Nitrogen Dynamics in Soil Fertilized with Slow Release Brown Coal-Urea Fertilizers

A Machine Learning Assisted Non-Enzymatic Electrochemical Biosensor to Detect Urea Based on Multi-Walled Carbon Nanotube Functionalized with Copper Oxide Micro-Flowers

Detecting urea is crucial for diagnosing related health conditions and ensuring timely medical intervention. The addition of machine learning (ML) technologies has completely changed the field of biochemical sensing, providing enhanced accuracy and reliability. In the present work, an ML-assisted screen-printed, flexible, electrochemical, non-enzymatic biosensor was proposed to quantify urea concentrations. For the detection of urea, the biosensor was modified with a multi-walled carbon nanotube-zinc oxide (MWCNT-ZnO) nanocomposite functionalized with copper oxide (CuO) micro-flowers (MFs). Further, the CuO-MFs were synthesized using a standard sol-gel approach, and the obtained particles were subjected to various characterization techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectroscopy. The sensor's performance for urea detection was evaluated by assessing the dependence of peak currents on analyte concentration using cyclic voltammetry (CV) at different scan rates of 50, 75, and 100 mV/s. The designed non-enzymatic biosensor showed an acceptable linear range of operation of 0.5-8 mM, and the limit of detection (LoD) observed was 78.479 nM, which is well aligned with the urea concentration found in human blood and exhibits a good sensitivity of 117.98 mA mM-1 cm-2. Additionally, different regression-based ML models were applied to determine CV parameters to predict urea concentrations experimentally. ML significantly improves the accuracy and reliability of screen-printed biosensors, enabling accurate predictions of urea levels. Finally, the combination of ML and biosensor design emphasizes not only the high sensitivity and accuracy of the sensor but also its potential for complex non-enzymatic urea detection applications. Future advancements in accurate biochemical sensing technologies are made possible by this strong and dependable methodology.

Dune soil nitrogen leaching for Chinese-yam cultivation: Impact of microbe-decomposable slow-release fertilizer

Chinese yam production is thriving in Aomori Prefecture, a cold and snowy region in Japan. Recently, there has been an increasing risk of nitrogen leaching in Chinese-yam fields, which consist of sandy soil, due to localized torrential rain. The relationships between the type of fertilizer used for Chinese-yam cultivation, the amount of nitrogen (N) leaching, and the timing of leaching remain unknown. Therefore, this study aimed to fill this knowledge gap by investigating the effects of different fertilizers (fast-acting and/or slow-release fertilizer) and irrigation practices (conventional and/or excessive irrigation) in order to mitigate the detrimental impact of nitrogen leaching on groundwater quality. An enhanced mathematical model and the spatiotemporal dynamics of inorganic nitrogen concentration in soil pore water were evaluated the negative impact of nitrogen leaching on the groundwater environment was evaluated. The results showed that the combined use of slow-release fertilizers could significantly reduce nitrate-nitrogen concentration in soil-water, especially during the harvest season. This study demonstrated that cultivating Chinese yam with a fertilizer application system that includes the use of slow-release fertilizer can diminish the negative impact of nitrogen leaching on the groundwater environment, contributing to our understanding of sustainable agricultural practices in regions facing similar environmental challenges. Therefore, our findings represent an important advancement providing new approaches to maintaining productivity while mitigating the adverse impacts on groundwater environments, as well as offering guidelines for agricultural practices in regions facing similar environmental challenges.

Multifunctional soybean protein isolate-graft-carboxymethyl cellulose composite as all-biodegradable and mechanically robust mulch film for "green" agriculture

Multifunctional mulch films with robust mechanical behaviors of biopolymer-based biodegradable mulch materials were highly demanded in promoting the development of "green" agriculture. Herein, a sort of mechanically robust and all-biodegradable soybean protein isolate-graft‑sodium carboxymethyl cellulose composite mulch film was innovatively proposed through the amidation reactions between -COOH on protonated sodium carboxymethyl cellulose and -NH2 on soybean protein isolate. Arising from the reinforced intermolecular interactions upon chemical covalent bonds and physical hydrogen bonds, the maximum tensile strength and the elongation at break were increased from 10.61 MPa and 20.67 % for sodium carboxymethyl cellulose film to 42.15 MPa and 24.8 % for the optimized soybean protein isolate-graft‑sodium carboxymethyl cellulose composite mulch film, respectively. In addition, experimental results showed that the optimized soybean protein isolate-graft‑sodium carboxymethyl cellulose composite mulch film possesses soil moisture retention and controlled urea release properties. When employed as mulch film in practice, the cabbage seed presents higher germination when soil was covered with this versatile mulch film compared to commercial low-density polyethylene mulch film. Our discoveries build a prototype for the manufacture of eco-friendly mulch films with high mechanical strength, soil moisture retention, controlled urea release features.

Combined application of Pseudomonas fluorescens and urea can mitigate rapid acidification of cropland Ultisol

Rhizobacteria maintain a healthy soil required for crop growth. This has led to increased interest in the use of bacteria-based biofertilizers in agriculture as they improve soil nutrient content and protect plants against pathogens. However, the effect of bacteria inoculum on N transformation and soil physicochemical properties during urea fertilization remains unexploited. Thus, this study investigated the effect of Pseudomonas fluorescens on urea N transformation in an acidic Ultisol within a 70-d incubation period. The results revealed that (1) soil pH peaked on d 5 (pH 5.58) and 20 (pH 6.23) and rapidly decreased till d 62 (pH 4.10) and 50 (pH 4.93) for urea and urea + bacteria treatments, respectively, and remained constant thereafter. After 70 d, the pH of the bacteria-treated Ultisol remained higher (0.78 pH units) than that of urea-treated Ultisol; (2) the change in soil pH was in agreement with the mineralization trend of N, as the concentration of NH4+-N peaked on d 5 (134.2 mg N kg-1) and 20 (423 mg N kg-1) before decreasing to 62.1 and 276.1 mg N kg-1 on d 70 in urea-treated and bacteria-treated Ultisol, respectively; and (3) P. fluorescens consumed protons produced during nitrification to retard rapid decrease in soil pH, decreased soil exchangeable acidity (33.3 %), increased soil effective cation exchange capacity (32.8 %), and increased the solubility of soil exchangeable base cations (68.4 %, Ca2+ + Mg2+ + K+ + Na+). Thus, bacterial inoculum could promote N mineralization, enhance nutrient solubility, and retard soil acidification during N transformation in soils.

Comparisons among barley-pea mixed crop combinations in a replacement design as related to N fertilization and soil variation

Two field trials (2017 and 2018) evaluated the performance of barley-pea mixed cropping by comparing different sowing densities (replacement design) and tailoring N fertilization on barley sowing density (split-plot design). High and Low N inputs were applied to whole plots whereas barley and pea, as pure and in mixed crops, were applied to subplots. The 2017 trial suggested the occurrence of an interaction between soil physical properties and N fertilization. Therefore, in 2018 a pedological survey allowed the soil effect to be included in the ANOVA model applied to evaluate crop performance parameters, showing that N fertilization positively affected barley performance only in the soil unit located downslope. A significantly lower presence of weeds was observed in mixed crops rather than in pea pure crops. Overall, increasing pea density and reducing barley density in mixed crops, and tailoring N fertilization were effective approaches to obtain a more balanced mixed grain at harvest. The combination of crop performance evaluation and assessments of soil conditions suggested that more sustainable agricultural systems, based on mixed cropping and a significant reduction of N fertilizers and herbicides, can be achieved with barley-pea mixed cropping as an alternative to pure cropping systems.

Effect of a nitrogenous nanocomposite on leaching and N content in lettuce in soil columns

Nanofertilizers could promote nutrient efficiency with slow release compared to conventional fertilizers (CF). Most of the applied nitrogen is lost on the soil by leaching, due to the rapid release behavior of CF. Clays can function as a nanosized porous structure to retain and slowly release nutrients. The objective of this study was to evaluate a nitrogenous nanocomposite (NCN) and its effect on leaching and N content of lettuce (Lactuca sativa). The treatments applied were: 100% conventional fertilizer, 100% nitrogenous nanocomposite and the mixture in percentage of CF/NCN 25/75, 50/50, 75/25 and 25/0, 50/0 75/0% on columns of soil with lettuce for 45 days. Leachates at the end of the cycle increased in treatments with NCN. Treatments with NCN have higher N content in the leaf. In regard to biomass growth, leaf area, leaf N, drained variables, electrical conductivity and NO₃^- content, it was possible to show that the doses of 50 and 75% of NCN match the characteristics of the crop compared to the control, which allows us to use lower doses than those recommended with CFs.

Lignite Scaffolding as Slow-Release N-Fertilizer Extended the SN Retention and Inhibited N Losses in Alkaline Calcareous Soils

Conventional nitrogen (N) fertilizers particularly urea mineralized quickly in soil. Without sufficient plant uptake, this rapid mineralization favors the heavy N losses. Lignite is a naturally abundant and cost-effective adsorbent capable of extending multiple benefits as a soil amendment. Therefore, it was hypothesized that lignite as an N carrier for the synthesis of lignite-based slow-release N fertilizer (LSRNF) could offer an eco-friendly and affordable option to resolve the limitations of existing N fertilizer formulations. The LSRNF was developed by impregnating urea on deashed lignite and pelletized by a mixture of polyvinyl alcohol and starch as a binder. The results indicated that LSRNF significantly delayed the N mineralization and extended its release to >70 days. The surface morphology and physicochemical properties of LSRNF confirmed the sorption of urea on lignite. The study demonstrated that LSRNF also significantly decreased the NH₃-volatilization up to 44.55%, NO₃-leaching up to 57.01%, and N₂O-emission up to 52.18% compared to conventional urea. So, this study proved that lignite is a suitable material to formulate new slow-release fertilizers, suiting to alkaline calcareous soils favorably where N losses are further higher compared to non-calcareous soils.

A Controlled-Release Nanofertilizer Improves Tomato Growth and Minimizes Nitrogen Consumption

Minimizing the consumption of agrochemicals, particularly nitrogen, is the ultimate goal for achieving sustainable agricultural production with low cost and high economic and environmental returns. The use of biopolymers instead of petroleum-based synthetic polymers for CRFs can significantly improve the sustainability of crop production since biopolymers are biodegradable and not harmful to soil quality. Lignin is one of the most abundant biopolymers that naturally exist.In this study, controlled-release fertilizers were developed using a biobased nanocomposite of lignin and bentonite clay mineral as a coating material for urea to increase nitrogen use efficiency. Five types of controlled-release urea (CRU) were prepared using two ratios of modified bentonite as well as techniques. The efficiency of the five controlled-release nano-urea (CRU) fertilizers in improving the growth of tomato plants was studied under field conditions. The CRU was applied to the tomato plants at three N levels representing 100, 50, and 25% of the recommended dose of conventional urea. The results showed that all CRU treatments at the three N levels significantly enhanced plant growth parameters, including plant height, number of leaves, fresh weight, and dry weight, compared to the control. Additionally, most CRU fertilizers increased total yield and fruit characteristics (weight, length, and diameter) compared to the control. Additionally, marketable yield was improved by CRU fertilizers. Fruit firmness and acidity of CRU treatments at 25 and 50% N levels were much higher than both the 100% CRU treatment and the control. The vitamin C values of all CRU treatments were lower than the control. Nitrogen uptake efficiencies (NUpE) of CRU treatments were 47-88%, which is significantly higher than that of the control (33%). In conclusion, all CRU treatments at an N level of 25% of the recommended dose showed better plant growth, yield, and fruit quality of tomatoes than the conventional fertilizer.

Crystallization of struvite-K from pumpkin wastes

BACKGROUND

Use of slow-release fertilizers derived from biological sources is important in sustainable agricultural development. Struvite-K (KMgPO₄ ·6H₂ O) is magnesium potassium phosphate mineral that has high potential for use as fertilizer in agriculture. Struvite-K is particularly suitable for slow-release fertilizer systems since struvite-K crystals are sparingly soluble in water. Seeds of pumpkin Cucurbita pepo L. are recovered and consumed as food, but the remaining pulp has no economic value.

RESULTS

The present study evaluated the feasibility of struvite-K crystals recovery from pyrolysis products of pumpkin wastes. In the study C. pepo pulp was decomposed at high temperatures and potassium was extracted from the residue and then crystalized from the solution by addition of NaH₂ PO₄ ·2H₂ O and MgCl₂ ·6H₂ O salts. Struvite-K was characterized by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) spectroscopy and X-ray diffraction (XRD) analysis.

CONCLUSIONS

The study revealed pumpkin wastes can be evaluated as source of potassium and 80% of potassium could be recovered as struvite-K crystals, which have a potential use as a slow-release mineral fertilizer for sustainable agriculture operations. © 2021 Society of Chemical Industry.

Biochar Phosphate Fertilizer Loaded with Urea Preserves Available Nitrogen Longer than Conventional Urea

Biochar, a carbon-rich material obtained by pyrolysis of organic wastes, is an attractive matrix for loading nutrients and producing enhanced efficiency fertilizers. In this study, poultry litter (PL) was enriched with phosphoric acid (H3PO4) and MgO to produce a biochar-based fertilizer (PLB), which was loaded with urea in a 4:5 ratio (PLB:urea, w/w) to generate a 15–15% N–P slow-release fertilizer (PLB–N) to be used in a single application to soil. A greenhouse experiment was carried out in which a common bean was cultivated followed by maize to evaluate the agronomic efficiency and the residual effect of fertilization with PLB–N in Ultisol. Six treatments were tested, including four doses of N (100, 150, 200, and 250 mg kg−1) via PLB–N in a single application, a control with triple superphosphate (TSP—applied once) and urea (split three times), and a control without N-P fertilization. The greatest effect of PLB–N was the residual effect of fertilization, in which maize showed a linear response to the N doses applied via PLB–N but showed no response to conventional TSP + urea fertilization. Biochar has the potential as a loading matrix to preserve N availability and increase residual effects and N-use efficiency by plants.

Hydrochemical Characteristics and Quality Assessment of Shallow Groundwater in the Xinzhou Basin, Shanxi, North China

The hydrochemistry and quality of local shallow groundwater was assessed within the Xinzhou basin in Shanxi, North China. Piper diagrams, correlation analysis, principal component analysis, chloro-alkaline indices, ion proportion diagrams, and Gibbs diagrams were used to reveal the hydrochemical characteristics and evolution mechanisms of groundwater. Besides, two indicators of sodium adsorption ratio and soluble sodium percentage, USSL and Wilcox diagrams, and water quality index models were used to evaluate the groundwater quality for irrigation and drinking. In general, groundwater in most areas of the basin is fresh water with total dissolved solid lower than 1000 mg/L. But there are salt water in some parts of the southern basin, with total dissolved solid higher than 1000 mg/L, due to industrial and domestic pollution. The hydrochemical facies of groundwater in most areas are HCO3-Ca and mixed HCO3-Ca·Mg·Na types, while it is HCO3·SO4·Cl-Na type in a small part of the basin. Nitrate pollution widely occurred in the basin because of the use of nitrogenous fertilizers. The dominant mechanism controlling the evolution of groundwater chemistry compositions was the weathering of rock minerals. It mainly reflected in the dissolution of carbonate minerals. And the carbonate dissolution is the major origins of HCO3−, Ca2+, and Mg2+ in groundwater. However, Na-Ca exchange is the important source of Na+. Shallow groundwater was suitable for irrigation and drinking except for some southern parts of the basin. These results will be helpful for the protection and efficient management of groundwater in the Xinzhou basin.

The impact of liquefaction disaster on farming systems at agriculture land based on technical and psychosocial perspectives

This research aims to determine the attitudes of the farmers whose lands are affected by liquefaction in Jono Oge, Central Sulawesi Province, The Republic of Indonesia. The methods used here were integrated survey and experimental design. The survey approach was intended to figure out the attitudes of the farmers viewpoints: (1) to return to their activities on the agricultural lands affected by liquefaction; (2) to consume their own agricultural products; and (3) of their willingness to be relocated. The experimental design approach was used to figure out the effectiveness of organic material input combined with the SP-36 fertilizer. The obtained results were analyzed using the Likert Scale, diversity test, correlational test, and regression test. The results showed that the farmers persevered farming on the lands affected by liquefaction (Index = 88.82%) yet refused to consume their own agricultural products with the reason that corpses remained buried beneath their lands (Index = 27.82%); and they also refused to be relocated (Index = 28.80%). The continued production suitability of the affected land was also investigated. Terrain profile identification results in Jono Oge showed the disaster impact was dominantly landslide as it still showed a clear characteristic horizon between the topsoil and the sub soil. This contrasts to terrain at Petobo, Central Sulawesi Province, where the high mix of the topsoil with the sub soil of agricultural land affected by liquefaction, prevented demarcation of the horizon. The land treatment of organic material and SP-36 fertilizer showed that the combined dose (M) of 40-kg ha-1 with P 300-kg ha-1 had the highest effect by changing the field pH from 5.7 to 6.41, increased the availability of P and increased the corncob indicator plant weight. Based on these indications, the lands affected by the liquefaction in Jono Oge can still be used as agricultural lands through restoration, from both social and technical aspects.

Nitrogen use efficiency and critical leaf N concentration of Aloe vera in urea and diammonium phosphate amended soil

Aloe vera L. is widely cultivated in many countries due to its importance as an all-purpose herbal or medicinal plant. The growth and yield of this plant can be enhanced by application of fertilizer. It is expected that a higher and balanced nutrient supply will result in higher crop production maintaining soil health, which is possible when the applied fertilizers are done in way that is efficient. So, there is a need to understand the amount of applied and type of fertilizer that will give the best output for farmers and to formulate economical market products. This study was conducted to investigate the effect of N fertilizer on leaf yield, its uptake and requirement, critical concentration, use efficiency and economics of Aloe vera L. Plants were grown at six levels of N: 0, 40, 80, 100, 150 and 200 kg ha⁻¹ from urea and diammonium phosphate (DAP) following completely randomized design with three replicates under field condition. The highest values of yield and yield attributes and profit based on benefit cost ratio (3.81 for urea and 2.91 for DAP) were obtained with 150 kg N ha⁻¹ (urea) and 100 kg N ha⁻¹ (DAP). Leaf biomass yield increased by 18–128 % in urea-N and 30–139 % in DAP-N fertilized plant over control while DAP > urea by 7.59 %. Sucker production (mean number) was urea-N (4.95 Plant⁻¹) > DAP-N (2.28 Plant⁻¹). Both gel and leaf N concentration and uptake was highest at 200 kg ha⁻¹ for both sources. For 80 % leaf biomass yield, minimum requirement of N was ca 74.90 (urea) and 89.60 kg ha⁻¹ (DAP). Growth and yield parameters to N application exhibited significant and positive correlations. Critical leaf N concentration was ca 0.88% (DAP) and 0.90% (urea) while mean and maximum NUE was 34% and 64 % (urea) and 43% and 69% (DAP), respectively. Farmers can be advised to apply N at the rate of 150 kg ha⁻¹ from urea for producing economically higher yield and better-quality A. vera leaves.

A method for determining glyphosate and its metabolite aminomethyl phosphonic acid by gas chromatography-flame photometric detection

As a globally popular herbicide, glyphosate (GLY) and its metabolite aminomethylphosphonic acid (AMPA) pose potential hazards to the ecological environment. In this study, a sensitive and reliable method for detecting GLY and AMPA was utilized to facilitate exposure risk assessment of the analytes in environmental systems such as water and soil. GLY and AMPA were extracted from the sample using a solid-phase extraction (SPE) procedure, derivatized by heptafluorobutyric anhydride and heptafluorobutanol, and detected by gas chromatography-flame photometric detection (GC-FPD). The linearities of GLY and AMPA in the range of 10-1000 ng/mL were good (r=0.9998, r=0.9991), and the limits of quantitation (LOQ) for GLY and AMPA were 0.37 and 0.81 ng/mL, respectively. The method has been successfully applied for detecting GLY and AMPA in water, soil and monitoring the degradation of GLY under different environmental conditions. Simulated migration characteristics of GLY and AMPA in soil were investigated for evaluating the potential hazards of GLY and AMPA to the ecological environment.