Negative charge — pH dependence of organic matter of forest soil under influence of liming as determined from titration curves

The dependences between negative charge and pH for organic matter of limed and unlimed profiles of sandy acidic forest soils were determined on the base of ion exchange and titration curves measurements. Subtracting the titration curves of the supernatant from the titration curves of the respective suspensions the quantities of base consumed by solid phases were determined. They were interpreted in terms of negative charge after corrections with the quantities of initial exchangeable basic cations and exchangeable hydrogen. For investigated organic material the charge increased slowly in acidic pH region and much faster in alkaline pH region. The zones of the fast increase of charge occured at higher pH's for deeper horizons, enriched with fulvic acids. The observed changes of organic matter charge due to liming were related to the increase of fulvic to humic acids ratio. The negative charges of organic matter in limed and unlimed profiles estimated for high pH were better correlated with fulvic to humic acids ratio than when estimated for lower pH levels.     

Modifications of the mineralogical composition and surface properties of soils as related to steppe climate dynamics in historical time

This work presents the results of a study of changes in the soil mineral components and the related modifications of the chemical composition and surface properties of soils in the desert-steppe zone in the southern part of the Ergeni Upland. Burial mounds dating back to the Bronze epoch have been investigated. According to radiocarbon data, their ages are estimated at 5100 ± 50, 4410 ± 100, 4260 ± 120, 4120 ± 70, and 3960 ± 40 years. The substantial transformation of the clay minerals, the molar chemical coefficients, the magnetic mineralogy, and the surface properties of the soils permits us to assess the rates of the mineralogical transformations caused by the climate change during the time interval of less than <∼100 years. The ratio between the content of the mineral phases in the buried soils of different ages testifies to the primary importance of climatic factor in comparison with the total duration of weathering or the soil existence on the land surface prior to its burial, i.e., the soil age.     

Some characteristics of organic soils irrigated with municipal wastewater

Soil irrigation with wastewater (WW) gives the opportunity to solve the problems of its disposal, final purification or reuse. Many studies have examined mineral soils upon continued WW application. The aim of this paper was to examine the properties of organic soils 3 years after WW application was discontinued. Peat‐muck soil planted with Populus spp. or Salix spp., and mineral‐muck soil under grasses were irrigated for 4 years with municipal WW at a low (comparable with intensive NPK fertilization) and high WW rate (600 and 1200 mm yearly, respectively). Soils were analysed for organic matter (OM), pH, bulk density (BD), water holding capacity (WHC), P₂O₅, Fe₂O₃, Al₂O₃, MnO, Zn, Pb, Cu, Cr, magnetic susceptibility (MS) and dehydrogenase and catalase activities. The results were compared with control soils which have never received WW. The study showed that only P₂O₅, MnO and catalase activity (CA) were significantly affected by former WW application. On average, P₂O₅ increased by 30 per cent, whereas MnO decreased by 35 per cent with no differences between the two WW rates. CA decreased by 18 per cent at the high WW rate. Most of tested characteristics were determined by soil type. The peat‐muck soil showed higher OM, WHC, P₂O₅, MnO, Pb and CA than mineral‐muck soil and lower BD, MS, Fe₂O₃, Al₂O₃ and Cr. Soil depth influenced Fe₂O₃, MnO, Zn, MS and enzyme activities, while basic soil properties (OM, pH, BD, WHC and P₂O₅) were not changed by soil depth. Heavy metals (Zn, Cr, Cu and Pb) were below upper permissible limits. Copyright © 2010 John Wiley & Sons, Ltd.     

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non‐surgical embryo recovery in oestrous‐induced Santa Inês ewes

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.     

Water stability of aggregates in subtropical and tropical soils (Georgia and China) and its relationships with the mineralogy and chemical properties

Water-stable aggregates isolated from three subtropical and one tropical soil (Western Georgia and China) were studied for their organic carbon, cation exchange capacity (CEC), specific surface area, magnetic susceptibility, and total chemical elements. The soils were also studied for their particle-size distribution, mineralogy, and nonsilicate Fe and Al oxides. Describe the water stability, three indices have been used: the content of water-stable macroaggregates (>0.25 mm), the mean weighted diameter of the aggregates, and the numerical aggregation index. The yellow-cinnamonic soil (China) was neutral, and the three other soils were acid. The soils were degraded with a low content of organic matter. The yellow-cinnamonic soil was characterized by the lowest water stability due to the predominantly vermiculite composition of the clay. The high water stability of the Oxisol structure was determined by the kaolinites and high content of oxides. In three out of the four soils studied, the hierarchical levels of the soil structure organization were defined; they were identified by the content of organic matter and the Ca + Mg (in Oxisols). Iron oxides mainly participated in the formation of micro-aggregates; Al and Mn contributed to the formation of macroaggregates. The water-stable aggregates acted as sorption geochemical barriers and accumulated Pb, Zn, Cd, Cs, and other trace elements up to concentrations exceeding their levels in the soil by 5 times and more. The highest correlations were obtained with CEC, Mn, and P rather than with organic carbon and Fe.     

Combined treatment with oestradiol benzoate,d‐cloprostenol and oxytocin permits cervical dilation and nonsurgical embryo recovery in ewes

This study examined the feasibility of transcervical embryo recovery after the hormonal treatment to induce cervical dilation, following the 7‐day oestrous synchronization protocol in multiparous Santa Inês ewes. A total of 23 cyclic ewes received two doses of 37.5 μg of d‐cloprostenol by latero‐vulvar route 7 days apart. After the second injection of d‐cloprostenol, the ewes were checked for oestrus (every 12 hr) and then mated by fertile rams throughout the oestrous period. All ewes received 37.5 μg of d‐cloprostenol (latero‐vulvar) and 1 mg of oestradiol benzoate by either intramuscular (EBim group; n = 12) or intravaginal (EBivg group; n = 11) route 16 hr before embryo flushing. Twenty minutes before the flushing, 50 IU of oxytocin were administered intravenously. The oestrous response (i.e., the percentage of ewes that showed signs of oestrous behaviour after the second d‐cloprostenol injection) was 91.3% (21/23). The proportion of successfully penetrated ewes (81.8% compared with 80.0%), the mean duration of embryo flushing (24.7 ± 2.0 min compared 26.2 ± 1.9 min), the flushing fluid recovery rate (94.8 ± 1.3% compared with 91.0 ± 2.9%) and the average number of structures recovered per ewe (0.5 ± 0.4 compared with 0.8 ± 0.4) did not vary (p > 0.05) between the EBim and EBivg groups. Viable embryos were recovered from 41.2% (7/17) of successfully penetrated ewes. It can be concluded that nonsurgical (i.e., transcervical) embryo collection can be performed in oestrous‐synchronized Santa Inês ewes pretreated with d‐cloprostenol, oxytocin and oestradiol benzoate, with the latter hormone administered by either the intramuscular or intravaginal route.     

Surface area and CEC as related to qualitative and quantitative changes of forest soil organic matter after liming

Water vapor adsorption isotherms were used for estimation of (apparent) surface areas of samples of limed and unlimed plots of an acidic sandy forest soil. Samples were taken at two microrelief (ridge and furrow) positions from five subsequent 10 cm layers. Values of surface area and CEC correlated linearly with organic matter content but only for four bottom layers. Surface areas and CEC values calculated per the unit mass of organic carbon were higher in upper layers than in lower layers for control samples. For limed samples an opposite trend was observed. The estimated average (apparent) charge densities of organic matter showed a better correlation with humic to fulvic acids ratio. Values of surface charge densities for every investigated profile increased with depth and they were lower in limed than in unlimed profiles.     

Comparison of fractal dimensions of soils estimated from adsorption isotherms,mercury intrusion,and particle size distribution

The values of the surface fractal dimensions were determined for several samples of Cambisols and Luvisols from analysis of nitrogen and water vapor adsorption isotherms and from mercury intrusion data. Moreover, the values of fractal dimension characterizing the particle size distributions of soil samples were calculated by using a number‐based method. For almost all investigated soils the values of the surface fractal dimension, obtained from water vapor isotherms were lower than those obtained from nitrogen isotherms. Largest were the surface fractal dimensions evaluated form mercury intrusion data. No significant correlations between different kinds of surface fractal dimensions were found, and the reasons of this finding are discussed. However, the values of the surface fractal dimensions calculated from mercury intrusion data correlate with those characterizing the texture of soils. The paper also reports on correlations between of the values of surface area, fractal dimensions and some selected physico‐chemical characteristics of soils.     

Reaction of sewage farm soils to different irrigation solutions in a column experiment 2. Heavy metals and their leaching

Heavy metal polluted soils from a recent and a former sewage farm were studied in a 2.5 years‐column experiment under various irrigation regimes and/or liming treatment. The copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) concentrations in the soil and the leaching of these elements were studied. The amounts of the metals leached differed markedly between both soils, however, the effect of various irrigation treatments was less pronounced. The heavy metal content in the soil solid phase depended on the organic carbon content, however these dependencies differed for both soils as well as for particular metals. In lower soil horizons, the amount of heavy metals bound by unit mass of organic carbon was constant. It was assumed that the same amount of the heavy metals can be bound by the unit mass of the DOC. Under this assumption the amount of the DOC in the former sewage farm soil was in general too small to carry all heavy metals leached. Therefore leaching of their cationic forms has been postulated. The amount of the DOC in the present sewage farm soil could carry more heavy metals than these being leached. Therefore, an undersaturation of the DOC in heavy metals could occur in this soil.<?show $6#>