Combined effect of diuron and simazine on photosystem II photochemistry in a sandy soil and soil amended with solid olive-mill waste

Diuron (3-(3,4-dichlorophenyl)- = 1,1-dimethylurea) and simazine (6-chloro-N(2), N(4)-diethyl-1,3,5-triazine-2,4-diamine) are soil-applied herbicides used in olive crops. The objective of this study is to investigate the effect of these herbicides on Photosystem II photochemistry of Olea europaea L., and whether the amendment of soil with an organic waste (OW) from olive oil production industry modifies this effect. For this purpose, herbicide soil adsorption studies, with unamended and OW-amended soil, and chlorophyll fluorescence measurements in adult olive leaves, after one, two and three weeks of soil herbicide treatment and/or OW amendment, were performed. Soil application of these herbicides reduced the efficiency of Photosystem II photochemistry of olive trees due to chronic photoinhibition, and this effect is counterbalanced by the addition of OW to the soil. OW reduces herbicide uptake by the plant due to an increase in herbicide adsorption.     

Combined effect of diuron and simazine on photosystem II photochemistry in a sandy soil and soil amended with solid olive-mill waste

Diuron (3-(3,4-dichlorophenyl)- = 1,1-dimethylurea) and simazine (6-chloro-N ², N ⁴-diethyl-1,3,5-triazine-2,4-diamine) are soil-applied herbicides used in olive crops. The objective of this study is to investigate the effect of these herbicides on Photosystem II photochemistry of Olea europaea L., and whether the amendment of soil with an organic waste (OW) from olive oil production industry modifies this effect. For this purpose, herbicide soil adsorption studies, with unamended and OW-amended soil, and chlorophyll fluorescence measurements in adult olive leaves, after one, two and three weeks of soil herbicide treatment and/or OW amendment, were performed. Soil application of these herbicides reduced the efficiency of Photosystem II photochemistry of olive trees due to chronic photoinhibition, and this effect is counterbalanced by the addition of OW to the soil. OW reduces herbicide uptake by the plant due to an increase in herbicide adsorption.     

施用城市污泥堆肥对土壤微生物群落结构变化的影响简

在温室条件下进行了15周的盆栽实验,考察了施用城市污泥堆肥后,土壤中养分含量的变化规律,重点研究了施用城市污泥堆肥对土壤微生物群落结构变化的影响。实验发现,污泥堆肥能改善土壤养分,有机质和氮、磷含量得到显著提高。经PCR-DGGE分析,施肥1周后土壤中细菌和真菌的群落结构均发生了较大的变化。随着施肥时间的延长,细菌在富含有机质及氮、磷等养分的土壤环境下大量生长,多样性提高,其优势菌群属于γ变形菌、α变形菌和芽单胞菌;随着有机质的不断消耗,细菌的生长活性受到抑制,最终由于养分的缺乏,细菌种群多样性呈现小幅度的降低,优势菌群变为绿弯菌门、γ变形菌亚纲和厚壁菌门。对于真菌,其多样性指数在堆肥前3周逐渐提升,在第3~12周的监测中呈现相对稳定的变化趋势,优势菌群主要为座囊菌纲和散囊菌纲。     

施用城市污泥堆肥对土壤微生物群落结构变化的影响

在温室条件下进行了15周的盆栽实验,考察了施用城市污泥堆肥后,土壤中养分含量的变化规律,重点研究了施用城市污泥堆肥对土壤微生物群落结构变化的影响。实验发现,污泥堆肥能改善土壤养分,有机质和氮、磷含量得到显著提高。经PCR—DGGE分析,施肥1周后土壤中细菌和真菌的群落结构均发生了较大的变化。随着施肥时间的延长,细菌在富含有机质及氮、磷等养分的土壤环境下大量生长,多样性提高,其优势菌群属于γ变形菌、α变形菌和芽单胞菌;随着有机质的不断消耗,细菌的生长活性受到抑制,最终由于养分的缺乏,细菌种群多样性呈现小幅度的降低,优势菌群变为绿弯菌门、γ变形菌亚纲和厚壁菌门。对于真菌,其多样性指数在堆肥前3周逐渐提升,在第3～12周的监测中呈现相对稳定的变化趋势,优势菌群主要为座囊菌纲和散囊菌纲。     

Terbuthylazine persistence in an organic amended soil

The aim of this work was to study the effect of the application of a solid waste from olive oil production (alperujo) on the movement and persistence of the herbicide terbuthylazine (N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine). An experimental olive grove was divided in two plots: (i) Plot without organic amendment (blank) and (ii) Plot treated with alperujo during 3 years at a rate of 17920 kg of alperujo ha(- 1). Terbuthylazine was applied to both plots at a rate of 2 kg ha(- 1) a.i. Triplicates from each plot were sampled at 3 depths (0-10, 10-20 and 20-30 cm), air-dried, remains of olive leaves, grass roots, and stones removed and sieved through a 5 mm mesh sieve. Terbuthylazine was extracted with methanol 1:2 weight:volume ratio, the extracts were evaporated to dryness, resuspended in 2 mL of methanol, filtered and anylized by high performance liquid chromatography (HPLC). Higher amounts of terbuthylazine were detected at each sampling depth in plots treated with alperujo. The increase in soil organic matter content upon amendment with alperujo slightly increased sorption, suggesting that other factors beside sorption affect terbuthylazine degradation rate in organic amended soils.     

Terbuthylazine persistence in an organic amended soil

The aim of this work was to study the effect of the application of a solid waste from olive oil production (alperujo) on the movement and persistence of the herbicide terbuthylazine (N²-tert-butyl-6-chloro-N⁴-ethyl-1,3,5-triazine-2,4-diamine). An experimental olive grove was divided in two plots: (i) Plot without organic amendment (blank) and (ii) Plot treated with alperujo during 3 years at a rate of 17920 kg of alperujo ha^{? 1}. Terbuthylazine was applied to both plots at a rate of 2 kg ha^{? 1} a.i. Triplicates from each plot were sampled at 3 depths (0–10, 10–20 and 20–30 cm), air-dried, remains of olive leaves, grass roots, and stones removed and sieved through a 5 mm mesh sieve. Terbuthylazine was extracted with methanol 1:2 weight:volume ratio, the extracts were evaporated to dryness, resuspended in 2 mL of methanol, filtered and anylized by high performance liquid chromatography (HPLC). Higher amounts of terbuthylazine were detected at each sampling depth in plots treated with alperujo. The increase in soil organic matter content upon amendment with alperujo slightly increased sorption, suggesting that other factors beside sorption affect terbuthylazine degradation rate in organic amended soils.     

Leaching of benzimidazole antiparasitics in soil columns and in soil columns amended with sheep excreta

Environmental Science and Pollution Research - Benzimidazoles are anthelmintics frequently used in sheep farming due to the high susceptibility of these animals to parasitic diseases. Sheep excreta...     

Fate of pyrene in contaminated soil amended with alternate electron acceptors

Creosote-contaminated soil samples from the Libby Ground Water Contamination Superfund Site in Libby, MT, were amended with the potential alternate electron acceptors (AEA) nitrate (KNO3), manganese oxide (MnO2), and amorphous iron oxyhydroxide (FeOOH) and incubated at low oxygen tensions (0-6% O2). The fate of 14C-pyrene was evaluated with respect to the different soil amendments. The fate of 14C from the radiolabeled pyrene with regard to mineralization and bound residue formation within soil humic fractions was not significantly different from controls for the iron and manganese amended soils. Nitrate amendments appeared to stimulate 14C-pyrene mineralization at a level of 170 mg NO3-N kg(-1), and inhibit mineralization at 340 mg NO3-N kg(-1). The stimulatory effect did not appear to be the result of nitrate serving as an electron acceptor. Although AEA amendments did not significantly affect the rate or extent of 14C-pyrene mineralization, results of oxygen-deprived incubations (purged with N2) indicate that AEA may be utilized by the microbial community in the unsaturated contaminated soil system.     

Behaviour of oxyfluorfen in soils amended with edaphic biostimulants/biofertilizers obtained from sewage sludge and chicken feathers. Effects on soil biological properties

We studied the behaviour of oxyfluorfen herbicide at a rate of 4 l ha^?1 on biological properties of a Calcaric Regosol amended with two edaphic biostimulants/biofertilizers (SS, derived from sewage sludge; and CF, derived from chicken feathers). Oxyfluorfen was surface broadcast on 11 March 2013. Two days after application of oxyfluorfen to soil, both biostimulants/biofertilizers (BS) were also applied to the soil. An unamended soil without oxyfluorfen was used as control. For 2, 4, 7, 9, 20, 30, 60, 90 and 120 days of the application of herbicide to the soil and for each treatment, the soil dehydrogenase, urease, β-glucosidase and phosphatase activities were measured. For 2, 7, 30 and 120 days of the application of herbicide to the soil and for each treatment, soil microbial community was determined. The application of both BS to soil without the herbicide increased the enzymatic activities and soil biodiversity, mainly at 7 days of beginning the experiment. However, this stimulation was higher in the soil amended with SS than for CF. The application of herbicide in organic-amended soils decreased the inhibition of soil enzymatic activities and soil biodiversity. Possibly, the low-molecular-weight protein content easily assimilated by soil microorganisms is responsible for less inhibition of these soil biological properties.     

响应曲面法优化土壤镉浸提过程

以温度、提取时间、土液比为研究因素,考察浸提剂乙二胺四乙酸二钠（EDTA-2Na）对土壤Cd浸提率的影响。首先,以单因素实验为基础,研究3因素单独对土壤Cd浸提率的影响,结果发现随着3因素水平的提高,土壤Cd浸提率整体呈上升趋势,在一定的范围内（温度20~25 ℃、提取时间50~90 min、土液比1:2~1:5）,土壤Cd浸提率增大较为明显,分别上升了35%、8%、17%,而随着3因素水平的提升（温度30~35 ℃、提取时间130~170 min、土液比1:7~1:10）,土壤Cd浸提率上升了5%、1%、4%;其次,采用响应曲面分析法中Box-Behnken中心实验设计法,建立了基于土壤Cd浸提率影响因素的二次函数预测模型,结果表明,模型预测值与实验实测值较为接近,各实验点几乎全部位于1:1线。在3因素研究范围内,当温度为30 ℃、提取时间为130 min、土液比约为1:6.5时,土壤Cd浸提率效果最佳。所得结论有助于进一步改进浸提剂EDTA-2Na对土壤Cd的浸提效率。     

2,4-Dichlorophenoxy acetic acid mineralization in amended soil

The application of municipal biosolid or liquid hog manure to agricultural soils under laboratory conditions at 20 degrees C influenced the fate of the herbicide 2,4-D [2,4-(dichlorophenoxy)acetic acid] in soil. When 2,4-D was added to soil at agronomic rates immediately after the addition of manure or biosolids to a coarse-textured soil, the percentage of 2,4-D mineralized at 100 days was about 47% for both treatments, compared to only 31% for control soils without amendments. The enhanced 2,4-D mineralization as a result of amendment addition was due to an increased heterotrophic microbial activity, with the greatest increases in soil respiration occurring for soils amended with biosolids. When additions of 2,4-D were delayed for one, two, or four weeks after the amendments were applied, the additions of amendments generally reduced 2,4-D mineralization in soil, particularly for manure, indicating that the effect of amendments on enhancing soil microbial activities diminished over time. In contrast, the mineralization of 2,4-D in control soils was less dependent on when 2,4-D was applied in relation to pre-incubations of soil for zero, one, two, or four weeks. The effect of manure on decreasing 2,4-D mineralization in specific soils was as large as the effect of soil texture on differences in 2,4-D mineralization across soils. Because manure was not found to impact 2,4-D sorption by soil, it is possible that 2,4-D mineralization decreased because 2,4-D transformation products were strongly sorbed onto organic carbon constituents in manure-amended soils and were therefore less accessible to microorganisms. Alternatively, microorganisms were less likely to metabolize the herbicide because they preferentially consumed the type of organic carbon in manure that is a weak sorbent for 2,4-D.     

Assessing the chemical and biological accessibility of the herbicide isoproturon in soil amended with biochar

Decamethylcyclopentasiloxane (D5) is a cyclic volatile methyl siloxane (cVMS) commonly found in commercially available products. D5 is expected to enter the terrestrial environment through the deposit of biosolids from sewage treatment plants onto agricultural fields for nutrient enrichment. Little to no information currently exists as to the risks of D5 to the terrestrial environment. In order to evaluate the potential risk to terrestrial organisms, the toxicity of a D5 contaminated biosolid in an agricultural soil was assessed with a battery of standardized soil toxicity tests.D5 was spiked into a surrogate biosolid and then mixed with a sandy loam soil to create test concentrations ranging from 0 to 4074 mg kg⁻¹. Plant (Hordeum vulgare (barley) and Trifolium pratense (red clover)) and soil invertebrates (Eisenia andrei (earthworm) and Folsomia candida (springtail)) toxicity tests were completed to assess for lethal and sub-lethal effects. Plant testing evaluated the effects on seedling emergence, shoot and root length, and shoot and root dry mass. Invertebrate test endpoints included adult lethality, juvenile production, and individual juvenile dry mass (earthworms only). Soil samples were collected over time to confirm test concentrations and evaluate the loss of chemical over the duration of a test. The toxicity of the D5 was species and endpoint dependent, such that no significant adverse effects were observed for T. pratense or E. andrei test endpoints, however, toxicity was observed for H. vulgare plant growth and F. candida survival and reproduction. Chemical losses of up to 50% were observed throughout the tests, most significantly at high concentrations.     

Metal extraction by Arabidopsis halleri grown on an unpolluted soil amended with various metal-bearing solids: a pot experiment.

Most studies dealing with phytoremediation have considered metal extraction efficiency in relation to metal concentration of bulk soil samples or metal concentration of the soil solution. However, little is known about the effect of various metal-bearing solids on plant growth and metal extraction of hyperaccumulators. In this study, we investigated the ability of Arabidopsis halleri to grow and extract metals from different substrates consisting in an unpolluted soil amended with various metal-bearing solids collected in soils around a Zn smelter complex. The metal-bearing solids used as amendments were: fresh and decomposing organic residues in the soil, a soil clay fraction and two waste slags. Pure mono-metallic salt (ZnSO4) was also used. Two series of substrates were produced, one moderately polluted, and the other highly polluted. An additional substrate was formed by the unamended soil, and used as an unpolluted control. Zn, Cd, Cu, and Pb were measured in the substrates, and in the roots and shoots of A. halleri. The dry matter yield of A. halleri was shown not to depend on the nature of the metal-bearing solid used, except when Cu-toxicity was suspected. On highly-polluted substrates, Zn extraction by A. halleri depended on the nature of metal-bearing solids used, showing the following trend: pure mono-metallic salt > waste slags and soil clay fraction > fresh and decomposing organic matter. We explained these differences by the high solubility of Zn in the mono-metallic salt, whereas in the mineral metal-bearing solids and in both fresh and decomposing organic matter, Zn release required mineral weathering or organic matter mineralization, respectively. This work clearly showed that phytoremediation studies have to consider the nature of metal-bearing solids in contaminated soils to better predict the efficiency of plant extraction.     

Cation and anion leaching and growth of Acacia saligna in bauxite residue sand amended with residue mud, poultry manure and phosphogypsum

Purpose  

To examine (1) the effect of organic (poultry manure) and inorganic (residue mud and phosphogypsum) amendments on nutrient leaching losses from residue sand and (2) whether amendments improve the growth of plants in residue sand.     

Fractionation and mobility of phosphorus in a sandy forest soil amended with biosolids

Goal, Scope and Background Biosolids, i.e., treated sewage sludge, are commonly used as a fertilizer and amendment to improve soil productivity. Application of biosolids to meet the nitrogen (N) requirements of crops can lead to accumulation of phosphorus (P) in soils, which may result in P loss to water bodies. Since 1996, biosolids have been applied to a Pinus radiata D. Don plantation near Nelson City, New Zealand, in an N-deficient sandy soil. To investigate sustainability of the biosolids application programme, a long-term research trial was established in 1997, and biosolids were applied every three years, at three application rates, including control (no biosolids), standard and high treatments, based on total N loading. The objective of this study was to evaluate the effect of repeated application of biosolids on P mobility in the sandy soil. Materials and Methods Soil samples were collected in August 2004 from the trial site at depths of 0–10, 10–25, 25–50, 50–75, and 75–100 cm. The soil samples were analysed for total P (TP), plant-available P (Olsen P and Mehlich 3 P), and various P fractions (water-soluble, bioavailable, Fe and Al-bound, Ca-bound, and residual) using a sequential P fractionation procedure. Results and Discussion Soil TP and Olsen P in the high biosolids treatment (equivalent to 600 kg N ha⁻¹ applied every three years) had increased significantly (P<0.05) in both 0–10 cm and 10–25 cm layers. Mehlich 3 P in soil of the high treatment had increased significantly only at 0–10 cm. Olsen P appeared to be more sensitive than Mehlich 3 P as an indicator of P movement in a soil profile. Phosphorus fractionation revealed that inorganic P (Al/Fe-bound P and Ca-bound P) and residual P were the main P pools in soil, whereas water-soluble P accounted for approximately 70% of TP in biosolids. Little organic P was found in either the soil or biosolids. Concentrations of water-soluble P, bioavailable inorganic P (NaHCO₃ Pi) and potentially bioavailable inorganic P (NaOH Pi) in both 0–10 and 10–25 cm depths were significantly higher in the high biosolids treatment than in the control. Mass balance calculation indicated that most P applied with biosolids was retained by the top soil (0–25 cm). The standard biosolids treatment (equivalent to 300 kg N ha⁻¹ applied every three years) had no significant effect on concentrations of TP, Mehlich 3 P and Olsen P, and P fractions in soil. Conclusions The results indicate that the soil had the capacity to retain most biosolids-derived P, and there was a minimal risk of P losses via leaching in the medium term in the sandy forest soil because of the repeated biosolids application, particularly at the standard rate. Recommendations and Perspectives Application to low-fertility forest land can be used as an environmentally friendly option for biosolids management. When biosolids are applied at a rate to meet the N requirement of the tree crop, it can take a very long time before the forest soil is saturated with P. However, when a biosolids product contains high concentrations of P and is applied at a high rate, the forest ecosystem may not have the capacity to retain all P applied with biosolids in the long term. ESS-Submission Editor: Dr. Jean-Paul Schwitzguébel jean-paul.schwitzguebel@epfl.ch     

Heavy metal accumulation in wheat plant grown in soil amended with industrial sludge

The concentrations of different forms of Zn, Cu, Mn, Ni, Cd, Cr, Pb and Fe metals were determined for the roadside sludge collected from pickling-rolling and electroplating industrial area. In sludge the relative abundance of total heavy metals were Fe>Mn>Cr>Ni>Cu>Pb>Zn>Cd and DTPA-extractable metals were in the order--Fe>Ni>Mn>Cr>Cu>Zn>Pb>Cd. Pot-culture experiment was conducted in soils amended with sludge (0%, 10%, 20%, 30%), pretreated with lime (0%, 0.5% and 1%). The soils were alkaline in nature (pH>8.3) with organic carbon contents were 0.34% and 0.72%. The most abundant total and bio-available metal was Fe. Two wheat seedlings were grown in each pot containing 3kg sludge-amended or control soil and the experiment was conducted till harvesting. Application of sludge increased both total and bio-available forms of metals in the soils, while lime application decreased the bioavailability of heavy metals in sludge-amended soils. The content of organic carbon showed positive correlation with all metals except Zn, Cr and Pb. CEC also showed a strong positive correlation (R2>0.7) with Fe, Mn, Cu, Ni and Cd. Though wheat plants are not accumulators, the translocation efficiency was appreciably high. The translocation factor from shoot to grain was found smaller than that of root to shoot of wheat plants. This makes an implication that the heavy metal accumulation was proportionally lesser in grain than in shoot. In, 10% sludge with 0.5% lime-amended soils; each of these toxic heavy metals was found to be within permissible range (USEPA). Hence, on the basis of present study, the best possible treatment may be recommended.     

Leaching and degradation of S-Metolachlor in undisturbed soil cores amended with organic wastes

Environmental Science and Pollution Research - Organic waste (OW) reuse in agriculture is a common practice fostered by benefits in terms of waste recycling and crop production. However, OW...     

Microbially mediated cadmium sorption/desorption processes in soil amended with sewage sludge

A multi-compartment system was used to study the importance of microorganisms for Cd desorption from soil amended with sewage sludge and simultaneous resorption of the mobilized metal by soil constituents. Using this system made it possible to study the participation of microorganisms (Arthrobacter, Trichoderma), montmorillonite, humic acids, and iron oxides in resorption of the released Cd. A filter-sterilized water extract of root-free soil of pH 6.7 (RF) or RF supplemented with glucose (RFG) were used to mobilize Cd from soil at 14 degrees C in 48 h. Cadmium found in those extracts after 48-h incubation was recognized as bioavailable. Changes in pH values and enrichment of soil extracts with organic acids and siderophores resulted from microbial growth. RFG with lower pH and a higher content of ligands mobilized, on average, 40% of Cd introduced with sewage sludge amended soil, whereas RF mobilized only 20% of it. Sequential extractions of Cd at time 0 and Cd remaining in soil showed that RFG had mobilized Cd mostly from the fraction bound with Fe and Mn oxides. Microbial biomass accounted for only up to 3.4% (w/w) of the soil constituents used in the experiments but resorbed 25% of mobilized Cd. The chemical composition of mobilizing soil extracts and the solid-to-mobilizing-extracts volume ratio had a significant effect on the amount of bioavailable Cd. The results of the study suggest that microbial metabolites were involved in Cd mobilization, while the biomass of microorganisms was involved in Cd resorption as a biosorbent.     

Accumulation and mobility of zinc in soil amended with different levels of pig-manure compost

Applying manure compost not only results in zinc accumulation in the soil but also causes an increase in zinc mobility and enhances zinc leaching. In this study, the physical and chemical characteristics of zinc, zinc profiles, and zinc balance were investigated to characterise the fate of zinc in fields where the quality and amount of pig manure compost applied have been known for 13 years. Moreover, we determined zinc fractionation in both 0.1 mol L^?1HCl-soluble (mobile) and -insoluble (immobile) fractions. Adsorption of zinc in the soil was enhanced with increasing total carbon content following the application of pig manure compost. The 159.6 mg ha^?1 year^?1manure applied plot (triplicate) exceeded the Japanese regulatory level after only 6 years of applying pig manure compost, whereas the 53.2 mg ha^?1 year^?1 manure applied plot (standard) reached the regulatory level after 13 years. The zinc loads in the plots were 17.0 and 5.6 kg ha^?1 year^?1, respectively. However, 5.9 % and 17.2 % of the zinc loaded in the standard and the triplicate pig manure compost applied plots, respectively, were estimated to be lost from the plough layer. Based on the vertical distribution of mobile and immobile zinc content, a higher rate of applied manure compost caused an increase in the mobile zinc fraction to a depth of 40 cm. Although the adsorption capacity of zinc was enhanced following the application of pig manure compost, a greater amount of mobile zinc could move downward through the manure amended soil than through non manure-amended soil.     

Enhancing bioremediation of diesel oil and gasoline in soil amended with an agroindustry sludge

This paper presents a study of the bioremediation of diesel oil and gasoline by a series of controlled laboratory tests. Sludge from an agroindustry was used to enhance bioremediation of both gasoline and diesel oil mixed with a soil mass to compare its efficiency with that of a mineral fertilizer. Effects of soil microbiology and soil mixtures were investigated by means of evolution of CO2, microorganism populations at 90 days, pH at 65 and 95 days, mineral nitrogen, and gas chromatographic analysis of the benzene, toluene, methyl tertiary butyl ether, C8, and C9+total aromatics at the end of the experiments. Treatments containing sludge showed better soil conditions after 170 days of treatment (inorganic nitrogen and microbiota activity) compared with gasoline and diesel oil without amendments. Samples had no detectable traces of the measured hydrocarbons at 170 days of treatment.