Adsorption of sugar beet herbicides to Finnish soils

Three sugar beet herbicides, ethofumesate, phenmedipham and metamitron, are currently used on conventional sugar beet cultivation, while new varieties of herbicide resistant (HR) sugar beet, tolerant of glyphosate or glufosinate-ammonium, are under field testing in Finland. Little knowledge has so far been available on the adsorption of these herbicides to Finnish soils. The adsorption of these five herbicides was studied using the batch equilibrium method in 21 soil samples collected from different depths. Soil properties like organic carbon content, texture, pH and partly the phosphorus and oxide content of the soils were tested against the adsorption coefficients of the herbicides. In general, the herbicides studied could be arranged according to their adsorption coefficients as follows: glyphosate>phenmedipham>ethofumesate approximately glufosinate-ammonium>metamitron, metamitron meaning the highest risk of leaching. None of the measured soil parameters could alone explain the adsorption mechanism of these five herbicides. The results can be used in model assessments of risk for leaching to ground water resulting from weed control of sugar beet in Finland.     

Improvement of soil characteristics and growth of Dorycnium pentaphyllum by amendment with agrowastes and inoculation with AM fungi and/or the yeast Yarowia lipolytica

The effectiveness of two microbiologically treated agrowastes [dry olive cake (DOC) and/or sugar beet (SB)] on plant growth, soil enzymatic activities and other soil characteristics was determined in a natural soil from a desertified area. Dorycnium pentaphyllum, a legume plant adapted to stress situations, was the test plant to evaluate the effect of inoculation of native arbuscular mycorrhizal (AM) fungi and/or Yarowia lipolytica (a dry soil adapted yeast) on amended and non-amended soils. Plant growth and nutrition, symbiotic developments and soil enzymatic activities were limited in non-amended soil where microbial inoculations did not improve plant development. The lack of nodules formation and AM colonization can explain the limited plant growth in this natural soil. The effectiveness and performance of inocula applied was only evident in amended soils. AM colonization and spores number in natural soil were increased by amendments and the inoculation with Y. lipolytica promoted this value. The effect of the inoculations on plant N-acquisition was only important in AM-inoculated plants growing in SB medium. Enzymatic activities as urease and protease activities were particularly increased in DOC amended soil meanwhile dehydrogenase activity was greatest in treatments inoculated with Y. lipolytica in SB added soil. The biological activities in rhizosphere of agrowaste amended soil, used as indices of changes in soil properties and fertility, were affected not only by the nature of amendments but also by the inoculant applied. All these results show that the lignocellulosic agrowastes treated with a selected microorganism and its further interaction with beneficial microbial groups (native AM fungi and/or Y. lipolytica) is a useful tool to modify soil physico-chemical, biological and fertility properties that enhance the plant performance probably by making nutrients more available to plants.     

Interaction of soil pH and phosphorus efficacy: Long-term effects of P fertilizer and lime applications on wheat,barley, and sugar beet

Phosphorus (P), a plant macronutrient, must be adequately supplied for crop growth. In Germany, many soils are high in plant-available P; specifically in arable farming, P fertilizer application has been reduced or even omitted in the last decade. Therefore, it is important to understand how long these soils can support sustainable crop production, and what concentrations of soil P are required for it. We analyzed a 36-year long-term field experiment regarding the effects of different P application and liming rates on plant growth and soil P concentrations with a crop rotation of sugar beet, wheat, and barley. Sugar beet reacted to low soil P and low soil pH levels more sensitively than wheat, which was not significantly affected by the long-term omitted P application. All three crop species showed adequate growth at soil P levels lower than the currently recommended levels, if low soil pH was optimized by liming. The increase in efficacy of soil and fertilizer P by reduced P application rates therefore requires the adaptation of the soil pH to a soil type-specific optimal level.     

Azadirachtin induced changes in feeding,dietary utilization and midgut carboxylesterase activity of the final instar larvae of spodoptera litura (fabricius) (lepidoptera: Noctuidae)

Abstract

Final (sixth) instar larvae of Spodoptera litura were fed in increasing amounts of azadirachtin and the effects on feeding activity, dietary utilization and mid‐gut carboxylesterase activity were determined. The antifeedant activity of azadirachtin did not increase in a dose‐dependent manner as reflected by the decline in antifeedant effect at higher doses of 30 and 50 ppm. Dietary concentrations of azadirachtin although significantly lowered the efficiencies of conversion of both ingested (ECI) and digested (ECD) food, it failed to lower the approximate digestibility (AD). The latter however, increased significantly with increasing concentrations of azadirachtin. Feeding of higher doses (30 and 50 ppm) resulted in significant increase in midgut carboxylesterase activity. Thus insensitivity to antifeedant effects and induction of midgut carboxyesterase activity in the older larvae of S.litura In response to high doses of azadirachtin observed in this study can have adverse consequences unless particular attention is paid in developing application strategies for azadirachtin based biopesticides for use in pest control protocols.     

Persistence of azadirachtin A and B in soil: Effects of temperature and microbial activity

Abstract

The persistence of two insecticidally active compounds from the neem tree, azadirachtin A and B, was determined at two different temperatures (15 and 25°C) in the laboratory after application of the commercial neem insecticide, Margosan‐O, to a sandy loam soil. The influence of microbial activity on degradation was also examined by comparing autoclaved and non‐autoclaved soils also at 15 and 25°C. Temperature influenced degradation rates. The DT ₅₀ (time required for 50% disappearance of the initial concentration) for azadirachtin A was 43.9 and 19.8 d for non‐autoclaved soil kept at 15 and 25°C, respectively. The DT ₅₀ for azadirachtin B was 59.2 and 20.8 d for non‐autoclaved soil kept at 15 and 25°C, respectively. Microbial activity was also responsible for faster degradation because DT ₅₀ ’s for autoclaved soil were much longer than for non‐autoclaved soils. DT ₅₀ ‘_s for azadirachtin A in autoclaved soil were 91.2 (15°C) and 31.5 d (25°C). DT50’s for azadirachtin B in autoclaved soil were 115.5 (15°C) and 42.3 d (25°C). Two degradation products of azadirachtin were detected, but were not identified. Higher levels of the two degradation products were detected in non‐autoclaved soil.     

Effects of chemical oxidation on sorption and desorption of PAHs in typical Chinese soils

In situ chemical oxidation is a commonly applied soil and groundwater remediation technology, but can have significant effects on soil properties, which in turn might affect fate and transport of organic contaminants. In this study, it was found that oxidation treatment resulted mainly in breakdown of soil organic matter (SOM) components. Sorption of naphthalene and phenanthrene to the original soils and the KMnO₄-treated soils was linear, indicating that hydrophobic partitioning to SOM was the predominant mechanism for sorption. Desorption from the original and treated soils was highly resistant, and was well modeled with a biphasic desorption model. Desorption of residual naphthalene after treating naphthalene-contaminated soils with different doses of KMnO₄ also followed the biphasic desorption model very well. It appears that neither changes of soil properties caused by chemical oxidation nor direct chemical oxidation of contaminated soils had a noticeable effect on the nature of PAH-SOM interactions.     

Soil amendments reduce trace element solubility in a contaminated soil and allow regrowth of natural vegetation

We tested the effects of three amendments (a biosolid compost, a sugar beet lime, and a combination of leonardite plus sugar beet lime) on trace element stabilisation and spontaneous revegetation of a trace element contaminated soil. Soil properties were analysed before and after amendment application. Spontaneous vegetation growing on the experimental plot was studied by three surveys in terms of number of taxa colonising, percentage vegetation cover and plant biomass. Macronutrients and trace element concentrations of the five most frequent species were analysed. The results showed a positive effect of the amendments both on soil chemical properties and vegetation. All amendments increased soil pH and TOC content and reduced CaCl(2)-soluble-trace element concentrations. Colonisation by wild plants was enhanced in all amended treatments. The nutritional status of the five species studied was improved in some cases, while a general reduction in trace element concentrations of the aboveground parts was observed in all treated plots. The results obtained show that natural assisted remediation has potential for success on a field scale reducing trace element entry in the food chain.     

Trace elements in soil and biota in confined disposal facilities for dredged material

We studied the relation of trace element concentrations in soil to those in house mice (Mus musculus), common reed (Phragmites australis) and ladybugs (Coccinella septempunctata at five disposal facilities for dredged material. The sites had a wide range of soil trace element concentrations, acid soils and a depauperate fauna. They were very poor wildlife habitat because they were dominated by the common reed. Bioassay earthworms exposed to surface soils from three of the five sites died, whereas those exposed to four of five soils collected a meter deep survived, presumably because the deeper, unoxidized soil, was not as acid. Concentrations of Ni and Cr in the biota from each of the sites did not seem to be related to the concentrations of the same elements in soil. Although Pb, Zn and Cu concentrations in biota were correlated with those in soil, the range of concentrations in the biota was quite small compared to that in soil. The concentrations of Pb detected in mice were about as high as the concentrations previously reported in control mice from other studies. Mice from the most contaminated site (530 ppm Pb in soil) contained only slightly more Pb (8 ppm dry wt) than did mice (2-6 ppm dry wt) from sites containing much less Pb (22-92 ppm in soil). Despite the acid soil conditions, very little Cd was incorporated into food chains. Rather, Cd was leaching from the surface soil. We concluded that even the relatively high concentrations of trace elements in the acid dredged material studied did not cause high concentrations of trace elements in the biota.     

The toxicity and behavioural effects of neem limonoids on Cnaphalocrocis medinalis (Guenée), the rice leaffolder

Meliaceae plant products have been shown to exert pesticidal properties against a variety of insect species. In agricultural pest control programs, such products may have the potential to be used successfully as botanical insecticides. The effect of the neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and deacetylnimbin on the biology and mortality of rice leaffolder larvae was investigated. In laboratory experiments, treatment with neem limonoids suppressed leaf folding behaviour of C. medinalis. Biological parameters (larval duration, pupal duration adult longevity and fecundity) were also affected by the treatment. Azadirachtin, salannin, and deacetylgedunin showed high bioactivity at all doses, while the rest of the neem limonoids were less active, and were only biologically active at high doses. Azadirachtin was most potent in all experiments and produced almost 100% larval mortality at 1 ppm concentration. These results indicate neem limonoids affect the larval behaviour. These effects are most pronounced in early instars.     

Zinc, copper and nickel concentrations in soil extracts and crops grown on four soils treated with metalloaded sewage sludges

Sludges containing high concentrations of zinc, copper or nickel and an uncontaminated sludge were added to two sandy loams (pH 6.5 and 7.1), a heavy clay (pH 6.3) and a calcareous clay (pH 7.8) to give ten sludge treatments for each soil. The mixtures were incubated fallow, cropped continuously with clover, or cropped with barley and red beet in rotation for 21 months. The quantity of added metal either in the soil solution or extracted by 0.1m CaCl(2) depended on the metal loading, pH and soil cation exchange capacity, and changed with time after mixing soils and sludges. Crop metal concentrations, and the occurrence of metal-induced yield reductions, also depended on soil properties as well as metal loading. The best chemical extractant for predicting plant metal concentrations was 0.1m CaCl(2).     

Carbofuran residues in organic soils in Southwestern Ontario, 1977

Organic soils from 22 farms with a history of carbofuran use for soil insect control were sampled in November, 1977. Analysis for carbofuran was by electron capture gas chromatography of the heptaflurobutyric derivative. Nineteen of the 22 soils contained detectable (sensitivity 0.02 ppm) carbofuran residues. However only 8 of the soils contained greater than 0.5 ppm total carbofuran. The highest total carbofuran residue was 1.5 ppm, of which 0.31 ppm was 3-ketocarbofuran. In other soil samples 3-ketocarbofuran comprised 7-50% of the total carbofuran residue. No 3-hydroxycarbofuran was detected. The order of persistence of granular application of 3 insecticides as seed-furrow treatments was ethion greater than fonofos greater than carbofuran.     

EDTA and HCl leaching of calcareous and acidic soils polluted with potentially toxic metals: remediation efficiency and soil impact

The environmental risk of potentially toxic metals (PTMs) in soil can be diminished by their removal. Among the available remediation techniques, soil leaching with various solutions is one of the most effective but data about the impact on soil chemical and biological properties are still scarce. We studied the effect of two common leaching agents, hydrochloric acid (HCl) and a chelating agent (EDTA) on Pb, Zn, Cd removal and accessibility and on physico-chemical and biological properties in one calcareous, pH neutral soil and one non-calcareous acidic soil. EDTA was a more efficient leachant compared to HCl: up to 133-times lower chelant concentration was needed for the same percentage (35%) of Pb removal. EDTA and HCl concentrations with similar PTM removal efficiency decreased PTM accessibility in both soils but had different impacts on soil properties. As expected, HCl significantly dissolved carbonates from calcareous soil, while EDTA leaching increased the pH of the acidic soil. Enzyme activity assays showed that leaching with HCl had a distinctly negative impact on soil microbial and enzyme activity, while leaching with EDTA had less impact. Our results emphasize the importance of considering the ecological impact of remediation processes on soil in addition to the capacity for PTM removal.     

Impact of sewage sludge spreading on heavy metal speciation in tropical soils (Réunion, Indian Ocean)

This study was designed to evaluate the impact of sewage sludge spreading on tropical soilborne heavy metal speciation. Sludgeborne heavy metal speciation was also assessed, and the potential mobility of the elements was classified as follows: Zn>Ni>Cu approximately Cr. Two sequential extraction procedures were applied to study Cr, Cu, Ni and Zn speciation in control soils and sludge-amended soils. We demonstrated that sewage sludge spreading over a 2-year period did not have an impact on soilborne heavy metal concentrations but affected speciation of the most mobile fractions of Ni and Zn. Both protocols were consistent for the organic matter fractions, with an increase in Cu, Zn and Cr concentrations in the amended soil as compared to the control soil. In addition, we highlighted that the two protocols characterized different pools of organic matter and that organic compounds remained in the solid matrix after extraction. With respect to the reducible fraction, completely opposite results were obtained with the two protocols and the solid residue study revealed that the two schemes were ineffective in characterizing iron and manganese fractions.     

The effect of landuse on soil organic carbon chemistry and sorption of pesticides and metabolites

Earlier studies had shown significant differences in sorption of nine pesticides in soils collected from two landuses (native vegetation and market gardens), which could not be explained on the basis of organic carbon content alone. Consequently it was hypothesised that the differences in sorption behaviour between the two landuses may be due to variation in the chemistry of the organic carbon. In this study the relationship between sorption behaviour of the nine chemicals and soil organic carbon chemistry, as determined by solid-state (13)C NMR spectroscopy, was investigated. No significant differences were found between the two landuses in the distribution of the four main spectral regions of the (13)C NMR spectra of soil OC, except for the carbonyl fraction (165-220ppm), which may reflect the low OC content of the soils from both landuses. For all chemicals, except prometryne, the most significant (P<0.01 or P<0.001) relationship between K(d) values and types of OC was found with the aromatic (110-165ppm) or the alkyl (0-45ppm) fraction. A comparison was made of the variability of K(d) values normalized over OC (i.e. K(oc)), alkyl, aromatic and alkyl+aromatic fractions. Expressing K(d) values for all chemicals, except azinphos methyl, in soils under native vegetation as K(alkyl) or K(aromatic) greatly decreased the variability compared with the K(oc) value. However in the cultivated soils only the sorption coefficients for DEA, DIA and fenamiphos showed a decrease in variability when expressed as K(alkyl) or K(aromatic). This reflected the stronger relationship between sorption coefficients and the alkyl and aromatic fraction of soil OC in soils from native vegetation compared with those determined from the market garden soils. The different relationships between sorption coefficients and types of OC of the two landuses also suggests that the type of aromatic and alkyl carbon under the two landuses is different and NMR characterisation of the OC was not sufficient to distinguish these differences.     

The sensitivity of soil enzymes,microorganisms and spring wheat to soil contamination with carfentrazone-ethyl

Herbicides pose a significant threat to the natural environment, in particular in soils that are most exposed to plant protection agents. Prolonged herbicide use leads to changes in soil metabolism and decreases soil productive potential. In this study, the influence of carfentrazone-ethyl (CE) on the microbiological and biochemical properties of soil and the yield of Triticum aestivum L. was evaluated. Carfentrazone-ethyl was applied to sandy loam (pH_KCl – 7.0) in doses of 0.000, 0.264, 5.280, 10.56, 21.18, 42.24, 84.48 and 168.96 µg kg^?1 DM soil. Soil samples were subjected to microbiological and biochemical analyses on experimental days 30 and 60. Carfentrazone-ethyl disrupted the biological equilibrium in soil by decreasing the abundance and biodiversity of soil-dwelling microorganisms, the activity of soil enzymes, the values of the biochemical activity indicator and spring wheat yields. Carfentrazone-ethyl had the most adverse effects when applied in doses many fold higher than those recommended by the manufacturer. The toxic effects of CE were also determined by its soil retention time. Soil treated with CE was characterized by higher counts of oligotrophic bacteria, organotrophic bacteria, bacteria of the genus Azotobacter, actinomycetes and fungi on day 60, and spore-forming oligotrophic bacteria on day 30. The activity of dehydrogenases, urease, alkaline phosphatase and β-glucosidase was higher on day 30 than on day 60.     

Effects of mussel shell addition on the chemical and biological properties of a Cambisol

The use of a by-product of the fisheries industry (mussel shell) combined with cattle slurry was evaluated as soil amendment, with special attention to the biological component of soil. A wide number of properties related to soil quality were measured: microbial biomass, soil respiration, net N mineralization, dissolved organic carbon, dissolved organic nitrogen, dissolved inorganic nitrogen, dehydrogenase, β-glucosidase, urease and phosphomonoesterase activities. The amendments showed an enhancement of soil biological activity and a decrease of aluminium held in the cation exchange complex. No adverse effects were observed on soil properties. Given that mussel shells are produced in coastal areas as a by-product and have to be managed as a waste and the fertility constraints in the local soils due to their low pH, our research suggest that there is an opportunity for disposing a residue into the soil and improving soil fertility.     

Effect of a base-catalyzed dechlorination process on the genotoxicity of PCB-contaminated soil

We evaluated the genotoxicity of dichloromethane (DCM) extracts of PCB-contaminated soil before and after the soil had been treated by a base-catalyzed dechlorination process. The treatment process involves heating a mixture of the soil, polyethylene glycol (or hydrocarbons with boiling points of 310–387°C), and sodium hydroxide to 250–350°C. Dechlorination reduced by >99% the PCB concentration of the soil, which was initially 2,200 ppm. The DCM extracts of both control and treated soils were not mutagenic in strain TA100 of Salmonella, but they were mutagenic in strain TA98. Based on results in strain TA98, the base-catalyzed dechlorination process reduced the mutagenic potency of the soil by approximately one-half. The DCM extracts of the soils before and after treatment were equally genotoxic in a prophage-induction assay in . , which detects some chlorinated organic carcinogens that are not detected by the Salmonella mutagenicity assay. These results suggest that treatment of PCB-contaminated soil by base-catalyzed dechlorination reduced the mutagenicity of the soil slightly.     

Impact of PCB-118 and transformer oil toxicity on anaerobic digestion of sludge: Anaerobic toxicity assay results

In this study, possible toxicity of increasing doses of PCB-118 and transformer oil (TO) on anaerobic sludge digestion was investigated. For this purpose, five different sets of reactors were prepared in which four different PCB-118 concentration (1, 10, 20, and 30 mg L⁻¹) and three different TO concentration (0.38, 0.76, and 1.52 g L⁻¹) were applied. Throughout the study, biogas production and composition, pH, TS, VS, and COD as well as PCB concentration were monitored. Toxicity was investigated by anaerobic toxicity assay (ATA) evaluating the reduction in methane production. A notable inhibition was observed mostly in 30 mg L⁻¹ PCB reactors. A negative influence of PCB-118 and TO was observed on COD and solids removal. A maximum of 26.5% PCB-118 removal was attained.     

Effect of Cuscuta campestris parasitism on the physiological and anatomical changes in untreated and herbicide-treated sugar beet

The effects of field dodder on physiological and anatomical processes in untreated sugar beet plants and the effects of propyzamide on field dodder were examined under controlled conditions. The experiment included the following variants: N—noninfested sugar beet plants (control); I - infested sugar beet plants (untreated), and infested plants treated with propyzamide (1500 g a.i. ha^?1 (T₁) and 2000 g a.i. ha^?1(T₂)). The following parameters were checked: physiological—pigment contents (chlorophyll a, chlorophyll b, total carotenoids); anatomical -leaf parameters: thickness of epidermis, parenchyma and spongy tissue, mesophyll and underside leaf epidermis, and diameter of bundle sheath cells; petiole parameters: diameter of tracheid, petiole hydraulic conductance, xylem surface, phloem cell diameter and phloem area in sugar beet plants. A conventional paraffin wax method was used to prepare the samples for microscopy. Pigment contents were measured spectrophotometrically after methanol extraction. All parameters were measured: prior to herbicide application (0 assessment), then 7, 14, 21, 28 and 35 days after application (DAA). Field dodder was found to affect the pigment contents in untreated sugar beet plants, causing significant reductions. Conversely, reduction in the treated plants decreased 27% to 4% for chlorophyll a, from 21% to 5% for chlorophyll b, and from 28% to 5% for carotenoids (T₁). Also, in treatment T_2, reduction decreased in infested and treated plants from 19% to 2% for chlorophyll a, from 21% to 2% for chlorophyll b, from 23% to 3% for carotenoids and stimulation of 1% and 2% was observed 28 and 35 DAA, respectively. Plants infested (untreated) by field dodder had lower values of most anatomical parameters, compared to noninfested plants. The measured anatomical parameters of sugar beet leaves and petiole had significantly higher values in noninfested plants and plants treated with propyzamide than in untreated plants. Also, the results showed that propyzamide is an adequate herbicide for control of field dodder at the stage of early infestation.     

Heavy metals in urban soils of East St. Louis, IL, Part I: Total concentration of heavy metals in soils

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals--As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.