The Influence of Biochar Production on Herbicide Sorption Characteristics

Biochar is the by-product of a thermal process conducted under low oxygen or oxygen-free conditions (pyrolysis) to convert vegetative biomass to biofuel (Jha et al., 2010). There are a wide variety of end-products that can be manufactured depending on processing parameters and initial feedstocks (Bridgewater, 2003). The pyrolytic process parameters such as temperature, heating rate, and pressure can change the recovery amounts of each end-product, energy values of the bio-oils, and the physico-chemical properties of biochar (Yaman, 2004)

Precision Farming Protocols: Part 1. Grid Distance and Soil Nutrient Impact on the Reproducibility of Spatial Variability Measurements

To determine temporal changes in soil nutrient status, reproducible results must be obtained at each time step. The objective of this paper was to determine the impact of grid distance on the reproducibility of spatial variability measurements. Soil samples from the 0 to 15 cm depth were collected from a 30 by 30 m grid in May 1995 in a 65 ha notill corn (Zea mays L.) field. Each bulk sample contained 15 individual cores, collected at sample points located every 11.4 cm along a transect that transversed 3 corn rows (57 cm). At each sampling point latitude, longitude, elevation, landscape position, and soil series were determined. The 30 m grid was used to develop 4 and 9 independent data sets having a 60 and 90 m, grids, respectively. Semivariograms, nugget to sill ratios, and mean squared errors were calculated for each data set. At 60 m: (i) the total N, total C, and pH semivariograms, of different start points, were similar, while semivariograms for Olsen P, K, and Zn were different; (ii) the spatial dependence ratings, based on the nugget to sill ratio, for total N, total C, and pH semivariograms were consistent and suggested moderate spatial dependence; (iii) the spatial dependence rating for Olsen P, K, and Zn for the 4 semivariograms were not consistent and ranged from weak to moderate spatial dependence. At 90 m all soil nutrients had different semivariograms for each start point, while the spatial dependence rating for each total N, total C, and pH start point were consistent and showed moderate spatial dependence. The total C, P, K, Zn, and pH MSE values at 60 m, were 30, 30, 41, 28, and 72% lower than the variance, respectively. This study showed that semivariogram, semivariance, MSE, and nugget to sill ratios reproducibility were dependent on soil nutrient and grid distance

Chemical Amendments of Dryland Saline–Sodic Soils Did Not Enhance Productivity and Soil Health in Fields without Effective Drainage

A common restoration treatment for saline–sodic soils involves improving soil drainage, applying soil amendments (e.g., CaSO4, CaCl2, or elemental S), and leaching with water that has a relatively low electrical conductivity. However, due to high subsoil bulk densities and low drainable porosities, these treatments many not be effective in glaciated dryland systems. A 3-yr field study conducted in three model systems determined the impact of chemical amendments (none, CaCl2, CaSO4, and elemental S) on plant growth, microbial composition, temporal changes in electrical conductivity (ECe ), and the relative sodium content (%Na). Chemical amendments (i) either reduced or did not increase maize (Zea mays), soybean (Glycine max), and sorghum (Sorghum bicolor) yields; (ii) did not increase water infiltration or microbial biomass as determined using the phospholipid-derived fatty acid (PLFA) technique; and (iii) did not reduce ECe or %Na. These results were attributed to high bulk densities and low drainable porosities that reducing the drainage effectiveness in the model backslope and footslope soils, the presence of subsurface marine sediments that provided a source for sodium and other salts that could be transported through capillary action to the surface soil, high sulfate and gypsum contents in the surface soil, and relatively low microbial biomass values. The results suggests that an alternative multistep saline sodic soil restoration approach that involves increasing exchangeable Ca+2 through enhanced microbial and root respiration and increasing transpiration and soil drainage by seeding full season deep rooted perennial vegetation should be tested

Nitrate Sorption and Desorption in Biochars from Fast Pyrolysis

Increasing the nitrate (NO3- role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; font-style: normal; font-weight: normal; line-height: normal; font-size: 16.2px; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3e NO3-) sorption capacity of Midwestern US soils has the potential to reduce nitrate leaching to ground water and reduce the extent of the hypoxia zone in the Gulf of Mexico. The objective of this study was to determine the sorption and desorption capacity of non-activated and chemically activated biochars from microwave pyrolysis using selected biomass feedstocks of corn stover (Zea mays L.), Ponderosa pine wood chips (Pinus ponderosa Lawson and C. Lawson), and switchgrass (Panicum virgatum L.). Surface characteristics such as surface area and net surface charge have shown significant effects on nitrate sorption and desorption in biochars. Freundlich isotherms performed well to fit the nitrate sorption data (R2 \u3e 0.95) of biochars when compared to Langmuir isotherms. Nitrate sorption and desorption was significantly influenced by solution pH and presence of highly negative charged potential ions such as phosphate (PO43- role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; font-style: normal; font-weight: normal; line-height: normal; font-size: 16.2px; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3e PO43-) and sulfate (SO42- role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; font-style: normal; font-weight: normal; line-height: normal; font-size: 16.2px; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3e SO42-) in aqueous solution. Chemical activation with concentrated HCl had significant effect on surface characteristics of biochars and enhanced the nitrate sorption capacity. The first order model fit the nitrate desorption kinetics of biochars with a high coefficient of determination (R2 \u3e 0.95) and low standard error (SE)

Phosphorus Sorption and Availability fromBiochars and Soil/Biochar Mixtures

In an energy‐limited world, biomass may be converted to energy products through pyrolysis. A byproduct of this process is biochar. A better understanding is needed of the sorption characteristics of biochars, which can influence the availability of plant essential nutrients and potential water contaminants such as phosphorus (P) in soil. Knowledge of P retention and release mechanisms when applying carbon‐rich amendments such as biochar to soil is needed. The objectives of this study were to quantify the P sorption and availability from biochars produced from the fast pyrolysis of corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.). We determined the impact of biochar application to soils with different chemical characteristics on P sorption and availability. Sorption of P by biochars and soil–biochar mixtures was studied by fitting the equilibrium solution and sorbed concentrations of P using Freundlich and Langmuir isotherms. Biochar produced from Ponderosa pine wood residue had very different chemical characteristics than corn stover and switchgrass. Corn stover biochar had the highest P sorption (in average 79% of the initial solution P concentration) followed by switchgrass biochar (in average 76%) and Ponderosa pine wood residue biochar (in average 31%). Ponderosa pine wood residue biochar had higher bicarbonate extractable (available) P (in average 43%) followed by switchgrass biochar (33% of sorbed P) and corn stover biochar (25% of sorbed P). The incorporation of biochars to acidic soil at 40 g/kg (4%) increased the equilibrium solution P concentration (reduced the sorption) and increased available sorbed P. In calcareous soil, application of alkaline biochars (corn stover and switchgrass biochars) significantly increased the sorption of P and decreased the availability of sorbed P. Biochar effects on soil P was aligned with their chemical composition and surface characteristics

Detection of fish antigens aerosolized during fish processing using newly developed immunoassays

Background: Aerosolization of fish proteins during seafood processing has been identified as a potential route for allergic sensitization and occupational asthma among workers involved in high-risk activities. The aim of this study was to develop immunological assays for the quantification of aerosolized fish antigens in a fish-processing factory. \ud \ud Methods: Polyclonal antibodies to the main fish species processed in the factory (anchovy and pilchard) were generated in rabbits and compared by ELISA inhibition assay and immunoblotting. These antisera were utilized to develop ELISA assays for the detection of fish antigens. The ELISA inhibition assays were evaluated by analyzing environmental air samples collected from three areas in a fish-processing factory: pilchard canning, fish meal production and lobster processing. \ud \ud Results: By immunoblotting, the rabbit polyclonal antibodies demonstrated IgG antibody binding patterns comparable with IgE antibodies of fish-sensitized patients, particularly in regard to the major fish allergens parvalbumins. The sensitivity of the fish-specific ELISA assays developed was 0.5 μg/ml. The ELISA inhibition assays were able to differentiate between the two different fish species of interest but did not recognize a crustacean species. Notable differences in exposure levels to canned pilchard and anchovy antigens were demonstrated in the three different working areas of the factory, with assays having a detection limit as low as 105 ng/m3. \ud \ud Conclusion: These ELISA-based assays are sensitive and specific to quantify differential exposure levels to fish antigens produced during fish processing, making it possible to investigate exposure-disease response relationships among workers in this industry

Different Techniques to Identify Management Zones Impact Nitrogen and Phosphorus Sampling Variability

he efficiency of the management zone approach to improve fertilizer recommendations relies on accurately locating zone boundaries. The objective of this study was to determine the impact of different techniques of identifying management zones on soil NO− 3–N and Olsen-P (sodium bicarbonate extractable-P) sampling variability. Soil samples were collected on a 60 by 60 m or denser grid, in three fields (65, 53, and 40 ha). These samples were analyzed for NO− 3–N and Olsen-P. Soil nutrient data was used to simulate the effect of different techniques to identify P and N management zone boundaries. Approaches evaluated for locating management zone sampling boundaries included: (i) sampling areas impacted by old homesteads or animals separately from the rest of the field; (ii) sampling different grid cells; (iii) use of geographic information systems (GIS) or cluster analysis to identify zones based on apparent electrical conductivity (ECa), elevation, aspect, and distance (connectedness); and (iv) sampling each soil series separately. An F statistic was used to determine if the sampling approach reduced nutrient sampling variability. Results suggested that: (i) old homesteads or areas impacted by animals should be sampled separately from the rest of the field; (ii) grid-cell sampling was more consistent in reducing within zone soil-test variability than the other techniques tested; and (iii) zones that are not continuous should be sampled and managed separately

Temperature-controlled encapsulation and release of an active enzyme in the cavity of a self-assembled DNA nanocage

We demonstrate temperature-controlled encapsulation and release of the enzyme horseradish peroxidase using a preassembled and covalently closed three-dimensional DNA cage structure as a controllable encapsulation device. The utilized cage structure was covalently closed and composed of 12 double-stranded B-DNA helices that constituted the edges of the structure. The double stranded helices were interrupted by short single-stranded thymidine linkers constituting the cage corners except for one, which was composed by four 32 nucleotide long stretches of DNA with a sequence that allowed them to fold into hairpin structures. As demonstrated by gel-electrophoretic and fluorophore-quenching experiments this design imposed a temperature-controlled conformational transition capability to the structure, which allowed entrance or release of an enzyme cargo at 37 °C while ensuring retainment of the cargo in the central cavity of the cage at 4 °C. The entrapped enzyme was catalytically active inside the DNA cage and was able to convert substrate molecules penetrating the apertures in the DNA lattice that surrounded the central cavity of the cage