Underestimation of Available Phosphorus by Resin–Bicarbonate and Olsen Tests in Calcareous Soils treated with Gypsum

In the present study, Olsen [0.5 M sodium bicarbonate (NaHCO₃), pH 8.5] and resin–bicarbonate (HCO₃) tests underestimated available phosphorus (P) in calcareous soils treated with gypsum (CaSO₄). The reaction of CaSO₄ and HCO₃ ^? ion or resin–HCO₃ to form calcium carbonate (CaCO₃) precipitate reduced the strength of the Olsen NaHCO₃ extractant and resin–HCO₃ strip for P extraction. The iron (Fe) oxide–impregnated filter paper (Pi strip) was independent of CaSO₄ influence and thus correctly estimated soil‐available P with respect to plant response to soil‐available P. Two greenhouse experiments were conducted with maize and wheat grown on calcareous soils treated with different rates of CaSO₄. The results confirmed that Olsen and resin–HCO₃ tests should not be used to measure available P or labile P in the P fractionation scheme in the calcareous soils containing significant amounts of gypsum.     

Short‐Term Effect of Lime,Phosphorus, and Iron Amendments on Water‐Extractable Lead and Arsenic in Orchard Soils

Abstract

Lead arsenate was extensively used to control insects in apple and plum orchards in the 1900s. Continuous use of lead arsenate resulted in elevated soil levels of lead (Pb) and arsenic (As). There are concerns that As and Pb will become solubilized upon a change in land use. In situ chemical stabilization practices, such as the use of phosphate‐phosphorus (P), have been investigated as a possible method for reducing the solubility, mobility, and potential toxicity of Pb and As in these soils. The objective of this study was to determine the effectiveness of calcium carbonate (lime), P, and iron (Fe) amendments in reducing the solubility of As and Pb in lead‐arsenate‐treated soils over time. Under controlled conditions, two orchard soils, Thurmont loam (Hapludults) and Burch loam (Haploxerolls), were amended with reagent‐grade calcium carbonate (CaCO₃), iron hydroxide [Fe(OH)₃], and potassium phosphate (KH₂PO₄) and incubated for 16 weeks at 26°C. The experimental results suggested that the inorganic P increased competitive sorption between H₂PO₄ ^? and dihydrogen arsenate (H₂AsO₄ ^?), resulting in greater desorption of As in both Thurmont and Burch soils. Therefore, addition of lime, potassium phosphate, and Fe to lead‐arsenate‐contaminated soils could increase the risk of loss of soluble As and Pb from surface soil and potentially increase these metal species in runoff and movement to groundwater.     

Tillage and Lime Rate Effects on Soil Acidity and Grain Yields of a Ten-Year Corn–Soybean Rotation

Reduced tillage and no-tillage systems provide shallow incorporation of surface applied materials at best. Due to concern of over-liming the surface of agricultural soils, producers either reduce lime rates (and apply more often) or perform some sort of soil inversion to mix the lime deeper into the soil profile. The objective of the authors in this field study was to evaluate the effects of tillage, lime rate, and time of limestone application on corn and soybean growth, and assess the changes in soil acidity to an already acidic soil. Treatments consisted of a no lime check, two no-tillage systems with either a 4.5 ton ha^?1 lime application every two years or an annual application of 450 kg pelleted lime ha^?1, a continuous annual chisel tillage system with a 9.0 ton ha^?1 lime application every four years, and two inversion systems utilizing a rotary tiller (Howard Rotovator) where 9.0 ton lime ha^?1 was mixed into the soil followed by either continuous chisel tillage or continuous no-tillage. Inversions occurred in 1999, 2003, and 2007. Soil samples were collected annually in increments of 5 cm to a 30 cm depth for pH determinations. After 10 years, the continuous chisel system increased soil pH in the top 20 cm and had grain yields comparable to the no-tillage system, but not different than the no lime treatment. The no-tillage system increased the pH in the surface 15 cm of soil. The inversion treatments after soybean mixed the lime more thoroughly in the top 15 cm than inversion after corn and also increased the pH to a deeper depth. The pelleted lime had no effect on soil acidity. Soybean yields were affected by lime treatment with the no lime and pelleted lime having the lowest yields. This is most likely due to manganese (Mn) toxicity with these treatments. There was no perceived benefit of inversion of the soil with no-till or chisel systems.     

Accumulation of Lead and Arsenic by Potato Grown on Lead–Arsenate-Contaminated Orchard Soils

There are concerns of potential food chain transfer of metals in crops grown on lead–arsenate-contaminated soils. The objective of this study was to investigate lead and arsenic uptake by four potato (Solanum tuberosum L.) cultivars grown on lead–arsenate-contaminated soils with lead and arsenic concentrations ranging from 350 to 961 and 43 to 290 mg kg^?1, respectively. Yield was not reduced due to treatment. Potato tubers were washed thoroughly before peeling. Lead concentration in both peeled tubers and peel was below instrument detection limit. Arsenic concentration in peeled tubers grown on the lead–arsenate soils ranged from 0.24 to 1.44 mg kg^?1. Arsenic concentration was 60% higher in the peel than in the peeled tuber. The relatively high arsenic levels in the peel demonstrated that arsenic was taken up into the potato peel tissue. It is recommended that if potatoes are grown on these soils they should be peeled before consumption.

Abbreviations Pb, lead; As, arsenic; DW, dry weight; FW, fresh weight     

Comparison of Multi-element to Single‐Element Extractants for Macro‐ and Micronutrients in Acid Soils from Spain

Abstract

Different chemical reagents are used to assess plant‐available nutrients from soils with similar properties. The use of different extractants is a serious limitation when comparing results between different soil‐testing laboratories, often leading to large differences in fertilizer recommendations for similar crops.

In this study, 80 samples from acid soils from Galicia (Spain) were used to compare several soil nutrient extractants. Traditional and tested extractants for acid soil such as Bray 2 and ammonium acetate were used to evaluate multielement extractants such as ethylenediaminetetraacetic acid–ammonium acetate (EDTA‐aa), ammonium bicarbonate–diethylenetriaminepentaacetic acid (AB‐DTPA), and Mehlich 3.

Linear regression analyses were performed to relate the amount of each nutrient obtained by traditional soil extractants to the amount obtained by multielement extractants. Strong correlation was found between extractable Bray 2 P and Mehlich 3 P (r²=0.97, slope=0.87, and intercept=?0.48). The slope of the regression line between EDTA‐aa‐extractable calcium (Ca) and that from ammonium acetate (Aa) approached 1∶1 (r²=0.86). Similar results were obtained for magnesium (Mg) (r²=0.99). Soil zinc (Zn) concentrations extracted by Mehlich 3 and EDTA‐aa were similar; slope of the regression line was 0.95 (r²=0.88). With regard to copper (Cu), Mehlich 3 extracted approximately 20% more Cu than EDTA‐aa.

The results showed that Mehlich 3 and EDTA‐aa are suitable for assessment of plant available phosphorus (P), potassium (K), Ca, Mg, Cu, Zn, and iron (Fe) in acid soils.     

Effect of Organic Matter and Salinity on Ethylenediaminetetraacetic Acid–Extractable and Solution Species of Cadmium and Lead in Three Agricultural Soils

Abstract

A study was conducted to investigate the chemical speciation of added cadmium (Cd) and lead (Pb) and their availability as influenced by fresh organic matter (OM) and sodium chloride (NaCl) in three agricultural soils. The soils were treated with 20 mg Cd/kg as cadmium nitrate [Cd(NO₃)₂ · 4H₂O], 150 mg Pb/kg as lead nitrate [Pb(NO₃)₂], 20 g/kg alfalfa powder, and 50 mmol/kg of NaCl and then incubated for 3 months at 60% water‐holding capacity (WHC) and constant temperature (25 °C). Subsamples were taken after 1, 3, 6, and 12 weeks of incubation, and electrical conductivity (EC), pH, dissolved organic carbon (DOC), and concentrations of cations and anions were determined in the 1:2.5 soil/water extract. Available Cd and Pb were determined in 0.05 M ethylenediaminetetraacetic acid (EDTA) extract. Concentrations of organic and inorganic species of Cd and Pb in soil solution were also predicted using Visual Minteq speciation program. The most prevalent species of dissolved Pb and Cd in the soils were Pb‐DOC and Cd²⁺ species, respectively. Salinity application increased the available and soluble Cd significantly in the acid and calcareous soils. It, however, had little effect on soluble Pb and no effect on available Pb. Organic‐matter application decreased availability of added Pb significantly in all soils. In contrast, it raised soluble Pb in all soils except for the acid one and approximated gradually to the added Pb with time. Impact of OM on available Cd was somewhat similar to that of Pb. Soluble Cd increased by OM application in the calcareous soil, whereas it decreased initially and then increased with time in the other soils.     

Evaluation of Extractants and Quantity–Intensity Relationship for Estimation of Available Potassium in Some Calcareous Soils of Western Iran

Accurate estimation of the available potassium (K⁺) supplied by calcareous soils in arid and semi‐arid regions is becoming more important. Exchangeable K⁺, determined by ammonium acetate (NH₄OAc), might not be the best predictor of the soil K⁺ available to crops in soils containing micaceous minerals. The effectiveness of different extraction methods for the prediction of K‐supplying capacities and quantity–intensity relationships was studied in 10 calcareous soils in western Iran. Total K⁺ uptake by wheat grown in the greenhouse was used to measure plant‐available soil K⁺. The following methods extracted increasingly higher average amounts of soil K⁺: 0.025 M H₂SO₄ (45 mg K⁺ kg^?1), 1 M NaCl (92 mg K⁺ kg^?1), 0.01 M CaCl₂ (104 mg K⁺ kg^?1), 0.1 M BaCl₂ (126 mg K⁺ kg^?1), and 1 M NH₄OAc (312 mg K⁺ kg^?1). Potassium extracted by 0.01 M CaCl₂, 1 M NaCl, 0.1 M BaCl₂, and 0.025 M H₂SO₄ showed higher correlation with K⁺ uptake by the crop (P < 0.01) than did NH₄OAc (P < 0.05), which is used to extract K⁺ in the soils of the studied area. There were significant correlations among exchangeable K⁺ adsorbed on the planar surfaces of soils (labile K⁺) and K⁺ plant uptake and K⁺ extracted by all extractants. It would appear that both 0.01 M CaCl₂ and 1 M NaCl extractants and labile K⁺ may provide the most useful prediction of K⁺ uptake by plants in these calcareous soils containing micaceous minerals.     

Comparison of the Effects of Salt Stress and Salt–Alkaline Mixed Stress on the Mineral Nutrition of Sunflower

Sunflowers (Helianthus annuus L.) were treated with salt stress and salt–alkaline mixed stress, which were established by mixing proportions of sodium chloride (NaCl), sodium sulfate (Na₂SO₄), sodium bicarbonate (NaHCO₃), and sodium carbonate (Na₂CO₃). The physiological indices of seedlings, including photosynthesis, growth, and mineral element contents, were determined to compare differences in the physiological responses of sunflower to salt stress and salt–alkaline mixed stress. The results showed that the destructive effects of salt–alkaline mixed stress on growth and photosynthesis were more severe than those of salt stress. The contents of mineral elements in the plants stressed were significantly less under salt–alkaline mixed stress than under salt stress. Data analysis indicated that both stresses caused ionic activity and free concentrations of some mineral elements to decline and even caused precipitation. This was coupled with a reduction of absorption capacity of roots. In conclusion, the mineral nutrition in sunflowers was affected under both salt and salt–alkaline mixed stresses, but the effects were more severe under salt–alkaline mixed stress than salt stress.     

Evaluation of manganese inorganic fertilizer sources and Mehlich‐3 extractant for prediction of manganese deficiency in soybeans on a Sharkey silty clay

Abstract

A greenhouse experiment was conducted on two Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquept) soils (SharkeyA and‐B) to compare MnSO₄ and two Mn‐oxysulfatc sources (oxysulfate‐A and‐B) and to evaluate the Mehlich‐3 extractant. Soils were collected from a soybean [Glycine max (L.) Merr.] field with (Sharkey‐A) and without (Sharkey‐B) a history of Mn deficiency symptoms. Treatments consisted of two lime treatments, O and 2000 mg kg^‐1, and three Mn rates, 0, 20, and 40 mg kg^‐1. Each source was broadcast in granular form. Manganese sulfate was also applied in solution. Soybean plants were grown for 40 days. Dry weight, whole‐plant Mn concentration, and total Mn uptake were measured. Extractable soil Mn was determined using the Mehlich‐3 extractant. Dry weight was increased by applied Mn only on the Sharkey‐A soil, especially for the limed treatment. The Mehlich‐3 extractant delineated between the responsive (2.3 mg Mn kg^‐1) and non‐responsive (6.0 mg Mn kg^‐1) Sharkey soils. On the limed Sharkey‐A soil, sulfate applied in the granular form was more effective than sulfate applied in solution. It was also more effective than the oxysulfate sources, and the oxysulfate‐A was superior to the oxysulfate‐B source. Whole‐plant Mn concentration and uptake followed trends similar to those observed with dry weight, particularly on the Sharkey‐A soil. Multiple regression analyses suggested that soil pH, along with Mehlich‐3 extractable Mn, may improve the Mn soil test interpretation.     

Comparative Evaluation of Inductively Coupled Plasma–Atomic Emission Spectroscopy and Colorimetric Methods for Determining Hot-Water-Extractable Boron in Soils

Frequency of boron (B) deficiency is increasing in rainfed systems, and hence there is a need to diagnose the deficiency. Colorimetric methods are still widely used in soil-testing laboratories in India for measuring B. Little information is available on the comparative evaluation of the colorimetric and inductively coupled plasma (ICP) methods for determining extractable B in soils. We describe results of the comparative evaluation of these methods for measuring extractable B in 57 soil samples with pH values ranging from 5.3 to 9.5. There was a significant correlation between B values determined by the two methods, and the correlation coefficient was greater for soil samples with pH in the neutral to alkaline range. Interaction between soil samples and methods (ICP or colorimetric) was significant except for soil samples in the pH range of 8.0 to 9.5. Precision for B determination was greater with the ICP than with the colorimetric method.     

Comparative Evaluation of Inductively Coupled Plasma–Optical Emission Spectroscopy and Atomic Absorption Spectrophotometry for Determining DTPA-Extractable Micronutrients in Soils

A study was conducted for comparative evaluation of atomic absorption spectrophotometry (AAS) and inductively coupled plasma–optical emission spectroscopy (ICP-OES) for determining extractable zinc (Zn), copper (Cu), manganese (Mn), and iron (Fe) in sixty diverse soil samples having a wide range in pH and organic carbon (C). The results were significantly affected by the method of analysis and soil type but generally did not follow a definite trend. Results for extractable Fe in Alfisol samples were significantly greater when using ICP-OES than AAS; and the results for Zn, Cu, and Mn were not significantly different for the two methods. For Vertisol samples, the results for extractable Cu were significantly greater by ICP-OES than by AAS, whereas extractable Fe and Zn were significantly greater by AAS than by ICP-OES, and the results for Mn were not significantly different for the two methods. The results are discussed relative to soil type and differences in soil organic carbon and pH of the samples used in the study.     

Assessing the Efficiency of Humic Substances as Washing Agents for Oil–Contaminated Soils and Peats under Model Experimental Conditions

Two humic preparations of different origins have been compared as washing agents for oil-contaminated soils and peat under model experimental conditions using a sample from the plow horizon of soddypodzolic soil artificially contaminated with oil or diesel fuel and a sample of high-moor peat contaminated with crude oil because of a spill occurred 15 years ago. Soil and peat were washed by shaking with solutions of the humic preparations Gumat Sakhalinskii and Lignogumat in a 1: 10 (m/v) ratio. Control samples were washed with distilled water. Washing with a synthetic surfactant (sodium dodecyl sulfate) was also added to the experimental design. After washing, soil and peat samples were air-dried and used for the determination of the total content of petroleum hydrocarbons; the characterization of their hydrocarbon composition; and the assessment of hydrophobicity from the contact angle and the efficiency of colonization by oil-destructing microorganisms Rhodococcus sp. and Candida sp., which are components of the preparation Bioros recommended for oil contaminations. It has been shown that the extraction efficiency of petroleum hydrocarbons by humic preparations did not differ from the extraction efficiency by water and was less than that by sodium dodecyl sulfate in all cases. No appreciable changes in the contact angles of soil and peat have been observed at the use of water and humic preparations as washing agents, while the contact angle decreased to less than 90o after washing with sodium dodecyl sulfate, which indicated the hydrophobicity of the surface of substrate particles. It has been found that humic preparations favor the colonization of soil and peat by oil-destructing microorganisms Rhodococcus sp. and Candida sp. Based on the obtained results, humic preparations have been recommended for further study as preparations favoring the ability of oil-destructing microorganisms to colonize oil-contaminated substrates.     

Inoculation of Earthworms and Plant Growth–Promoting Rhizobacteria (PGPR) for the Improvement of Vegetable Growth via Enhanced N and P Availability in Soils

A pot trial was conducted to investigate the single, dual, and triple inoculation of earthworms or plant growth–promoting rhizobacteria (PGPR), including nitrogen-fixing bacteria (NFB) (Azotobacter chroococcum HKN-5) and phosphate-solubilizing bacteria (PSB) (Bacillus megaterium HKP-1), on the growth of Brassica parachinenesis and nitrogen (N) and phosphorus (P) availability in soils. All of the five inoculation treatments significantly (P < 0.05) increased the shoot growth of B. parachinenesis. The greatest shoot and root biomass were recorded in the triple inoculation of earthworm, NFB, and PSB. All of the five inoculation treatments significantly (P < 0.05) increased the concentrations of ammonium (NH₄ ⁺)-N, NO_x-N, and sodium bicarbonate (NaHCO₃)–extractable P in soils. Based on plant growth and availability of N and P in soils, the present study suggested that the triple inoculation may be a promising approach for reducing the need for chemical fertilizers in growing vegetables.     

Effects of Linear Alkylbenzene Sulphonates (LASs) on Exogenous Organic Matter Content and Evolution in Sewage Sludge–Amended Soils

Abstract

Linear alkylbenzene sulphonates (LASs) are anionic surfactants commonly used in commercial detergents. A potential risk associated with the recycling of sewage waste materials is the presence of LASs and their primary degradation products, which could accumulate in sludge, especially during anaerobic processing. The long‐term accumulation of these contaminants in soils and especially the potential disturbance of soil functions need to be studied in more detail. In our study, the influence of the amendment added to an agricultural soil with different organic wastes containing LASs on organic matter content and nitrogen (N) content evolution and mineralization was studied in field conditions. A completely randomized 3×3 factorial arrangement, representing two sewage sludge types (composted and uncomposted) and three levels of LAS presence (0, 15, and 30 g/m²) in treated soils, was established using field plots (7×2 m); the results are compared with untreated plots. Statistical models based on covariance analysis were used to understand the dynamics of and the main factors influencing carbon (C) and N mineralization in sewage sludge amended–soils in the presence of LAS. LAS seemed to alter nitrogen mineralization, especially the nitrate dynamics.     

The Use of the Soil-Geomorphological Database for Studying the Spatial Variability of the Humus Content,Physical Clay,and Clay in the Soils of the Kuznetsk–Salair Geomorphological Province

Eurasian Soil Science - Based on archival data on the soils of the Kuznetsk–Salair geomorphological province (within Novosibirsk oblast) and the results of processing digital elevation...     

Adsorption Kinetics of Pb2+ and Cu2+ on Variable Charge Soils and Minerals: Ⅱ. Equations for Describing Experimental Data

Different mathematical methods,including linearization,differential,integration and nonlinear least squares approximation (Newton-Marquardt method),were used to fit different kinetic equations,such as zero-order,first-order (i.e.membrane diffusion),second-order,parabolic-diffusion,Elovich,two-constant equations,to the experimental data of Pb^2 and Cu^2 adsorption on variable charge soils and kaolinite.Assuming each M^2 occupied two adsorption sites,two more equations,the so-caled surface second-order equation and third-order equation were derived and compared with the above equations according to the fitting results,which showed that the second-order equation and surface second-order equation,being one equation in different expressions under some conditions,were better than the other equations in describing the Pb^2 and Cu^2 adsorption kinetics,and the latter was the best.     

Effect of Integrated Nutrient Management on Soil Physical Properties and Crop Productivity under a Maize (Zea mays)–Mustard (Brassica campestris) Cropping Sequence in Acidic Soils of Northeast India

A five-year (2001/02–2006/07) field experiment was carried out on acidic clay loam soil classified as Typic Hapludalf with a maize–mustard crop sequence to study the effect of continuous application of nitrogen, phosphorus, and potassium (NPK) fertilizers alone and in combination with lime, farmyard manure (FYM), and biofertilizers on soil physical properties, soil organic carbon (SOC), soil microbial biomass carbon (SMBC), and crop yields on the hilly ecosystem of Meghalaya. Significant improvement in the soil physical conditions of the soil was observed under integrated application of organic manure and inorganic fertilizers. Addition of NPK fertilizers along with organic manure, lime, and biofertilizers increased soil organic carbon (SOC) content, aggregate stability, moisture-retention capacity, and infiltration rate of the soil while reducing bulk density. The SOC content under the treatment of 100% NPK + lime + biofertilizer + FYM was significantly greater (68.58%) than in control plots. Maize and mustard crop yields also significantly increased (4.73- and 21.09-folds, respectively) with continuous application of balanced inorganic (100% NPK) + lime + biofertilizer + FYM as compared to the control plots. However, crop yields drastically reduced under application of integrated nutrients without FYM as compared to the treatment with FYM application. Thus, the results suggest that integrated use of a balanced inorganic fertilizer in combination with lime and organic manure sustains a soil physical environment that is better for achieving higher crop productivity under intensive cropping systems in the hilly ecosystem of northeastern India.     

Some comments on: Mao et al. (2018) “Bibliometric analysis of insights into soil remediation” Journal of Soils and Sediments, 18(7): 2520–2534

In order to improve the bias of using the Web of Science databases for bibliometric studies, the “front page” has been proposed by Ho’s group in 2012. Using the “front page” as the filter resulted in a huge difference compared to the method from the original paper of Mao et al. Furthermore, a cited reference plays an important role in a published paper. Readers are interested in the paper’s statements and might find useful information from the following researches. The reference section is an important part in a paper; however, it was easily ignored by the authors. This comment also offered information for citing the original idea of publication indicators used for the comparison of countries’ and institutions’ publication performances.

     

Reply to comments on: Mao et al. (2018) “Bibliometric analysis of insights into soil remediation” Journal of Soils and Sediments, 18(7):2520–2534

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