Fertilizer Ammonium Research Articles

REMOVAL OF AMMONIA FROM SOLID WASTE LANDFILL WASTEWATER BY BLOWING

An urgent task at the current level of society's development is to clean the environment from pollution caused by human activity. It is necessary to maintain and increase the capacity of water and land recycling and reuse systems, and to develop waste-free and resource-saving technologies. The problem of treating wastewater (leachate) from solid waste landfills is one of the most pressing issues of national importance. Such leachates from solid waste landfills pose a serious threat to the environment due to large-scale and uncontrolled pollution of groundwater and surface water. Today, in Ukraine, landfill leachate is usually not treated and flows into surface and groundwater without any treatment, causing enormous environmental damage. Therefore, the aim of this work is to study the process of ammonia blowing in order to obtain quantitative regularities necessary for further design of the relevant equipment and determine the required technological modes. The results of the work showed that increasing the pH of the filtrate during liming creates favourable conditions for ammonia blowing off at the pre-membrane treatment stage. It has also been shown that ammonia blowing under these conditions can reduce the concentration of ammonium nitrogen by 10 times or more, which makes it possible to bring its content in the filtrate to the standards for discharge into the sewer after further baromembrane treatment, as well as to obtain a valuable fertiliser by capturing it with acid in the form of ammonium nitrate or sulphate. Thus, it can be concluded that the proposed technological method is effective and economically justified for the treatment of landfill leachate. The results of the studies carried out in this work on laboratory equipment show the high efficiency of the application of the studied methods in the technology of water purification from ammonium compounds with subsequent recovery for the production of ammonium fertilisers. The theoretical regularities of the studied processes presented in this work make it possible, taking into account the minimum number of experimental measurements, to graphically determine the values required for further technological calculations, in particular, to determine the energy consumption of the relevant technological operations.

Effects of combined application of Se and ammonium fertilizers on the growth and nutritional quality of maize in Hg-polluted soil under two irrigation conditions and its health risk assessment

The interactive effects of Se (Na2SeO3) and ammonium fertilizers ((NH4)2SO4 and NH4Cl) on the growth and quality of maize (Zea mays L.) in mercury (Hg)-contaminated soil were studied under different water conditions. This study determined how two nutrient sources (Se and NH4+-N) interacted to improve the yield, quality, and safety of maize to ensure food security and quality assurance under the stress of heavy metal Hg. The experiment was conducted under two irrigation conditions: W1 (complete irrigation condition, 60–70% of water-holding capacity) and W2 (restricted irrigation condition, 40–50% of water-holding capacity). The combined treatment of Se and ammonium fertilizers significantly improved the growth of maize and the quality of grain in Hg-polluted soil. When Na2SeO3 and (NH4)2SO4 were combined, the growth and quality of maize increased the highest among all treatments. The interaction between Na2SeO3 and ammonium fertilizers significantly affected the available Hg/methylmercury (MeHg) content in soil and the Hg/MeHg concentration in maize. NH4Cl significantly increased the content of available Hg/MeHg in soil and increased the accumulation of Hg/MeHg in maize tissues due to Cl−. However, the treatments containing Na2SeO3 or (NH4)2SO4 significantly reduced the content of available Hg/MeHg in soil, reduced the accumulation of Hg/MeHg in maize tissues, and significantly reduced the possible health risks to human beings. The treatments containing Na2SeO3 or (NH4)2SO4 promoted maize growth by increasing the Se content in maize tissues and reducing the Hg/MeHg content, relieving the stress induced by Hg, and increasing the nutrient content. The combined treatment of Na2SeO3 and (NH4)2SO4 had the best effect in this experiment. This study also showed that this strategy is helpful in reducing the opportunities for consumers to accumulate Hg/MeHg by eating maize and its derivatives, thus ensuring food safety. Se and ammonium fertilizer can be used together to increase maize yield and develop agricultural production in Hg-polluted areas, which may have a significant impact on global food production. In addition, this simple method can help farmers manage soil affected by heavy metal pollution.

Time-course analysis of the transcriptome of Arabidopsis thaliana leaves under high-concentration ammonium sulfate treatment

ABSTRACT Ammonium fertilization is of great interest for future agriculture, as unlike nitrate, ammonium use efficiency does not decrease in C3 plants, even in environments with elevated CO2 concentrations. However, excess ammonium often results in toxic effects such as growth suppression and chlorosis, i.e. ammonium toxicity. The addition of nitrate, a major source of nitrogen commonly found in soils, has been shown to alleviate these toxic effects. Understanding the mechanisms of ammonium toxicity in the presence of nitrate is crucial for the effective use of ammonium fertilizers in crop cultivation. To elucidate these responses, a time-course analysis of the transcriptome was performed on A. thaliana leaves treated with high concentrations of ammonium sulfate in the presence of sufficient nitrate. The expression of nitrate-inducible genes tended to be downregulated by the treatment. The expression of genes relating to abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and membrane trafficking was upregulated, whereas that of photosynthesis-, auxin-, and cytokinin-related genes involved in growth and development was downregulated. The induction of many osmotic stress-responsive genes and nitric oxide (NO)-inducible genes suggests the involvement of osmotic stress and NO signaling in the response. This study provides a novel and comprehensive overview of transcriptional changes occurring in response to high ammonium sulfate concentrations with sufficient nitrate, and sheds light on potential pathways involved in ammonium toxicity under these conditions.

Assessing the Effectiveness of Different Kinetic Models in Simulating the Soil Nitrification Process of Ammonium Fertilizers

ABSTRACTPrecise estimation of the soil nitrification process of ammonium fertilizers is crucial to improving soil fertility and reducing environmental pollution since nitrification is closely related to ammonia volatilization and nitrate leaching. However, the applicability and effectiveness of different kinetic models in simulating the soil nitrification process have not been systematically evaluated in previous studies. Here, we compared the effectiveness of one self‐established model (T‐function) and three commonly‐used kinetic models (L‐function, zero‐order kinetic model, and first‐order kinetic model) using data extracted from peer‐reviewed publications. Results showed that the average determination coefficients (R2) of the T‐function and L‐function were 3% higher than that of the first‐order kinetic model, while the average root mean square errors (RMSE) of the T‐function and L‐function were 30% lower than that of the first‐order kinetic model. In addition, first‐order kinetic model could not function properly when it was applied to simulate linear data. Zero‐order kinetic model was not suitable for predicting soil nitrification process because its mathematical nature was inconsistent with the actual soil nitrification process. Further investigations of the parameters of the T‐function and L‐function revealed that p1 (parameter 1) represented the soil net nitrate production of the applied N fertilizer, while p1 × p3 represented the soil nitrification rate. The response of the parameters of the T‐function was more sensitive to soil pH, TN, and C/N ratio changes than those of the L‐function. Therefore, the T‐function is slightly more accurate than the L‐function, but it requires more data points to achieve the best performance. In general, T‐function and L‐function are the most suitable models for simulating the soil nitrification process of N fertilizers and have the potential to be incorporated into soil N cycling models.

The role of proton excreted by Advenella kashmirensis DF12 during ammonium assimilation in phosphate solubilization.

Phosphate-solubilizing bacteria (PSB) can solubilize soil fixed phosphorus (P) to plant available forms. In previous studies, the mechanisms of inorganic phosphate solubilization by PSB mostly focused on the acidolysis of organic acids. Here we screened a highly efficient PSB, Advenella kashmirensis DF12, with the maximum P solubilization of 590 mg L- 1 at 6 days. In addition to its P solubilizing ability, DF12 also showed a tolerance to pH from 5 to 10 and a nitrogen fixation potential. The multiple functions of DF12 and its wide adaptability to various environmental conditions make it a promising biofertilizer candidate. The combined analysis of extracellular metabolites and intracellular metabolome data revealed that the production of organic acid (mainly gluconic acid) is not the only mechanism of P solubilized by DF12, the solubilized P content was not correlated with the gluconic acid concentration but was in a highly significant positive correlation with proton concentration, extrusion of proton during NH4+ assimilation plays a key role in phosphate solubilization. Moreover, the contribution of NH4+ assimilation to phosphorus solubilization is generally present in PSB. Therefore, we proposed that applying ammonium fertilizer in P-deficient soil is more appropriate, it can not only supplement nitrogen fertilizer, but also enhance P use efficiency, which contributes to worldwide fertilizer use reduction and efficiency improvement.

Nitrogen Transport Pathways and Source Contributions in a Typical Agricultural Watershed Using Stable Isotopes and Hydrochemistry

The increasing global nitrogen input poses a significant threat to aquatic environments, particularly in agricultural watersheds, where intensive human activities and insufficient water protection infrastructure exacerbate the risk of nitrogen pollution. Accurate identification of nitrogen pollution sources and the associated transformation processes is essential for protecting watershed ecosystems. In this study, a combination of hydrochemical analysis, correlation and principal component analysis, and stable nitrate isotopes (δ15N-NO3− and δ18O-NO3−) were employed to trace nitrogen transport pathways and source contributions in both surface water and groundwater within a typical agricultural watershed. The results revealed the presence of nitrogen pollution, including total nitrogen (TN), ammonia nitrogen (NH3-N), and nitrate nitrogen (NO3−-N), with significant spatial and seasonal variations in both surface water and groundwater. The spatiotemporal evolution of hydrochemical indicators and nitrate isotope compositions highlighted multiple potential sources of nitrogen, including soil input, agricultural input, and manure and sewage input. The results from stable isotope analysis in an R (SIAR) model indicated that ammonium fertilizers (7.1~78.4%) and manure and sewage (2.6~69.7%) were the primary sources of nitrates in surface water, while manure and sewage were the main sources in groundwater (67.9~73.7%). This research demonstrated that nitrification, seasonal variations, and human activities significantly impact nitrogen migration and transformation in agricultural watersheds. However, the issue of groundwater severely polluted by manure and sewage has received insufficient attention. To effectively control nitrogen pollution in agricultural watersheds, it is necessary to improve septic tanks and sewage networks, as well as implement scientific fertilization practices.

Hydrochemical processes and inorganic nitrogen sources of shallow groundwater in the Sanjiang Plain, northeast China.

This study investigates the chemical characteristics, formation, and sources of inorganic nitrogen (IN) of shallow groundwater across the Sanjiang Plain, aiming to enhance drinking water safety management and pollution control. A total of 167 groundwater and 27 surface water samples were collected for constituents and isotopes (H2 and O18). The hydrogeochemical characteristics showed that the major type is HCO3- Ca·Mg, with low total dissolved solids and a neutral to weak alkaline nature. Rock weathering processes govern the hydrochemical composition of groundwater. Hydrogen and oxygen stable isotopes analyses revealed that precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO3-N concentrations, with sewage, manure, and fertilizers being the primary IN sources. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes, causing the loss of NO3-N and leaving NH4-N as the dominant IN form. Organic matter mineralization is likely a more significant contributor to NH4-N concentrations than ammonium fertilizers. These findings provide valuable information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions. PRACTITIONER POINTS: Rock weathering processes govern the hydrochemical composition of groundwater, and precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO3-N. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes. Organic matter mineralization is likely a more significant contributor to NH4-N concentrations than ammonium fertilizers. These findings provide references for water management and information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions.

Polarity Switching As a Technique for Enhanced Electrochemical Treatment of Waste Activated Sludge for Nutrient Recovery

Traditionally, fertilizers have been produced with ammonia (which is produced from the Haber-Bosch process) as the main feedstock. The Haber-Bosch process which requires the reaction of atmospheric nitrogen with hydrogen at high temperature and pressure is energy and cost intensive [1]. Only about half fraction of reactive nitrogen in the produced ammonia fertilizers is used by the plants with the rest remaining in the soil as waste [2]. These ‘excess’ nutrients find a way into water bodies and wastewater treatment plants (WWTP) as run-offs and this poses a big threat to the nitrogen balance in the environment. This research aims to recover these nutrients primarily nitrogen and phosphorous to produce a low-cost fertilizer of at least compatible potency as commercial fertilizers.Waste Activated Sludge (WAS), the solids obtained from the primary and secondary clarifiers in WWTPs contain a wide range of organic compounds as well as valuable nutrients such as phosphorus and nitrogen which can account for up to 4% and 9% of dry sludge, respectively [3]. The leachate from landfills can release these nutrients into the environment, raising serious environmental pollution concerns. Therefore, recovering nutrients from WAS presents a significant opportunity towards a nitrogen circular economy.Most of the research in sludge treatment are exclusively focused on improving biological treatment processes like anaerobic digestion and composting which can take anywhere from a month to three months and thermal treatments such as pyrolysis and hydrothermal treatments [4] which are energy intensive and expensive. This work provides a novel approach to recover nutrients at low energy consumption with nickel based electrocatalysts [5].The hypothesis here is that the alkaline medium will help break the floc structure of the sludge to release the proteins and other organic compounds which will then be hydrolyzed by the nickel oxyhydroxide (NiOOH) group formed on the electrode surface by application of a small voltage sufficient to form NiOOH. The NiOOH is consumed quickly on the surface of the electrode by the organic nitrogen present in solution [6]. Hence, alternating the polarity between two identical nickel electrodes will ensure that NiOOH is always present on the electrode surface. The approach square wave potential pulses also enhance the desorption of species and clean the surface of the electrodes, especially when dealing with a complex mixture of organics that can polymerize in the surface of electrodes during the oxidation/reduction process. The effect of frequency of polarity oscillation, electrode surface area, pH and conductivity on nutrient recovery are being studied and results will be reported at the conference. Since sludge treatment accounts for a sizable portion i.e., close to 60% of wastewater treatment plant operational costs [7], WAS nutrient recovery could also provide economic benefits. This research highlights the potential for electrochemical approaches to address environmental concerns, improve resource efficiency and provide a sustainable solution for sludge management. Acknowledgement This work is funded by the National Science Foundation, EEC Division of Engineering Education and Centers, NSF Engineering Research Center for Advancing Sustainable and Distributed Fertilizer production (CASFER), NSF 20-553 Gen-4 Engineering Research Centers award # 2133576. References Appl M. The Haber-Bosch heritage: The ammonia production technology. In 50th Anniversary of the IFA Technical Conference 1997 Sep 25 (Vol. 25). Spain: Seville.Galloway JN, Aber JD, Erisman JW, Seitzinger SP, Howarth RW, Cowling EB, Cosby BJ. The nitrogen cascade. Bioscience. 2003 Apr 1;53(4):341-56.Bi W, Li Y, Hu Y. Recovery of phosphorus and nitrogen from alkaline hydrolysis supernatant of excess sludge by magnesium ammonium phosphate. Bioresource technology. 2014 Aug 1;166:1-8.Wu B, Dai X, Chai X. Critical review on dewatering of sewage sludge: Influential mechanism, conditioning technologies and implications to sludge re-utilizations. Water research. 2020 Aug 1;180:115912. Jafari, M., Botte, G.G. Electrochemical treatment of sewage sludge and pathogen inactivation. Appl. Electrochem. 51, 119–130 (2021). https://doi.org/10.1007/s10800-020-01481-6Wang D, Botte GG. In situ X-ray diffraction study of urea electrolysis on nickel catalysts. ECS Electrochemistry Letters. 2014;3(9):H29.Andreoli CV, Von Sperling M, Fernandes F. Sludge treatment and disposal. IWA publishing; 2007.

Mechanisms underlying episodic nitrate and phosphorus leaching from poorly drained agricultural soils.

Poorly drained depressions within tile-drained croplands can have disproportionate environmental and agronomic impacts, but mechanisms controlling nutrient leaching remain poorly understood. We monitored nitrate and soluble reactive phosphorus (SRP) leaching using zero-tension soil lysimeters across a depression to upland gradient over 2 years in a corn-soybean (Zea mays L.-Glycine max [L.] Merr.) field in Iowa. We also measured stable isotopes (δ15N and δ18O) of nitrate to examine its sources and transformations. SRP concentrations peaked during winter and early spring after phosphorus (P) fertilization (mean=3mg P L-1), with highest values in the depression, and SRP was relatively stable thereafter (mean=0.3mg P L-1) irrespective of periods of high soil moisture that led to widespread iron (Fe) reduction across the field. During a near-average precipitation year, nitrate stable isotopes indicated direct leaching of fertilizer nitrate within days of application, followed by nitrification of fertilizer ammonium and several weeks of denitrification in depressional soils. Nevertheless, nitrate concentrations remained high (mean=28mg N L-1) in the depression despite strong isotopic evidence for denitrification (>48% N removal). During a wet year, nitrate concentrations were lower in the depression than upland and nitrate isotopes were highly variable, consistent with nearly complete nitrate removal by denitrification in the depression and significant denitrification in upland soils. We conclude that poorly drained depressional soils can potentially decrease nitrate leaching via denitrification under sustained wet conditions, but they inconsistently denitrify and are vulnerable to high nitrate and SRP losses when soils are not saturated, especially following fertilization.

Comprehensive evaluation of nitrogen contamination in water ecosystems of the Miyun reservoir watershed, northern China: distribution, source apportionment and risk assessment.

Miyun Reservoir plays a vital role as a source of drinking water for Beijing, however it grapples with nitrogen contamination issues that have been poorly understood in terms of their distribution, source, and associated health risks. This study addresses this knowledge gap by employing data on nitrate nitrogen (NO3--N), chloride (Cl-), dual isotopic compositions of NO3- (δ15N-NO3- and δ18O-NO3-) data in water ecosystems, systematically exploring the distribution, source and health risk of nitrogen contaminants in Miyun reservoir watersheds. The results showed that over the past 30years, surface water runoff has exhibited a notable decrease and periodic fluctuations due to the combined influence of climate and anthropogenic activities, while the total nitrogen (TN) concentration in aquatic ecosystems presented an annual fluctuating upward trend. The TN concentration in the wet season was predominantly elevated because a large amount of nitrogen contaminants migrated into water ecosystems through heavy rainfall or river erosion. The concentration of NO3--N, the main contaminant of the water ecosystems, showed distinct variations across different watersheds, followed as rivers over the Miyun reservoir. Moreover, NO3--N levels gradually increased from upstream to downstream in different basins. NO3--N in surface water was mainly derived from the mixture of agricultural ammonia fertilizer and sewage and manure, with a minority of samples potentially undergoing denitrification. Comparatively, the main sources of NO3--N in groundwater were soil N and sewage and manure, while the denitrification process was inactive. The carcinogenic risks caused by NO3--N in groundwater were deemed either nonexistent or minimal, while the focus should predominantly be on potential non-carcinogenic risks, particularly for infants and children. Therefore, it is crucial to perform proactive measures aimed at safeguarding water ecosystems, guided by an understanding of the distribution, sources, and associated risks of nitrogen contamination.

Improving growth and productivity of shallot (Allium ascalonicum L.) applied using organic and inorganic fertilizer

Objective: This research aims to identify and examine organic and inorganic fertilizer on the growth and productivity of shallots. Materials and Methods: This study was carried out under field conditions in the research and application fields of Faculty of Agriculture, Hasanuddin University. The main plot is the liquid organic fertilizer (LOF) consisting of control, 10 mL/L, and 20 mL/L. The subplots, namely the zwavelzure ammonium (ZA) fertilizer, consist of control, 50 kg/ha, 100 kg/ha, and 150 kg/ha. Results: Based on the research conducted, it can be seen that the interaction between the application of LOF (20 mL/L) and ZA fertilizer (150 kg/ha) recorded the highest average fresh bulb weight (145.60 g). Applying LOF (20 mL/L) can increase the average plant height (23.50 cm at 21 days after planting (DAP)), number of leaves (25.60 at 35 DAP), the number of bulbs (10.93), bulb diameter (2.77 cm), production per hectare (21.91 t), and chlorophyll index (20.48) of shallot plants. On the other hand, ZA fertilizer (150 kg/ha) influences plant height (44.03 cm at 42 DAP), number of leaves (26.67), production per hectare (20.96 t), and chlorophyll index (20.64) of shallot plants. Conclusion: The application of organic and inorganic fertilizers has a significant influence on the growth and production of shallot plants, both in interaction and individually.

Cost-competitive decentralized ammonia fertilizer production can increase food security

The current centralized configuration of the ammonia industry makes the production of nitrogen fertilizers susceptible to the volatility of fossil fuel prices and involves complex supply chains with long-distance transport costs. An alternative consists of on-site decentralized ammonia production using small modular technologies, such as electric Haber–Bosch or electrocatalytic reduction. Here we evaluate the cost-competitiveness of producing low-carbon ammonia at the farm scale, from a solar agrivoltaic system, or using electricity from the grid, within a novel global fertilizer industry. Projected costs for decentralized ammonia production are compared with historical market prices from centralized production. We find that the cost-competitiveness of decentralized production relies on transport costs and supply chain disruptions. Taking both factors into account, decentralized production could achieve cost-competitiveness for up to 96% of the global ammonia demand by 2030. These results show the potential of decentralized ammonia technologies in revolutionizing the fertilizer industry, particularly in regions facing food insecurity.

Enhanced electrochemical nitrate reduction on copper nitride with moderate intermediates adsorption

Nitrate in surface and underground water caused systematic risk to the ecological environment. The electrochemically reduction of nitrate into ammonia (NO3RR), offering a sustainable route for nitrate containing wastewater treatment and ammonia fertilizer conversion. Exploration of catalyst with improved catalytic activity with lower energy barriers is still challenging. Here, we report a copper nitride (Cu3N) catalyst with moderate *NOx and *H2O intermediates adsorptions showed enhanced NO3RR performance. Density functional theory calculations reveals that the unique electronic structure of Cu3N provides efficient active sites for NO3RR, thus enabled balanced adsorption of *NO3 and *H2O (ΔE descriptor), sufficient active hydrogen, and moderate intermediate (*NO3 → HNO3, *NH2→*NH3) adsorption energy. Notably, the in-situ analysis technology revealed potential-driven reconstruction and rehabilitation of Cu3N, forming possible nitrogen vacancy, thus implied for better mechanism understanding. The NO3RR activity of Cu3N surpasses that of most recent catalysts and demonstrates superior stability and implies the application for NH4+ fertilizer recovery, which maintaining an NH3 Faradaic efficiency of 93.1 % and high yield rate of 2.9 mg cm2h−1 at −0.6 V versus RHE. These findings broaden the application scenarios of Cu3N catalyst for ammonia synthesis and provide strategy on improving NO3RR performance.

Intensive ammonium fertilizer addition activates iron and carbon conversion coupled cadmium redistribution in a paddy soil under gradient redox conditions

While over-fertilization and nitrogen deposition can lead to the enrichment of nitrogen in soil, its effects on heavy metal fractions under gradient moisture conditions remains unclear. Here, the effect of intensive ammonium (NH4+) addition on the conversion and interaction of cadmium (Cd), iron (Fe) and carbon (C) was studied. At relatively low (30–80 %) water hold capacity (WHC) NH4+ application increased the carbonate bound Cd fraction (F2Cd), while at relatively high (80–100 %) WHC NH4+ application increased the organic matter bound Cd fraction (F4Cd). Iron‑manganese oxide bound Cd fractions (F3Cd) and oxalate-Fe decreased, but DCB-Fe increased in NH4+ treatments, indicating that amorphous Fe was the main carrier of F3Cd. The variations in F1Cd and F4Cd observed under the 100–30-100 % WHC treatment were similar to those observed under low moisture conditions (30–60 % WHC). The C=O/C-H ratio of organic matter in soil decreased under the 30–60 % WHC treatment, but increased under the 80–100 % WHC treatment, which was the dominant factor influencing F4Cd changes. The conversion of NH4+ declined with increasing soil moisture content, and the impact on oxalate-Fe was greater at 30–60 % WHC than at 80–100 % WHC. Correspondingly, genetic analysis showed the effect of NH4+ on Fe and C metabolism at 30–60 % WHC was greater than at 80–100 % WHC. Specifically, NH4+ treatment enhanced the expression of genes encoding extracellular Fe complexation (siderophore) at 30–80 % WHC, while inhibiting genes encoding Fe transmembrane transport at 30–60 % WHC, indicating that siderophores simultaneously facilitated Cd detoxification and Fe complexation. Furthermore, biosynthesis of sesquiterpenoid, steroid, butirosin and neomycin was significantly correlated with F4Cd, while glycosaminoglycan degradation metabolism and assimilatory nitrate reduction was significantly correlated with F2Cd. Overall, this study gives a more comprehensive insight into the effect of NH4+ on activated Fe and C conversion on soil Cd redistribution under gradient moisture conditions.

Nitrogen Sources Reprogram Carbon and Nitrogen Metabolism to Promote Andrographolide Biosynthesis in Andrographis paniculata (Burm.f.) Nees Seedlings.

Carbon (C) and nitrogen (N) metabolisms participate in N source-regulated secondary metabolism in medicinal plants, but the specific mechanisms involved remain to be investigated. By using nitrate (NN), ammonium (AN), urea (UN), and glycine (GN), respectively, as sole N sources, we found that N sources remarkably affected the contents of diterpenoid lactone components along with C and N metabolisms reprograming in Andrographis paniculata, as compared to NN, the other three N sources raised the levels of 14-deoxyandrographolide, andrographolide, dehydroandrographolide (except UN), and neoandrographolide (except AN) with a prominent accumulation of farnesyl pyrophosphate (FPP). These N sources also raised the photosynthetic rate and the levels of fructose and/or sucrose but reduced the activities of phosphofructokinase (PFK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoenolpyruvate carboxylase (PEPC) and pyruvate dehydrogenase (PDH). Conversely, phosphoenolpyruvate carboxykinase (PEPCK) and malate enzyme (ME) activities were upregulated. Simultaneously, citrate, cis-aconitate and isocitrate levels declined, and N assimilation was inhibited. These results indicated that AN, UN and GN reduced the metabolic flow of carbohydrates from glycolysis into the TCA cycle and downstream N assimilation. Furthermore, they enhanced arginine and GABA metabolism, which increased C replenishment of the TCA cycle, and increased ethylene and salicylic acid (SA) levels. Thus, we proposed that the N sources reprogrammed C and N metabolism, attenuating the competition of N assimilation for C, and promoting the synthesis and accumulation of andrographolide through plant hormone signaling. To obtain a higher production of andrographolide in A. paniculata, AN fertilizer is recommended in its N management.

High-performance of Mg2+ additive for addressing NH3 escape in inorganic ammonia carbon capture

The urgency to reduce the energy consumption of organic amine carbon capture, while the inorganic ammonia carbon capture (IACC) and co-production of ammonium fertilizer eliminates the desorption energy consumption. Inhabiting NH3 escape at the end of IACC process requires a large amount of water consumption, and there is a lack of corresponding process parameters and technical routes. In this paper, Mg2+, one of major components in desulfurization wastewater, was used as an NH3 inhibitor. It’s found that the addition of MgCl2 can increase the total NH3 absorption rate by 13.02 % and reduce the total NH3 escape rate by 87.02 %. Furthermore, the effects of six process parameters in the forward and reverse NH3 mass transfer experiments could be distinctly quantified by the normalization method to determine the differentiation between priority and others. It’s concluded that NH3 can enter the first solvent shell of Mg2+ to replace some H2O based on the first-principles calculations, which is the main cause for the decrease of NH3 diffusion coefficient. Finally, simulation with Aspen Plus was applied to construct the complete process route, and the Arrhenius formula for the Mg(OH)2 nucleation was used to refine the reaction kinetic parameters of the simulation. The heat and water balance of IACC could achieve within this system, and the excellent NH3 inhibition effect of added Mg2+ was verified, which could effectively keep from the NH3 escape within 3 ppm.

CHEMICAL CHARACTERIZATION OF SOME AGRICULTURAL LAND OF THE ARGES COUNTY SUB-CARPATHIAN AREA

The High Plain of Pitesti in the south of Arges county is an excellent location for food production. However, Arges county is experiencing a significant decrease in productivity due to the acidity of its soil. This acidity is related to the behavior of certain soil properties essential for plant growth. The present work aims to study the pH behavior according to certain chemical parameters such as: exchangeable aluminum. To achieve this goal, forty-four soil samples were taken in the Costesti locality and sent to the soil laboratory where physical-chemical analyzes were performed. High concentrations of Al3+ in the nutrient solution cause harmful effects on the roots, which undergo morphological changes, turn black, reduce their growth in length and thickness, and fundamental changes in the capacity to absorb and retain cations occur. Thus, Al3+ ions cause a desorption of Ca2+, K + and Mg2+ ions and other species of cations from the pectocellubasic layer of root hairs, worsening nutrition, the absorption of these cations decreasing and increasing that of Al3+. It also reduces phosphorus nutrition, which precipitates as aluminum phosphates on the root surface. The risks of aluminum toxicity should not be overlooked. The rate of ammonia fertilizer use in the study area should be reduced, especially in soils with a pH below 5.4. It is recommended that strong bases input be used in these slightly acidic or acidic soils.

Hydrochemical Evolution and Nitrate Source Identification of River Water and Groundwater in Huashan Watershed, China

The combined hydrochemical analysis, factor analysis, and isotopic signals of water and nitrate were applied to explore the hydrochemical origin and identify the sources and transformation of nitrate in river water and groundwater in the Huashan watershed. Additionally, a Bayesian isotope mixing model (SIAR) was employed for quantitative assessment of the nitrate sources. The results indicated that both river water and groundwater were dominated by HCO3-Ca and HCO3-Ca·Mg types; both originated from precipitation and were influenced by evaporation. The main constituent ions in the river water and groundwater primarily originated from carbonate and silicate dissolution, with the presence of cation exchange in the groundwater. The water chemistry of river water was greatly influenced by physicochemical factors, while that of groundwater was mainly controlled by water–rock interaction. NO3− in river water was mainly influenced by soil nitrogen (SN) and manure and septic wastes (MSWs), while NO3− in groundwater was jointly affected by ammonium fertilizers (AF), SN, and MSWs. With the exception of denitrification observed in the groundwater at the watershed outlet, denitrification was absent in both groundwater in the piedmont area and in river water. The SIAR model results demonstrated that the contribution rates of atmospheric precipitation (AP), AF, SN, and MSWs to river water were 12%, 21%, 25%, and 42%, respectively, while to groundwater, they were 16%, 27%, 10%, and 47%, respectively. Overall, MSWs were the main sources of nitrate in the river water and groundwater. It is necessary to prevent the leakage of MSWs when managing water resources.

Effect of Fertigation with Struvite and Ammonium Nitrate on Substrate Microbiota and N2O Emissions in a Tomato Crop on Soilless Culture System

Struvite and ammonium nitrate (AN), as wastewater-recovered products, are possible alternatives as raw materials for nutrient solutions. However, their impact on the rhizosphere microbiota and N2O emissions is scarcely known. Therefore, the present research studies the ecological changes in the bulk-substrate microbiome and its correlation with N2O emissions in a perlite-based system tomato crop under (i) conventional synthetic fertigation management; (ii) fertigation with struvite; and (iii) struvite and AN. A high bacterial diversity and the natural presence of plant-growth-promoting rhizobacteria in a soilless system are highlighted. However, the different N-NH4+:N-NO3− ratios influence the ecological niches of ammonia-oxidizing archaea (AOA) and bacteria (AOB), with a stronger response by AOB community, while AOA kept constant regarding the fertilization applied. Despite this, enrichment of N-transforming bacterial phylotypes was relatively enhanced (mainly Nitrosomonas, Nitrosospira, and Nitrospira) concomitant with the production of N2O emissions when ammonium fertilization was overapplied. In the absence of a plant, N2O emissions were positively correlated, respectively, with Nitrosospira and AOB:AOA ratio, suggesting potential indicators for ammonium availability in the substrate. Fertilizer blends using recovered nutrients are a feasible alternative for increasing circularity in horticulture. Nevertheless, optimum fertilizer management is needed due to its influence on rhizosphere microbiota and N2O emissions.

Iron hydroxyphosphate electro-Fenton catalyst for efficient removal of sulfamethoxazole and resource recycling into slow-release fertiliser ammonium ferrous phosphate

Although the electro-Fenton (EF) process is effective for wastewater treatment, recycling spent catalysts remain a major challenge. Therefore, we introduce a reuse strategy for spent catalysts where an iron hydroxyphosphate [Fe5(PO4)4(OH)3·2H2O] catalyst is utilized. Fe5(PO4)4(OH)3·2H2O obtained •OH and •O2− by activating in-situ produced H2O2, and the degradation rate of sulfamethoxazole reached 94.5% after 120 min and showed excellent stability (maintained above 90%) for 10 cycles. Finally, the used catalyst was converted into slow-release ammonium ferrous phosphate (NH4FePO4·H2O) fertiliser at a conversion rate of 85.6%. NH4FePO4·H2O significantly promoted plant and seed growth within 6 days, highlighting the contribution of the resource recycling of the spent catalyst. This study serves as a valuable reference for the efficient utilization of spent catalysts. This study successfully applied EF catalysts and explored the recycling of spent catalysts.