The content of microelements and iron in soils and plants in the basin of lake Kotokel’ in Western Transbaikalia

The content of microelements (Mn, Zn, Cu, Co, Ni, Cr, Pb, and Cd) and Fe is determined in the soils and plants of the Lake Kotokel’ basin. Their content in the soils is proved not to exceed the regional background and the existing MPC and APC. The content of Cd is revealed to exceed its clarke value for the world soils, which is related to the natural origin of this element. The concentrations of Mn, Co, and Pb are close to their clarke values, and those of Zn, Cu, Ni, and Cr are lower than their clarkes. The studied soils are specified by the maximal amount of the mobile forms of microelements. The profile distribution of the microelements differs depending on the genetic soil type. For Mn, Zn, and Cu, a significant biogenic accumulation is pronounced in the organic soil horizons. The content of microelements in the aboveground phytomass exceeds the maximal permissible levels for Mn, Co, Cr, and Fe. The intensity of the microelements absorption by the plants varies widely, being specified by the high coefficient of the biological adsorption (except for Fe). Mn, Zn, and Cu are accumulated in the plant phytomass the most intensely.     

Bioavailability of β-cryptoxanthin in the presence of phytosterols: in vitro and in vivo studies

Bioactive compounds are used in the design and development of new food products with potential health benefits, although little is known regarding their bioavailability and interactions. This study assessed the stability, in vitro bioaccessibility, and human bioavailability of β-cryptoxanthin from β-cryptoxanthin-rich drinks with and without added phytosterols developed for this purpose. The developed drinks showed no difference in the content of β-cryptoxanthin, and they were stable over 6 months. In vitro, hydrolysis of β-cryptoxanthin esters and the amount of free β-cryptoxanthin at duodenal and micellar phases were similar regardless of the presence of phytosterols. In the human study, the daily intake provoked significant increments of β-cryptoxanthin in serum regardless of the type of the drink. In conclusion, in vitro and in vivo human studies have shown that the bioavailability of β-cryptoxanthin is not significantly affected by the presence of phytosterols when they are simultaneously supplied in a drink.     

Transformation and Availability of Various Forms of Zinc in Soils

The transformation and availability of various forms of Zn applied into a cinnamon soil and a carbonate meadow soil as well as the effects of fertillizer-P on them were studied by using the field experiment method and chemically sequential extraction procedure.Zn added into the soils was found to be rapidly transformed into the various forms. In the cinnamon soil,the amount of Zn transformed into the carbonate bound form was the highest,and the carbonate bound form was proven by the analyses of intensity factor and capacity factor to be the primary available Zn pool.But in the carbonate meadow soil,the Zn transformed was relatively homogeneously distributed in the various forms though the amount of Zn transformed into the Mn-oxide bound form was relatively high,and the organically bound,Mn-oxide bound and amorphous Fe-oxide,bound forms were found to be the main available Zn pool.Fertilizer-P took part in the regulation and control of available Zn in the soils to a certain degree.In the carbonate meadow soil,application of P fertilizer probably aggravated Zn deficiency at low Zn rate,while it was favorable to the storage of available Zn in the case of high Zn rate.     

Efficiency of Phosphogypsum and Mined Gypsum in Reclamation and Productivity of Rice–Wheat Cropping System in Sodic Soil

In this study, efficacies of mined gypsum and phosphogypsum (PG), when applied at equivalent doses, were compared for sodic soil reclamation and productivity of rice–wheat system. Application of PG, followed by karnal grass as first crop, resulted in the greatest reduction of soil pH and exchangeable sodium percentage (ESP) followed by PG applied at 10 Mg ha^?1 alone. Application of PG at 10 Mg ha^?1 resulted in greater yields of both rice and wheat than other treatments. Ditheylenetriaminepentaacetic acid (DTPA)–extractable micronutrients of PG-treated soil were greater than in mined gypsum–treated soil. A greater portion of applied P entered the calcium (Ca)–phosphorus (P) fraction in PG-treated soil, which also resulted in more soluble P than the mined gypsum–treated soil. Phosphogypsum effected greater increase in aggregation, soil organic carbon, microbial biomass carbon, and aggregate associated carbon and decrease in zeta potential, leading to increased hydraulic conductivity and moisture retention capacity in soil over mined gypsum–treated soil.     

Toxicity of Cu and Cd in Soils and Detoxication by Additives

Results from laboratory experiments indicated that the concentrations and toxicities of both water-soluble and 0.1 M HCl-extractable Cu and Cd from soils were in the order of red soil> yellow brown earth> black earth. The toxicity of soil varied with the concentrations of metals. The form, concentration and toxicity of Cu and Cd in soils were determined by cation exchange capacity, content of organic matter and composition of clay minerals in the soil. Addition of CaCO3 could significantly decrease the concentration and toxicity of water-soluble and 0.1 M HCl-extractable Cu or Cd from the red soil, and could notably transform the Cu and Cd from the water-soluble or exchangeable form into the organic, free oxides-occluded or sulfic form.     

Streamflow and Soil Moisture of Agroforestry and GrassWatersheds in Hilly Area

A study was conducted in a hilly area of Sichuan Province, Southwestern China, to compare the streamflow and soilmoisture in two upland watersheds with different land use patterns. One was an agroforestry watershed, which consistedmainly of trees with alder (Alnus cremastogyne Burkill) and cypress (Cupressus funebris Endl.) planted in belts or stripswith a coverage of about 46%, and the other was a grassland primarily composed of lalang grass (Imperata cylindricavar. major (Nees) C.E.Hubb.), filamentary clematis (Clematis filamentosa Dunn) and common eulaliopsis (Eulaliopsisbinata (Retz.) C. E. Hubb) with a coverage of about 440/o. Streamflow measurement with a hydrograph established atthe watershed outlet showed that the average annual streamflow per 100 mm rainfall from 1983 to 1992 was 0.36 and1.08 L s^-1 km^-2 for the agroforestry watershed and the grass watershed, respectively. This showed that the streamflowof the agroforestry watershed was reduced by 67% when compared to that of the grass watershed. The peak averagemonthly streamflow in the agroforestry watershed was over 5 times lower than that of the grass watershed and lagged byone month. In addition, the peak streamfiow during a typical rainfall event of 38.3 mm in August 1986 was 37% lowerin the agroforestry watershed than in the grass watershed. Results of the moisture contents of the soil samples from 3slope locations (upper, middle and lower slopes) indicated that the agroforestry watershed maintained generally highersoil moisture contents than the grass watershed within 0-20 and 20-80 cm soil depths for the upper slope, especially forthe period from May through July. For the other (middle and lower) slopes, soil moisture contents within 20-80 cm depthin the agroforestry watershed was generally lower than those in the grass watershed, particularly in September, revealingthat water consumption by trees took place mainly below the plow layer. Therefore, agroforestry land use types mightoffer a complimentary model for tree-annual crop water utilization.     

Effect of cooking on concentrations of β-estradiol and metabolites in model matrices and beef

Because beef food products are generally cooked prior to consumption, the behavior of chemicals in these cooked foods is important in estimating human exposure. The heat stability of the natural estrogen β-estradiol (β-E2) and its metabolites α-estradiol (α-E2), estrone (E1), and several catechol estrogens was examined in heated vegetable oil and aqueous solutions. The chemicals were also incorporated into regular and extra lean ground beef and subjected to cooking. E1 and E2 were stable in aqueous solutions at 100°C, whereas the catechol estrogens exhibited first-order decay curves with half-lives of 2-10 min. Their stability improved to the same level as the other test chemicals when an antioxidant was added to the solution, suggesting that their disappearance was due to oxidation rather than thermal degradation. E1 and E2 were also stable in heated vegetable oil (160-180°C), whereas catechol estrogen decreased 30-50% over the 2 h duration of the experiments. Chemical losses from cooked beef appear to be related to the fat content of the beef, with greater losses occurring in regular ground beef (25-30%), compared to extra lean ground beef (5-20%). This study shows that cooking reduces but does not eliminate the potential for dietary exposure to growth promoters in ground beef.     

Diurnal variations in uptake,transport and assimilation of NO3 ‐and efflux of OH‐ in maize plants

Maize plants, grown for 7 and 21 days on a nutrient solution with NO₃ ^‐ as the sole nitrogen source showed a clear diurnal pattern with respect to the in vivo NRA. Especially in roots dark/light fluctuations of the enzyme activity were high. Also in NO₃ ^‐ uptake, OH^‐ efflux and endogenous content of water soluble carbohydrates a diurnal variation was found. The plant age did not significantly affect the daily rhythm.

Because day/night changes of the in vivo root NRA and nitrate uptake were proportional, the relative content of reduced N in the xylem sap of the plants was constant during a day/night interval. At both day 7 and day 21 about 40–50% of the N was transported via the xylem as amino N. As a result of non‐synchronous variation of the specific root and shoot NRA, root reduction capacity showed a great within‐day variation. It varied between 20 and 40% of the whole plant reduction capacity. Since the ratio N‐organic to N‐total in the xylem sap was about 0.5, cycling of organic nitrogen was very likely in these maize plants.     

Assessment and prediction of changes in the reserves of organic carbon in abandoned soils of European Russia in 1990–2020

Experimental studies and the analysis of published data have shown that carbon reserves in soils generally increase upon soil exclusion from agricultural use. The rate of carbon accumulation in the abandoned soils depends on the soil type, the time elapsed since the soil abandoning (the restoration period), and the thickness of the layer for which the rate of carbon accumulation is determined. For the upper 20-cm-thick layer, it varies from 66 to 175 g C/m² per year in dependence on the type of soil and averages 111 g C/m² per year. The highest rate is typical of the first 10–15 years of soil restoration. According to our calculations, the carbon sequestration in the upper 20-cm-thick layer of Russian soils due to changes in land use was 184–673 Mt C in 1990–2005 and may reach 282–1030 Mt C by 2020.     

Acid–Base Characteristics and Clay Mineralogy in the Rhizospheres of Norway Maple and Common Spruce and in the Bulk Mass of Podzolic Soil

Eurasian Soil Science - Acid–base characteristics and composition of clay minerals were estimated in the rhizospheres of Norway maple (Acer platanoides) and common spruce (Picea abies) and in...     

Radiocarbon pollution and self-purification of humus in chernozems of the East-European plain in 1900–2008

The dynamics of the ¹⁴C content in the humus of chernozems in 1900?C2008 are considered. The elevated ¹⁴C content in the atmosphere because of nuclear weapons tests has led to the contamination of humus with bomb radiocarbon. In 1966?C1968, the ¹⁴C reserves in the profiles of chernozems exceeded the background ones by 15%; in 1978, by 12%; and, in 1998, by 2%. By the year of 2008, its reserves became equal to the background ones. The ¹⁴C distribution along the soil profiles changed. By 1978, the 0- to 30-cm-thick soil layer became free from radiocarbon due to its self-purification; however, at depths of 40?C70 and 100?C115 cm, its weak accumulation was registered. By 2008, the whole soil profile was free from ¹⁴C. The main mechanism of the soil self-purification from radiocarbon is suggested to be the constant substitution of fragments of humus compound structures for those of fresh organic matter entering the soils with the ¹⁴C content being in equilibrium with the atmospheric one, i.e., due to the renewal of the carbon in the humus. The rate of the carbon renewal and its migration in the soils are assed based on the ¹⁴C concentrations in the humus.     

Effects of iron nutritional status and time of day on concentrations of phytosiderophores and nico‐tianamine in different root and shoot zones of barley

The diurnal pattern in concentrations of phytosiderophores (PS) and its precursor nicotianamine (NA) was studied in different root and shoot zones of iron (Fe)‐sufficient and Fe‐deficient barley (Hordeum vulgare L. cv. Europa) grown in nutrient solution. Roots were separated into apical (0–3 cm) and basal zones (>3 cm) and shoots into young (3 cm basal zones of youngest two leaves) and old (remaining zones of youngest two leaves and oldest leaf) parts. The main PS in barley was identified as epi‐hydroxymugineic acid (epi‐HMA). Regardless of the sampling zone and time of day, epi‐HMA concentrations were several times higher in Fe‐deficient than in Fe‐sufficient plants and several times higher in the roots than in the shoots. In roots and shoots, epi‐HMA concentrations were always higher in the younger compared with the older zones. In both root zones of Fe‐deficient plants, an inverse diurnal rhythm occurred in epi‐HMA concentrations and in its release by the roots. In contrast, such a rhythm was absent in roots of Fe‐sufficient plants and in the shoots regardless of the Fe nutritional status. Nicotianamine concentrations in roots were not affected by the Fe nutritional status in apical zones but slightly enhanced under Fe deficiency in basal zones. In contrast to roots, NA concentrations in both shoot parts were lower in Fe‐deficient than in Fe‐sufficient plants. Regardless of the Fe nutritional status in roots and shoots, NA concentrations were higher in young than in old parts and no consistent diurnal variations were observed. The results suggest that PS are also synthesized in the shoot, although at much lower rates than in roots. As with roots, PS synthesis in the shoot is enhanced under Fe deficiency and is mainly localized in young growing tissue. The distinct diurnal rhythm in PS release in roots is apparently not regulated by variation in the rate of PS synthesis during the day.     

Fixation and Recovery of Added Phosphorus and Potassium in Different Soil Types of Pulse‐Growing Regions of India

Abstract

Fixation and recovery of added phosphorus (P) and potassium (K) were studied in different soil types of pulse‐growing regions. Amounts of P and K fixed increased in all the soils irrespective of type and texture. With the increase in levels of added P and K, maximum P fixation was observed at lower levels of added P (50 mg kg^?1). Alfisols showed maximum P‐fixation capacity (92.7%), followed by Vertisols (86.5%) and Inceptisols (76.6%) at 50 mg kg^?1 added P. However, K fixation increased with increasing levels of added K up to 200 mg kg^?1, and thereafter fixation either decreased or was maintained at similar levels. Vertisols showed higher K fixation than Inceptisols and Alfisols. Fertilizer P requirement per unit increase in available P in soil was highest in Bangalore (3.23) and lowest in Delhi (2.38). Fertilizer K requirement per unit increase in available K in soil was highest in Raipur and Gulbarga (1.75) and lowest in Ranchi (1.28).     

Age and Some Genetic Characteristics of Vertisols in China

The ages of organic matter of some dark-colored horizons and calcareous concretions in some Vertisols from tropical,subtropical and warm-temperate zones of China were studied using radiocarbon dating method.The relationship between soil age and genesis of Vertisols was also expounded based on the study of their genetic characteristics and micromorphological features.The results show that although Vertisols have developed for a relatively long time,their weathering and soil forming process are weak and young with little horizonation.This is closely related to their special grochemical soil forming environment.Low-lying terrain,heavy texture,clay minerals dominated by montmorillonites and alternative drying-wetting climate give rise to the vertic features expressed in intense swelling-shrinking and cracking-closing in soils.As a result,the soil development and soil leaching process are resisted,and the climatic effect on the horizonation is impeded.Moreover,pedoturbation eliminates the horizonation in the upper part of soil profile,and postpones their evolution into zonal soils.So vertisols show certain pedogenic inertia and stay at relatively young developmental stage.Therefore,Vertisols are intrazonal soils dominated by local soil forming factors such as the relief and parent materials.     

Speciation and biochemical transformations of sulfur and copper in rice rhizosphere and bulk soil—XANES evidence of sulfur and copper associations

Purpose  

Contamination of heavy metals in soil and its subsequent accumulation along the food chain is a potential risk to human health. Cu speciation in soil–plant system, particularly on the availability to plant roots, has obtained great attention. X-ray absorption near-edge structure spectroscopy (XANES) provides information about the bonding of Cu soil components at the molecular scale. In paddy soils, changes of redox conditions led to microbially mediated sulfur transformation, thus affecting heavy metal behavior. The objective of this work was to investigate how sulfur transformation in a paddy soil affected Cu biogeochemical processes.     

Persistence and Profiles of Tetracycline Resistance Genes in Swine Farms and Impact of Operational Practices on Their Occurrence in Farms’ Vicinities

Animal farms are recognized as a major contributor to environmental pollution with antibiotic resistance genes, the persistence at the source and the discharge routes to the environment of which need better understanding. The presence of 16 tetracycline resistance genes (TRG) was assessed in feed, feces, manure lagoons, and the vicinities of three Georgia swine farms varied on antibiotic usage and other operational characteristics. In these farms, TRG profiles of feces and lagoons were composed of the same “persistent” and “transient” genes, with the former consistently observed in farms’ proximities and the latter quickly attenuated in the lagoons. Fourteen TRG incidents, 13 of which occurred in gullies, ponds, and creeks, were detected around farms. Their frequency correlated to the cumulative antibiotic usage (R ² = 0.99), number of lagoons (R ² = 0.73), and precipitation (R ² = 0.83), but not to the size of herd or the amount of manure used for fertilization. Gene-specific amplicons of TRG from the farms’ proximities were similar to those of “persistent” TRG from corresponding farms. Our data suggested the independency of TRG profiles of antibiotic usage, variability in TRG persistence in manure lagoons, correlations between operational practices and TRG incidence in farms’ vicinities, and spills and seepage from lagoons as TRG environmental routes.     

Input and migration of dissolved organic carbon in soils of forest ecosystems in the subzone of deciduous–coniferous forests

The results of four-year monitoring of natural waters in forest ecosystems of the Zvenigorod Biological Station (Moscow State University, Moscow oblast) show regular changes in the concentrations and fluxes of dissolved organic carbon (DOC) within the atmospheric precipitation–throughfall–soil waters system. Precipitation passing through the tree canopy is enriched with DOC (2–3 and 9–24 mg/L). The average carbon concentration in soil waters reaches 100–110 mg/L in complex spruce and pine–spruce forests and does not exceed 40–60 mg/L in spruce–birch forests.