-term 18 years field experiments with different fertilizing systems. The field experiments are located at three sites with different soil and climatic conditions in the Czech Republic (Červený Újezd, Humpolec and Prague-Suchdol). Same fertilizing systems and crop rotation (potatoes (maize) - winter wheat - spring barley) are realized at each site with following fertilizing treatments: (1) unfertilized treatment (control), (2) farmyard manure (FYM), (3) and (4) sewage sludge (SS 1 and SS 3), (5) mineral nitrogen (N), (6) mineral nitrogen with straw (N + straw) and (7) mineral nitrogen with phosphorus and potassium (NPK). The long-term fertilizing effect on available P content changes in soil was observed. Bioavailable phosphorus content in soil increased in treatments with organic fertilization after 18 year experiment at all sites. The treatments SS 3 had the highest increase at all sites. The highest bioavailable P content increase compared to control (258 mg/kg) was determined at site Červený Újezd. On the contrary, available phosphorus content decreased at treatments with mineral fertilization and control treatment among all sites. Bioavailable P content decrease in the treatment NPK was observed, although phosphorus was applied. The lowest differences in available P content among all fertilizing treatments were observed at the location Prague-Suchdol.

Electrokinetic remediation (EKR) is a powerful technique aimed at pollutant removal in soil, sludge, mine tailings, and so on. In the current work, we performed a bibliometric analysis of the research on EKR for the period of 1900-2018 on the basis of the core database of the Science Citation Index Expanded. In addition to a basic analysis of the research characteristics, keywords were analysed for four major participants: USA, China, Spain, and South Korea. The periods of 1990-2001, 2002-2008, and 2009-2018 were studied using the keyword analysis method to gain insights into the development of EKR and predict its future trends. The results revealed that the related research field in the USA was broad during the study periods. Meanwhile, China was interested in fluorine pollution and contamination in red soil. Spain paid close attention to pollution due to agricultural contamination. South Korea focused on radioactive element pollution. The number of papers published over a period of 28 years increased steadily and continued to rise after 2008. The combined techniques of EKR + phytoremediation and EKR + bioremediation were successively utilised by scholars over time, and the latter is expected to demonstrate vitality in the future.

Gravel mulching is a characteristic agricultural technique that has been used for hundreds of years in the north-western Loess Plateau of China. However, the effects of the gravel-sand mulch on the processes of the runoff, soil erosion, and nutrient losses are neither fully distinguished nor even known in many parts of the world. This study investigated how different gravel particle sizes in the mulch affected the runoff, erosion as well as the extent of the nutrient losses in the surface runoff. The laboratory experiments were conducted using a rainfall simulator with three gravel mulch treatments: (1) fine gravel mulch (FG); (2) medium gravel mulch (MG); (3) coarse gravel mulch (CG) and a control group, bare soil (BS). The results of these rainfall simulation experiments gave estimates on how the grain size influences the runoff and losses of the soil and its nutrients. Applying the gravel mulch significantly delayed the runoff's starting time when compared with the bare soil. Both the total runoff and soil loss increased with the grain size of the gravel mulch. Compared with the bare soil, the lowest surface runoff and soil loss was observed from the fine gravel treatment. These results clearly show that gravel mulch plays an important role in the runoff and sediment generation processes, and that it significantly reduces the surface runoff and soil loss. The losses of the total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) from the bare soil were much higher than those under the gravel mulching. The fluctuations in these nutrient-loss processes were the most intense in the CG treatment, while the TC content, in initial runoff, was significantly higher in the FG than the other treatments. Our findings suggest gravel mulch is a useful water and soil conservation technique in the loess area of north-western China, and these results can inform one on the theoretical principles for properly utilising gravel-mulched fields.

Soils that contain rock fragments (particles > 2 mm in diameter) are distributed all over the world. The presence of these small rock fragments can have a great impact on soil water retention properties, as well as on the soil-water infiltration and vegetation restoration in semi-arid regions. To quantitatively describe the transport of water in stony soils, repacked soil cores were used to determine the infiltration rates for different rock fragment contents (0%, 10%, 20%, 30%, and 40%) and rock fragment sizes (2-5, 5-8, 8-11, and 2-11 mm). The results showed that both the content and size of the rock fragments and their interaction significantly affected the infiltration process. The infiltration rates over time and the saturated hydraulic conductivity (K_s) decreased with an increasing rock fragment content to an observed minimum value for a 40% rock fragment content. The soil-water infiltration processes were accurately described by the Kostiakov model. The measured and calculated K_s values decreased with an increasing rock fragment content, which was in accordance with the published data and in accordance with the K_s obtained by five empirical methods. The variations in the measured K_s were likely due to the variations in the soil properties caused by the soil sample repacking. The results of this study may improve the understanding of the effects of the rock fragment content and size on the infiltration processes in arid and semi-arid desert steppes.

The Štiavnické vrchy Mts. were strongly affected by pollution mostly from an aluminium plant in 1953-1989. This paper compares contamination of soils between Štiavnické vrchy Mts. and the neighbouring little polluted Kremnické vrchy Mts. from results of a 25-year study. After a decrease of emissions in Slovakia at the beginning of the 1990s the sulphate sulphur content, acidity and conductivity of soil water have decreased only on the surface and at a depth of 0.10 m at the study site in the Štiavnické vrchy Mts. At the depth 0.25 m the increase of sulphurization (23.68 kg/ha S-SO₄^2- per year) and acidity (pH 4.92) was observed. During the research, the total sulphate sulphur influx to this soil depth was 568.3 kg/ha. The average sulphur input in the study areas of the Kremnické vrchy Mts. decreased with depth: from 18.48 kg/ha/year in the surface humus to 6.85 kg/ha/year at a depth of 0.25 m. The maximum sulphur influx at the open plot was 24.06 kg/ha/year and in total 553.34 kg S-SO₄^2-. A small increase of acidity at soil depths of 0.25 m at some sites was observed also in the Kremnické vrchy Mts. Regression analysis revealed a statistically significant influence of sulphate sulphur content in the atmospheric precipitation on the sulphur amount in the soil water. A significant correlation was also observed between the precipitation amount and the sulphur content in soil water. Data from monitoring revealed significant differences between the sulphur amounts at depths of 0.10 m and 0.25 m in these study areas.

The negative effects of the current agricultural practices include erosion, acidification, loss of soil organic matter (dehumification), loss of soil structure, soil contamination by risky elements, reduction of biological diversity and land use for non-agricultural purposes. All these effects are a huge risk to the further development of soil quality from an agronomic point of view and its resilience to projected climate change. Organic matter has a crucial role in it. Relatively significant correlations with the quality or the health of soil parameters and the soil organic matter or some fraction of the soil organic matter have been found. In particular, Ctot, Cox, humic and fulvic acids, the C/N ratio, and glomalin. Our work was focused on glomalin, a glycoprotein produced by the hyphae and spores of arbuscular mycorrhizal fungi (AMF), which we classify as Glomeromycota. Arbuscular mycorrhiza, and its molecular pathways, is not a well understood phenomenon. It appears that many proteins are involved in the arbuscular mycorrhiza from which glomalin is probably one of the most significant. This protein is also responsible for the unique chemical and physical properties of soils and has an ecological and economical relevance in this sense and it is a real product of the mycorrhiza. Glomalin is very resistant to destruction (recalcitrant) and difficult to dissolve in water. Its extraction requires specific conditions: high temperature (121°C) and a citrate buffer with a neutral or alkaline pH. Due to these properties, glomalin (or its fractions) are very stable compounds that protect the soil aggregate surface. In this review, the actual literature has been researched and the importance of glomalin is discussed.

Magnesium is one of the most important nutrient elements. Soils are tested for magnesium in many countries with several extractants. Each country has its own validated methods, best-suited for its soils. The current study was designed to compare different magnesium content measuring methods with 80 Hungarian samples. The magnesium content was determined by the potassium chloride (1 M KCl 1:10), Mehlich 3 and CoHex (cobalt hexamine trichloride) methods. The maximum, mean and median values resulting from all the Mg determination methods showed the following order of measured magnitude: KCl < CoHex < M3.

The effect of tertiary treated sewage effluents on the plant cover and the physico-chemical properties of the surface soil (environmental characteristics) before and after the Al Rass sewage plant was investigated. The data were illustrated via TWINSPAN and canonical correspondence analysis (CCA). Five sites, 1 km apart, after the discharge point and one site (control site) before the sewage plant were examined. Eleven vegetation characteristics and ten physico-chemical properties of surface soil were studied. The obtained results revealed that discharging of treated sewage effluents altered quantitatively and qualitatively the pattern of species dominance and the physico-chemical properties of the soil. Soil electrical conductivity (EC), total dissolved solids (TDS), organic matters (OM), soluble cations, and soluble anions showed increased values compared to the control (resulting in salination), whereas soil pH decreased as a result of sewage disposal. It was also noticed that the physico-chemical values of EC, TDS, Ca⁺⁺, Mg⁺⁺, Na⁺, Cl^- after the sewage plant were higher than the permissible limits for agriculture recommended by FAO, whereas K⁺ and HCO₃^- were within the recommended values. The dominance of Suaeda vermiculata Forssk. ex J.F.Jmel. after the sewage plant and its absolute absence before the sewage plant may be used as an environmental bioindicator of pollution.

The use of sludge in agriculture within the European Union (EU) is currently regulated only by the limits of heavy metals (Cd, Cu, Hg, Ni, Pb and Zn) listed in Council Directive 86/278/EEC. This document is now more than 30 years old. Several European countries have introduced more stringent requirements in comparison with the directive, and have adopted limits for concentrations of other heavy metals, synthetic organic compounds and microbial contamination. The paper provides an overview of the current limits of these substances in sewage sludge and concentration limits of heavy metals in soil intended for sludge application, together with applicable laws and regulations in European Union countries. There is a need to update these regulations taking into account the current risks associated with the application of sludge to agricultural land, with the possibility of using ecotoxicological tests to assess the risks. A wide range of technologies for sewage sludge processing is used in EU countries. The predominant choice is a direct application in agriculture followed by composting. The use of sewage sludge in agriculture in 2014 and 2015 in 13 EU countries that provided data amounted to 22.6% (2014) and 22.1% (2015) of produced sludge and 23.3% (2014) and 23.1% (2015) of sludge disposed. It is also highly variable within EU countries ranging between zero (Malta, Slovenia, Slovakia) and 80% (Ireland). Over 50% of sewage sludge is used in agriculture in Bulgaria according to 2015 data.

Anthropogenic activity along the Velhas River (São Francisco River basin) has destabilized the banks of the river channel across an urban fragment. To improve the physical stabilization, the base of the slope was stabilized with urban construction waste. After this, the slope was revegetated with native species and arbuscular mycorrhiza fungi (AMF) inoculation was applied with a successfully restoration of the vegetative cover and ecological functions. This study aims to evaluate the role of the AMF population in the soil aggregation and stabilization of the revegetated slope. The soil aggregation was higher at the experimental site than at the disturbed site, especially under the AMF inoculation. The aggregates improvement was accompanied by an increase of soil humic acid and glomalin contents 24 months after the transplantation despite a flood impact 12 months after the transplantation. A scatter plot based on Principal Component Analysis of aggregates Showed that the preserved site samples clustered with most of those from experimental site. However, some samples from experimetal site were found between those from preserved and disturbed sites. This result shows that the recovering site is evolving toward the conditions of the preserved site and that the rehabilitation process is in an intermediate phase related to the aggregate formation. The AMF inoculation of woody species was indicated in the rehabilitation procedures.

Forests occupy one third of the world's land area and govern carbon (C) transfers and influence nitrogen (N) content in the biosphere. Afforestation leads to soil changes of specific dynamics, often accompanied by acidification. Especially at higher altitudes this effect is accelerated and increased with the stand age since forestation. The change in soil C and N content following afforestation is controlled by a number of factors, including: previous land use (grasslands, cropland, etc.), tree species, soil cultivation method, soil properties (clay content, pH), stand age, site management, topography, and climate. In the Czech Republic, large area changes in land use took place in the last centuries - forests covering roughly 20% in the 18^th century currently occupy almost 34%, with still increasing tendencies. This paper compares basic soil properties (soil reaction, total soil organic carbon as well as total nitrogen contents) of the agricultural land and land afforested 40-60 years ago. The results confirmed the key role of afforestation in the change of soil organic matter dynamics after establishing new forests on the former agricultural lands in the uppermost mineral soil part of the Orlické hory Mts. region in the Czech Republic. During that time, comparatively substantial changes in soil organic matter and nitrogen were registered. Afforestation considerably increased organic matter content in the studied A-horizons of different land use types. Soil development resulted in a high production of C and N pools under the forest stands, contrary to agricultural land. In general, afforestation caused significant soil acidification. The common tendency of higher acidity of forest soils compared to agricultural ones was documented in the studied case as well. The general tendencies of soil reaction and soil organic matter dynamics at the studied sites are comparable to those in other regions of the Czech Republic.

In this paper we determined the phosphorus (P) concentration in precipitation, and calculated the annual P deposition rate at three study sites located in northern Poland. We observed that the mean annual volume-weighted concentration of mineral phosphorus (P_min) in wet deposition varies from site to site. The estimated annual wet deposition rate of P_min in the study region amounted from 0.1 to 0.39 kg/ha. The concentration and deposition rate of P_min in the southern part of the study region was significantly lower than that in the northern and central part. We detected that the P_min deposition was strongly positively correlated with the fraction of arable land in the study site vicinity, and also positively correlated with the mineral P fertilizer consumption in the area. The mean annual volume-weighted concentration of P_min in wet deposition varied from 0.015 mg/l in the area of the lowest arable land percentage and the lowest mineral fertilizer consumption, to 0.046 mg/l in the area where the arable lands comprise 84% of agricultural land, and mineral P fertilizer consumption exceeded 33 kg/ha. In the P soil surface balance the atmospheric wet deposition represents 2.1-5.6% of annual total inputs of total P. The level of atmospheric P input varies widely by catchment and is related to land use (fertilizing, intensity and type of crop production).

In the context of the overall competition for water resources it is important to understand the complex dynamics of crop water management including evapotranspiration, water quality, and leaching requirement, each of them depending on the site-specific conditions. The research started with grain maize and continued with sunflower, grain maize, and wheat, at the experimental field. On both grain maize and sunflower, 10 irrigation treatments were compared that resulted from the factorial combination of two types of water (fresh and brackish water) with five irrigation regimes; the scheduled treatments were applied by furrow irrigation. The amount of salts brought into the soil with the irrigation water during the three irrigation seasons of our trial increased shifting from the lowest to the highest irrigation regime and with the increase of salinity in the irrigation water. From the study of salt distribution in the soil it follows that at the end of the irrigation season the salt concentration increased by passing from the middle of the furrow, a zone more subject to leaching during irrigation, to the intermediate zone between the furrow and the ridge, and in the middle of the ridge between two contiguous furrows, an area of confluence of the wetting and salt accumulation fronts. The leaching water supplied during the irrigation season was poorly efficient in leaching the salts brought in through irrigation, whereas the rainfall water of the autumn-winter period after the irrigation season ensured a good control of soil salinity.

Soil structure is a key determinant of many soil environmental processes and is essential for supporting terrestrial ecosystem productivity. Management of arable soils plays a significant role in forming and maintaining their structure. Between 1994 and 2011, we studied the influence of soil tillage and fertilisation regimes on the stability of soil structure of loamy Haplic Luvisol in a replicated long-term field experiment in the Dolná Malanta locality (Slovakia). Soil samples were repeatedly collected from plots exposed to the following treatments: conventional tillage (CT) and minimum tillage (MT) combined with conventional (NPK) and crop residue-enhanced fertilisation (CR+NPK). MT resulted in an increase of critical soil organic matter content (St) by 7% in comparison with CT. Addition of crop residues and NPK fertilisers significantly increased St values (by 7%) in comparison with NPK-only treatments. Soil tillage and fertilisation did not have any significant impact on other parameters of soil structure such as dry sieving mean weight diameters (MWD), mean weight diameter of water-stable aggregates (MWD_WSA), vulnerability coefficient (Kv), stability index of water-stable aggregates (Sw), index of crusting (Ic), contents of water-stable macro- (WSA_ma) and micro-aggregates (WSA_mi). Ic was correlated with organic matter content in all combinations of treatments. Surprisingly, humus quality did not interact with soil management practices to affect soil structure parameters. Higher sums of base cations, CEC and base saturation (Bs) were linked to higher Sw values, however higher values of hydrolytic acidity (Ha) resulted in lower aggregate stability in CT treatments. Higher content of K⁺ was responsible for higher values of MWD_WSA and MWD in CT. In MT, contents of Ca²⁺, Mg²⁺ and Na⁺ were significantly correlated with contents of WSA_mi and WSA_ma. Higher contents of Na⁺ negatively affected St values and positive correlations were detected between Ca²⁺, Mg²⁺ and Na⁺ and Ic in NPK treatments.

According to the Soil Pollution Prevention and Control Action Plan released in May 2016, the soil quality of 666 666.7 ha of agricultural soil requires remediation before 2020. Despite the survey on the environmental quality of soil in China released in 2014, detailed data on current pollutant concentrations remain unavailable. To date, reports on soil environmental quality on the national scale are few. The current research aimed to gain a detailed understanding of soil pollution in China through literature study and data analysis. Data for eight potentially toxic elements (i.e., arsenic (As), cadmium (Cd), zinc (Zn), chromium (Cr), mercury (Hg), copper (Cu), nickel (Ni), and lead (Pb)) and two organic pollutants (i.e., hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethanes (DDTs)) were collected from 367 areas involving 163 prefecture-level cities. Principal component analysis and clustering analysis were conducted to understand the relationships among pollutants. Results indicated that organic pollution was less severe than inorganic pollution. In terms of land-use types, garden soil showed the heaviest pollution, followed by arable land and woodland. Regarding geographic distribution, the south central and southwest areas displayed heavy pollution. Principal component and clustering analyses revealed that As, Hg, HCH, and DDTs were mainly contributed by anthropogenic sources; Cr, Cu, Ni, and Zn were primarily caused by natural background; and Cd and Pb were contributed by both sources. The soil pollution status varied among land-use types and geographic areas. The implementation of proper remediation strategies requires detailed investigations on soil environmental quality.

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 (Červený Újezd, Hněvčeves, 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 Červený Újezd (Haplic Luvisol), Hněvčeves (Haplic Luvisol), and Lukavec (Stagnic Cambisol) sites, soil pH decreased by all treatments. Only at Hněvčeves 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 Hněvčeves site. By the treatments FYM and SS the highest decrease was registered at Červený Újezd (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.

The influences of six different tillage treatments and five different crops on soil losses by water erosion were studied during a twenty-year period (1995-2014) on Stagnosol in central lowland Croatia. The aim of the study was to determine how the quantity of soil sediment, different tillage treatments and crops influence the particle size distribution (PSD) of soil sediment. During the studied period, total number of non-eroded soil samples was 60 and total number of soil sediments samples was 445. Significantly lower amounts of fine sand and higher amounts of clay and silt were determined in sediments compared to the non-eroded soil regardless of cover crop and tillage treatment, with the exception of bare cultivated soil. Generally, when quantities of soil sediments were higher, textural differences between non-eroded and eroded soil were lower. Very week negative correlation was determined between the quantity of soil sediment and the content of clay (r = -0.25) as well as the content of silt (r = -0.23). A very weak positive correlation (r = 0.23) was determined between the content of fine sand and the quantity of soil sediment, while non correlation (r = -0.02) was determined between the content of coarse sand and the quantity of soil sediment.

Colluvial soils, resulting from accelerated soil erosion, represent a significant part of the soil cover pattern in agricultural landscapes. Their specific terrain position makes it possible to map them using geostatistics and digital terrain modelling. A study of the relationship between colluvial soil extent and terrain and soil variables was performed at a morphologically diverse study site in a Luvisol soil region in Central Bohemia. Assessment of the specificity of the colluviation process with regard to profile characteristics of Luvisols was another goal of the study. A detailed field survey, statistical analyses, and detailed digital elevation model processing were the main methods utilized in the study. Statistical analysis showed a strong relationship between the occurrence of colluvial soil, various topographic derivatives, and soil organic carbon content. A multiple range test proved that four topographic derivatives significantly distinguish colluvial soil from other soil units and can be then used for colluvial soil delineation. Topographic wetness index was evaluated as the most appropriate terrain predictor. Soil organic carbon content was significantly correlated with five topographic derivatives, most strongly with topographic wetness index (TWI) and plan curvature. Redistribution of the soil material at the study site is intensive but not as significant as in loess regions covered by Chernozem. Soil mass transport is limited mainly to the A horizon; an argic horizon is truncated only at the steepest parts of the slope.

The efforts to introduce the micro irrigation system in Iran go back as far as the year 1990. The area under micro irrigation system in Iran covers about 400 000 ha and it is estimated to double (800 000 ha) during the next five years. The field performance of micro irrigation systems was studied in ten Iranian sites. Physical, chemical, and biological analyses of water samples derived from each site included pH, electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), Fe, Mn, Mg, Ca, and bacterial number (BN). In this study relative emitter discharge (R), percentage of completely clogged emitters (P_clog), emission uniformity (EU), absolute uniformity emission (EU_a), statistical uniformity (Us), coefficient of variation due to emitter performance in the field (V_pf), and sector emission uniformity (EUs) were evaluated. Results showed that performance of micro irrigation systems in Iran is low and poor. Average EU, Us, and V_pf values in different sites were 52.8, 61.3, and 38.2%, respectively. Most frequent problems detected in irrigation units were: inadequate working pressure, emitters clogging, and lacking farmers' training.

A long-term (18 years) effect of different fertilization and tillage management practices- fallowing treatment (no fertilizer, no cultivation); CK (no fertilizer, cultivation); N (nitrogen fertilizer); NP (nitrogen and phosphorus fertilizer); NK (nitrogen and potassium fertilizer); PK (phosphorus and potassium fertilizer); NPK (nitrogen, phosphorus, and potassium fertilizer); M1NPK (chemical fertilizer plus manure); 1.5M1NPK (1.5 times M1NPK); NPKS (mineral fertilizer plus straw); Rot (3-year crop rotation of maize-maize-soybean with M1NPK), and M2NPK (2 times manure plus mineral fertilizer) - on the content of total nitrogen and organic forms of nitrogen and the nitrogen content in different particle-size fractions were studied in topsoil (0-20 cm) in Black Soil of NE China by using the methods of Bremner. The results showed that the combined application of organic and mineral fertilizers could significantly increase the contents and proportions of total nitrogen and organic nitrogen forms in soil. Comparing to CK treatment, the content of total nitrogen and hydrolyzable nitrogen increased in the fallow and organic materials treatments. Compared with M1NPK treatment, rotation was more beneficial to increasing organic nitrogen content, especially remarkably increasing amino acid nitrogen. The nitrogen response of sand, silt, and clay was most sensitive on manure; the effects of fallow and manure treatments on sand were notable, the nitrogen content in sand with NPKS increased by 40.86% compared with CK treatment. Our results imply that fallow/rotation managements, and manure/straw application can improve soil fertility.

The Vistula is the longest river in Poland. It stretches from the Silesian Beskids to the Gulf of Gdańsk. Water from the Vistula is the source of drinking water for many cities and is used in industry, and therefore its quality and microbiological purity is an important issue. The quality of water in the Vistula depends, among others, on the quality of water in its basin. The aim of this study is to assess microbiological hazard to the Vistula waters from its tributaries in the vicinity of Kraków. The analyses were carried out on 10 tributaries of the Vistula: Prądnik, Dłubnia, Drwina Długa, Drwinka, Raba, Uszewka, Szreniawa, Uszwica, Kisielina, and Dunajec. The examinations were carried out in four series, from May 2012 to March 2013. The numbers of coliforms, faecal coliforms, Enterococcus faecalis, and sulphate reducing Clostridium were determined using the membrane filtration method, while the serial dilutions method was used to determine the numbers of mesophilic and psychrophilic bacteria, Staphylococcus and Salmonella. There was a large variation in the number of microorganisms in the examined watercourses, however in most cases the water could be classified as clean, whereas waters of the Vistula in the vicinity of Kraków are microbiologically contaminated. Thus, the examined watercourses do not pose a serious threat to the quality of the Vistula. Among the analyzed tributaries, the waters of the Prądnik were characterized by the worst sanitary condition, while the best microbiological quality was observed in the Dunajec.

Recently, geophysical methods have been widely used in many fields including pedology. Two of them, ground penetrating radar (GPR) and vertical electrical sounding (VES) were employed at the Dehtáře experimental site with the aim to evaluate their application in the Cambisol and Stagnosol soil types and crystalline bedrock survey in Czech conditions. These measurements were complemented by the classical soil survey using a gouge auger. As a result, interpreted soil and rock environment profiles were obtained, with the identification of boundaries of Bg, C, and R soil horizons and bedrock at various degrees of weathering. The interpretation of measurement records demonstrated suitability of the VES and GPR method application, using GPR for imaging the soil profile and the top of bedrock, while the VES method gave better results in imaging greater depths. The research demonstrated advantages of the geophysical methods such as instancy, continuous imaging, and no disturbance of the subsurface. In spite of needing classical survey data for interpretation of the results obtained by the geophysical methods, their usage can bring better quality to the soil profile imaging.

The interactions of different organic acids such as citric, malic, oxalic, and fulvic with aluminium were studied using ion-exchange chromatography (IC) and high performance liquid chromatography (HPLC). The experiments were carried out at low pH (1.5-3.1). The results of IC experiments on the interaction between Al and oxalate, citrate, and malate were compared with model chemical equilibrium calculations. The strongest effect on Al speciation was observed with oxalic acid and fulvic acid. These two ligands formed more than one type of complex with Al. In contrast, there was no significant effect of malic acid on Al speciation and a rather weak effect caused by citric acid. The studies show that the formed complexes are stable even at low pH.