Fresh Residues Research Articles

Development of alkaline electrochemical characteristics demonstrates soil formation in bauxite residue undergoing natural rehabilitation

AbstractMining and mineral processing industries have generated a large amount of polymineral wastes, causing the destruction and degradation of huge areas of landscapes at extensive geographical locations. Rehabilitation of these mine waste landscapes is critical to social and economic sustainability of mining and metallurgy operations, such as alumina refineries. The Bayer process to refine alumina generates large amounts of highly alkaline bauxite residues that are hazardous to plant growth. Innovative methodologies are urgently needed to address this economic and environmental challenges, one of which is soil formation from bauxite residues. Mineral weathering appears the prerequisite to the initiation of soil formation and development of functional soil properties in bauxite residue disposal areas. The present study investigated natural changes of mineralogy, zeta potential, isoelectric point, surface protonation, active alkaline groups, and associated implications for rehabilitation of the bauxite residue disposal area. Alkaline calcite, hydrogarnet, and sodalite minerals were slowly transformed or dissolved with declining levels over weathering time. Amorphous and semiamorphous minerals also decreased with a corresponding decrease in specific surface area and sorption sites. Zeta potential curve of fresh residue had steeper slope than those of aged residues. The isoelectric point of fresh residue was significantly higher, but those of aged residues were significantly lower, with a significant decrease of isoelectric point with increasing time. These attributes in mineralogy and electrochemical characteristics such as transformation of alkaline minerals, and decreases of surface protonation and active alkaline groups, may be used to help the assessment of soil formation status in the bauxite residues of different age and associated rehabilitation requirements.

Effects of abamectin on two spotted spider mite and Trichogramma brassicae and efficacy of its residual effects applied on the bean plants

For evaluating lethal effects of abamectin on T. urticae leaf dipping method was used. Then T. brassicae adults were treated with LC10 and LC50 values obtained from probit analysis of the mite bioassay results using toxicity bioassay with fresh residue method. For evaluating residual effects of abamectin, bean plants were sprayed with twentieth of recommended field dose of abamectin (equal to 25 ppm of trade product). Leaf pieces were prepared from treated plants in different time intervals and the adult mites were transferred on them. Mortality was recorded after 24 h. Probit analysis of lethal experiment against T. urticae revealed 0.05, 0.417 and 3.26 ppm from trade product as LC10, LC50 and LC90 values, respectively. Results of residual effects experiment showed that mite mortality was 100% in 1 day after plant spraying which decreased to 55.62% in 21 days after spraying. LC10 and LC50 values of abamectin tended to 53.87 and 72.57% mortality of T. brassicae, respectively.

Influence of site and soil properties on the DRIFT spectra of northern cold-region soils

We investigated the influence of site characteristics and soil properties on the chemical composition of organic matter in soils collected from a latitudinal transect across northern cold-region through analysis of diffuse reflectance Fourier transform mid infrared (DRIFT) spectra of bulk soils. The study included 119 soil samples collected from 28 sites including tundra, boreal forest, grassland, and coastal rainforest ecosystems. Organic, mineral, and cryoturbated soil horizons, both seasonally and perennially frozen, representing a variety of depths and edaphic conditions were examined. The amount and chemical composition of organic matter, as well as site and soil properties, exerted a strong influence on the DRIFT spectra. The spectra were highly sensitive to the extent of organic matter decomposition, enabling the ordination of organic (Oi, Oe and Oa) horizons. Differences in absorbance intensity for several spectral bands indicated that Oi horizons contained greater abundance of relatively fresh residues, phenolic-OH compounds, aliphatic compounds, and carbohydrates. In contrast, Oa horizons had a greater presence of amide groups, aromatics, CC bonds, carboxylates and carboxylic acids. Another significant factor differentiating these horizons was the incorporation of clays and silicates into the Oa horizons. Calculated ratios of characteristic spectral bands showed a clear trend of increasing decomposition from Oi to Oe to Oa. The DRIFT spectra were related to many site/soil attributes including land cover type, parent material, and associated factors, such as permafrost presence/absence, drainage class, horizon depth, bulk density, cation exchange capacity, and pH. A single DRIFT spectral band was identified that might be used in future studies to quickly estimate the organic carbon, total nitrogen, and carbon:nitrogen ratios of northern soils. Our results demonstrate that the information contained in DRIFT spectra of soil integrates the quantity and chemical composition of soil organic matter with soil properties and highlights the potential for using this information to assess the degradation state of organic matter stored in northern cold-region soils.

Survival and Locomotory Behavior of Earwigs After Exposure to Reduced-Risk Insecticides.

The conservation of natural enemies is an important tactic to promote biological control of arthropod pests. The earwig Doru luteipes (Sccuder) is the most important predator of the fall armyworm Spodoptera frugiperda (J.E. Smith) in corn fields. One way of conserving these predators in the field is by using only selective insecticides when the pest population reaches the economic threshold. Some recent insecticides such as azadirachtin, chlorantraniliprole, and novaluron have been claimed to pose reduced risk for natural enemies. Nevertheless, there is a dearth of information regarding the selectivity of these insecticides upon earwigs in specific. In this study, we carried out a series of laboratory assays to examine the survivorship and locomotory behavior of D.luteipes after exposure to fresh dry residue of azadirachtin, chlorantraniliprole, and novaluron. Our results show a significant survival reduction for D. luteipes nymphs exposed to fresh residues of chlorantraniliprole and novaluron. In the behavioral studies, adults of D. luteipes stopped more often, spent more time resting (inactive), and moved more slowly immediately after exposure to chlorantraniliprole residue. These results suggest that chlorantraniliprole may mediate an impaired movement and a behavior arrestment of earwigs after contact with this insecticide fresh residue. This could translate into reduced foraging efficiency, and increase exposure and insecticide uptake. Although chlorantraniliprole and novaluron showed a potential to undermine the biological control provided by earwigs, it is yet essential to conduct field trials in order to confirm our laboratory results.

Impacts of soil incorporation of pre-incubated silica-rich rice residue on soil biogeochemistry and greenhouse gas fluxes under flooding and drying

Incorporation of silica-rich rice husk residue into flooded paddy soil decreases arsenic uptake by rice. However, the impact of this practice on soil greenhouse gas (GHG) emissions and elemental cycling is unresolved particularly as amended soils experience recurrent flooding and drying cycles. We evaluated the impact of pre-incubated silica-rich rice residue incorporation to soils on pore water chemistry and soil GHG fluxes (i.e., CO2, CH4, N2O) over a flooding and drying cycle typical of flooded rice cultivation. Soils pre-incubated with rice husk had 4-fold higher pore water Si than control and 2-fold higher than soils pre-incubated with rice straw, whereas the pore water As and Fe concentrations in soils amended with pre-incubated straw and husk were unexpectedly similar (maximum ~0.85μM and ~450μM levels, respectively). Pre-incubation of residues did not affect Si but did affect the pore water levels of As and Fe compared to previous studies using fresh residues where straw amended soils had higher As and Fe in pore water. The global warming potential (GWP) of soil GHG emissions decreased in the order straw (612±76g CO2-eqm−2)>husk (367±42gCO2-eqm−2)>ashed husk=ashed straw (251±26 and 278±28gCO2-eqm−2)>control (186±23gCO2-eqm−2). The GWP increase due to pre-incubated straw amendment was due to: a) larger N2O fluxes during re-flooding; b) smaller contributions from larger CH4 fluxes during flooded periods; and c) higher CH4 and CO2 fluxes at the onset of drainage. In contrast, the GWP of the husk amendment was dominated by CO2 and CH4 emissions during flooded and drainage periods, while ashed amendments increased CO2 emissions particularly during drainage. This experiment shows that ashed residues and husk addition minimizes GWP of flooded soils and enhances pore water Si compared to straw addition even after pre-incubation.

Differential sensitivity of an invasive and an indigenous ladybeetle to two reduced‐risk insecticides

AbstractThe invasive multicoloured Asian lady beetle, Harmonia axyridis (Pallas), and the indigenous twelve spotted lady beetle, Coleomegilla maculata DeGeer (Col., Coccinellidae), are two important generalist predators commonly found in apple orchards in Quebec, Canada. Both species are exposed to two reduced‐risk insecticides, recently adopted to control codling moth, Cydia pomonella (L.) (Lep., Tortricidae) in south‐eastern Canada. Chlorantraniliprole (Altacor® 35 WG), an anthranilic diamide insecticide, causes paralyses of the muscle cells by interfering with the insect ryanodine receptors, whereas novaluron (Rimon® EC 10), a benzoylphenyl urea, inhibits the chitin synthesis. The aim of this study was to compare the sensitivity of both the invasive ladybeetle H. axyridis and the indigenous C. maculata to reduced‐risk insecticides through the assessment of lethal effect on eggs and larvae following topical contact, ingestion of treated prey and exposure to fresh residues, at field rates (50.75 g a.i./ha chlorantraniliprole and 100 g a.i./ha novaluron) in laboratory conditions. Eggs of both species were not affected. Following 6 days of residual contact, chlorantraniliprole and novaluron caused more than 98% mortality to larvae of both ladybeetle species. In topical contact and ingestion trials, chlorantraniliprole caused less than 18% mortality to larvae of the two species after 6 days following exposure. Novaluron had a drastically different impact on the two predators. It did not affect the indigenous C. maculata, whereas it killed 91% and 96% of H. axyridis individuals after 6 days, respectively, following topical contact and ingestion. These results illustrate a differential sensitivity to novaluron between two relatively close species (subfamily Coccinellinae), a potential impact on the invasion process by H. axyridis, and consequently on the ladybeetle assemblage in the field.

Economic implications of grinding, transporting, and pretreating fresh versus aged forest residues for biofuel production

The moisture content in forest harvest residues is a key factor affecting the supply cost for bioenergy production. Fresh harvest residues tend to contain higher amounts of water, thus making transportation inefficient. Additionally, fresh harvest residues contain greater amounts of needles and bark that may reduce the polysaccharide content, thus affecting the production of liquid fuels derived from cellulosic components. In this study, we estimated the downstream economic effect in the supply chain of collecting, grinding, transporting and pretreating fresh versus aged residues. Specifically, we analyzed the effect of feedstock moisture content on grinder fuel consumption, bulk density, bark and needle content, and polysaccharide proportion. Fresh forest harvest residues were 60% moisture content (wet basis) and aged forest residues were 15% moisture content. The bark and needle proportion is 6.1% higher in fresh residue than in aged residue. Polysaccharides were 26% higher in aged residue than in fresh residue. On a dry-tonne basis, the cost of grinding fresh residues was about the same as that of aged residues. However, considering the difference in bulk density on transportation cost and the difference in polysaccharide yield, the value gain for in-field drying ranges from US$29.60 to US$74.90 per ovendry tonne.

Validation of NBudget for estimating soil N supply in Australia's northern grains region in the absence of soil test data

Effective management of fertiliser nitrogen (N) inputs by farmers will generally have beneficial productivity, economic and environmental consequences. The reality is that farmers may be unsure of plant-available N levels in cropping soils at sowing and make decisions about how much fertiliser N to apply with limited information about existing soil N supply. NBudget is a Microsoft (Armonk, NY, USA) Excel-based decision support tool developed primarily to assist farmers and/or advisors in Australia’s northern grains region manage N. NBudget estimates plant-available (nitrate) N at sowing; it also estimates sowing soil water, grain yields, fertiliser N requirements for cereals and oilseed crops and N2 fixation by legumes. NBudget does not rely on soil testing for nitrate-N, organic carbon or soil water content. Rather, the tool relies on precrop (fallow) rainfall data plus basic descriptions of soil texture and fertility, tillage practice and information about paddock use in the previous 2 years. Use is made of rule-of-thumb values and stand-alone or linked algorithms describing, among other things, rates of mineralisation of background soil organic N and fresh residue N. Winter and summer versions of NBudget cover the 10 major crops of the region: bread wheat, durum, barley, canola, chickpea and faba bean in the winter crop version; sorghum, sunflower, soybean and mung bean in the summer crop version. Validating the winter crop version of NBudget estimates of sowing soil nitrate-N against three independent datasets (n=65) indicated generally close agreement between measured and predicted values (y=0.91x+16.8; r2=0.78). A limitation of the tool is that it does not account for losses of N from waterlogged or flooded soils. Although NBudget also predicts grain yields and fertiliser N requirements for the coming season, potential users may simply factor predicted soil N supply into their fertiliser decisions, rather than rely on the output of the tool. Decisions about fertiliser N inputs are often complex and are based on several criteria, including attitudes to risk, history of fertiliser use and costs. The usefulness and likely longevity of NBudget would be enhanced by transforming the current Excel-based tool, currently available on request from the author, to a stand-alone app or web-based tool.

Natural evolution of alkaline characteristics in bauxite residue

Bauxite residue, a highly alkaline solid waste, is extremely hazardous to the surrounding environment and current research approaches have largely focused on the removal and separation of alkaline substances. Natural weathering processes may be a step forward in terms of their regeneration. In this study, natural evolution of basic alkalinity, electrical conductivity, exchangeable ions and acid neutralizing capacity of residue in the disposal areas was discussed. Minerals, exchangeable cations and alkaline anions were analyzed by X-ray powder diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and titration, respectively. Acid neutralizing capacity was carried out by batch neutralization experiments. Basic alkalinity, electrical conductivity, cation exchange capacity and exchangeable sodium percentage decreased with increasing disposal duration. Sodium was the predominant exchangeable cation in fresh residue but its concentration significantly decreased with increasing time from initial disposal. The acid neutralizing capacity of bauxite residue was investigated by incubation with hydrochloric acid. Acid neutralizing capacity curves changed with disposal duration and each revealed a characteristic buffering behavior that could be controlled by its alkaline components.

Eco-toxicological risk and impact of pesticides on important parasitoids of cabbage butterflies in cruciferous ecosystem

Eco-toxicological risk and impact of pesticides was estimated on three important parasitoids of butterflies viz., Hyposoter ebeninus, Cotesia glomerata and Pteromalus puparum. Four commonly used pesticides were evaluated using standard protocol (of IOBC/WPRS-group). In laboratory tests, the survival of the female wasps decreased significantly on fresh contact and ingestion of deltamethrin, spinosad and azadirachtin; whereas Bacillus thuringiensis var kurstaki (Btk) was found harmless pesticide. Under semi-field conditions, parasitoid mortality decreased significantly on fresh contact with the pesticides. Although, at 72 h after treatment, spinosad and deltamethrin were found harmful (Class-IV) and azadirachtin was moderately harmful (Class-III), whereas Btk was harmless (Class-I). Furthermore, 15-day-old residues of pesticides (except deltamethrin) were harmless to all parasitoid species under semi-field conditions. Notably, adult emergence and pupal duration in pesticide-treated cocoons were not significantly affected; however, their survival decreased after emergence except in Btk. The contact and oral toxicity trends of the pesticides were almost similar for three species of parasitoid females and pupae; however little variability was observed in toxicity to the host caterpillars parasitized by H. ebeninus (HCPHE) and C. glomerata (HCPCG). In semi-field tests, fresh residues of all the pesticides were harmful to HCPHE and HCPCG. However, action of Btk was slightly delayed and toxicity was rather low for HCPCG. In 15-day-old residues, deltamethrin and azadirachtin were slightly harmful to the parasitized caterpillars, whereas those of Btk and spinosad were harmless. Since, Btk appeared to be safe for parasitoids; it could be used for managing cabbage butterflies in brassicaceous crops.

English

A good soil structure is indicated by the abundance of soil aggregates which has an important role in sustainable agricultural management and soil productivity. As it affects hydraulic conductivity, gases transport within the soil and seed germination, root respiration and eventually plant growth. The different sized fractions of soil aggregates are influenced significantly by both the amount and the composition of organic matter present in the soil (Piccolo, 1996). The degree of soil aggregation and aggregate stability is the result of the interaction between organic and inorganic soil components. Soil structure degradation occurs mostly due to the decrease in soil organic carbon caused by excessive soil cultivation and soil erosion. Eroded soils have consistently shown lower soil organic carbon and nutrient concentrations in upper profiles than cultivated soils, this is also true for other physical properties such as soil texture and saturated hydraulic conductivity (Heckrath et al., 2005). Soil organic carbon (SOC), includes soil organisms (e.g. microbial biomass), simple organic compounds (e.g. polysaccharides), large and complex humic substances, as well as relatively fresh residue at various stages of decomposition (Weil and Magdoff, 2004). The effect of different composted and un composted products on soil aggregate stability across time scales vary from weeks, months to years after the incorporation (Monnier, 1965). The various components of organic carbon such as microbial biomass carbon, polysaccharides and humic substances play very important role in the aggregate formation mechanism. The polysaccharides are highly complex polymers, consisting of many structural units, and are naturally resistant to decomposition or become resistant through reaction with other soil constituents and serve as binding agents. Microbial biomass carbon is an active form of carbon and it influences aggregate formation and stability. Humic substances account for the largest and most decomposed proportion of soil organic matter (SOM) with chemically complex and ill-defined structure, and act as persistent binding agent for stabilization of aggregates. Stabilization of aggregates by organic matter (Six et al., 2004) and interactions between aggregative factors and aggregate structures is well documented. In most studies, the organic matter additions were characterized by their elemental composition but additional information such as contents of humic and non-humic substances were seldom provided. In this study we hypothesized that addition of organic sources on equivalent carbon level basis affect the soil aggregate formation differently as composition of materials vary. The objectives of the present study were, to examine the quality (fundamental characteristics) of the traditional organic manures and their direct effect upon formation, Pak. J. Agri. Sci., Vol. 53(4), xxx-xxx; 2016 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI: 10.21162/PAKJAS/16.4205 http://www.pakjas.com.pk

An evaluation of C and N on fresh and aged crop residue from mixed long-term no-till cropping systems

ABSTRACTConservation crop residue management increases soil organic carbon (SOC) storage, nutrient cycling and availability and improves soil quality. This study was conducted to evaluate the amount of residue biomass, residue carbon to nitrogen (C:N) ratio, residue carbon (C) and nitrogen (N), and residue N fertilizer deficit (supplemental N fertilizer requirement) from crop residue decomposition in long-term no-till production. Aboveground aged and fresh residues were collected in spring 2011 and fall 2012, respectively. Results showed slightly greater residue dry matter weight in aged residue than fresh residue. C:N ratios were wider in fresh residue than the aged residue. Both aged and fresh residue also showed wider C:N ratio in the corn (Zea mays L.)-soybean (Glycine max L.) rotation (66.6 and 64.4, respectively) and narrower C:N ratio in the spring wheat (Triticum aestivum L.)-winter wheat (Triticum aestivum L.)-alfalfa (Medicago sativa L.)-alfalfa-corn (Zea mays L.)-soybean (Glycine max L.) (45.6 and 35.7, respectively). Individual fresh crop residues showed narrower C:N ratios for legume and cover crops than non-legume crops. Analysis of potential supplemental N fertilizer requirements showed greater potential N requirement for the fresh residue than the aged residue.

The Possibility of Meeting Greenhouse Energy and CO2 Demands Through Utilisation of Cucumber and Tomato Residues

The article examines the possibility of using residues from greenhouse cucumber and tomato cultivation as biomass for energy and CO2 production in order to meet greenhouse needs. Methane fermentation and combustion were compared. Moreover, the legitimacy of ensiling as a storage method for biogas plant was evaluated. The tested waste was found to be an unsuitable feedstock for the production of silage due to low sugar and high protein content. Fresh waste had a higher biogas yield than silage; however, its fermentation lasted longer. Furthermore, the results showed that, in the case of fresh residues, the methane fermentation proved to be a more energy-efficient process, while air-dry biomass is a more sustainable feedstock for combustion. The energy and CO2 balance showed that, regardless of the method used, the available quantity of waste is too small to meet the greenhouse needs.

Lethal and sublethal effects of pesticides on Chrysoperla carnea larvae (Neuroptera: Chrysopidae) and the influence of rainfastness in their degradation pattern over time.

The predator Chrysoperla carnea is a model species for the study of non-target effects of pesticides under different scenarios: registration of plant protection products under the European Union and effects of the Bt toxin. Laboratory and persistence studies were carried out with six pesticides currently used in corn crops in Spain that were applied at their maximum field recommended concentrations. The assessed end-points were larval mortality, survivorship until adult stage, duration of the larval and pupal periods, fecundity, fertility and sex ratio of the emerged adults. Based on the total effect (lethal and sublethal) caused to L3 larvae in contact with fresh residues in the laboratory, pendimethalin was harmless (IOBC 1), lambda-cyhalothrin, abamectin, and hexythiazox were slightly harmful (IOBC 2), deltamethrin was moderately harmful (IOBC 3) and chlorpyrifos was harmful (IOBC 4). Afterwards, the residues of the two most toxic pesticides in the lab (deltamethrin and chlorpyrifos) were aged under greenhouse conditions (22±2°C, 40±10% R.H., 16.9 μmol m(-2) s(-1) UV radiation) in the presence and absence of artificial rainfall (10lm(-2)h(-1), applied 24h after pesticide application). Deltamethrin was classified as short lived (IOBC A) in both cases. However, degradation of chlorpyrifos residues was accelerated in the presence of rainfall, leading to the classification as slightly persistent (IOBC B), while in absence of rainfall it behaved as persistent (IOBC D). Every pesticide can be recommended for inclusion in corn IPM programs where the predator is present except chlorpyrifos that exhibited high direct toxicity in the lab and prolonged residual action even in the presence of rainfall.

Decomposition of olive-mill waste compost, goat manure and Medicago sativa in Lebanese soils as measured using the litterbag technique

Organic amendments, green manure and plant residues are the main sources of nutrients under organic farming. The decomposition of compost from olive-mill waste, aged goat manure and lucerne (alfalfa, Medicago sativa) shoots was studied in subhumid Mediterranean conditions. The locations of Abdeh, Lebaa and Sour were distinguished by their respective clay (521, 315 and 260 g kg–1 soil) and calcium carbonate (42, 591 and 269 g kg–1 soil) contents. Nutrients release was evaluated over 1 year by using litter bags buried at 10 cm depth. Despite close initial total nitrogen (N) contents, shoots lost 50–60% of N, whereas the stable compost and manure mineralised 20–26% after 30 days of incubation. Calculated coefficients of decomposition for organic carbon (OC) were significantly higher for shoots (0.0061 day–1) than for manure (0.0020 day–1) and compost (0.0011 day–1). Coefficients for total N were very similar to those for OC: shoots (0.0050 day–1) > manure (0.0018 day–1) and compost (0.0017 day–1). OC was the parameter most discriminating between fresh residue and decomposed products, and potassium the least. Of the soil properties, the calcium carbonate rather than the clay content affected decomposition. Coefficients of decomposition of OC were significantly different with Sour (0.0036 day–1) > Abdeh (0.0030 day–1) > Lebaa (0.0026 day–1). Coefficients for total N were also different with Abdeh ≡ Sour > Lebaa. Fresh and stable products could be a source of nutrients even during winter in Mediterranean conditions.

Risk of Using Crop Residues and Water that are Contaminated with Pesticides for Feeding Cattle's in Nuwara Eliya DS Division

Farmers who cultivate upcountry vegetables in Nuwara Eliya apply high amounts of pesticides, due to the intensive cultivation of hybrid crop varieties and highly favorable weather conditions. The extensive use of pesticides may lead to environmental and food contamination. Presently highest milk production was reported in Nuwara Eliya. Abundance of crop residues in substantial amounts lead farmers to feed them adequately for cattle. The objectives of this study were to identify the types of pesticides used in the area, crop residues that are used as feed material and sources of contaminants which have an impact to the milk industry in Nuwara Eliya. Forty farmers in four villages of Nuwara Eliya DS division namely Bambarakelle, Shanthipura, Galpalama and Ambewela were interviewed. Present breeds were Friesian, Jersey and local crossbreds (69, 23 and 7% respectively) and major crops were carrot, leeks, cabbage and potato. Due to grasslands scarcity, 70% of farmers carry out intensive rearing. Farmers provide grasses (87%) and crop residues (13%) to cattle. Fresh grasses and crop residues were directly fed to cattle without any treatments. Farmers used tap water (53%) and well water (47%) as water sources. The majority (>90%) disposed the empty pesticide containers by throwing in the crop land itself. Farmers applied Maneb (31%), Fipronil (31%) and Propineb (20%) as pesticides for cultivation of vegetables nearby water sources while fungicides (Propineb 28% and Maneb 24%) applied nearby farm lands. Feeding with crop residues, grasses and water which were contaminated with pesticides encountered high risk to contain pesticide residues in milk.

Incorporation of 13C labelled shoot residues in Lumbricus terrestris casts: A combination of transmission electron microscopy and nanoscale secondary ion mass spectrometry

Earthworms transform organo-mineral associations in soil, especially by incorporating fresh residues inside casts where the microbial abundance and activity are enhanced. The heterogeneous distribution of organic carbon in these structures influences decomposition levels at the microscale. The incorporation of 13C labelled plant residues by Lumbricus terrestris inside cast was investigated, through the innovative combination of two fine scale imaging techniques: transmission electron microscopy and nanoscale secondary ion mass spectrometry (NanoSIMS). The association of these methods sheds new lights on organo-mineral structures. Different types of organic matter (plant residues, microbial remains) were identified in the casts and the freshly incorporated residues could be differentiated from the indigenous organic matter thanks to δ13C NanoSIMS mapping. 13C labelled bacteria and fungi abundance and diversity highlight their preeminent role in litter decomposition within casts. Labelled plant residues observed at various stages of decomposition and microorganisms presented highly variable δ13C values, emphasizing the complexity of organic matter dynamics and the importance of microscale analyses to describe this variability. Thus, the combination of NanoSIMS and TEM shows great potential to relate organic matter stages of decomposition with their 13C signature.

Acute Toxicity and Sublethal Effects of Fenpyroximate to Amblyseius swirskii (Acari: Phytoseiidae).

Knowledge about the effects of pesticides on biological control agents is required in order to successfully implement integrated pest management programs. The predatory mite Amblyseius swirskii Athias-Henriot has been used to control thrips, whiteflies, and broad mites in vegetable production; however, effects of fenpyroximate, an acaricide and insecticide used in vegetable crops, on A. swirskii have not been evaluated. The effect of four residual concentrations of fenpyroximate on A. swirskii females was measured under laboratory conditions including its effect on their fecundity and larval survival. Fresh residues of fenpyroximate were significantly toxic to adult females and larvae. Mortality increased and fecundity decreased as the concentration (0.026-0.208 ml/50 ml of water) and time after treatment (24-120 h) increased. Fifty percent of the larvae survived on the two lower concentrations (0.026 and 0.052 ml/50 ml of water) after 120 h.

Concentration-Response and Residual Activity of Insecticides to Control Herpetogramma phaeopteralis (Lepidoptera: Crambidae) in St. Augustinegrass.

Tropical sod webworm, Herpetogramma phaeopteralis Guenée, is an important pest of warm-season turfgrass in the Gulf Coast states of the United States, the Caribbean Islands, and Central America. Current control recommendations rely on topical application of insecticides against caterpillars. The objective of this study was to generate resistance baseline data of H. phaeopteralis to six insecticide classes. Residual activity of clothianidin, chlorantraniliprole, and bifenthrin was also compared under field conditions in Central Florida. Chlorantraniliprole was the most toxic compound tested (LC50 value of 4.5 ppm), followed by acephate (8.6 ppm), spinosad (31.1 ppm), clothianidin (46.6 ppm), bifenthrin (283 ppm) and Bacillus thuringiensis kurstaki, (342 ppm). In field tests, all compounds at label rates were effective (≥94% mortality of larvae exposed to fresh residues). However, a more rapid decline in activity of clothianidin and bifenthrin was observed compared with chlorantraniliprole. Clothianidin had no statistically detectable activity after 4 wk post-application in spring and the fall, and bifenthrin had no detectable activity after 3 wk in the spring and the fall. However, chlorantraniliprole maintained significant activity (≥84% mortality) compared with other treatments throughout the 5-wk study period. This study provides new information regarding the relative toxicities and persistence of current insecticides used for H. phaeopteralis and other turfgrass caterpillars.

Pressurized liquid extraction of bioactive compounds from blackberry (Rubus fruticosus L.) residues: a comparison with conventional methods

Extracts with antioxidant compounds were obtained from residues of blackberries (Rubus fruticosus L.) through pressurized liquid extraction (PLE). The influence of solvent type (water, acidified water pH=2.5, ethanol and ethanol+water 50% v:v) and temperature (60, 80 and 100°C) on global yield (X0), total phenolics (TP), monomeric anthocyanins (MA) and antioxidant activity (AA) (by DPPH and ABTS) of the extracts was evaluated. Moreover, anthocyanins were identified and quantified by UHPLC-QToF-MS e UHPLC-UV-Vis, respectively. The best PLE condition was compared to conventional extractions (Soxhlet and maceration). Results showed positive influence of temperature on global yield, TP and AA. Ethanol+water as solvent at 100°C was chosen as the best PLE condition, providing TP=7.36 mgGAE/g fresh residue, MA=1.02mg C3GE/g fresh residue, AA=76.03μmol TE/g fresh residue and X0=6.33%. Excepting MA, all other results were over those of conventional extractions. Four anthocyanins were identified by UHPLC in the extracts, and their higher yields were achieved with acidified water as solvent at 60 and 80°C. PLE has proved to be a promising alternative to recover bioactive compounds from blackberry residues, as well as other food by-products.