Bioaccumulation of 60Co2+ ions in tobacco plants

Tobacco has previously been used in investigations of metals and radionuclide uptake. This study presents determination of bioaccumulation and translocation of 60Co2+ ions in tobacco plants (Nicotiana tabacum L.) grown in Hoagland’s nutrient solution. Cobalt concentration in tobacco plants increased with increasing concentration in nutrient solution. Bioaccumulation from the initial concentration C0 = 0.96 μM Co reached 90% after 7 day cultivation. Only small amounts of Co accumulated in roots, up to 2 - 4 % were removable from roots by washing with 0.1 M CoCl2, indicating that this portion of Co is bound to the root surface in ion-exchangeable form. Tobacco roots retained approximately 2/3 of accumulated cobalt and 1/3 was transported to shoots. Autoradiography revealed that 60Co was preferentially localized in younger leaves. Prolongation of cultivation time did not change the [Co]roots : [Co]shoots ratio significantly. Relationships between growth rate, transpiration rate, uptake and distribution of cobalt in plant tissue are discussed.

Potassium status of sod-podzolic loamy soils

Potassium is one of the essential plant nutrients. Despite numerous surveys, some issues related to the transformation of potassium in soils require additional study. The purpose of the research was to study the potassium transformation in sod-podzolic loamy soils and its entry into plants influenced by various farming methods in long-term field experiments of different duration. Field experiments were conducted at the experimental station of the FSBSI “Pryanishnikov Institute of Agrochemistry” located in the Moscow region, Domodedovo district, village of Barybino. To study the potassium status, an archive of soil samples created in the Geographical Network of Experiments with Fertilizers was used. Soil samples were collected in long-term field experiments after their closure (experiment SH-8, year of laying – 1971–1973, duration – 14 years) or modification (experiment SH-5, year of laying – 1964-1966, duration – 28 years). The experimental schemes included the systematic introduction of various fertilizing systems (organic, mineral, organo-mineral) and the determination of their impact on crop rotation productivity and soil fertility. Previous studies have shown that the formation of the crop yield in the context of long-term potassium deficiency burdened by the absence of fertilization was chiefly due to the consumption of non-exchangeable potassium by plants. For the 14–year period, the annual use of non-exchangeable potassium in the control and NP variants was 62.0-63.0 kg K2O/ha. As potassium reserves in the soil of the control variant become depleted (longer experiment), its assimilation from the non-exchangeable form decreased by 1.6 times and amounted to 39.5 kg K2O/ha. The use of a mineral fertilizing system (potassium dose < 90 kg/ha for 14 years) increased the annual mobilization of the non-exchangeable form of the element (over 100 kg/ha of K2O). The transformation of soil potassium forms that differed in the degree of their availability for plants was determined by the fertilizing systems, the doses of potassium fertilizers in the systems, as well as the duration of the experiments.

Potassium Adsorption Phenomenon in Calcareous Soils of Shahrazur Plain

A laboratory study for adsorption of potassium (K) determination was conducted on six soils located in Sharazur plain from the Kurdistan Region of Iraq in 2021 using the batch technique method. Potassium (K) adsorption isotherms were achieved by equilibrating 5.0 g of soil samples with eight grades of K (0 to 300 mg L-1) as KCl in 50 ml of 0.01M CaCl2 solution. To match the data of adsorption, Freundlich, Langmuir, and Temkin adsorption isotherms were used. The results show that the amount of adsorbed K ranged between (45.78 to 52.49) % added K. The Freundlich model fit the equilibrium K adsorption data better for the Serwan location of soil (silty loam), as demonstrated by a greater coefficient of determination (R2 =0.90). The value of heterogeneity factor 1/n for the Freundlich model ranged from (0.34 to 0.47) kg mg-1, which was less than one. The sorption processes for all of the studied soils were normal adsorption. The constant of the Langmuir isotherm (KL) aligned from (0.107 to o.425) L mg-1. Smaller KL values mean that more adsorbed K would be transformed to a non-exchangeable form, either through the creation of crystalline K or through ion occultation. The RL values indicate the type of isotherm, the values of RL> 1 that means the adsorption nature to be unfavorable. The Temkin equilibrium binding constant (AT) was high for all studied soils except the soils of Bestan Sur and Grdigo locations, the high value of AT indicates high binding energy. The Temkin constant (bT) ranged from (10.46 to 13.47) J mole-1 that was related to the nature of the adsorption energy, a positive value indicates that the adsorption process is exothermic.

Characteristics and Driving Factors of the Aerobic Denitrifying Microbial Community in Baiyangdian Lake, Xiong’an New Area

Here, the ion-exchangeable form of nitrogen (IEF-N), weak-acid extractable form of nitrogen (WAEF-N), strong-alkali extractable form of nitrogen (SAEF-N), strong-oxidant extractable form of nitrogen (SOEF-N), residue nitrogen (Res-N), and total nitrogen (TN) showed spatial differences, and most of the sediment nitrogen fractions exhibited positive correlations in Baiyangdian Lake. High-throughput sequencing analysis revealed that the aerobic denitrification microbial community was composed of proteobacteria (42.04%–99.08%) and unclassified_bacteria (0.92%–57.92%). Moreover, the microbial community exhibited significant differences (R2 = 0.4422, P < 0.05) on the basis of the adonis analysis. T(temperature), Moisture content (MC), sediment total phosphorus (STP), ion-exchangeable form of ammonia (IEF-NH4+-N), weak-acid extractable form of ammonia (WAEF-NH4+-N), weak-acid extractable form of nitrate (WAEF-NO3−-N), and strong-alkali extractable form of ammonia (SAEF-NH4+-N) were the dominant environmental factors and explained 11.1%, 8.2%, 10.7%, 6.9%, 9.3%, 8.1%, 10.5%, 7.5%, and 7% variation, respectively, of the total variation in the microbial community. Furthermore, the network analysis showed that symbiotic relationships accounted for a major percentage of the microbial networks. The keystone aerobic denitrifying bacteria belonged to Comamonas, Rhodobacter, Achromobacter, Aeromonas, Azoarcus, Leptothrix_Burkholderiales, Pseudomonas, Thauera, unclassified_Burkholderiales, and unclassified_bacteria. The composition of the keystone aerobic denitrifying microbial community also exhibited significant differences (R2 = 0.4534, P < 0.05) on the basis of the adonis analysis. T, STP, IEF-NH4+-N, ion-exchangeable form of nitrate (IEF-NO3−-N), WAEF-NO3−-N, SAEF-NH4+-N, and TN were the dominant environmental factors that explained 8.4%, 6.2%, 4.6%, 5.9%, 5.9%, 4.5%, and 9.4% variation, respectively, of the total variation in the keystone aerobic denitrifying microbial community. The systematic investigation could provide a theoretical foundation for the evolution mechanism of the aerobic denitrifying microbial community in Baiyangdian Lake.

Potassium availability in Brazilian semiarid soils cultivated with melon

ABSTRACT Haplic Vertisols and Typic Quartzipsamments are among the main classes of soils used for melon production in the Brazilian semiarid region. Potassium (K) is the nutrient most extracted by yellow melon fruits and, for this reason, high doses of potassium fertilizers are often applied to these soils. This study aimed to evaluate potassium fractions in soils of the Brazilian semiarid region, during the cultivation cycle of fertigated yellow melon. Two experiments were carried out with two types of soil (Haplic Vertisol and Typic Quartzipsamment). For the Vertisol, a 7 x 2 [seven evaluation periods and two soil layers (0-20 cm and 20-40 cm)] factorial arrangement was established, with four replications, totaling 56 experimental units. For the Quartzipsamment, a 9 x 2 [nine collection times and two soil layers (0-20 cm and 20-40 cm)] factorial arrangement was used, with four replications, totaling 72 experimental units. The non-exchangeable K fraction was dominant in both soils, mainly in the 0-20 cm layer, and represents an important reserve of this nutrient for melon cultivation, especially in Haplic Vertisols. The decrease in the concentrations of the soluble and exchangeable forms and the increase in the non-exchangeable form indicated an increase in the fixation of this nutrient, by fixation in the Vertisol and leaching in the Quartzipsamment, at the end of the melon cycle, when the amount of K accumulated by the plant was lower.

Potassium release Characteristics in Relation to Soil Properties in Soils of Major Cropping Systems in Kurnool District

Sixty representative surface soil samples (0-15 cm) were collected from 5 major cropping systems (rice-rice, fallow-bengal gram, groundnut-groundnut, maize-maize, rice-maize/mustard) covering 13 mandals in Kurnool district of Andhra Pradesh. Based on K status, the potassium releasing characteristics of thirty soils were studied by repeated extractions with boiling 1N HNO3 and their relationship between soil properties and different forms of potassium. The soils were moderately coarse to fine in texture and neutral to slightly alkaline, non-saline and non-calcareous. Potassium release characteristics and different forms of potassium were highest in maize-maize cropping system and the lowest in groundnut-groundnut cropping system. Most of the soils had lower step-K and cumulative-K. The K release parameters were positively and significantly correlated with non-exchangeable form of soil K, pH, OC, CEC and clay fraction of soil and negatively correlated with sand fraction of soil.

Characterization of heavy metal in soils as affected by long-term irrigation with industrial wastewater

Investigation of heavy metals (HM) fractions in soils irrigated with wastewater (WW) would ascertain their bioavailability and contamination level in soils. This study investigated HM fractions in soils after long-term WW irrigation. WW irrigation profoundly affected HM fractions in soil. The ranges of HM concentrations in soils irrigated with WW were apparently wide. All fractions were significantly higher in the fields irrigated with industrial WW than rain-fed fields. HM concentrations varied in the soils as Pb &gt; Cu &gt; Ni &gt; Zn &gt; Fe &gt; Cd &gt; Mn after WW irrigation. In rainfed fields, HM concentrations differed in soils as Fe &gt; Zn &gt; Mn &gt; Pb &gt; Cd &gt; Cu &gt; Ni. The HM fractions were dominant in the residual form followed by oxides bound and carbonate associated fractions in WW-irrigated soils. Lower contents of HM in the soil were obtained in the exchangeable fraction. WW irrigation resulted in the transformation of HM into different fractions as residual &gt; oxide associated &gt; carbonate associated &gt; organically bound &gt; exchangeable form. Repeated WW irrigation increased pH values of the soils. The higher EC of soil indicated an accumulation of salts in the soils due to WW irrigation. Mitigation of HM contamination in Hattar industrial effluent is required before irrigation.

Copper and zinc forms in soil fertilized with pig slurry in the bean crop

ABSTRACT The application of pig slurry may have different influence on copper (Cu) and zinc (Zn) dynamics in the soil compared with mineral fertilization. The aim of this research was to determine the different forms of Cu and Zn in soil and their uptake by bean plants in response to the application of mineral fertilizer and pig slurry (PS). The treatments were: mineral fertilizer (Cu and Zn oxides) and liquid pig slurry, at increasing rates (0/0, 1.7/6.0, 3.4/12.0 and 6.8/24.0 kg ha-1 Cu/Zn, respectively) applied in a Rhodic Kandiudox. PS increased the Cu content in soil in the exchangeable form, Fe oxides and residual, while the mineral fertilizer increased Cu contents in the fraction associated with soil organic matter. Soil Zn contents in the fractions available, exchangeable and SOM were highest under mineral fertilization, while in the soluble fraction the contents were highest under PS. The fertilizers had not impact on Cu and Zn contents associated with Al oxides, and these elements were mostly associated with Fe oxides in the soil. PS promoted the highest biomass production in shoots and roots of the bean plants, reflecting in the highest accumulation of Cu and Zn.

Chemical properties of organic soils developed from lacustrine chalk near the lakes Strzeszowskie, Sitno, and Sierakowo (Western Pomerania, north Poland)

The genesis of organic soils is closely connected with water. The occurrence of carbonate deposits in the central and lower part of organic soil profile points to the link between their genesis and post-glacial lakes. The studies conducted in the years 2009–2012 focused on organic soils near lakes: Strzeszowskie, Sitno (Myśliborskie Lakeland) and Sierakowo (Ińskie Lakeland), north Poland. The goal of the present study was to characterize chemical properties of organic soils developed on carbonate deposits. The examined soils belonged to organic muck and sapric peat soils. They contained variable amount of organic matter (32,4–66,6%). The C/N ratio depended on the degree of mineralization. The soils under study, had a high level of available forms of Ca and low level of P, K, Cu, and Zn. Both in surface and subsurface horizons of muck and sapric peat soils the content of exchangeable cations may be ranked as follows: Ca > Mg > K > Na. Basic cations total in organic horizons was distinctly higher than in calcareous sediments. In organic horizons and limnic deposits, the share of exchangeable form of Ca in the sum of basic cations exceeded 95%.