共查询到20条相似文献，搜索用时 46 毫秒
1.
Xinqiang Liang Yi Jin Yue Zhao Zhibo Wang Rongqiang Yin Guangming Tian 《Journal of Soils and Sediments》2016,16(3):842-853
Purpose
Colloid-facilitated migration of phosphorus (P) is a widely accepted phenomenon in surface and subsurface environment. Release and migration of colloidal P (Pcoll) in agricultural fields are closely related to P fertilization regimes. In this study, a site-specific experiment with rice/oilseed rape rotation was conducted to determine the export potential of Pcoll from the field and literatures reporting the impact of P fertilization regimes on release and migration of Pcoll in other agricultural fields were compared.Materials and methods
In this 2-year field experiment, four P fertilization regimes (no fertilizer control, inorganic P fertilizer of low and high rates, and swine manure treatment) with three replicates were conducted. Floodwater and runoff samples were collected in flooding season and the 100-cm-depth soil samples were collected after both crops’ harvest seasons. Colloidal particles were separated by microfiltration and ultracentrifugation processes and determined gravimetrically. The Pcoll value was calculated as the difference between the concentration of total P in non-ultracentrifuged and ultracentrifuged samples. The same method was applied for the colloidal mineral elements (Fe and Al) and organic carbon.Results and discussion
Total P concentration in paddy floodwater significantly increased after fertilization but decreased quickly in the following days, maintaining at 6.0 mg m?2. In soil extracts, concentration of Pcoll was low but stable, which ranged from 6 to 22 % of total P after oilseed rape season and from 7 to 18 % after rice season. In runoff samples, there were positive correlations between Pcoll, colloidal Fe (Fecoll), colloidal Al (Alcoll), and colloidal TOC (TOCcoll); the majority of P forms was molybdate reactive P. In both crops’ seasons, the amount of colloids increased with soil depth. Content of soil Pcoll was low and occupied 0.1–2 % of total P. The literature review showed that Pcoll in soil solution, runoff, and leachate ranged from 1.4 to 94 % of total P.Conclusions
These results suggested that although the concentrations of Pcoll were not high, they widely distributed in paddy floodwater, runoff, and soil profile. Fertilization regimes and planting systems had a significant influence on the contents of Pcoll. Moreover, the Pcoll binding with Fe/Al minerals and organic carbon might be an alternative route of P loss in paddy field.2.
Influence of pH on the redox chemistry of metal (hydr)oxides and organic matter in paddy soils 总被引：1，自引：0，他引：1
Yunyu Pan Gerwin F. Koopmans Luc T. C. Bonten Jing Song Yongming Luo Erwin J. M. Temminghoff Rob N. J. Comans 《Journal of Soils and Sediments》2014,14(10):1713-1726
Purpose
The primary purpose of this study was to determine how flooding and draining cycles affect the redox chemistry of metal (hydr)oxides and organic matter in paddy soils and how the pH influences these processes. Our secondary purpose was to determine to what extent a geochemical thermodynamic equilibrium model can be used to predict the solubility of Mn and Fe during flooding and draining cycles in paddy soils.Material and methods
We performed a carefully designed column experiment with two paddy soils with similar soil properties but contrasting pH. We monitored the redox potential (Eh) continuously and took soil solution samples regularly at four depths along the soil profile during two successive flooding and drainage cycles. To determine dominant mineral phases of Mn and Fe under equilibrium conditions, stability diagrams of Mn and Fe were constructed as a function of Eh and pH. Geochemical equilibrium model calculations were performed to identify Mn and Fe solubility-controlling minerals and to compare predicted total dissolved concentrations with their measured values.Results and discussion
Flooding led to strong Eh gradients in the columns of both soils. In the acidic soil, pH increased with decreasing Eh and vice versa, whereas pH in the alkaline soil was buffered by CaCO3. In the acidic soil, Mn and Fe solubility increased during flooding due to reductive dissolution of their (hydr)oxides and decreased during drainage because of re-oxidation. In the alkaline soil, Mn and Fe solubility did not increase during flooding due to Mn(II) and Fe(II) precipitation as MnCO3, FeCO3, and FeS. The predicted levels of soluble Mn and Fe in the acidic soil were much higher than their measured values, but predictions and measurements were rather similar in the alkaline soil. This difference is likely due to kinetically limited reductive dissolution of Mn and Fe (hydr)oxides in the acidic soil. During flooding, the solubility of dissolved organic matter increased in both soils, probably because of reductive dissolution of Fe (hydr)oxides and the observed increase in pH.Conclusions
Under alternating flooding and draining conditions, the pH greatly affected Mn and Fe solubility via influencing either reductive dissolution or carbonate formation. Comparison between measurements and geochemical equilibrium model predictions revealed that reductive dissolution of Mn and Fe (hydr)oxides was kinetically limited in the acidic soil. Therefore, when applying such models to systems with changing redox conditions, such rate-limiting reactions should be parameterized and implemented to enable more accurate predictions of Mn and Fe solubility. 相似文献3.
Kongcao Xiao Lu Yu Jianming Xu Philip C. Brookes 《Journal of Soils and Sediments》2014,14(9):1513-1525
Purpose
Initial soil pH determines the direction and magnitude of pH change after residue addition. This study aimed to evaluate the relative importance of initial soil pH and rate of residue application in determining subsequent pH change, nitrogen (N) mineralization, and soil-exchangeable aluminum (Al).Materials and methods
An incubation experiment was conducted for 102 days on a Plinthudult soil and a Paleudalf soil, where pH gradients were produced after application of direct current (DC). Rates of vetch applications were 0, 5, 15, 30, and 50 g kg?1 soil.Results and discussion
Increasing rates of vetch application caused greater increases in soil pH, but no consistent increase in soil pH at higher initial pH range (4.40～6.74), because of nitrification. There was a positive correlation between alkalinity production and the initial soil pH at day 14, while correlations became negative at days 56 and 102. Mineral N accumulated as NH4 +–N in low pH soils, due to limited nitrification, while NO3 ?–N dominated in higher pH soils. Application of vetch decreased KCl-extractable Al, probably because of complexation of Al by organic matter and precipitation of Al as a result of increased pH, reductions in Al concentration increased with increasing rates of vetch application. However, this amelioration effect on Al concentration weakened with time in higher pH soils.Conclusions
Application of vetch residue can significantly increase soil pH and concentrations of mineral N and reduce exchangeable Al. These amelioration effects are enhanced with increased rate of vetch addition and vary with time depending on the initial pH of the soil. 相似文献4.
María Nazaret González-Alcaraz José álvarez-Rogel Antonio María-Cervantes Consuelo Egea Héctor Miguel Conesa 《Journal of Soils and Sediments》2012,12(9):1316-1326
Purpose
The aim of this study was to evaluate the behaviour of P in saline Spolic Technosols flooded with eutrophic water, with and without plant rhizosphere, in order to assess the role of these soils as sinks or sources of this nutrient.Materials and methods
Samples were taken from basic (pH?~7.8), carbonated and acidic (pH?~6.2), de-carbonated soils of salt marshes polluted by mine wastes. Three treatments were assayed: pots with Sarcocornia fruticosa, pots with Phragmites australis and pots without plants (bare soil). The pots were flooded for 15?weeks with eutrophic water (PO 4 3? ~6.92?mg?L?1) and pH, Eh and water-soluble organic carbon and PO 4 3? concentrations were monitored in the soil solution. A soil P fractionation was applied before and after the flooding period.Results and discussion
The PO 4 3? concentration in the soil solution decreased rapidly in both soils, with and without plant, being diminished by 80?C90?% after 3?h of flooding. The Fe/Mn/Al oxides and the Ca/Mg compounds played an important role in soil P retention. In pots with S. fruticosa, the reductive conditions due to flooding induced P release from metal oxides and P retention to Ca/Mg compounds. In turn, P. australis may have favoured the release of P from carbonates, which was transferred to Fe/Mn/Al compounds.Conclusions
The retention of P by the soil was the main mechanism involved in the removal of PO 4 3? from the eutrophic flooding water but to evaluate the capacity of these systems as long-term P sinks, the combined effect of metals, Ca/Mg compounds and specific plant species should be considered. 相似文献5.
pH change, carbon and nitrogen mineralization in paddy soils as affected by Chinese milk vetch addition and soil water regime 总被引：1，自引：0，他引：1
Yunfeng Wang Xingmei Liu Clayton Butterly Caixian Tang Jianming Xu 《Journal of Soils and Sediments》2013,13(4):654-663
Purpose
The aim of the research was to explore the effect of Chinese milk vetch (CM vetch) addition and different water management practices on soil pH change, C and N mineralization in acid paddy soils.Materials and methods
Psammaquent and Plinthudult paddy soils amended with Chinese milk vetch at a rate of 12 g?kg?1 soil were incubated at 25 °C under three different water treatments (45 % field capacity, CW; alternating 1-week wetting and 2-week drying cycles, drying rewetting (DRW) and waterlogging (WL). Soil pH, dissolved organic carbon, dissolved organic nitrogen (DON), CO2 escaped, microbial biomass carbon, ammonium (NH4 +) and nitrate (NO3 ?) during the incubation period were dynamically determined.Results and discussion
The addition of CM vetch increased soil microbial biomass concentrations in all treatments. The CM vetch addition also enhanced dissolved organic N concentrations in all treatments. The NO3–N concentrations were lower than NH4–N concentrations in DRW and WL. The pH increase after CM vetch addition was 0.2 units greater during WL than DRW, and greater in the low pH Plinthudult (4.59) than higher pH Paleudalfs (6.11) soil. Nitrogen mineralization was higher in the DRW than WL treatment, and frequent DRW cycles favored N mineralization in the Plinthudult soil.Conclusions
The addition of CM vetch increased soil pH, both under waterlogging and alternating wet–dry conditions. Waterlogging decreased C mineralization in both soils amended with CM vetch. Nitrogen mineralization increased in the soils subjected to DRW, which was associated with the higher DON concentrations in DRW than in WL in the acid soil. Frequent drying–wetting cycles increase N mineralization in acid paddy soils. 相似文献6.
Fatima Rukshana Clayton R. Butterly Jian-Ming Xu Jeff A. Baldock Caixian Tang 《Journal of Soils and Sediments》2014,14(2):407-414
Purpose
This study aimed to investigate the effect of initial soil pH and organic anion-to-acid ratio on changes in soil pH.Materials and methods
Two soils (Podosol and Tenosol) along with two carboxylic acids (malic and citric acid) and their anions (sodium malate and citrate), commonly found in plant residues, were used in this study. Stock solutions of either malic acid and disodium malate or citric acid and trisodium citrate were added to pre-incubated soils at anion-to-acid ratios of 0:100, 10:90, 25:75, 50:50, 75:25, 90:10, 100:0 and at 0.25 g C kg?1 soil. Soils were adjusted to 80 % field capacity and mixed thoroughly, and three replicates of 50 g of each soil were transferred into individual plastic cores and incubated at 25 °C in the dark for 30 days. Soil pH, respiration, NH4 +, and NO3 ? were determined.Results and discussion
Soil pH increased linearly with increasing organic anion-to-acid ratio. The addition of organic anions to soil resulted in net alkalinisation. However, the addition of organic acids immediately decreased soil pH. During subsequent incubation, soil pH increased when the organic anions were decomposed. Alkalinity generation was lower in the Podosol (initial pH 4.5) than in the Tenosol (initial pH 6.2), and was proportional to anion-to-acid ratio across all the treatments. Cumulative CO2-C release was approximately three times lower in the Podosol than the Tenosol at day 2 due to lower microbial activity in the low-pH Podosol.Conclusions
Increasing anion-to-acid ratio of organic compounds increased soil pH. Increases in soil pH were mainly attributed to direct chemical reactions and decomposition of organic anions. Low pH decreased the amount of alkalinity generated by addition of organic compounds due to incomplete decomposition of the added compounds. This study implies that organic anion-to-acid ratio in plant residues plays an important role in soil pH change. 相似文献7.
Ana Romero-Freire Manuel Sierra-Aragón Irene Ortiz-Bernad Francisco J. Martín-Peinado 《Journal of Soils and Sediments》2014,14(5):968-979
Purpose
The present work evaluates the influence of different soil properties and constituents on As solubility in laboratory-contaminated soils, with the aim of assessing the toxicity of this element from the use of bioassays to evaluate the soil leachate toxicity and thereby propose soil guideline values for studies of environmental risk assessment in soil contamination.Materials and methods
Seven soils with contrasting properties were artificially contaminated in laboratory with increasing concentrations of As. Samples were incubated for 4 weeks, and afterwards, soil solution (1:1) was obtained after shaking for 24 h. The soil leachate toxicity was assessed with two commonly used bioassays (seed germination test with Lactuca sativa and Microtox ® test with Vibrio fischeri).Results and discussion
The relationship between soluble As and soil properties indicated that iron oxides and organic matter content were the variables most closely related to the reduction of the As solubility, while pH and CaCO3 increased As solubility in the soil solutions. Toxicity bioassays showed significant differences between soils depending on their properties, with a reduction of the toxicity in the iron-rich soil (no observed effect concentration (NOEC)?=?150 mg kg?1) and a significant increase in the highly carbonate samples (NOEC between 15 and 25 mg kg?1).Conclusions
Soil guideline values for regulatory purposes usually set a single value for large areas (regions or countries) which can produce over- or underestimation of efforts in soil remediation actions. These values should consider different levels according to the main soil properties controlling arsenic mobility and the soil leachate toxicity. 相似文献8.
土壤胶体因具有较大的比表面积及较强的吸附与迁移能力，其所携带的磷（胶体磷）已成为农田磷流失过程中的重要形态。为评估不同有机替代方式下稻田土壤胶体磷（Pcoll）的活性和流失潜力，本文依托两种有机肥部分替代化肥（控氮控磷与控氮不控磷）方式下稻麦轮作长期定位试验，探讨了Pcoll含量变化、流失风险及其与不同土壤活性磷组分之间的关系。控氮控磷试验（4 a）设有3个处理：不施磷肥（CK）、单施化肥（CF）、猪粪有机肥替代30%化学磷肥（OF）；控氮不控磷试验（24 a）设有3个处理：不施肥（CK）、单施化肥（CF）、猪粪有机肥替代40%化学氮肥（OF）。结果表明：在控氮控磷条件下，有机替代处理较单施化肥处理，土壤有机碳（SOC）、Pcoll含量及其流失潜力（LPP）均无显著性差异，胶体钼蓝反应磷占比（RMRP，MRPcoll/Pcoll）显著降低1.76%（P < 0.05）。在控氮不控磷条件下，有机替代处理的土壤Pcoll和SOC含量分别为13.08 mg/kg和20.19 g/kg，显著高于单施化肥78%和212.6%（P < 0.05）；较单施化肥，土壤LPP和RMRP分别显著升高了1.89%和16.05%（P < 0.05）。两种有机替代方式下土壤Pcoll与土壤全磷（TP）、真溶解态磷（TSP）、Olsen-P、CaCl2-P等均呈极显著正相关（P < 0.01）；与土壤有机碳（SOC）在控氮不控磷条件下呈极显著正相关（P < 0.01），在控氮控磷条件下无显著相关性。以上结果表明，较控氮控磷有机替代方式，长期仅控氮的有机肥施用显著增加了土壤有机碳、胶体磷和不同活性磷组分含量，磷流失风险升高。因此，有机肥部分替代化肥养分等量控制是改善农田磷流失可行的施肥方式。 相似文献
9.
The objective of this study was to investigate possible ways of mobilizing residual fertilizer P as a result of local pH elevation caused by urea hydrolysis. The response of water-soluble P (Pw) and dissolved organic C (DOC) to urea hydrolysis was monitored in three cultivated soils and at two P levels for up to 127–135 d and compared with corresponding changes in soils limed with Ca(OH)2. Hydrolysis of urea was complete in 8–15d during which soil pH increased by 1–1.5 units at the maximum. Subsequently, the pH decreased to or below the original level owing to nitrification. Mobilization of soil P was enhanced substantially in parallel with the increase in pH, the peak Pw occurring simultaneously with the highest pH value. In all urea-treated soils, Pw remained at an elevated level for at least 60d. As compared to urea, elevation of soil pH with Ca(OH)2 had only a minor and inconsistent influence on Pw. In mobilization of soil P, the urea-induced increase in pH and a simultaneous production of NH4+ ions proved to be superior to liming with Ca(OH)2. It was hypothesized that when an acid soil is amended with urea, phosphate is first displaced by OH? ions, resulting in elevated solution P concentrations. A simultaneous dissolution of organic matter contributes to the persistence of high P concentration by competition for sorption sites on Fe and Al oxides, and thus retards the resorption of P. 相似文献
10.
The bioaccumulation of Cd in rice grains in paddy soils as affected and predicted by soil properties 总被引：2，自引：0，他引：2
Xinxin Ye Hongying Li Yibing Ma Liang Wu Bo Sun 《Journal of Soils and Sediments》2014,14(8):1407-1416
Purpose
The area of cadmium (Cd)-contaminated soil in China is increasing due to the rapid development of the Chinese economy. To ensure that the rice produced in China meets current food safety and quality standards, the current soil quality standards for paddy soils urgently need to be updated.Materials and methods
We conducted a pot experiment with 19 representative paddy soils from different parts of China to study the effects of soil properties on bioaccumulation of Cd in rice grains. The experiment included a control, a low treatment concentration (0.3 mg kg–1 for pH?<?6.5 and 0.6 mg kg–1 for pH?≥?6.5), and a high treatment concentration (0.6 mg kg–1 for pH?<?6.5 and 1.2 mg kg–1 for pH?≥?6.5) of Cd salt added to soils.Results and discussion
The results showed that the Cd content in grains of the control and low and high Cd treatments ranged from 0.021 to 0.14, 0.07 to 0.27, and 0.12 to 0.33 mg kg–1, respectively. Stepwise multiple regression analysis indicated that soil pH and organic carbon (OC) content could explain over 60 % of the variance in the (log-transformed) bioaccumulation coefficient (BCF) of Cd in grains across soils. Aggregated boosted trees analysis showed that soil pH and OC were the main factors controlling Cd bioavailability in paddy soils. Validation of the models against data from recent literature indicated that they were able to accurately predict the BCF in paddy soils.Conclusions
These quantitative relationships between the BCF of Cd in grains and soil properties are helpful for developing soil-specific guidance on Cd safety threshold value for paddy soils. 相似文献11.
Nitrification and acidification from urea application in red soil (Ferralic Cambisol) after different long-term fertilization treatments 总被引：1，自引：1，他引：0
Zejiang Cai Boren Wang Minggang Xu Huimin Zhang Lu Zhang Suduan Gao 《Journal of Soils and Sediments》2014,14(9):1526-1536
Purpose
Long-term manure applications can prevent or reverse soil acidification by chemical nitrogen (N) fertilizer. However, the resistance to re-acidification from further chemical fertilization is unknown. The aim of this study was to examine the effect of urea application on nitrification and acidification processes in an acid red soil (Ferralic Cambisol) after long-term different field fertilization treatments.Materials and methods
Soils were collected from six treatments of a 19-year field trial: (1) non-fertilization control, (2) chemical phosphorus and potassium (PK), (3) chemical N only (N), (4) chemical N, P, and K (NPK), (5) pig manure only (M), and (6) NPK plus M (NPKM; 70 % N from M). In a 35-day laboratory incubation experiment, the soils were incubated and examined for changes in pH, NH4 +, and NO3 ?, and their correlations from urea application at 80 mg N kg?1(?80) compared to 0 rate (?0).Results and discussion
From urea addition, manure-treated soils exhibited the highest acidification and nitrification rates due to high soil pH (5.75–6.38) and the lowest in the chemical N treated soils due to low soil pH (3.83–3.90) with no N-treated soils (pH 4.98–5.12) fell between. By day 35, soil pH decreased to 5.21 and 5.81 (0.54 and 0.57 unit decrease) in the NPKM-80 and M-80 treatments, respectively, and to 4.69 and 4.53 (0.43 and 0.45 unit decrease) in the control-80 and PK-80 treatments, respectively, with no changes in the N-80 and NPK-80 treatments. The soil pH decrease was highly correlated with nitrification potential, and the estimated net proton released. The maximum nitrification rates (K max) of NPKM and M soils (14.7 and 21.6 mg N kg?1 day?1, respectively) were significantly higher than other treatments (2.86–3.48 mg N kg?1 day?1). The priming effect on mineralization of organic N was high in manure treated soils.Conclusions
Field data have shown clearly that manure amendment can prevent or reverse the acidification of the red soil. When a chemical fertilizer such as urea is applied to the soil again, however, soil acidification will occur at possibly high rates. Thus, the strategy in soil N management is continuous incorporation of manure to prevent acidification to maintain soil productivity. Further studies under field conditions are needed to provide more accurate assessments on acidification rate from chemical N fertilizer applications. 相似文献12.
Phosphorus (P) forms were sequentially extracted from peat derived soils (Eutric Histosols and Gleysols) at eight sites in Saxony‐Anhalt (Germany) to disclose general differences in P pools between mineral and organic soils and to investigate effects of peat humification and oxidation in conjunction with land use and soil management on the P status of soils. Overall 29 samples providing a wide variety of basic chemical properties were subjected to the Hedley fractionation. The Histosol topsoils contained more total P (Pt) (1345 ± 666 mg kg—1) than the Gleysol topsoils (648 ± 237 mg kg—1). The predominant extractable fractions were H2SO4‐P (36—63 % of Pt) in calcareous and NaOH‐Po (0—46 % of Pt) in non‐calcareous Histosols. These soils had large pools of residual P (13—93 % of Pt). Larger contents and proportions of Po and of labile P fractions generally distinguished organic from mineral soils. Regression analyses indicated that poorly crystalline pedogenic oxides and organic matter were binding partners for extractable and non‐extractable P. Intensive management that promotes peat humification and oxidation results in disproportional enrichments of labile P fractions (resin‐P, NaHCO3‐Pi, and NaHCO3‐Po). These changes in P chemistry must be considered for a sustainable management of landscapes with Histosols and associated peat derived soils. 相似文献
13.
Inês Rocha Edgar Pinto Isabel M. P. L. V. O. Ferreira Manuela V. da Silva Rui S. Oliveira 《Journal of Soils and Sediments》2014,14(4):829-834
Purpose
Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds commonly found as soil contaminants. Fungal degradation is considered as an environmentally friendly and cost-effective approach to remove PAHs from soil. Acenaphthylene (Ace) and Benzo[a]anthracene (BaA) are two PAHs that can coexist in soils; however, the influence of the presence of each other on their biodegradation has not been studied. The biodegradation of Ace and BaA, alone and in mixtures, by the white rot fungus Pleurotus ostreatus was studied in a sandy soil.Materials and methods
Experimental microcosms containing soil spiked with different concentrations of Ace and BaA were inoculated with P. ostreatus. Initial (t 0) and final (after 15 days of incubation) soil concentrations of Ace and BaA were determined after extraction of the PAHs.Results and discussion
P. ostreatus was able to degrade 57.7% of the Ace in soil spiked at 30 mg kg?1 dry soil and 65.8% of Ace in soil spiked at 60 mg kg?1 dry soil. The degradation efficiency of BaA by P. ostreatus was 86.7 and 77.4% in soil spiked with Ace at 30 and 60 mg kg?1 dry soil, respectively. After 15 days of incubation, there were no significant differences in Ace concentration between soil spiked with Ace and soil spiked with Ace + BaA, irrespective of the initial soil concentration of both PAHs. There were also no differences in BaA concentration between soil spiked with BaA and soil spiked with BaA + Ace.Conclusions
The results indicate that the fungal degradation of Ace and BaA was not influenced by the presence of each other’s PAH in sandy soil. Bioremediation of soils contaminated with Ace and BaA using P. ostreatus is a promising approach to eliminate these PAHs from the environment. 相似文献14.
Phosphate (PO4-P) sorption characteristics of soils and bedrock composition were determined in catchments of two mountain lakes, Ple?né Lake (PL) and ?ertovo Lake (CT), situated in the Bohemian Forest (Czech Republic). The aim was to explain higher terrestrial P export to mesotrophic PL compared to oligotrophic CT. Concentrations of Al and Fe oxides were the dominant parameters affecting soil ability to adsorb PO4-P. Depending on concentrations of Al and Fe oxides, P sorption maxima varied from 9.7 to 70.5 mmol kg?1 and from 7.4 to 121 mmol kg?1 in organic and mineral soil horizons, respectively. The catchment weighted mean PO4-P sorption capacity was 3.4 mol m?2 and 11.9 mol m?2 in the PL and CT soils, respectively. The higher PO4-P sorption capacity in the CT catchment was predominantly associated with higher pools of soil and Fe oxides. The CT bedrock (mica schist) released one order of magnitude less P than the PL bedrock (granite) within a pH range of catchment soils (pHCaCl2 of 2.5–4.5). The higher ability of PL bedrock to release P and the lower ability of PL soils to adsorb PO4-P thus contributed to the higher terrestrial P loading of this lake. 相似文献
15.
Aimé J. Messiga Yuxin Ba Noura Ziadi Gilles Bélanger Jean Lafond 《Archives of Agronomy and Soil Science》2013,59(10):1445-1458
We analyzed in soils with contrasting cultivation histories the depletion of P following sequential extractions with soil testing solutions. Soil samples were collected in three experiments in eastern Canada (L’Acadie, Lévis, and Normandin) and P was sequentially extracted 16 times, once daily, using Mehlich-3 (M3) or Olsen (Ol) solution. The cumulative amount of P extracted was 252 mg PM3 kg?1 and 77 mg kg?1 POl for L’Acadie, 212 mg PM3 kg?1 and 66 mg POl kg?1 for Lévis, and 424 mg PM3 kg?1 and 83 mg POl kg?1 for Normandin. The depletion of P was described by a logarithmic function (Y = a ln (N) + b) for PM3, and a power function (Y = αNβ) for POl. The inorganic P pool decreased in the three soils. The organic P pool did not decrease possibly because soil testing solutions did not directly extract P from this pool. This study demonstrated that laboratory soil testing analysis using M3 or Ol solution principally target P from the inorganic pool, suggesting that P fertilizer recommendations to mineral soils relying on these methods do not account for the potential of the organic P pool to contribute to soil P availability. 相似文献
16.
Purpose
Little information is currently available regarding the influence of different root exudate components (RECs) on the availability of persistent organic pollutants in the soil environment. In this study, we investigated the impacts of different RECs including organic acids, amino acids, and fructose on the availability of pyrene as a representative polycyclic aromatic hydrocarbon (PAH) in soils.Materials and methods
Citric acid, oxalic acid, malic acid, serine, alanine, and fructose were used in the experiments as representative RECs. Pyrene-spiked soils (TypicPaleudalfs) with present RECs were incubated for 30 days, and the available fraction of pyrene was determined using n-butanol extraction procedure.Results and discussion
The amount of n-butanol-extractable pyrene in soil increased with the addition of tested RECs and increased when REC concentrations are enhanced within the range of 0–21 g kg?1. The extractability of pyrene in soil with REC treatments and the enhancement ratio (r, %) of the extractable pyrene in soil by the addition of RECs after a 30-day incubation decreased in the following order: organic acids (oxalic acid ≥ citric acid > malic acid) > amino acid (alanine > serine) > fructose. This decrease was observed irrespective of soil sterilization, although the concentrations of extractable pyrene were lower in non-sterilized soils compared to sterilized soils. The concentrations of metal cations and dissolved organic matter (DOM) in solution increased when organic acids were added.Conclusions
The tested RECs at concentrations of 0–21 g kg?1 clearly enhanced the availability of pyrene in soils, and larger amounts of RECs resulted in higher pyrene availabilities in the tested soils. Microbial biodegradation diminished the amount of available pyrene irrespective of the presence of RECs. The mechanism of REC-influenced availability of pyrene in soil may be related to the metal dissolution and release of DOM from soil solids. The results of this study will be useful in assessing PAH-related risks to human health and the environment and will be instructive in food safety and remediation strategies at contaminated sites. 相似文献17.
Impact of organic matter addition on pH change of paddy soils 总被引：1，自引：1，他引：0
Yunfeng Wang Caixian Tang Jianjun Wu Xingmei Liu Jianming Xu 《Journal of Soils and Sediments》2013,13(1):12-23
Purpose
The objective of the present study was to explore the effect of initial pH on the decomposition rate of plant residues and the effect of residue type on soil pH change in three different paddy soils.Materials and methods
Two variable charge paddy soils (Psammaquent soil and Plinthudult soil) and one constant charge paddy soil (Paleudalfs soil) were used to be incubated at 45 % of field capacity for 105 days at 25 °C in the dark after three plant residues (Chinese milk vetch, wheat straw, and rice straw) were separately added at a level of 12 g?kg?1 soil. Soil pH, CO2 escaped, DOC, DON, MBC, MBN, NH 4 + , and NO 3 ? during the incubation period were dynamically determined.Results and discussion
Addition of the residues increased soil pH by 0.1–0.8 U, and pH reached a maximum in the Psammaquent and Plinthudult soils with low initial pH at day 105 but at day 3 in the Paleudalfs soil with high initial pH. Incorporation of Chinese milk vetch which had higher concentration of alkalinity (excess cations) and nitrogen increased soil pH more as compared with incorporation of rice and wheat straws. Microbial activity was the highest in Chinese milk vetch treatment, which resulted in the highest increase of soil pH as compared with addition of rice and wheat straws. However, nitrification seemed to be inhibited in the variable charge soils of Psammaquent and Plinthudult but not in the constant charge soil of Paleudalfs.Conclusions
The effectiveness of increasing soil pH after incorporation of the plant materials would be longer in low initial pH soils of Psammaquent and Plinthudult than in high initial pH soil of Paleudalfs. In order to achieve the same degree of pH improvement, higher amounts of plant residues should be applied in constant charge soils than in variable charge soils. 相似文献18.
Purpose
Heavy metal content in soils could be a consequence of geogenic and different anthropogenic sources. In ancient times, soils in the Mediterranean region were affected by agriculture and viticulture, whereas more recently, industry and traffic might contribute more to their pollution. The aim of the study is to determine the extent of multisource heavy metal pollution in soils within the Koper area.Materials and methods
Along the northern Adriatic Sea coast, around the port city of Koper/Capodistria, 24 topsoil samples were collected; sets of six samples representing four possible pollution sources: intensive agriculture, viticulture, port activities and industry. The parent material of the soil is mainly derived from the Eocene flysch weathered marls and calcarenites and the soil types are eutric. The chemical composition of the samples was determined by ICP-ES for oxides and several minor elements and by ICP-MS for heavy metals. The mineral composition of the selected samples was checked using X-ray powder diffraction. Different statistical analyses were performed on the normally distributed data.Results and discussion
The mean concentrations of all samples are: Cr 215 mg kg?1, Ni 81 mg kg?1, Zn 67 mg kg?1, Cu 44 mg kg?1 and Pb and Co 18 mg kg?1. The ANOVA showed significant differences only in CaO, C/TOT, P2O5, Co and Pb between those locations within reach of the different contamination sources. The observed average values of heavy metals are well below Slovenia’s Directive limit for Cu, Pb and Zn, close to but not above it for Co and above the action value for Cr and Ni. According to Igeo, soils from all the sampling locations are uncontaminated with Co, Ni and Pb, and uncontaminated to moderately contaminated with Cu and Zn at one port location, and with Cr at all locations.Conclusions
The very high Cr and Ni levels could still be geogenic because soils developed on Eocene flysch rocks are enriched in both metals. Cr and Ni are not correlated because of their different levels of sorption and retention in carbonate soils. Cr was retained and concentrated in the sand fraction but Ni has been mobilised in solution. The only serious threat to the environment seems to be an illegal waste dumping area near the port. 相似文献19.
Yi Cheng Zucong Cai Scott X. Chang Jing Wang Jinbo Zhang 《Journal of Soils and Sediments》2013,13(5):863-868
Purpose
The effects of soil pH manipulation and KCl addition on N2O production in adjacent forest and grassland soils in central Alberta were studied in a 16-day laboratory incubation experiment.Materials and methods
The soils were subjected to four pH and two salt treatments: CK (control)—no addition of acid or alkali solution (pH 4.50 and 4.48 for the forest and grassland soils, respectively; same below); HCl—addition of HCl solution to lower soil pH (3.95 and 3.75); L-KOH and H-KOH—addition of 6 mL of 0.2 (5.36 and 5.57) and 0.4 (6.41 and 6.72)?mol?L?1 KOH solution, respectively, to increase soil pH to two different levels. In order to differentiate between the effect of a change in pH and of changed salt concentrations on N2O production, 6 mL of 0.2 (L-KCl) (4.56 and 4.41) or 0.4 mol?L?1 (H-KCl) (4.59 and 4.42) KCl solutions were also applied as treatments to create two levels of salt application rates.Results and discussion
Increasing pH promoted gross nitrification and cumulative N2O production in both soils, particularly in the forest soil. However, cumulative N2O production decreased in the forest soil but increased in the grassland soil when pH decreased. Cumulative N2O production in the grassland soil was 36 times higher in the L-KCl treatment (1,442 μg?N?kg?1) than in the CK (40 μg?N?kg?1), whereas the H-KCl treatment reduced cumulative N2O production. In contrast, in the forest soil, both KCl treatments reduced cumulative N2O production.Conclusions
(1) The most important factor to increase N2O production in this study was increasing soil pH, suggesting that careful soil pH management could be used as a tool to control soil N2O production; (2) salt effect was also involved in affecting N2O production. 相似文献20.
Marie Reimer Clara Kopp Tobias Hartmann Heidi Zimmermann Reiner Ruser Rudolf Schulz Torsten Müller Kurt Möller 《植物养料与土壤学杂志》2023,186(2):217-233