Search Results (136)

Nitrogen (N) fertilizer management in winter wheat production faces challenges from volatilization losses and sub-optimal application strategies. This is particularly problematic in the Southern Great Plains, where environmental conditions during top-dressing periods favor N losses. This study evaluated the effects of a fertilizer placement method, enhanced-efficiency fertilizers, and application timing on grain yield and protein concentration (GPC) across six site-years in Oklahoma (2016–2018). Treatments included broadcast applications of untreated urea and SuperU^® (urease/nitrification inhibitor-treated urea). These were compared with subsurface placement using single-disc and double-disc drilling systems, applied at 67 kg N ha⁻¹ during January, February, or March. Subsurface placement increased the grain yield by 324–391 kg ha⁻¹ compared to broadcast applications at sites with favorable soil conditions. However, responses varied significantly across environments. Enhanced-efficiency fertilizers showed limited advantages over untreated urea. Benefits were most pronounced during February applications under conditions favoring volatilization losses. Application timing effects were more consistent for GPC than for the yield. Later applications (February–March) increased GPC by 0.8–1.2% compared to January applications. Treatment efficacy was strongly influenced by soil pH, equipment performance, and post-application environmental conditions. This indicates that N management benefits are highly site-specific. These findings demonstrate that subsurface placement can improve nitrogen use efficiency (NUE) under appropriate conditions. However, success depends on matching application strategies to local soil and environmental factors rather than adopting universal recommendations. Full article

There are discrepancies regarding the effectiveness of enhanced efficiency nitrogen (N) fertilizer (EENF) products on ammonia loss from unincorporated, surface applications of urea-based fertilizers. Soil properties and management practices may account for the differences in the performance of EENF. However, few studies have investigated the performance of urea- and urea ammonium nitrate (UAN)-based EENF on soils with contrasting properties. Controlled-environment incubation experiments were conducted on two soils with different properties to evaluate the efficacy of urea and UAN forms of EENF to minimize ammonia volatilization losses. The experiments were set up as a completely randomized design, with seven treatments replicated four times for 16 days. The N treatments, which were surface-applied at 134 kg N ha⁻¹, included untreated urea, untreated UAN, urea+ANVOL^TM (urease inhibitor product), UAN+ANVOL^TM, environmentally smart nitrogen (ESN^®), SUPERU^® (urease and nitrification inhibitor product), and urea+Excelis^® (urease and nitrification inhibitor product). In this study, urea was more susceptible to ammonia loss (24.12 and 26.49% of applied N) than UAN (5.24 and 16.17% of applied N), with lower ammonia volatility from soil with a pH of 5.8 when compared to 7.0. Urea-based EENF products performed better in soil with a pH of 5.8 compared to the soil with pH 7.0, except for ESN, which was not influenced by pH. In contrast, the UAN-based EENF was more effective in the high-pH soil (7.0). Across both soils, all EENFs reduced cumulative ammonia loss by 32–91% in urea and 27–70% in UAN, respectively, when compared to their untreated forms. The urea-based EENF formulations containing both nitrification and urease inhibitors were the least effective among the EENF types, performing particularly poorly in high-pH soil (pH 7.0). In conclusion, the efficacy of EENF is dependent on soil pH, N source, and the form of EENF. These findings underscore the importance of tailoring EENF applications to specific soil conditions and N sources to optimize N use efficiency (NUE), enhance economic returns for producers, and minimize environmental impacts. Full article

Microbially induced carbonate precipitation (MICP) offers an eco-friendly approach to stabilize porous materials. This study evaluates its feasibility for protecting agricultural drainage ditch slopes through laboratory tests. Liquid experiments assessed calcium carbonate (CaCO₃) precipitation rates under varying bacteria–cementation solution ratios (BCR), cementation solution concentrations (1–2 mol/L), and urease inhibitor (NBPT) contents (0–0.3%). Soil experiments further analyzed the effects of solidified layer thickness (4 cm vs. 8 cm) and curing cycles on soil stabilization. The results showed that CaCO₃ precipitation peaked at a BCR of 4:5 and declined when NBPT exceeded 0.1%. Optimal parameters (0.1% NBPT, 1 mol/L cementation solution, BCR 4:5) were applied to soil tests, revealing that multi-cycle treatments enhanced soil water retention and CaCO₃ content (up to 7.6%) and reduced disintegration rates (by 70%) and permeability (by 83%). A 4 cm solidified layer achieved higher Ca²⁺ utilization, while an 8 cm layer matched or exceeded 4 cm performance with shorter curing. Calcite crystals dominated CaCO₃ formation. Crucially, reagent dosage should approximate four times the target layer’s requirement to ensure efficacy. These findings demonstrate that MICP, when optimized, effectively stabilizes ditch slopes using minimal reagents, providing a sustainable strategy for agricultural soil conservation. Full article

Urine, which has a high concentration of urea, can be used as a sustainable resource for nutrient recovery and sustainable energy. However, urea undergoes hydrolysis, catalyzed by urease, generating ammonia and carbon dioxide. As ammonia is released during hydrolysis in stored urine, the pH rises progressively until the pK_a of ammonium is reached (i.e., 9.3). At elevated pH levels, struvite and other related precipitates are formed. These reactions lower the efficiency of ammonia and urea nitrogen recovery and often cause scaling, pipe blockage, and odors. Herein, we explore an approach to stabilize urea, using pharmaceuticals and their metabolites that are commonly present in human urine. Based on a survey of the urease inhibitory effects of twenty-three pharmaceuticals and metabolites, we determined that the polyphenolic and disulfide-containing compounds had the highest urease inhibition efficiency. Specifically, outstanding inhibitors include catechol (CAT), hydroquinone (HYD), and disulfiram (DSF). Furthermore, when added to urine, these compounds resulted in the retardation of urease-catalyzed hydrolysis, leading to longer-term urine stabilization upon storage. Reaction mechanisms for urease inhibition by polyphenolics and disulfiram are proposed. Evidence is provided that pharmaceutical metabolites can stabilize urea and thus could lead to a sustainable method for nitrogen nutrient recovery from stored urine. Full article

Helicobacter pylori is a Gram-negative bacterium that infects almost half of the global population and is linked to gastric conditions like peptic ulcers and gastric cancer, as well as other diseases such as neurological disorders, cardiovascular problems, and iron deficiency anemia. Its survival in the acidic stomach environment is due to virulence factors like urease, flagella, and adhesion proteins (BabA, SabA). Current treatments involve a combination of antibiotics (clarithromycin, metronidazole, amoxicillin, tetracycline) and proton pump inhibitors, but increasing antibiotic resistance, especially to clarithromycin and metronidazole, poses a major challenge. Resistance mechanisms include mutations in drug targets, efflux pump overexpression, and enzymatic degradation of antibiotics. This has prompted exploration of alternative therapies targeting bacterial processes like urease activity, biofilm formation, and metabolic pathways (energy production, amino acid synthesis, iron acquisition). Natural compounds, such as chitosan and plant extracts, show promise in combating H. pylori growth and virulence. Vaccine development is also ongoing, with DNA vaccines showing potential for broad immune responses. However, no vaccine is yet close to widespread clinical use. Full article

The application of urease inhibitors (UIs) and optimizing nitrogen (N) split application ratio (NSR) can both minimize ammonia (NH₃) volatilization and increase rice yield. However, few studies have analyzed the combined effects of these two practices with straw returning on rice yield and NH₃ volatilization. In this study, based on a field experiment involving rice yield, aboveground dry matter (ADM), crop N uptake (N_upt), and NH₃ volatilization from 2018 to 2019 in Sichuan Basin, China, the WHCNS (soil water heat carbon nitrogen simulator) model was used to simulate the effects of straw returning, UI, and NSR on rice growth and NH₃ volatilization. The results showed that the WHCNS model performed well in simulating rice growth and NH₃ volatilization. With straw return amount exceeding 4 t ha⁻¹, rice yield increased slowly or stabilized, while N_upt and NH₃ volatilization continued to increase. Increasing the panicle fertilizer (PF) proportion enhanced N_upt during the PF stage, thereby promoting yield improvement. The NSR₃ (a 1:1:3 ratio of base fertilizer, tiller fertilizer, and PF) achieved the highest yield, exceeding that of 2:1:2 by 0.29, 0.23, and 0.08 t ha⁻¹ at straw return amounts of 2, 3, and 4 t ha⁻¹, respectively. However, the effects of UI on N_upt and yield enhancement were limited. Furthermore, optimized NSR and the application of UI reduced NH₃ volatilization during the basal or tiller fertilizer stages, leading to an average decrease of 5.5% and 8.5% in total NH₃ volatilization, respectively. Meanwhile, the increase in straw return amount reduced the NH₃ volatilization reduction effects of both practices. Overall, the combination of NSR₃ and UI with the straw return amount of 3 t ha⁻¹ was the optimal practice for balancing food security and environmental benefits in purple soil area. Full article

The denitrification process is the main process of the soil nitrogen (N) cycle in paddy fields, which leads to the production of large amounts of nitrous oxide (N₂O) and increases N loss in paddy soil. Plant-derived bio denitrification inhibitor procyanidins are thought to inhibit soil denitrification, thereby reducing N₂O emissions and soil N loss. However, the denitrification inhibition effect of procyanidins in paddy soils with high organic matter content remains unclear, and their high price is not conducive to practical application. Therefore, this study conducted a 21-day incubation experiment using low-cost proanthocyanidins (containing procyanidins) and paddy soil with high organic matter content in Northeast China to explore the effects of proanthocyanidins on N₂O emissions and related microorganisms in paddy soil. The results of the incubation experiment showed that the application of proanthocyanidins in paddy soil in Northeast China could promote the production of N₂O in the first three days but inhibited the production of N₂O thereafter. Throughout the incubation period, proanthocyanidins inhibited the enzyme nitrate reductase (NaR) activity and the abundance of nirS and nirk denitrifying bacteria, with a significant dose-response relationship. Although the application of proanthocyanidins also reduced the soil nitrate nitrogen (NO₃⁻-N) content, the soil NO₃⁻-N content increased significantly with increasing incubation time. In addition, the application of proanthocyanidins increased soil microbial respiration, ammonia-oxidizing archaea (AOA) amoA gene abundance, and soil ammonium nitrogen (NH₄⁺-N) content. Therefore, the application of proanthocyanidins to paddy soil in Northeast China can effectively regulate denitrification. However, in future studies, it is necessary to explore the impact of proanthocyanidins on the nitrification process and use them in combination with urease inhibitors and/or nitrification inhibitors to better regulate soil N transformation and reduce N₂O emissions in paddy soil. Full article

Improving nitrogen use efficiency (NUE) is critical to advancing sustainable cereal production, particularly under Mediterranean conditions where environmental pressures challenge input-intensive practises. This study evaluates NUE in Tritordeum, a climate-resilient wheat–barley hybrid, using a holistic experimental approach that integrates pre- and post-harvest soil analyses, including an electrical conductivity (EC) assessment, plant and seed nutrient profiling, and an evaluation of yield performance and nitrogen ratio dynamics. Four treatments were tested: conventional urea (T1), urea with an urease inhibitor (NBPT) (T2), urea with a nitrification inhibitor (DCD) (T3), and an unfertilised control (C). While conventional urea achieved the highest yield (1366 kg ha⁻¹), enhanced-efficiency fertilisers (EEFs) improved nutrient synchronisation and seed nutritional quality. Specifically, EEFs increased seed zinc (T2: 34.93 mg/kg), iron (T1: 33.77 mg/kg), and plant potassium (T2: 1.66%; T3: 1.61%) content, and also improved nitrogen remobilisation (elevated Nplant/Nseed ratios). EEFs also influenced soil properties, increasing organic matter (T3: 2.75%) and EC (T3: 290.78 μS/cm). These findings suggest that while EEFs may not always boost yield in the short term, they contribute to long-term soil fertility and nutrient density in grain. This study underscores the importance of synchronising nitrogen availability with Tritordeum’s phenological stages and highlights the crop’s suitability for sustainable, low-input agriculture under climate variability. Full article

Technological procedures for immobilizing agrochemical pollutants and activating soil enzymes that break down contaminants are still lacking due to industry’s ever-increasing number of new products to enhance agricultural production systems. Using animal manure as organic fertilizers in plant production is an affordable way to alleviate the production cost of inorganic fertilizers and improve crop yield and quality at an affordable price to limited-resource farmers. Microorganisms in animal manure secrete various extracellular hydrolyzing enzymes capable of breaking down organic matter and releasing C, N, and P for plant uptake. A field experiment was conducted to investigate the impact of combining biochar with animal manure on the activity of three enzymes involved in the N, C, and P cycles as a promising strategy for promoting soil health. The results have revealed variability among animal manure and biochar amendments in the activities of the three hydrolyzing enzymes. Biochar decreased the activity of urease and invertase in soil, indicating that some analytes in biochar act as enzyme inhibitors. The results also indicate that not all soil amendments promote soil enzymes activity, and this might be due to the various characteristics and composition of each animal manure. Full article

Nitrogen (N) fertilizer incorporation of efficiency enhancer is a well-established practice aiming at reducing N loss while enhancing crop yield. However, the effect of different kinds of fertilizer efficiency enhancer on N use efficiency (NUE) and gas loss are rarely compared and poorly comprehended. Here, we conducted a field experiment involving the combination of urease and nitrification inhibitor (NI), the biological inhibitor eugenol (DE) and the bioploymer poly-glutamic acid (PG) and their combinations (NI + PG, NI + DE, PG + DE) to evaluate their effects on crop yield, NUE, NH3 volatilization and greenhouse gas emissions (GHGs). Results indicated that NI, DE, PG and their combinations significantly enhanced the crop yield, N uptake and NUE. NI, DE and PG are all effective in reducing NH₃ volatilization and N₂O emission, averagely decreased by 11.13%, 6.83%, 8.29%, respectively, and by 11.15%, 4.32%, 8.35%, respectively, while have no significant effects on CO₂-C and CH₄-C fluxes, except PG significantly increases CO₂-C emission and thus global warming potential. The combination of these three efficiency enhancers has no multiply effect on maize yield, NUE and gas loss. These findings help to screen the fertilizer efficiency enhancer that can be more effectively utilized in agricultural practices and contribute to their application strategies within agricultural systems. Full article

Urease and nitrification inhibitors represent ways to reduce nitrogen losses; their presence modifies microbial and enzymatic activity in the soil, affecting pH and organic matter (OM), which in turn affects the mobility of heavy metals. To evaluate the effect of urea with inhibitors, pH, OM content, and pseudo-total and mobile metal content (Cu, Cd, Ni, Pb, Cr, Zn, and Mn) were determined in soil samples fertilized with six different urea variants with inhibitors. The modification in the pseudo-total content of heavy metals following fertilization (%) was as follows: Cu (−39.26 ÷ −8.82), Cd (10.74 ÷ 15.40), Ni (5.76 ÷ 18.84), Pb (−13.30 ÷ 12.46), Cr (−15.55 ÷ 11.60), Zn (35.10 ÷ 162.76), and Mn (−1.32 ÷ 12.17). The pH was situated in the range of 7.05 to 7.17, while OM content showed an average increase of 16%. The determined pollution indicators revealed an accumulation of Zn in the soil. The results showed a trend of accumulation of bioavailable heavy metals, with the greatest increase for Mn (43%). Only in the case of Zn, there was a decrease in mobile content with the lowest value when applying two urease inhibitors and one nitrification inhibitor. Inhibitors modify the OM content and soil pH, influencing the mobility and bioavailability of heavy metals. Full article

Ammonia (NH₃) volatilization caused by urea application has negative implications for human health, environmental quality, and the value of nitrogen fertilizers. It remains to be investigated how management strategies should be adopted to not only reduce NH₃ volatilization but also improve nitrogen use efficiency (NUE) in the agriculture industry at present. Hence, a two-year field trial, including subplots, was conducted to simultaneously evaluate the effects of mulching treatments (NM: non-mulching; SM: straw mulching) and different fertilizer treatments (U: urea; U + NBPT: urea plus 1% N-(n-butyl) thiophosphoric triamide; U + CRU: the mixture of urea and controlled-release urea at a 3:7 ratio; U + OF: urea plus commercial organic fertilizer at a 3:7 ratio) on NH₃ volatilization, crop production, and NUE in an oilseed rape–maize rotation system in the sloping farmland of purple soil in southwestern China between 2021 and 2023. Compared with NM + U, NH₃ volatilization losses under the NM + U + NBPT, NM + U + CRU, and NM + U + OF treatments decreased, on average, by 64.13%, 17.39%, and 15.09% during the oilseed rape growing season but by 64.01%, 11.67%, and 10.13% during the maize growing season, respectively. An average increase in NH₃ volatilization of 35.65% for the straw-mulching treatment was recorded during the oilseed rape season, while during the maize season, this parameter showed an increase of 10.69%, in comparison to NM + U. With the combination of urea with NBPT, CRU, and organic fertilizer, contrastingly, a reduction in NH₃ volatilization was achieved under the SM + U + NBPT, SM + U + CRU, and SM + U + OF treatments. When compared with NM + U, the difference in the NUE between the NM + U + NBPT, NM + U + CRU, and NM + U + OF treatments was not significant in the oilseed rape season. The NUE was around 4.27% higher under NM + U + NBPT during the maize season (p < 0.05). Compared with NM + U, under the NM + U + NBPT, NM + U + CRU, and NM + U + OF treatments, consistently lower values of yield-scaled NH₃ volatilization were noted: 13.15–65.66% in the oilseed rape season and 10.34–67.27% in the maize season. Furthermore, SM + U, SM + U + NBPT, SM + U + CRU, and SM + U + OF showed average annual emission factors (AEFs) of 14.01%, 5.81%, 12.14%, and 11.64%, respectively. Overall, straw mulching, along with the application of the mixture of NBPT and urea, was found to be the optimal strategy to effectively reduce the NH₃ emissions in the purple soil areas of southern China. Full article

Weeds significantly impact paddy yields, and herbicides offer a cost-effective, rapid, and efficient solution compared to manual weeding, ensuring agricultural productivity. Tripyrasulfone, a novel 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor developed by Qingdao Kingagroot Chemicals Co., Ltd., has demonstrated high efficacy when applied post-emergence, causing characteristic foliar bleaching in susceptible weed species, distinct from conventional acetolactate synthase, acetyl-CoA carboxylase, and synthetic auxin herbicides. This study investigates the impact of tripyrasulfone on the activity of key soil enzymes (urease (UE), acid phosphatase (ACP), sucrase (SC), catalase (CAT), and dehydrogenase (DHA)) in paddy soils from Jilin Province and Shandong Province. Different doses of tripyrasulfone (0.1, 1.0, and 2.5 mg kg⁻¹) were applied, and the enzymatic activities were measured. Results indicated that tripyrasulfone initially inhibited UE and ACP activities before activating them. On the 20th day after treatment, UE activity had returned to control levels, whereas ACP activity remained significantly higher, showing long-lasting activation. SC and CAT activities were inhibited but gradually recovered to control levels. Furthermore, DHA activity was activated with a sustained effect, remaining significantly higher than the control group even 20 days after treatment. Overall, the impact of tripyrasulfone on soil enzyme activities diminished over time, suggesting that tripyrasulfone posed minimal long-term ecological risk to soil health. Full article

Investigations into the phenolic constituents of the butanolic fraction of Crataegus monogyna were optimized using LC-ESI-MS/MS analysis, identifying and quantifying at least 23 fingerprint phytochemical compounds. The major phenolic compounds were epicatechin (99.916 ± 2.208 mg/g), isoquercetrin (53.31 ± 1.172 mg/g), chlorogenic acid (47.457 ± 1.010 mg/g), quinic acid (37.819 ± 1.406 mg/g), rutin (29.98 ± 0.740 mg/g), hesperidin (5.296 ± 0.177 mg/g, detected for the first time in the C. monogyna species), astragalin (1.774 ± 0.020 mg/g), and nicotiflorin (1.482 ± 0.016 mg/g). The antioxidant properties of the lyophilized butanolic fraction were evaluated using DPPH, GOR, ABTS, CUPRAC, and reducing power assays, all of which demonstrated that there was strong activity. Additionally, the neuroprotective effect was evaluated in vitro, showing a potent inhibitory effect on acetylcholinesterase (AChE) with an IC50 of 43.65 ± 2.10 µg/mL. The antidiabetic effect was investigated through α-amylase inhibition (IC50 = 91.19 ± 0.10 µg/mL), showing high inhibitory activity. In addition, the butanolic extract exhibited significant urease inhibition with an IC50 of 26.36 ± 0.05 µg/mL. These results suggest that Algerian C. monogyna has potential as a therapeutic agent for managing diabetes complications and as a natural source of AChE inhibitors, making it a promising subject for the treatment of urease-related conditions. Its high concentrations of natural antioxidants, such as epicatechin, isoquercetrin, chlorogenic acid, quinic acid, rutin, hesperidin, and astragalin, make it suitable for integration into medicine, pharmaceuticals, cosmetics, and the food sector. Full article

Designing and developing small organic molecules for use as urease inhibitors is challenging due to the need for ecosystem sustainability and the requirement to prevent health risks related to the human stomach and urinary tract. Moreover, imaging analysis is widely utilized for tracking infections in intracellular and in vivo systems, which requires drug molecules with emissive potential, specifically in the low-energy region. This study comprises the synthesis of a Schiff base ligand and its selected transition metals to evaluate their UV/fluorescence properties, inhibitory activity against urease, and molecular docking. Screening of the symmetrical cage-like ligand and its metal complexes with various eco-friendly transition metals revealed significant urease inhibition potential. The IC₅₀ value of the ligand for urease inhibition was 21.80 ± 1.88 µM, comparable to that of thiourea. Notably, upon coordination with transition metals, the ligand–nickel and ligand–copper complexes exhibited even greater potency than the reference compound, with IC₅₀ values of 11.8 ± 1.14 and 9.31 ± 1.31 µM, respectively. The ligand–cobalt complex exhibited an enzyme inhibitory potential comparable with thiourea, while the zinc and iron complexes demonstrated the least activity, which might be due to weaker interactions with the investigated protein. Meanwhile, all the metal complexes demonstrated a pronounced optical response, which could be utilized for fluorescence-guided targeted drug delivery applications in the future. Molecular docking analysis and IC₅₀ values from in vitro urease inhibition screening showed a trend of increasing activity from compounds 7d to 7c to 7b. Enzyme kinetics studies using the Lineweaver–Burk plot indicated mixed-type inhibition against 7c and non-competitive inhibition against 7d. Full article