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1.
Zejiang Cai Minggang Xu Boren Wang Lu Zhang Shilin Wen Suduan Gao 《Journal of Soils and Sediments》2018,18(9):2893-2903
Purpose
Crop straws and animal manure have the potential to ameliorate acidic soils, but their effectiveness and the mechanisms involved are not fully understood. The aim of this study was to evaluate the effectiveness of two crop (maize and soybean) straws, swine manure, and their application rates on acidity changes in acidic red soils (Ferralic Cambisol) differing in initial pH.Materials and methods
Two red soils were collected after 21 years of the (1) no fertilization history (CK soil, pH 5.46) and (2) receiving annual chemical nitrogen (N) fertilization (N soil, pH 4.18). The soils were incubated for 105 days at 25 °C after amending the crop straws or manure at 0, 5, 10, 20, and 40 g kg?1 (w/w), and examined for changes in pH, exchangeable acidity, N mineralization, and speciation in 2 M KCl extract as ammonium (NH4+) and nitrate plus nitrite (NO3??+?NO2?).Results and discussion
All three organic materials significantly decreased soil acidity (dominated by aluminum) as the application rate increased. Soybean straw was as effective (sometimes more effective) as swine manure in raising pH in both soils. Soybean straw and swine manure both significantly reduced exchangeable acidity at amendment rate as low as 10 g kg?1 in the highly acidic N soil, but swine manure was more effective in reducing the total acidity especially exchangeable aluminum (e.g., in the N soil from initial 5.79 to 0.50 cmol(+) kg?1 compared to 2.82 and 4.19 cmol(+) kg?1 by soybean straw and maize straw, respectively). Maize straw was less effective than soybean straw in affecting soil pH and the acidity. The exchangeable aluminum decreased at a rate of 4.48 cmol(+) kg?1 per pH unit increase for both straws compared to 6.25 cmol(+) kg?1 per pH unit from the manure. The NO3??+?NO2? concentration in soil increased significantly for swine manure amendment, but decreased markedly for straw treatments. The high C/N ratio in the straws led to N immobilization and pH increase.Conclusions
While swine manure continues to be effective for ameliorating soil acidity, crop straw amendment has also shown a good potential to ameliorate the acidity of the red soil. Thus, after harvest, straws should preferably not be removed from the field, but mixed with the soil to decelerate acidification. The long-term effect of straw return on soil acidity management warrants further determination under field conditions.2.
Lei Wang Clayton R. Butterly Wei Tian Herath M. S. K. Herath Yunguan Xi Jibing Zhang Xingji Xiao 《Journal of Soils and Sediments》2016,16(7):1933-1943
Purpose
To better understand the effect of fertilizer practices on soil acidification and soil organic matter (SOM) stocks in a rice-wheat system, a field experiment was conducted to (i) investigate the influence of fertilizer practices on the Al forms in solid phases and the distribution of Al species in water extracts and (ii) explore the relationship between the Al forms, the quantity and composition of SOM, and soil acidity.Materials and methods
Seven fertilizer treatments including CL (no fertilizer), NK, PK, NPK, N2PK (PK and 125 % of N), NP2K (NK and 125 % of P), and organic fertilizer (OF) were applied to induce various changes in pH and SOM composition (i.e., total C and N contents, C/N ratio, and SOM recalcitrant indices) in a rice-wheat system. After 6-year cultivation, different pools of Al forms (i.e., amorphous Al; organically bound Al of varying stability; exchangeable Al; water-soluble inorganic Al3+, Al-OH, Al-F, Al-SiO3, and Al-SO4; and organic Al monomers) were quantified and related with SOM composition and soil pH during the wheat phase.Results and discussion
Fertilizer types significantly changed soil pH and SOM composition and which explained 84 % of the variance of Al forms using redundancy analysis. An interaction between soil pH and SOM quality on Al forms also existed but only accounted for a very small (6 %) portion of the variation. Compared to CL and chemical fertilizer, OF practice with relative low SOM stabilization is likely to favor the formation of amorphous Al in order to bind more SOM. The decrease in exchangeable acidity and water-extractable Al via hydroxyl-Al precipitation but not in the form of organo-aluminum complexes evidenced this phenomenon. In contrast, chemical fertilizer input increased exchangeable Al and water extract Al (especially Al3+), partly at the expense of organically bound Al. The destabilization of organic-aluminum complexes was a mechanism of pH buffering evidenced by the increased soluble Al-dissolved organic matter (DOM) as soil pH decreases. Further, the magnitude of this trend was much greater for elevated N input compared with P input.Conclusions
Chemical fertilizer with relative high SOM stabilization favored the formation of exchangeable Al and soluble Al resulting in soil acidification, whereas OF with relative low SOM stabilization tended to transform exchangeable Al and soluble Al to amorphous Al, thereby alleviating soil acidification and enhancing C stocks in a rice-wheat system.3.
Purpose
The Al forms on maize and soybean roots were investigated to determine the main factors affecting the distribution of Al forms and its relationship with Al plant toxicity.Materials and methods
Solution culture experiments were conducted to obtain the fresh roots of maize and soybean. KNO3, citric acid, and HCl were used to extract the exchangeable, complexed, and precipitated forms of Al on the roots.Results and discussion
The complexed Al was higher than the exchangeable and precipitated Al. Root CECs of soybean and maize were 77 and 55 cmol kg?1, and functional groups on the soybean roots (262.4 cmol kg?1) were greater than on maize roots (210.8 cmol kg?1), which resulted in more exchangeable and complexed Al on soybean roots than on maize roots, and was one of the reasons for the increased Al toxicity to soybean. The total and exchangeable Al were the highest on the plant root tips and decreased gradually with increasing distance from the tips. Ca2+, Mg2+, and NH4 + cations reduced the exchangeable Al on the roots. Oxalate and malate also reduced the adsorption and absorption of Al by roots, and the effect of oxalate was greater than malate.Conclusions
Higher exchangeable and complexed Al on plant roots led to increased Al plant toxicity. Ca2+, Mg2+, and NH4 + and oxalate and malate can effectively alleviate Al plant toxicity.4.
Ren-yong Shi Jiu-yu Li Ni Ni Khalid Mehmood Ren-kou Xu Wei Qian 《Journal of Soils and Sediments》2017,17(8):2116-2126
Purpose
The purpose of this study is to examine the effects of combined application of biomass ash (BA), bone meal (BM), and alkaline slag (AS) on soil acidity, nutrient contents, uptake of the nutrients by wheat, and wheat growth.Materials and methods
A pot experiment with an Ultisol collected from Anhui province, China, was conducted to compare the effects of BA, BM, and AS applied alone and combined on soil acidity; soil nutrient contents; uptake of N, P, K, Ca, and Mg by wheat, and wheat growth.Results and discussion
Application of BA, BM, and AS alone and combined increased soil pH and decreased soil exchangeable Al3+. BA + BM + AS showed the greatest ameliorating effect on soil acidity, and soil pH of the treatment increased by 1.24 units compared with control. Application of BA + BM + AS reduced soil exchangeable Al3+ and increased soil exchangeable calcium and magnesium to a greater extent than BA + BM and single application of the amendments. The BM-containing amendments substantially increased soil available phosphorous by 66–93% compared with control. Application of the amendments alone and combined enhanced the uptake of N, P, K, Ca, and Mg by wheat and thus promoted wheat growth and increased yield of wheat grains. Application of BA + BM + AS and BA + BM showed greater effects on nutrient uptake and wheat growth than single application of the amendments. Wheat straw weights of the two treatments were 11.1 and 10.1 times greater than that of control. The data were 2.7, 4.8, and 5.6 times for the treatments of BA, AS, and BM. The contents of Cd, Cr, Zn, and Cu in wheat grains were lower than standard limits, except for the single BA treatment.Conclusions
BA + BM + AS is the best choice for amelioration of acid soils and promotion of crop production.5.
Anushka Upamali Rajapaksha Meththika Vithanage Sang Soo Lee Dong-Cheol Seo Daniel C. W. Tsang Yong Sik Ok 《Journal of Soils and Sediments》2016,16(3):889-895
Purpose
Sulfamethazine (SMT) is increasingly detected in environmental matrices due to its versatile use as antibiotics. We aimed to investigate the benefits and roles of steam activation of biochars with respect to SMT sorption kinetics and equilibrium sorption.Materials and methods
Biochars were produced from burcucumber plant and tea waste using a pyrolyzer at a temperature of 700 °C for 2 h. The biochar samples were treated with 5 mL min?1 of steam for an additional 45 min for post-synthesis steam activation. The SMT sorption on the unmodified and steam activated biochars were compared.Results and discussion
The time taken to reach equilibrium was significantly less for steam activated biochars (~4 h) than non-activated biochars (>24 h). Up to 98 % of SMT could be removed from aqueous solutions by steam activated biochars. The sorption kinetic behaviors were well described by the pseudo-second model and SMT sorption rates of steam activated biochars (k 2?~?1.11–1.57 mg g?1 min?1) were significantly higher than that of the unmodified biochars (k 2?~?0.04–0.11 mg g?1 min?1) because of increased availability of accessible porous structure with averagely larger pore diameters. Moreover, the equilibrium sorption on the unmodified biochars was significantly influenced by increasing solution pH (~30–50 % reduction) because of speciation change of SMT, whereas steam activated biochars manifested much stronger sorption resilience against pH variation (~2–4 % reduction only) because the enhanced porosity offset the effect of unfavorable electrostatic repulsion.Conclusions
The observed features of steam activated biochars would render their applications more versatile and reliable in field throughout changeable environmental conditions.6.
Purpose
The key factors influencing pH buffering capacity of acid soils from tropical and subtropical regions, and effects of soil evolution and incorporation of biochars on pH buffering capacity were investigated to develop suitable methods to increase pH buffering capacity of acid soils.Materials and methods
A total of 24 acid soils collected from southern China were used. The pH buffering capacity was determined using acid–base titration. The values of pH buffering capacity were obtained from the slope of titration curves of acid or alkali additions plotted against pH in the pH range 4.0–7.0. Two biochars were prepared from straws of peanut and canola using a low temperature pyrolysis method. After incubation of three acid soils, pH buffering capacity was then determined.Results and discussion
pH buffering capacity had a range of 9.1–32.1 mmol kg–1 pH–1 for 18 acid soils from tropical and subtropical regions of China. The pH buffering capacity was highly correlated (R 2?=?0.707) with soil cation exchange capacity (CEC) measured with ammonium acetate method at pH 7.0 and decreased with soil evolution due to the decreased CEC. Incorporation of biochars at rates equivalent to 72 and 120 t ha?1 increased soil pH buffering capacity due to the CEC contained in the biochars. Incorporation of peanut straw char which itself contained more CEC and alkalinity induced more increase in soil CEC, and thus greater increase in pH buffering capacity compared with canola straw char. At 5% of peanut straw char added, soil CEC increased by 80.2%, 51.3%, and 82.8% for Ultisol from Liuzhou, Oxisol from Chengmai and Ultisol from Kunlun, respectively, and by 19.8%, 19.6%, and 32.8% with 5% of canola straw char added, respectively; and correspondingly for these soils, the pH buffering capacity increased by 73.6%, 92.0%, and 123.2% with peanut straw char added; and by 31.3%, 25.6%, and 52.3% with canola straw char added, respectively. Protonation/deprotonation of oxygen-containing functional groups of biochars was the main mechanism for the increase of pH buffering capacity of acid soils with the incorporation of biochars.Conclusions
CEC was a key factor determining pH buffering capacity of acid soils from tropical and subtropical regions of China. Decreased CEC and content of 2:1-type clay minerals during evolution of tropical soils led to decreased pH buffering capacity. Incorporation of biochars generated from crop straws did not only ameliorate soil acidity, but also increased soil pH buffering capacity.7.
Lu Yu Xing Lu Yan He Philip C. Brookes Hong Liao Jianming Xu 《Journal of Soils and Sediments》2017,17(3):599-610
Purpose
Soil acidification is universal in soybean-growing fields. The aim of our research was to evaluate the effects of soil additives (N fertilizers and biochar) on crop performance and soil quality with specific emphasis on ameliorating soil acidity.Materials and methods
Four nitrogen treatments were applied as follows: no nitrogen (N0), urea (N1), potassium nitrate (N2), and ammonium sulfate (N3), each providing 30 kg N ha?1. Half plot area of the N1, N2, and N3 treatments was also treated with biochar (19.5 t ha?1) to form N-biochar treatments (N1C, N2C, N3C). Both bulk and rhizosphere soils were sampled separately for the following analyses: pH, exchangeable base cations (EBC), exchangeable acidity (EA), total inorganic N (IN), total N (TN), and microbial phospholipid fatty acids (PLFAs). Soybean biomass and nutrient contents were also determined. Correlation analysis was applied to analyze the relationships between soil chemical properties and soybean plant parameters.Results and discussion
With N-biochar additions (N1C, N2C, N3C), soil chemical properties changed as follows: pH increased by 0.6–1.2 units, EBC, IN, and TN increased by 175–419, 38.5–54.7, and 136–452 mg kg?1, respectively, and PLFAs increased by 23.6–40.9 nmol g?1 compared to the N0 in the rhizosphere. Microbial PLFAs had positive correlations with soil pH; EBC; exchangeable K, Ca, Na, and Mg; TN; IN; NH4 +; and NO3 ? (r?=?0.66–0.84, p?<?0.01). There were negative correlations between PLFAs and EA or exchangeable Al (r?=??0.64, ?0.66, p?<?0.01), which indicated that the additives increased microbial biomass by providing a suitable environment with less acid stress and more nutrients. The additives increased soil NH4 + and NO3 ? by promoting soil organic N mineralization and reducing NH4 + and NO3 ? leaching. Moreover, the soybean seed biomass and the nutrient contents in seeds increased with N-biochar additions, especially in the N3C treatment.Conclusions
N-biochar additions were effective in ameliorating soil acidity, which improved the microenvironment for more microbial survival. N-biochars influenced N transformations at the plant–soil interface by increasing organic N mineralization, reducing N leaching, and promoting N uptake by soybeans. The soil additive ammonium and biochar (N3C) were best in promoting soybean growth.8.
Mahtab Ahmad Sang Soo Lee Sung Eun Lee Mohammad I. Al-Wabel Daniel C. W. Tsang Yong Sik Ok 《Journal of Soils and Sediments》2017,17(3):717-730
Purpose
Remediation of metal contaminated soil with biochar is attracting extensive interest in recent years. Understanding the significance of variable biochar properties and soil types helps elucidating the meticulous roles of biochar in immobilizing/mobilizing metals/metalloids in contaminated soils.Materials and methods
Six biochars were produced from widely available agricultural wastes (i.e., soybean stover, peanut shells and pine needles) at two pyrolysis temperatures of 300 and 700 °C, respectively. The Pb-, Cu-, and Sb-contaminated shooting range soils and Pb-, Zn-, and As-contaminated agricultural soils were amended with the produced biochars. The mobility of metals/metalloids was assessed by the standard batch leaching test, principal component analysis and speciation modeling.Results and discussion
The changes in soil properties were correlated to feedstock types and pyrolysis temperatures of biochars based on the principal component analysis. Biochars produced at 300 °C were more efficient in decreasing Pb and Cu mobility (>93 %) in alkaline shooting range soil via surface complexation with carboxyl groups and Fe-/Al-minerals of biochars as well as metal-phosphates precipitation. By contrast, biochars produced at 700 °C outperformed their counterparts in decreasing Pb and Zn mobility (100 %) in acidic agricultural soil by metal-hydroxides precipitation due to biochar-induced pH increase. However, Sb and As mobility in both soils was unfavorably increased by biochar amendment, possibly due to the enhanced electrostatic repulsion and competition with phosphate.Conclusions
It is noteworthy that the application of biochars is not equally effective in immobilizing metals or mobilizing metalloids in different soils. We should apply biochar to multi-metal contaminated soil with great caution and tailor biochar production for achieving desired outcome and avoiding adverse impact on soil ecosystem.9.
Suresh Panta Richard Doyle Marcus Hardie Peter Lane Tim Flowers Gabriel Haros Sergey Shabala 《Journal of Soils and Sediments》2018,18(11):3290-3302
Purpose
The concept of irrigating crops with saline irrigation water is not new, but impacts of this practice on soil properties remain debatable, particularly the use of highly saline water. In this work, key soil chemical properties were assessed to a depth of 300 cm following 2.5 years of application of highly saline irrigation to a sodic texture-contrast soil (Brown Sodosol) in south-eastern Tasmania, Australia.Materials and methods
Control plots (rainfall only) were compared to irrigation treatments of low (0.8 dS/m) and high salinity (16 dS/m) waters at application rates of both 200 and 800 mm/year.Results and discussion
Whilst significant increases in both electrical conductivity and chloride concentration occurred throughout the soil profile in the high salinity treatment, these values were well below those of the irrigation water, indicating effective deep leaching. In the upper soil profile, 0–50 cm, of the high salinity treatments both the exchangeable Na+ and its ratio to total base cations (ESP) were significantly increased whilst the lower soil profile between 50 and 200 cm, was improved via both reduced alkalinity and sodicity. Leaching of the exchangeable base cations Ca2+, Mg2+ and K+ was significant in the upper soil profile (0–50 cm). As expected, the low salinity treatment (0.8 dS/m) had minimal impacts on soil chemical properties. The upper topsoil (0–10 cm) total organic carbon was significantly reduced in the high salinity plots and was negatively correlated with Cl? concentration.Conclusions
The data confirms the general concerns about application of saline irrigation, namely increased whole profile salinisation and upper soil profile (0–50 cm) sodicity, but they also show unexpected and desirable reductions in the lower soil profile (>?50 cm) alkalinity and sodicity. It appears the Na+ ions present in the saline waters led to differential leaching of base cations from the rooting zone, especially Ca2+ which then ameliorate the alkalinity and sodicity deeper in the soil profile (>?50 cm). Thus, surface application of gypsum may help sustain the application of highly saline waters; alternatively, subsurface irrigation above the sodic clayey subsoils could be trailed.10.
Kangyi Lou Anushka Upamali Rajapaksha Yong Sik Ok Scott X. Chang 《Journal of Soils and Sediments》2016,16(8):2081-2089
Purpose
Remediate metal contamination is a fundamental step prior to reclaim oil sands tailing ponds, and copper (Cu(II)) is the most abundant metal in the tailings water or oil sands process-affected water (OSPW). Biochars produced at four pyrolysis conditions were evaluated for sorption of Cu(II) in synthetic OSPW to explore different biochar potentials in removing Cu(II) from the contaminated water.Materials and methods
Pine sawdust biochars pyrolyzed at 300 and 550 °C with and without steam activation were investigated by batch sorption experiments. Isotherm and kinetic studies were conducted to compare the sorption capacities of the four biochars and to examine potential mechanisms involved.Results and discussion
For all the biochars, Langmuir and pseudo-second order models were the best-fit for isotherm and kinetic studies, respectively. According to the Langmuir parameters, the maximum adsorption capacities of the biochars produced at 550 °C were around 2.5 mg Cu(II)?g?1, which were 30-folds higher than those produced at 300 °C. However, steam activation did not cause any significant difference in the biochars’ sorption performance. The kinetic study suggested that chemisorption involving valence forces was the limiting factor of the sorption. In addition, ion exchange and precipitation were likely the primary mechanisms for Cu(II) sorption which outweigh complexation with functional groups on the biochars’ surface.Conclusions
Pine sawdust biochar produced at 550 °C without steam activation could be utilized as a sustainable and cost-effective material to remove Cu(II) from the OSPW.11.
Purpose
The combination of analytical chemistry and simulation methods provides more complete information about biochars.Materials and methods
The biochars prepared by pyrolysis of the crop straw at 300 and 500 °C were investigated by elemental analysis, pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and solid-state 13C nuclear magnetic resonance (NMR) spectrometry to build the 2D structural models of biochars. The most stable and balanced 3D conformations were gained by optimizing in the optimized potential for liquid simulation (OPLS) force field of molecular mechanic and molecular dynamic simulation of HyperChem® software.Results and discussion
There were few O-containing and N-containing compounds in biochars. According to the results of Py-GC-MS, 41 and 28 pyrolysis products were identified for the building of the conceptual models of 300 and 500 °C biochars. Solid-state 13C NMR data also demonstrated that there were very high values of unsaturated C in biochars. The agreement between elemental concentration and chemical functional groups of two simulated models and experimental biochars was successfully achieved. Quantitative structure activity relationship (QSAR) properties were calculated and indicated the correlation of molecular structures with properties such as surface area, volume, polarizability, refractivity, and hydration energy.Conclusions
The conceptual structural models of corn straw biochars produced at 300 and 500 °C were C78H68N2O25 and C59H29NO10, respectively. The simulation results showed that the 3D structure of the 300 °C biochar with ?4 charges and the nonprotonated 3D structure of the 500 °C biochar were the most stable. Deprotonation reaction is an endothermic process.12.
Hyuck Soo Kim Kwon-Rae Kim Seung-Heon Lee Anitha Kunhikrishnan Won-Il Kim Kye-Hoon Kim 《Journal of Soils and Sediments》2018,18(2):336-341
Purpose
A reclaimed tidal land along the shore has poor soil properties such as high exchangeable sodium percentage (ESP), and electrical conductivity (EC) due to excess sodium (Na) content. Therefore, Na content should be decreased to improve the land productivity, and for this, gypsum has been widely used. The objective of this study was to determine the changes in ESP and EC of the gypsum-treated reclaimed tidal soil in a field scale.Materials and methods
For this, gypsum was applied to Daeho reclaimed tidal land (500 ha) in Korea for 5 years (2006 to 2010). The Daeho reclaimed tidal land has been used as reclaimed paddy fields since 1993. The application rate of gypsum was calculated based on exchangeable calcium (Ca) contents and soil cation exchange capacity (CEC) to maintain 60 % exchangeable calcium percentage (ECP) of CEC in soil and the average amount treated was 1570 kg ha?1 year?1. The changes in ESP and EC were monitored from 2006 to 2010, and 2013.Results and discussion
The ESP dropped from 80 % in 2006 to 34 % in 2013. The EC of the soil was decreased by 73 %, from 11.5 dS m?1 in 2006 to 3.1 dS m?1 in 2013. Eventually, it was estimated that the ESP will be lowered below 15 % in 2023 with continuous treatment of gypsum according to ECP calculation, and EC will be declined to reach at 0.5 dS m?1 in 2035, the average EC level of Korean rice paddy.Conclusions
This field scale study evidenced that gypsum application effectively improves the soil properties of reclaimed tidal soil by decreasing ESP and EC.13.
Jiangpei Han Jiachun Shi Lingzao Zeng Jianming Xu Laosheng Wu 《Journal of Soils and Sediments》2017,17(2):471-480
Purpose
Sampling and analysis of greenhouse soils were conducted in Shouguang, China, to study continuous excessive fertilization effect on nitrifying microbial community dynamics in greenhouse environment.Materials and methods
Potential nitrification activity (PNA), abundance, and structure of nitrifying microbial communities as well as the correlations with soil properties were investigated.Results and discussion
Short-term excessive fertilization increased soil nutrient contents and the diversity of nitrifying microbial communities under greenhouse cultivation. However, the abundance and diversity of nitrifying communities decreased greatly due to the increase of soil acidity and salinity after 14 years of high fertilization in greenhouse. There was a significant positive correlation between soil PNA and the abundance of ammonia-oxidizing bacteria (AOB) but not that of ammonia-oxidizing archaea (AOA) in topsoil (0–20 cm) when pH ≥7. Soil PNA and AOB were strongly influenced by soil pH. The groups of Nitrososphaeraceae, Nitrosomonadaceae, and Nitrospiraceae were predominant in the AOA, AOB, and nitrite-oxidizing bacteria (NOB) communities, respectively. Nitrifying community structure was significantly correlated with soil electrical salinity (EC), organic carbon (OC), and nitrate nitrogen (NO3 ?–N) content by redundancy analysis (RDA).Conclusions
Nitrification was predominated by AOB in greenhouse topsoil with high fertilizer loads. Soil salinity, OC, NO3 ?–N content, and pH affected by continuous excessive fertilization were the major edaphic factors in shaping nitrifying community structure in greenhouse soils.14.
Ana Lorena Sanchez-Lizarraga Valeria Arenas-Montaño Erika Nahomy Marino-Marmolejo Luc Dendooven Jesus Bernardino Velazquez-Fernandez Gustavo Davila-Vazquez Jacobo Rodriguez-Campos Laura Hernández-Cuevas Silvia Maribel Contreras-Ramos 《Journal of Soils and Sediments》2018,18(11):3256-3270
Purpose
The aim of this research was to determine the vinasse irrigation effects on the arbuscular mycorrhizal fungi (AMF) population (total spore abundance (TSA), richness, relative abundance, and diversity indices) and soil parameters and nutrients at high doses. The irrigation of soil with vinasses derived from sugarcane, beet, or alcohol production is a common practice around the world. Little is known about how this affects the AMF community and soil nutrients.Materials and methods
The spider plant (Chlorophytum comosum, (Thunb.) Jacques), a mycorrhizable plant, was used to investigate the effect of 4 months of frequent vinasse irrigation (0, 25, 50, 75, and 100% vinasse concentration) on AMF and soil characteristics, e.g., electrical conductivity (EC), pH, mineral N, available P, Na+, K+, Ca2+, and Mg2+.Results and discussion
The vinasse irrigation decreased the TSA, AMF richness and diversity after 4 months, regardless of vinasse concentration. The vinasse irrigation did not acidify the soil, but the EC, mineral N and available P increased. The biomass of C. comosum decreased (77–81%) after vinasse irrigation for 4 months.Conclusions
Frequent irrigation with vinasse at concentrations ≥50% increases EC, K+, Na+, Mg2+, Ca2+ and available P in the soil, and decreases the amount of AMF spores, richness and diversity, which is not desirable in agricultural soils.15.
Sebastián Meier Gustavo Curaqueo Naser Khan Nanthi Bolan Joaquín Rilling Catalina Vidal Natalia Fernández Jacquelinne Acuña María-Eugenia González Pablo Cornejo Fernando Borie 《Journal of Soils and Sediments》2017,17(5):1237-1250
Purpose
Copper (Cu) contamination has been increasing in land ecosystems. Biochars (BCs) and arbuscular mycorrhizal fungi (AMF) are known to bind metals, and metallophyte can remove metals from soils. Will BC in combination with AMF contain the Cu uptake by a metallophyte growing in a metal-contaminated soil? The objective of this study was to investigate the effects of BCs on the Cu immobilization and over soil microbial communities in a metal-contaminated soil in the presence of AMF and metallophyte.Materials and methods
Two BCs were produced from chicken manure (CMB) and oat hull (OHB). A Cu-contaminated sandy soil (338 mg kg?1) was incubated with CMB and OHB (0, 1, and 5 % w/w) for 2 weeks. Metallophyte Oenothera picensis was grown in pots (500 mL) containing the incubated soils in a controlled greenhouse for 6 months. A number of analyses were conducted after the harvest. These include plant biomass weight, microbial basal respiration, and dehydrogenase activity (DHA), AMF root colonization, spore number, and glomalin production; changes in fungal and bacterial communities, Cu fractions in soil phases, and Cu uptake in plant tissues.Results and discussion
The BCs increased the soil pH, decreased easily exchangeable fraction of Cu, and increased organic matter and residual fraction of Cu. The BCs provided favorable habitat for microorganisms, thereby increasing basal respiration. The CMB increased DHA by ~62 and ~574 %, respectively, for the low and high doses. Similarly, the OHB increased soil microbial activity by ~68 and ~72 %, respectively, for the low and high doses. AMF root colonization, spore number, and total glomalin-related soil protein (GRSP) production increased by ~3, ~2, and ~3 times, respectively, in soils treated with 1 % OHB. Despite being a metalophyte, O. picensis could not uptake Cu efficiently. Root and shoot Cu concentrations decreased or changed insignificantly in most BC treatments.Conclusions
The results show that the BCs decreased bioavailable Cu, decreased Cu uptake by O. picensis, improved habitat for microorganisms, and enhanced plant growth in Cu-contaminated soil. This suggests that biochars may be utilized to remediate Cu-contaminated soils.16.
Sebastián Meier Gustavo Curaqueo Naser Khan Nanthi Bolan Mara Cea González María Eugenia Pablo Cornejo Yong Sik Ok Fernando Borie 《Journal of Soils and Sediments》2017,17(3):741-750
Purpose
Copper (Cu) contamination has been increasing in land ecosystems due to economic development activities. Excessive amount of Cu in soils is toxic to both plants and microorganisms. Biochar (BC) is known to immobilize soil Cu. The objectives of this research were to investigate the effects of chicken-manure-derived BC (CMB) on Cu immobilization, and growth of native metallophyte Oenothera picensis in a Cu-contaminated soil.Materials and methods
A Cu-contaminated sandy soil (338 mg Cu kg?1) was spiked and equilibrated with additional Cu (0, 100, and 500 mg Cu kg?1). The spiked soil was then amended with CMB (0, 5, and 10 % w/w) and incubated for 2 weeks. The metallophyte was grown on these treatments under greenhouse conditions for 3 months. Pore water solutions were collected from the plant pots every 30 days. After the harvest, soil and pore water pH, soil Cu fractions, pore water Cu concentration, soil microbial activity, plant biomass weight, and Cu concentration in plant parts were determined.Results and discussion
The CMB increased the pH of soils and soil pore water, and probably also soil major nutrients. It reduced the exchangeable fraction of Cu but increased its organic matter and residual fractions. At the same time, it decreased the Cu concentration in the soil pore water. The CMB increased basal respiration and dehydrogenase activity. The CMB application produced up to three and seven times more root and shoot biomass, respectively. In addition, shoots accumulated lesser Cu than control but roots did more. Plants survived in soil that was spiked with 500 mg Cu kg?1, only when CMB dose was 10 %.Conclusions
The CMB affected the Cu uptake in plant by altering the mobility, bioavailability, and spatial distribution of Cu in soils. The increase in available nutrients and decrease in Cu toxicity facilitated plant growth. The increased microbial activity probably also promoted the plant growth and reduced the Cu bioavailability. Therefore, CMB can be used to remediate Cu-contaminated soils.17.
Mirosław Kobierski Krystyna Kondratowicz-Maciejewska Magdalena Banach-Szott Piotr Wojewódzki José Matias Peñas Castejón 《Journal of Soils and Sediments》2018,18(8):2777-2789
Purpose
The paper describes rhizospheric (Rs) and non-rhizospheric (nRs) soil to demonstrate the zone of the plant root impact on physical and chemical properties of the soil. The effects of the process accompanying the transformations of organic matter into humic substances in the rhizosphere of “common dandelion” Taraxacum officinale have been determined, and the properties of humic acids (HAs) were described. The importance of iron and clay minerals for the formation of a stable and water-resistant soil structure has been emphasized.Materials and methods
The laboratory analysis involved determination of basic physical and chemical soil properties: texture, pH, cation exchange capacity (CEC), electrical conductivity, and content of total organic carbon (TOC) and dissolved organic carbon (DOC) and quality of humic substances: optical properties of HAs and its separation into hydrophilic (HIL) and hydrophobic (HOB) fractions, speciation of iron, glomalin operationally described as an easily extractable glomalin-related soil protein (EE-GRSP), and soil aggregate stability (SAS) of six size classes of soil aggregates.Results and discussion
The Rs was reported with a higher TOC and DOC content (measured in the CaCl2 extracts), however not significantly. The HAs isolated from Rs revealed a significantly higher content of humic substances at its initial decomposition stage, as compared with nRs. A significantly higher concentration of EE-GRSP was noted in the aggregates of the rhizospheric zone (mean 1.14 g kg?1) than in the aggregates collected from root-free soil (mean 0.94 g kg?1). There was noted the highest mean share of 1–3 mm soil aggregates in Rs as well as in nRs, respectively 44.4 and 38.3%. The soil material both in Rs and in nRs contained high amounts of exchangeable Ca2+, and smectite is the predominant clay mineral. It was favorable for the accumulation of organic carbon and for the formation of good soil physical condition (tilth). Higher but insignificant SAS values were observed for Rs (mean SAS?=?95.6%) than for nRs (mean SAS?=?93.9%).Conclusions
The studies confirm the role of common dandelion roots in the process of organic carbon accumulation in rhizospheric zone and a favorable effect on the mechanism of the formation of water-resistant aggregates. Higher values of SAS for the Rs were affected by the content of TOC, DOC, exchangeable Ca2+ and the concentration of EE-GRSP, and, less considerably, the content of Fe and clay minerals.18.
Bioavailability of Cd and Zn in soils treated with biochars derived from tobacco stalk and dead pigs
Xing Yang Kouping Lu Kim McGrouther Lei Che Guotao Hu Qiuyue Wang Xingyuan Liu Leilei Shen Huagang Huang Zhengqian Ye Hailong Wang 《Journal of Soils and Sediments》2017,17(3):751-762
Purpose
Previous studies show that application of biochar can reduce the bioavailability of heavy metals in soil. A plant growth experiment was carried out to evaluate the effect of tobacco stalk- and dead pig-derived biochars on the extractability and redistribution of cadmium (Cd) and zinc (Zn) in contaminated soil, and the impact on tobacco (Nicotiana tabacum L.) plant growth.Materials and methods
The top 20 cm of a soil contaminated with Cd and Zn was used in this study. Biochars derived from tobacco stalk and dead pig were applied to the soil at four application rates (0, 1, 2.5, and 5 %), and tobacco plants were grown. After 80-days growth, the pH, electrical conductivity (EC), CaCl2-extractable heavy metals and fractions of heavy metals in soil samples, as well as the plant biomass and the concentrations of heavy metals in the plant were determined.Results and discussion
The plant growth experiment demonstrated that tobacco stalk biochar and dead pig biochar significantly (P?<?0.05) increased the pH, but had no significant effect on the electrical conductivity (EC) of the soil. The CaCl2-extractable Cd and Zn content decreased as the application rates increased. The concentration of extractable Cd and Zn decreased by 64.2 and 94.9 %, respectively, for the tobacco stalk biochar treatment, and 45.8 and 61.8 %, respectively, for the dead pig biochar treatment at 5 % application rate. After biochar addition, the exchangeable Cd was mainly transformed to fractions bound to carbonates and Fe-Mn oxides, while the Zn was immobilized mainly in the fraction bound to Fe-Mn oxides. Tobacco stalk biochar increased the tobacco plant biomass by 30.3 and 36.2 % for shoot and root, respectively at the 5 % application rate. Dead pig biochar increased the tobacco plant biomass by 43.5 and 40.9 % for shoot and root, respectively, at the 2.5 % application rate. Both biochars significantly (P?<?0.05) decreased the Cd and Zn accumulation by tobacco plant.Conclusions
As a soil amendment, tobacco stalk biochar was more effective at removing Cd, whereas dead pig biochar was more effective at removing Zn, and a higher application rate was more effective than a lower application rate. Overall, biochar derived from tobacco stalk was more effective, than dead pig biochar, at remediating soil contaminated with Cd and Zn, as well as promoting tobacco growth.19.
Tingru Chen Xiaoyan Liu Xinying Zhang Yunyun Hou Xiao Chen Kaiyun Tao 《Journal of Soils and Sediments》2016,16(8):2090-2096
Purpose
This study aimed to evaluate the effect of combination of alkyl polyglucoside (APG) and nitrilotriacetic acid (NTA) on improving the efficiency of phytoremediation for pyrene and lead (Pb) co-contaminated soil by Scirpus triqueter.Materials and methods
Seedlings of S. triqueter with a similar size and biomass (3 g/pot) were grown on 2-month aged soil contaminated with 184.5 mg kg?1of pyrene and 454.3 mg kg?1 of Pb at pH?=?8.3. After growth for 10 days, different doses of APG and NTA were added into the soil. After 60 days, the height of plants, Pb concentrations in plants, and pyrene amounts in soil were determined.Results and discussion
Combined application of NTA and APG with lower dosage (1 + 1 g kg?1 soil and 1 + 2 g kg?1 soil) had no notable negative influence on the growth of S. triqueter. Moreover, significant synergy on Pb accumulation in S. triqueter was achieved with APG and NTA combined application. Besides, the dissipation of pyrene from soil after 60-day planting was increased in APG and NTA treatments when compared with the control treatments. Application of APG alone or combined with NTA had greater effect on enhancing dissipation of pyrene from soil than NTA alone.Conclusions
This study demonstrated that the remediation of Pb and pyrene co-contaminated soil by S. triqueter can be enhanced by combined application of APG and NTA. Long-term evaluation of this strategy is needed in co-contaminated field sites.20.
Dina G. Nevidomskaya Tatiana M. Minkina Alexander V. Soldatov Victoria A. Shuvaeva Yan V. Zubavichus Yulia S. Podkovyrina 《Journal of Soils and Sediments》2016,16(4):1183-1192