High Rate Applications Research Articles

Contrasting effects of biochar application rate in an alkaline desert cropland soil

Improving water and nutrient retention in desert croplands using soil organic amendments can be a major challenge because organic matter decomposes quickly under irrigated conditions in a hot climate. Biochar—a long-lasting carbon-rich soil organic amendment—has been proposed to improve soil water and nutrient retention, but only by carefully selecting an appropriate application rate. To better understand effects of biochar application rate on soil water and nutrient retention in desert croplands, we set up a mesocosm-scale experiment with biochar added at rates of 0, 19.8, 39.7, 79.4, 119.0, and 158.7 t ha−1 to an alkaline, sandy loam soil. After initial water retention measurements, we added fertilizer and then measured gaseous nitrogen losses as well as soil nitrate (NO3−) and phosphate (PO₄³⁻) leaching. Then, we measured biochar's effect on the soil's capacity to hold plant-available water (i.e., available water capacity, or AWC) using Tempe cells and a dewpoint potentiometer. We found contrasting effects of low and high biochar application rates. First, we found that applying a minimum of 79.4 t ha−1 biochar was necessary to improve soil water and PO₄³⁻ retention; application rates below 79.4 t ha−1 exacerbated PO₄³⁻ leaching whereas treatments above 79.4 t ha−1 improved AWC by up to 34% compared to the control treatment. While biochar application rate did not affect soil nitric oxide or ammonia emissions, we did find that low biochar application rates increased soil nitrous oxide emission while higher application rates reduced emission compared to soil with no biochar. Overall, we found that lower and higher rates of biochar application can have contrasting effects on soil water and nutrient retention in an alkaline, desert cropland soil. Therefore, farmers and other land managers must consider potential drawbacks of lower application rates and threshold responses of higher application rates prior to large-scale biochar use in arid agroecosystems.

Analysis of Citizens' Tax Avoidance Actions Based on Tax Laws in Indonesia

Tax avoidance is an effort to avoid taxes that are carried out legally and safely to taxpayers in accordance with applicable tax regulations. This is because the methods and techniques used are based on exploiting the weaknesses contained in the tax laws and regulations. This type of written research method is qualitative depending on the type of document. Qualitative research is a type of research whose results are not based on statistics or other calculations. Application of high tax rates is also an obstacle because it burdens taxpayers. Other disabilities include: Regulations that apply the law are often inconsistent with the law. There are many formal and informal taxes at the central and regional levels. Weak law enforcement, complicated bureaucracy, and so on, will certainly help achieve good governance in the form of clean and authoritative government, if done properly. Indonesia does not yet have strong enough regulations to regulate tax avoidance. This is because Article 18 of Law Number 36 of 2008 concerning the Fourth Amendment to Law Number 7 of 1983 concerning Income Tax only regulates one taxpayer effort to avoid taxes, namely the only application of the concept of transfer pricing. On the other hand, other forms of tax avoidance are not regulated. Therefore, the state needs to reform its tax system.

Biochar rate-dependent regulation of extended nitrogen supply by modifying stable aggregates-N and microbial responses

Besides carbon sequestration, biochar amendment in soils can regulate the loss of applied fertilizer-nitrogen (N) into the environment. Soil aggregates are essential in controlling soil N stocks' stabilization and supply. However, unraveling the rate-dependent impact of biochar on stable soil aggregates and their associated N in fertilized soils over an extended period is a prerequisite to understanding its implications on soil-N dynamics. We unraveled how high and low biochar application rates combined with inorganic fertilizer (20- and 40-tons ha−1 [FB1 and FB2]) affected soil N fractions, stable soil aggregates, aggregates associated-N, and microbial responses to regulate N supply for Nageia nagi after one year. Results revealed that biochar amendment, especially at higher rate, increased the concentration of inorganic N and some amino acids compared to sole fertilizer (F). Available N increased by 16.5% (p = 0.057), 23.8% (p = 0.033), and 34.8% (p = 0.028) in F, FB1, and FB2, respectively, compared to the control (C). Also, 28.1% and 32.8% significant increases in the availability of NH4+-N were recorded in FB1 and FB2, respectively, compared to F. NO3−-N availability was significantly increased by 15.2%, 21.8%, and 20.8% in FB1, FB2, and C, compared to F. Biochar amendment, irrespective of rate, increased stable microaggregates (< 0.25 mm). However, FB2 significantly increased macro- and intermediate-aggregate-N, and urease activity, and hence higher N supply capacity to meet the N need of N. nagi even after one year. Hence, the N content of N. nagi was 41.3%, 28.8%, and 12.2% higher in FB2, FB1, and F, respectively, compared to the control. Biochar amendment decreased bacterial species diversity but increased the proportion of NH4+-oxidizers (especially the Betaproteobacteria) to maintain the mineralization and slow release of N. Although a low biochar rate was more beneficial than sole fertilization, higher biochar application rate could sustain higher N supply by stabilizing soil microaggregates and increasing macro- and intermediate-aggregates N, its mineralization, and slow-release over longer periods.

A microbial bioherbicide for Striga hermonthica control: production, development, and effectiveness of a seed coating agent.

Witchweed (Striga hermonthica), also called striga, is a parasitic weed that causes high yield losses in maize on more than 200 000 ha in Kenya alone. A new commercial, biological herbicide developed in Kenya is able to control striga effectively. The product was approved for use by the Pest Control Products Board in Kenya in September, 2021. It is self-produced in villages using a secondary inoculum provided by a commercial company. The formulated product has some disadvantages, which are a complicated production process, a very short shelf life and high application rate. Additionally, the product has to be applied manually and therefore can only be used in manual production, leaving out the opportunity for farmers using mechanization. For this reason, efforts have been made to formulate the active ingredient Fusarium oxysporum f. sp. strigae strain DSM 33471, as a powder and to use it as a seed coating agent. This article deals with the production of the Fusarium spore powder, its properties, its application to the seed, and its herbicidal effect demonstrated in the first two field trials. The F. oxysporum strain was originally isolated from a wilting striga plant in Kenya. The strain was virulence enhanced to over produce the amino acids leucine, methionine and tyrosine. These amino acids are responsible for a second mode of action apart from the wilting causing effect of the fungus on striga. Whereas leucine and tyrosine have a herbicidal effect, ethylene from methionine triggers the germination of striga seeds in the soil. Additionally, the strain has been improved to be resistant to the fungicide captan, which is commonly used to treat maize seed in Kenya. Seed coating tests conducted on 25 striga-infested small holder farms spread out in six counties of western Kenya reported yield increases of up to 88%. A second trial carried out by the Kenyan Agricultural and Livestock Research Organization showed a 93% reduction of emerged striga plants. © 2023 Society of Chemical Industry.

CONTENT OF NITRATES IN SUNFLOWER SEEDS AND ITS PROCESSING PRODUCTS WHEN GROWN ON GRAY FOREST SOILS

The excessive accumulation of nitrates in plant products is a consequence of the uncontrolled application of high and ultra-high rates of mineral fertilizers, in particular, nitrogen fertilizers that contain nitrate nitrogen. During the last decades in Ukraine, intensive farming measures are used everywhere in agriculture, which are determined by the introduction of high and often unbalanced rates of mineral fertilizers. This led to an increase in the content of nitrates in field crops, in particular in grain, oil and other technical crops. With the targeted use of mineral fertilizers, it is possible to increase the content of nitrates both in sunflower seeds and in the products of its processing: oil, fusi oil, and meal. One of the important factors in preventing the accumulation of nitrates in plant products is the periodic agrochemical and agroecological monitoring of soils in order to identify imbalances in the content of nutrients, changes in acidity, humus, and the content of other substances. The purpose of the research is to determine the content of nitrates in sunflower seeds and their processing products: fusi from oil and meal, taking into account the indicators of the agrochemical composition of the gray forest soil. The research was conducted during 2021-2022 on the production crops of FG "Zorya Vasylivka" village. Vasylivka, Vinnytsia district, Vinnytsia region. The laboratory analysis of the agrochemical composition of the soil according to the indicators of humus content, easily hydrolyzed nitrogen, mobile phosphorus, exchangeable potassium, pH reaction of the soil solution was carried out at the Zhytomyr branch of the State Institution "Derzhgruntokhorona" (Institute of Soil Protection of Ukraine) according to standard methods. Laboratory analyzes of the content of nitrates in sunflower seeds, fuschia and meal were carried out at the Vinnytsia branch of the State Institution "Derzhgruntokhorona" (Institute of Soil Protection of Ukraine) according to standard methods. In the conditions of the right-bank forest-steppe, when growing sunflowers on gray forest medium-loamy soils with a low provision of easily hydrolyzable nitrogen, medium - mobile phosphorus and high - exchangeable potassium when N45P45K45 is applied under its sowing, the nitrate content in sunflower seeds is 32.2 mg/kg, which in 9 ,3 times less than the maximum permissible concentration. At the same time, when making meal from sunflower seeds, the nitrate content in it increases by 47%, which requires additional control when using it for fodder purposes. And the content of nitrates in sunflower oil fuzz is 24% lower than in sunflower seeds, which makes it safer for feed use than meal.

Plant growth regulation and the rebound effect when prohexadione calcium is applied to fairway‐height annual bluegrass and creeping bentgrass swards

AbstractPlant growth regulators (PGRs) are commonly used to manage turfgrass growth on golf courses. Growing degree day (GDD) models predict the need for reapplication of PGRs, such as trinexapac‐ethyl (TE) resulting in a potential loss of regulation. Optimal GDD models for application of prohexadione calcium (PC), a late‐stage gibberellin inhibitor, on fairway‐height turfgrasses are currently unknown. The effect of PC and TE on plant growth and stand health were evaluated in two separate seasons on mixed stands of creeping bentgrass (Agrostis stolonifera L.) and annual bluegrass (Poa annua L.) maintained at 9‐mm height at the Guelph Turfgrass Institute. Five treatments (control, PC 2.8 g 100 m−2 [0.09 oz 1000 ft−2], PC 5.6 g 100 m−2 [0.18 oz 1000 ft−2], PC 8.4 g 100 m−2 [0.27 oz 1000 ft−2], and TE 8.0 mL 100 m−2 [0.26 fl oz 1000 ft−2]) were applied based on a label rate GDD schedule. Plant clipping dry weight (DW), visual color ratings and normalized difference vegetative index (NDVI) were assessed. Most PC and TE treatments effectively reduced DW and had a positive effect on visual color and NDVI. A relationship was observed between PC application rates, suggesting that higher application rates allow for greater regulation of plant growth. Rebound effects or periods of excess growth, occurred when reapplication intervals exceeded 350 GDD and had an average of thermal time greater than 21.0 GDD over a 10‐day period. Using optimal GDD models for PC will assist in the effective regulation of turfgrass growth and improved stand health.

Mapping internal temperatures during high-rate battery applications.

Electric vehicles demand high charge and discharge rates creating potentially dangerous temperature rises. Lithium-ion cells are sealed during their manufacture, making internal temperatures challenging to probe1. Tracking current collector expansion using X-ray diffraction (XRD) permits non-destructive internal temperature measurements2; however, cylindrical cells are known to experience complex internal strain3,4. Here, we characterize the state of charge, mechanical strain and temperature within lithium-ion 18650 cells operated at high rates (above 3C) by means of two advanced synchrotron XRD methods: first, as entire cross-sectional temperature maps during open-circuit cooling and second, single-point temperatures during charge-discharge cycling. We observed that a 20-minute discharge on an energy-optimized cell (3.5 Ah) resulted in internal temperatures above 70 °C, whereas a faster 12-minute discharge on a power-optimized cell (1.5 Ah) resulted in substantially lower temperatures (below 50 °C). However, when comparing the two cells under the same electrical current, the peak temperatures were similar, for example, a 6 A discharge resulted in 40 °C peak temperatures for both cell types. We observe that the operando temperature rise is due to heat accumulation, strongly influenced by the charging protocol, for example, constant current and/or constant voltage; mechanisms that worsen with cycling because degradation increases the cell resistance. Design mitigations for temperature-related battery issues should now be explored using this new methodology to provide opportunities for improved thermal management during high-rate electric vehicle applications.

Rapid and Robust Analytical Method for the Determination of Copper Content in Commercial Pesticides and Antifouling Biocides

The quality control of the agrochemicals and biocidal products in the market requires valid determination methods for the active ingredient content and is of utmost interest to ensure environmental protection, human health, and successful pest control. Copper has been used as fungicide for centuries, and today is still in the market in hundreds of products for various uses and is applied in very high application rates, both in pesticides and biocides. The aim of the present study was to develop a new fast, efficient, and inexpensive analytical method for the determination of copper content in antifouling Product Type 21 (PT-21) biocides as well as in copper containing pesticides. The samples were oxidized by microwave-assisted acid digestion method and copper content was determined by flame atomic absorption spectrometry technique. The recoveries of the method ranged from 87.9% to 97.6% for antifouling paints, and 98.6% to 99.95% for pesticides, while the percentage Relative Standard Deviation (%RSD) was lower than 6% in all cases. The validated method Limit of Quantification (LOQ) was 5 μg mL−1 that was sufficient for the present analysis needs. As a result, it is concluded that the method is easily applicable and transferable, with reasonable consumption of reagents, characterized by high reliability and sensitivity; therefore, it is suitable for monitoring the levels of copper in antifouling products as well as pesticides containing copper as active substance.

Optimization of antimicrobial peptides for the application against biocorrosive bacteria

Microbiologically influenced corrosion is a common problem in the industrial field due to the deterioration of metals in the presence of various microorganisms, in particular sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB). A common method to reduce microbiologically influenced corrosion is the application of biocides. The limited number of suitable biocides and the resulting development of resistance, high dosage, and high application rate hinder an effective application. An environmentally friendly alternative could be the application of antimicrobial peptides (AMP), which have already been established in the field of medical devices for a while. Here, the successful treatment of different AMPs against 3 SRB and 1 SOB was demonstrated. The peptide L5K5W was favored due to its broad activity, high stability, and simple structure resulting in low synthesis costs. An alanine scan showed that substitution of leucine with tryptophan increased the activity of this peptide twofold compared to the original peptide against D. vulgaris, the main representative of SRB. Additional optimization of this modified peptide through changes in amino acid composition and lipidations significantly increased the effectiveness, finally resulting in a minimum inhibitory concentration (MIC) of 15.63 μg/mL against Desulfovibrio vulgaris. Even against the marine SRB Desulfovibrio indonesiensis with a required salt concentration of min. 2%, an activity of the peptides can be observed (MIC: 31.25 μg/mL). The peptides also remained stable and active for 7 days in the supernatant of the bacterial culture.Key points• Antimicrobial peptides provide an alternative to combat biocorrosive bacteria.• Optimization of the peptide sequence leads to a significant increase in activity.• The investigated peptides exhibit high stability, both in the medium and in the bacterial supernatant.Graphical abstract

Assessing the environmental sustainability of different soil disinfestation methods used in solar greenhouse vegetable production systems

Overuse of fertilizers and irrigation and continuous monocropping is increasingly jeopardizing vegetable production in solar greenhouses as it causes serious soil degradation and the spread of soil-borne diseases. As a countermeasure, the practice of anaerobic soil disinfestation (ASD) has been recently introduced, which is carried out during the summer fallow period. However, ASD may increase N leaching and greenhouse gas (GHG) emissions when large amounts of chicken manure are applied. This study assesses how the use of different amounts of chicken manure (CM) combined with rice shells (RS) or maize straw (MS) affects soil O2 availability, N leaching, and GHG emissions during and following the ASD period. Application of RS or MS alone effectively stimulated long-lasting soil anaerobiosis without major stimulating effects on N2O emissions and N leaching. Seasonal N leaching and N2O emissions were in the ranges of 144–306 and 3–44 kg N ha−1, respectively, and were strongly increasing with increasing rates of manure application. Combining high rates of manure application with the additional incorporation of crop residues further increased N2O emissions by 56 %–90 % as compared to the standard practice of farmers (1200 kg N ha−1 CM). About 56 %–91 % of seasonal N2O emissions occurred during the ASD period, whereas N leaching mainly occurred in the cropping period (75 %–100 %). Our study shows, that for priming ASD incorporation of crop residue is sufficient and that the addition of chicken manure for ASD is not needed and should be reduced or even prohibited as it does not improve yields but stimulates the emission of the strong GHG N2O.

Multivariate Analysis Applied to the Ground Application of Pesticides in the Corn Crop

Including the correct combination of factors for the application technology of pesticides can improve their distribution on their targets. The aim of this work was to use multivariate analysis to study the effect size and the order of influence of three factors that interfere with pesticide application technology in corn crops. A 2 × 2 × 3 factorial experiment was conducted with two droplet size classes (fine and coarse), two application rates (80 and 150 L ha−1), and the presence of adjuvants (mineral oil one and two, and no adjuvant). A knapsack boom sprayer was used for the applications. Droplet deposition on the corn leaves was evaluated by detecting a tracer added to the spray via spectrophotometry and the droplet spectrum by analyzing water-sensitive papers. Univariate and multivariate statistical analyses were performed to integrate the variables analyzed. Droplet size has proven to be the most important factor in spraying planning, and the second factor is the application rate. With the association between fine droplets and higher application rates, a better performance was obtained in coverage, droplet density, and droplet deposition.

Safe Rice Production in Cd-Contaminated Paddy Soil: Strategy and Environmental Implications

This field study explored safe rice production in Cd-contaminated red paddy soil by application of the combined Si-/Se- containing foliar inhibitors (Si or Se) and the mixture amendments of quicklime (Q), polyacrylamide (A), or/and sepiolite (S) at low (1) and high (2) application rates. The results showed that all treatments increased soil pH and decreased total P and soil organic matter (excluding QSe2). With the increasing application rates, QAS significantly decreased the available Cd because of the enhanced stabilization, while QSi and QSe significantly increased the available Cd because of the inhibited plant uptake. After remediation, QA1, QSi2, and QSe2 most effectively decreased the uptake Cd by rice to meet the threshold of National Food Safety Standard of China. The treatments excluding Q1, QA1, QSi1, and QSi2 did not dramatically change the bacterial community structure in soil. Collectively, QSe2 was recommended for remediating Cd-contaminated red paddy soil.

Pig manure biochar for contaminated soil management: nutrient release, toxic metal immobilization, and Chinese cabbage cultivation

Pig manure could be an effective fertilizer source for soil, but with high concentrations of xic elements. It has been shown that the pyrolysis method could largely reduce the environmental risk of pig manure. However, the comprehensive analysis of both toxic metals immobilization effect and environmental risk of pig manure biochar applied as a soil amendment is rarely addressed. To address the knowledge gap, this study was carried out with pig manure (PM) and pig manure biochar (PMB). The PM was pyrolyzed at 450 ℃ and 700 ℃, the corresponding biochar was abbreviated as PMB450 and PMB700, respectively. The PM and PMB were applied in a pot experiment growing Chinese cabbage (Brassica rape L. ssp. Pekinensis) with clay-loam paddy soil. The application rates of PM were set at 0.5% (S), 2% (L), 4% (M) and 6% (H). With the equivalent mass principle, PMB450 and PMB700 were applied at 0.23% (S), 0.92% (L), 1.84% (M), 2.76% (H), and 0.192% (S), 0.7% (L), 1.4% (M), 2.1% (H), respectively. Parameters of Chinese cabbage biomass and quality, total and available concentrations of toxic metals in soil, and soil chemical properties were systemically measured. The main results of this study showed that compared with PM, PMB700 was more effective than PMB450, which induced the highest reductions of Cu, Zn, Pb, and Cd contents in cabbage by 62.6%, 73.0%, 43.9%, and 74.3%, respectively. Both PM and PMB increased the total contents of metals (Cu, Zn, Pb, and Cd) in soil, and PMB decreased the mobility of Cu, Zn, Pb, and Cd at high application rates (≥2%). Treatment with H-PMB700 reduced CaCl2 extractable Cu, Zn, Pb, and Cd by 70.0%, 71.6%, 23.3%, and 15.9%, respectively. For Cu, Zn, Pb, and Cd fractions with BCR extraction, PMB treatments, especially PMB700, were more effective than PM in decreasing the available fractions (F1 +F2 +F3) at high application rates (≥2%). Overall, pyrolysis with high temperature (e.g., 700 ℃) could significantly stabilize the toxic elements in PM and enhance PM’s effect on toxic metals immobilization. The marked effects of PMB700 on toxic metal immobilization and cabbage quality improvement might be attributed to high ash contents and liming effect.

Biochar amendment of a metal contaminated soil partially immobilized Zn, Pb, and Cd and reduced ryegrass uptake

Soil heavy metals (HM) contamination threatens soil and water quality, which significantly affects humans and animals. This study focuses on the competitive immobilization of zinc (Zn), lead (Pb), and cadmium (Cd) in soils from a contaminated site using ryegrass (Lolium perenne) in a potting experiment amended with biochars. Increased rates of switchgrass- (SGB) and poultry litter-derived biochars (PLB) were applied before ryegrass cultivation. Soil HM phytoavailability and HM concentrations in plant shoots were determined. Multivariate regression models were used to evaluate the influence of several soil chemical attributes on the HM phytoavailability. The increased rates of both biochars reduced the Zn, Pb, and Cd availability (p &amp;lt; 0.001). Langmuir models showed that the maximum HM immobilization (IMAX) was 169.2 ± 29.5 mg kg–1 for Zn with SGB, and 20 ± 7.4 (Pb) and 1.08 mg kg–1 (Cd) with PLB. The extended Langmuir model (EL) showed competitive HM immobilization since there was a decrease in the IMAX of Zn (∼90 ± 28 mg kg–1 from SGB) and Cd (∼0.70 ± 0.21 mg kg–1). Negative values of Pb and Cd immobilization at low rates of SGB indicated an increase in those HM availabilities and preferential immobilization for Zn. The reduced Zn and Pb uptake in ryegrass shoots ranged from 70% to 98% and were optimum at rates of 0.50% ± 0.00%–0.60% ± 0.06% for both biochars, and 1.6% ± 0.4% of SGB for Cd. The stepwise multiple linear regression (SMLR) and partial least squares (PLS) revealed that pH and organic matter (OM) were the most responsible factors for reducing Zn bioavailability while OM was more impactful in decreasing Pb and Cd levels. This suggests that the preferential immobilization for Zn relies on its higher sensitivity to the pH increase. Also, the ubiquitous positive relationship among the metals studied shows that competitive immobilization is ceased at high rates of biochars application. Path analysis (PA) showed that pH and OM were the common contributors from both biochars to simultaneously affect Zn, Pb, and Cd availability regardless of the contrasting physicochemical properties of the two bioproducts. This work proved the potential of applying low rates of two contrasting feedstock-derived biochars to remediate the contaminants and safely grow ryegrass.

Modelling potential human exposure to the nitrification inhibitor dicyandiamide through the environment-food pathway

Dicyandiamide (DCD) is a nitrification inhibitor that effectively reduces nitrogen losses from fertiliser applied to pastures and has the potential to reduce greenhouse gas emissions. Detection of DCD in dairy products in New Zealand led to safety concerns of food products from animals grazing pastures treated with DCD at high application rates (10 kg/ha). This study explores potential risks associated with DCD's application to agricultural grasslands wherein DCD is applied with fertiliser-N at recommended rates. Probabilistic risk assessment method was employed to calculate human Estimated Daily Intake (EDI) of DCD from milk following two application methods (co-application of DCD with granular N-fertiliser and liquid N-fertiliser). The exposure assessment model consists of five separate modules covering application/soil conditions, field conditions, animal feeding, milk production and human exposure/risk to characterise risk in humans. The predicted mean DCD concentration in milk was 0.005 mg DCD/kg milk for the granular method and 0.05 mg DCD/kg milk for the liquid method, respectively. Furthermore, EDI of DCD for both the granular and liquid methods (1 × 10−5 mg and 1 × 10−4 mg DCD/kg body weight/ day, respectively) were well below the European Food Safety Authority set Tolerable Daily Intake limit of 1 mg DCD/kg body weight/ day. Back-calculation revealed that under the conditions of co-application of DCD with granular and liquid nitrogen fertilisers at maximum permissible rates, for EDI to exceed TDI of 1 mg DCD/kg body weight/ day, DCD application rate would need to exceed DCD fertiliser limit (2.25–4.5% by mass of urea nitrogen) set in Commission Regulation (EC) No 1107/2008, and the bio-transfer factor would need to be over 100%. From the sensitivity analysis, for both application types it was found that phytoaccumulation factors, milk intake and the bio-transfer factors are critical factors influencing the EDI. From the present study, the Margin Of Safety values for both application types exceed 1; indicating DCD does not present a significant risk to human health.

Agricultural drift depositional simulation of a copper-based fungicide and its effects on non-target terrestrial and freshwater compartments.

Our research investigated the potential impacts of the fungicide Bordeaux mixture drift processes on off-target species representing terrestrial vegetation and fluvial-lacustrine zooplankton. The simulation of drift events was carried out by a predictive scaling analysis of the quantities potentially exported to a predetermined area adjacent to an agricultural field. The theoretical rate of deposition on a terrestrial species, the lichen Pseudevernia furfuracea, was calculated following high (4 kg ha-1) and low (2 kg ha-1) rate treatments using anti-drift nozzles and non-anti-drift nozzles. The experimental set up consisted in 40 boxes holding lichen thalli, all stored in a climatic chamber for 40 days. Spraying of the fungicide was alternated with rainfall simulations to reproduce scenarios related to agricultural practices. Following a single simulation, anti-drift nozzles resulted in a higher overall load deposited per unit of lichen surface area compared to non-anti-drift nozzles, although both loads significantly differed from controls. However, only anti-drift nozzles, associated with the high rate, caused a remarkable impairment of several ecophysiological parameters, differing (p < 0.05) from controls. Rainfalls promoted activation of lichen metabolism, mitigating the cell damage, but exported only 2.5% of the copper deposited on the thalli surfaces. Nevertheless, the exposure of Daphnia magna neonates to leachates showed significant outcomes for the two rates. After only 24 h, leachates resulting from the high application rate led to widespread mortality, which appeared to be extremely relevant after 48 h, whereas the lower rate induced much lower toxicity for both exposure times.

An antidote to what’s ailing healthcare workers: a new (old) way of relational leadership

PurposeThe purpose of the study’s mixed-methods evaluation was to examine the ways in which a relational leadership development intervention enhanced participants’ abilities to apply relationship-oriented skills on their teams.Design/methodology/approachThe authors evaluated five program cohorts from 2018–2021, involving 127 interprofessional participants. The study’s convergent mixed-method approach analyzed post-course surveys for descriptive statistics and interpreted six-month post-course interviews using qualitative conventional content analysis.FindingsAll intervention features were rated as at least moderately impactful by at least 83% of participants. The sense of community, as well as psychological safety and trust created, were rated as impactful features of the course by at least 94% of participants. At six months post-intervention, participants identified benefits of greater self-awareness, deeper understanding of others and increased confidence in supporting others, building relationships and making positive changes on their teams.Originality/valueRelational leadership interventions may support participant skills for building connections, supporting others and optimizing teamwork. The high rate of skill application at six months post-course suggests that relational leadership development can be effective and sustainable in healthcare. As the COVID-19 pandemic and systemic crises continue to impact the psychological well-being of healthcare colleagues, relational leadership holds promise to address employee burnout, turnover and isolation on interprofessional care teams.

Performance analysis of the evacuated tube counter-flow absorber and direct-flow absorber to optimize the heat extraction rate for high flow rate applications

The evacuated tube collector (ETC) has gained extensive use in low-temperature applications due to its cheapness and high efficiency. The ETC can be used with a concentrator for medium temperature applications, in the range of 140–200 °C. However, the heat extraction rate of the absorber tube is a limitation factor, particularly at higher heat flux and high flow rates. The energy gained is not directly proportional to the concentration factor used. This work thus proposes a counter-flow copper absorber for increasing the heat extraction rate and compares its performance to the conventional direct-flow absorber. The designs are both optimized by varying the absorber diameters, and a material property analysis is done. COMSOL Multiphysics is used for the simulations. The performance of the 2 systems is evaluated using a conjugate heat transfer model at flow rate ranges of 0.02–0.2 kg/s and uniform theoretical heat flux of 1000, 2000, and 3000 W/m2. Analysis of the results indicates that the counter-flow with 0.01 and 0.02 m inner and outer diameter respectively has 4 times more energy gain than the direct-flow with a 0.01 m diameter. Increasing the heat flux by 2 at 0.02 and 0.2 kg/s flow rate increases the temperature by 1.5 and 1.1 for the counter-flow absorber and 1.2 and 1.04 for the direct-flow absorber. Tripling the heat flux at the same flow rate range increases the temperature by 2 and 1.4 for the counter-flow absorber and 1.5 and 1.07 for the direct-flow absorber. The counter-flow absorber is thus the best choice at higher heat flux and high flow rates which are typically required for industrial heating.

SNR-Outage-Based Robust Artificial Noise-Aided Beamforming for Correlated MISO Wiretap Channels Under Gaussian Channel Uncertainties

This article studies robust artificial noise-aided beamforming for correlated multiple-input-single-output eavesdropping channels under Gaussian channel uncertainties. In the case of high reception correlation, under a secrecy outage probability constraint, the achievable secrecy rate is very small and does not satisfy the requirements of some high-rate applications. In view of this, optimization designs on the premise of quality-of-service (QoS) assurance are considered. By exploiting the correlation and employing a novel QoS criterion of the signal-to-noise ratio (SNR) outage probability, two optimization problems, namely minimization of the target SNR at eavesdroppers and maximization of the loose secrecy rate, are formulated. Despite less rigorous secrecy, a much lower target SNR at eavesdroppers and a higher loose secrecy rate are achieved. Compared with the conventional SNR-QoS, SNR-outage-QoS is a more flexible criterion that can be applied to Gaussian channel uncertainties, although challenging probabilistic constraints are introduced into the optimization problems. To make the optimization problems feasible, two approaches, namely, the Bernstein-type inequality approach and ellipsoid bounding approach, are applied to approximate the probabilistic constraints. Simulation results show that the robust transmit designs contribute to a secrecy performance gain from the perspective of SNR-outage-QoS.

English

Irrigated vegetable production is an important agricultural activity and a significant source of income for millions of smallholder farmers in the Sahel. There is little information on the potential effects of intensive vegetable production using African Market Garden (AMG) technology on vegetable yields and soil chemical properties. Three contiguous 500-m2 plots were established to evaluate three vegetable management practices: (1) AMG, (2) Improved Management (IM), and (3) Farmer Practice (FP). These management practices were arranged in a randomized block design. AMG and IM management practices produced higher yields as compared to farmer practices. Tomato and onion yield for IM were 50 and 300% higher than for AMG, respectively; while yields for FP were consistently lower. The soil chemical properties at the end of the experiment displayed marked changes in all treatments compared to the initial soil status. Except for pH, which decreased by 0.2, 0.4, and 1.1 pH units, respectively, for FP, IM, and AMG, soil chemical properties increased as a direct response to management practices. These findings indicate that regular and high rates of manure application combined with mineral fertilizer enhance sandy soil fertility in the Sahel. These findings are important for developing sustainable vegetable production in the Sahel. Key words: Vegetable production, Drip irrigation, Farmer&rsquo;s practice, Productivity, Soil fertility.