Amount Of Nitrogen Research Articles

Self-driven hydrolysis mechanism of secondary aluminum dross (SAD) in the hydrometallurgical process without any additives

Secondary aluminum dross (SAD) containing high levels of AlN and fluorine/chlorine salt is a typical hazardous waste generated from aluminum electrolytic and recycling processes. Numerous studies have reported the denitrification of SAD by pyrometallurgical or hydrometallurgical techniques. However, these methods were always inefficient due to strict restrictions on raw materials or the risk of secondary pollution. In this study, a new idea of deep denitrification of SAD by self-driven hydrolysis of AlN and the enhancement of mechanical ball milling was proposed. Thermodynamic analysis suggested that Al(OH)3, Si and SiO2 can be dissolved in the alkaline environment generated by the hydrolysis of AlN alone under low liquid–solid ratio (L/S) conditions. The results of the kinetic fit indicated that the denitrification reaction was controlled by the chemical reaction at the early stage, then shifted to the mixing control as the reaction progressed. The experimental results confirmed that Al(OH)3, Si and SiO2 entered the solution as Al(OH)4- and H3SiO4- during the hydrolysis of SAD, then formed aluminosilicate precipitation (feldspar). This reaction promoted the dissolution of Al and Si, which in turn enhanced the removal of nitrogen. Under the optimal process conditions (L/S = 1.5, T = 80 °C, t = 300 min, ball mill speed = 200 rpm), the residual amount of nitrogen in SAD was reduced to 0.39 wt%, and the denitrification rate reached 93.05%.

Anaerobic methane oxidation: High-rate performance of a continuous bioreactor using nitrate and nitrite as electron acceptors

The anaerobic oxidation of methane coupled to denitrification (N-AOM) is an innovative biotechnology able to simultaneously remove dissolved methane and NO3–/NO2–, minimizing the environmental impact of anaerobic effluents discharge. Most N-AOM studies have been implemented in batch reactors. However, studies in continuous systems are required to assess the potential of this biotechnology for full-scale applications. In this work, a continuous N-AOM reactor was implemented with a hydraulic retention time as short as 17 h. Process performance was evaluated using NO3– alone and in a mixture with NO2–. Methane elimination capacity (EC) values from 20 to 39 g m-3h−1 were reached when NO3– was supplied as the only electron acceptor. When the mixture of NO3– and NO2– was fed, EC values from 48 to 61 g m-3h−1 were recorded, which constitute the best N-AOM performance so far reported in the literature. The amount of nitrogen directed to N2O formation was always below 0.55% of the total nitrogen removed. Data from the reactor and further batch tests evidenced that the pH value was a critical factor influencing methane oxidation, denitrification, and N2O emission. Microbial characterization using 16S rRNA sequencing and metagenomics revealed that the archaeon Methanoperedens nitroreducens and the bacterium Methylomirabilis oxyfera were not present in the reactor. Instead, bacteria belonging to Proteobacteria and Bacteroidetes phyla, and archaea from the Euryarchaeota and Halobacterota phyla were the most abundant microorganisms. Based on the metagenomic analysis, the potential metabolic mechanisms involved in the N-AOM process were proposed.

Effect of Deforestation on the Status of Soil Fertility

In Ethiopia, the soil's physicochemical composition is frequently altered through the transformation of natural forests to farmland, vast pastureland, and cultivated areas. Understanding the effect of deforestation on soil fertility is the main goal of this review. Farmland, grazing land, land for other uses, and unmanaged forests are the different land use types that were taken into account. This evaluation takes into account features of the soil, such as bulk density, soil texture, and soil physical characteristics, particularly soil moisture content. Contrarily, the chemical characteristics of the soil, such as pH, EC, CEC, soil organic carbon, total N, and accessible P, are taken into account when comparing the various land uses. In forestlands, there were greater levels of clay, Acidity, cation exchange capacity, exchangeable Ca2+, and the amount of organic matter and total nitrogen in the soil. Clay, available phosphorus, and exchangeable K+ were all higher in cultivated land while exchangeable Mg2+ was highest in grazing land. Sand, clay, soil organic matter, cation exchange capacity, exchangeable Ca2+, and Mg2+ all showed a greater mean difference in cultivated land compared to grazing land and forestland

Identifying the critical areas and primary sources for agricultural non-point source pollution management of an emigrant town within the Three Gorges reservoir area

Agricultural non-point source pollution is threatening water environmental health of the Three Gorges reservoir. However, current studies for precision management of the agricultural non-point source pollution within this area are still limited. The objective of this study was identifying the critical areas and primary sources of agricultural non-point source pollution for precision management. Firstly, the inventory analysis approach was used to estimate the discharge amount of total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) from farmland fertilizer, crop residues, livestock breeding, and daily activities. Afterwards, the deviation standardization method was applied to evaluate the emission intensity of TN, TP, and COD, as well as calculating the comprehensive pollution index (CPI) of each village, based on which the critical areas for agricultural non-point source pollution management could be distinguished. Moreover, the equivalence pollution load method was conducted to identify the primary pollution sources within each critical zone. The above methods were implemented to an emigrant town within the Three Gorges reservoir area named Gufu. Results showed that agricultural non-point source pollution in Gufu town has been alleviated to a certain extent since 2016. Nevertheless, in four areas of the town (i.e., Longzhu, Fuzi, Shendu, and Maicang), the agricultural non-point source pollution still deserved attention and improvement. For the mentioned critical areas, farmland fertilizer and livestock breeding were the primary sources causing agricultural non-point source pollution. The emission amount of TN and TP from farmland fertilizer accounted for 60% and 48% of the total, respectively. And those from livestock breeding were 29% and 46%. Our research could provide definite targets to relieve agricultural non-point source pollution, which had great significance to protect water environment while coordinating regional economic growth after emigrant resettlement.

Effects of nitrogen, phosphorus, and potassium base fertilizers on growth and yield of <i>Taraxacum kok-saghyz</i> Rodin

Taraxacum kok-saghyz (TKS) is a promising natural rubber plant. In the current study we investigated effects of nitrogen, phosphorus, and potassium base fertilizers on growth and yield of TKS through the field experiments. We found that appropriate application of nitrogen, phosphorus, and potassium base fertilizers can significantly increase root, rubber and total sugar yield of TKS. The TKS rubber yield enhanced significantly when the amount of nitrogen and phosphorus, potassium increased accordingly to 107.2, 10.5 and 35.3 g m–2. Maximum accumulation of rubber in the TSK roots is caused by application of potassium fertilizer.According to the obtained results the recommended amount of base fertilizers under conditions of Harbin Experimental Station (N45.592729°, E126.581668°) is 107.2 g m–2 of urea, 43.4 g m–2 of calcium superphosphate, 10.5 g m–2 of potassium chloride.

Potential Usage of Selected Agro-Residue as a Biofuel Production Sources: Physiochemical Evaluation Approach

This article present physiochemical characterization of commonly available agricultural waste residues on dry basis for: (Corn cob, Coconut shell, Cashew nut, Palm kernel shell and Cassava stem) with the view to evaluate their respective suitability for biofuel production using thermochemical conversion process. The investigated respective biomass feedstock milled samples was analyzed in the laboratory for fuel physiochemical characterization. The physiochemical characterization carried out on each biomass waste sample are Proximate Analysis, Ultimate Analysis, Elemental composition analysis and determination of their respective Higher heating Value(HHV). The obtained results revealed that of all the biomass samples characterized, the Coconut shell (CNS), Corn cob(CC) and Cassava stem(CS) samples proved to possess the most suitable characteristics for better bio-oil production. Palm kernel shell(PKS), Coconut shell(CNS) and Cashew nut(CN) due to their obtained low ash content, adequate hardness and fairly high fixed carbon content are generally regarded to be a potential source for making quality grade charcoal (bio-char) using Pyrolysis process. Gasification process is found desirable to producing high yield of bio-gas for Corncob(CC) and Cassava stem(CS) biomass samples due to their respectively obtainable high value of moisture content: (13.4%wt and 15.10%wt.) and fixed carbon contents of (67.94%wt and 74.13%wt) in this study. Moreover, among all other biomass sample investigated in this study, Coconut Shell(CNS) in comparison to all other samples characterized attained highest HHV of 31.2 MJ/kg. Negligible amount of Sulphur and Nitrogen which could resulted to lower emission of SO2 and NO2 if use directly for heating purposes aftermath application of any of the thermochemical conversion processes is also observed for the biomass waste samples analyzed independent of their types. These results show that the characterized biomass samples could be a suitable candidate for alternative energy fuels production in terms of quality and environment concern.

Impact of extreme rainfall on non-point source nitrogen loss in coastal basins of Laizhou Bay, China

Extreme rainfalls often lead to large amounts of nitrogen (N) loss from river basins. However, the composition and spatial variation of N loss caused by extreme events and the effects of control measures are not well understood. To shed light into this question, the Soil and Water Assessment Tool (SWAT) was used to evaluate the spatiotemporal characteristics of organic and inorganic nitrogen (ON and IN) losses in the coastal basins of Laizhou Bay during typhoons Rumbia and Lekima. The effects of best management practices on controlling N loss were also explored during such extreme rainfall events. Results showed that extreme rainfall promoted transport of ON more than IN. The mass of ON and IN transported by the two typhoons exceeded 57 % and 39 % of the average annual N flux, respectively, and the loads were positively correlated with streamflow. During the two typhoons, the loss of ON was mainly concentrated in areas with steep slopes (θ > 15°) and natural vegetation (forests, grasslands, and shrublands). The IN loss was higher in areas with a 5–10° slope. Furthermore, subsurface flow was the main IN transport mechanism in areas with steep slope (θ > 5°). Simulations showed that implementation of filter strips in areas with slopes exceeding 10° can reduce N loss, with much greater reductions in ON (>36 %) than IN (>0.3 %). This study provides important insights into N loss during extreme events and the key role filter strips can play in trapping them before they reach downstream waterbodies.

Effects of Combined Application of Fungal Residue and Chemical Fertilizer on Soil Microbial Community Composition and Diversity in Paddy Soil

Fungal residue is a unique abundant organic material undervalued in agricultural production. The application of chemical fertilizer combined with fungal residue can not only improve soil quality but also regulate the microbial community. However, it is unclear whether the response of soil bacteria and fungi to the combined application of fungal residue and chemical fertilizer is consistent. Therefore, a long-term positioning experiment in a rice field was conducted with a total of nine treatments. Chemical fertilizer (C) and fungal residue (F) were applied at 0, 50%, and 100% to evaluate 1 the change in soil fertility properties and microbial community structure and 2 the main driving factors of soil microbial diversity and species composition. The results showed that soil total nitrogen (TN) was highest after treatment C0F100 (55.56% higher than in the control), and the carbon to nitrogen ratio (C/N), total phosphorus (TP), dissolved organic carbon (DOC), and available phosphorus (AP) contents were highest after treatment with C100F100(26.18%, 26.46%, 17.13%, and 279.54% higher than in the control, respectively). The amounts of soil organic carbon (SOC), available nitrogen (AN), available potassium (AK), and pH were highest after treatment with C50F100 (85.57%, 41.61%, 29.33%, and 4.62% higher than in the control, respectively). Following the application of fungal residue with chemical fertilizer, there were significant changes in the α-diversity of bacteria and fungi in each treatment. Compared with that of the control (C0F0), different long-term applications of fungal residue with chemical fertilizer did not significantly change soil bacterial β-diversity but resulted in significant differences in fungal β-diversity, and the relative abundance of soil fungal Ascomycota and Sordariomycetes significantly decreased after the application of C50F100. The random forest prediction model indicated that AP and C/N were the main driving factors of bacterial and fungal α-diversity, respectively, and AN, pH, SOC, and DOC were the main driving factors of bacterial β-diversity, whereas AP and DOC were the main driving factors of fungal β-diversity. Correlation analysis suggested that the relative abundance of soil fungal Ascomycota and Sordariomycetes had a significantly negative correlation with SOC, TN, TP, AN, AP, AK, and C/N. PERMANOVA showed that variation in soil fertility properties, dominant species of soil bacteria at the phylum and class level, and dominant species of soil fungi at the phylum and class level were all best explained by fungal residue (46.35%, 18.47%, and 41.57%, respectively), and variation in bacterial diversity was best explained by fungal residue (23.84%) and to a lesser extent by the interaction between fungal residue and chemical fertilizer (9.90%). In contrast, the variation in fungal diversity was best explained by the interaction between fungal residue and chemical fertilizer (35.00%) and to a lesser extent by fungal residue (10.42%). In conclusion, the application of fungal residue has more advantages than chemical fertilizer in influencing soil fertility properties and microbial community structure changes.

STUDY OF THE KINETICS OF MILK KEFIR USING SOY GERM AS SUBSTRATE

The main objective of this study was to analyze the growth kinetics of milk kefir on bean sprouts (Glycine max) as a germinated substrate for 4 days by the glass jar method followed by extracts. Ratio 1:3 (soy: water). 3% kefir grains (activated) inoculated with soluble bud extracts. The soluble extract of bean sprouts has a total sugar content of 5.57% and a fermentable carbohydrate of 3.37 g / L (sucrose), which is a source of nutrition and energy reserves; 1.40% of lipids are used for catabolic grain activity, while protein increases the amount of soluble nitrogen by 6.66%. The pH is 6.67 and the acidity is 0.17%, inversely proportional to lactic acid. The number of microbial populations of soluble extracts of kefirada sprouts reached the logarithmic stage of development after 24 hours for lactic acid bacteria and 48 hours for acetic acid bacteria and yeast, consuming the nutrients of the beverage, influencing its metabolites on the pH of the medium; The period of decomposition of lactic acid bacteria, acetic acid and yeast is 72 hours, and the medium lacks nutrients. The symbiotic action of milk kefir using soluble sprouted extracts is mutual, as the microorganisms it contains grow synergistically and create favorable changes in pH and acidity, depletion of nutrients and the creation of an appropriate environment. To improve the texture it is recommended to combine with fruits or vegetables that contain a lot of sugar.

Self-interlocked down Biomass-based carbon fiber aerogel for highly efficient and stable solar steam generation

Carbon aerogels have demonstrated superior properties for generating clean water through sustainable solar steam generation. However, the complex, time-consuming preparation process and the various harmful chemicals involved seriously inhibit the development and applications of carbon aerogels. Herein, down biomass-based carbon fiber aerogel (DCFA) consisting of physically self-interlocked carbon fibers was developed through the simple low-temperature carbonization of natural down cluster (DC) for highly effective solar evaporation. The resulting DCFA has a large amount of carbon (>80 %) and small amounts of sulfur and nitrogen due to its natural disulfide bonds and amino groups, suggesting a unique self-doped carbon property. The low density and high porosity of the DCFA increased the total solar absorbance and suppressed the energy loss during evaporation. As a result, the DCFA possessed solar absorbance of 97.03 %, as well as high evaporation rates of 2.05 and 2.11 kg·m−2·h−1 for the treatment of saline water and dye water, respectively, which are higher than most reported results. Moreover, the resulting DCFA could self-float without external assistance, demonstrating that it could be a facile evaporator in practical applications. Additionally, the DCFA retained its evaporation performance after 10 times tests for the evaporation of 3.5 wt% saline water and actual dye wastewater, indicating a long-term capacity for practical employment. These findings suggest that the DCFA could be a feasible alternative for solar-driven evaporation. Simultaneously, the simple, efficient, and chemical-free strategy will inspire subsequent research on the construction of fiber-based functional aerogels and their further development/application in water treatment, thermal insulation, energy generation, energy storage, and other related areas.

Microanalysis of TiN phases formed in inclusions of electrogas weld metal

This study has been conducted to confirm the formation of TiN phase in the electrogas (EG) weld metal and, if it formed, to identify the nucleation potency of TiN for acicular ferrite. To facilitate this, a high-nitrogen EG weld meal deposited using a very high heat input was chosen. Inclusion analyses were mostly carried out in a scanning electron microscope (SEM) and analytical transmission electron microscope (TEM) equipped with energy dispersive analyzer (EDS) and electron energy loss spectroscopy (EELS). It was confirmed that the inclusions were nearly fully covered by TiO layer alloyed with a small amount of nitrogen, this TiO layer being partly coated with TiN phases having two different types of morphology: layer-type or patch-type. The layer-type was identified to be nearly pure TiN, being formed with a thickness of 10 nm on the outer surface of thick TiO layer. The patch-type appeared to be formed on the TiN/TiO layer and was characterized by its fine lamellar mixture of TiN and (Al,Mn)-oxide. As all these phases formed on the inclusion surface, they were suspected to influence the nucleation potency of inclusions but the relative potency of these phases to TiO layer was not clearly understood.

Addressing the Relationship between Leaf Nitrogen and Carbon Isotope Discrimination from the Three Levels of Community, Population and Individual.

The carbon, nitrogen and water cycles of terrestrial ecosystems are important biogeochemical cycles. Addressing the relationship of leaf nitrogen (N) and carbon isotope discrimination (Δ) will enhance the understanding of the links between these three cycles in plant leaves because Δ can reflect time-integrated leaf-level water-use efficiency (WUE) over the period when the leaf material is produced. Previous studies have paid considerable attention to the relationship. However, these studies have not effectively eliminated the interference of environmental factors, inter-species, and inter-individual differences in this relationship, so new research is necessary. To minimize these interferences, the present work explored the relationship at the three levels of community, population, and plant individual. Three patterns of positive, negative and no relationship were observed across communities, populations, and individuals, which is dependent on environmental conditions, species, and plant individuals. The results strongly suggested that there is no general pattern for the relationship between leaf N and Δ. Furthermore, the results indicated that there is often no coupling between leaf-level long-term WUE and leaf N in the metabolic process of carbon, N and water in leaves. The main reason for the lack of this relationship is that most plants do not invest large amounts of nitrogen into photosynthesis. In addition, the present study also observed that, for most plant species, leaf N was not related to photosynthetic rate, and that variations in photosynthetic rates are mainly driven by stomatal conductance.

Effect of Adding Organic Acid and Plowing Depth on the Available of NPK in the Soil and the Growth of the Yield of Wheat (Triticum eastvum L.)

To investigate the impact of organic acid addition and plowing depth on available NPK in the soil and the growth of wheat (Triticum eastvum L.) yield, a factorial experiment set up in a split-plot design was conducted during the 2021–2022 growing season in the Al Bandar area, which is 5 km from the center of the city of Samawah. Using the (R.C.B.D) design, the first factor included the depths of plowing with three depths of 8, 16 and 24 cm, symbolized by D1, D2 and D3, respectively, and the second factor was the addition of humic and fulvic acids at five levels 0, 10, 20, 30 and 40 liters H-1 and symbolized by H0 And H1, H2, H3 and H4 respectively, the land was divided into slabs, and included 45 experimental units in three sectors, size of the test area, in square meters (22) In the experiment, 8 lines of 2 m each were separated by 20 cm and 75 cm on the left. In conversations with others, the amount of nitrogen, phosphorous and potassium available in the soil and grain yield at harvest was measured The results showed that the H4 treatment was superior to the amount of potassium ready in the soil, which amounted to 184.89, and phosphorous, which amounted to 21.14, while the treatment of H3 was superior to the amount of nitrogen, which amounted to 28.39, and the grain yield amounted to 5.489. The results showed that the interaction treatment D2H3 and D2H4 was more than 5.571 in most of the studied traits, and the D2H3 treatment gave the highest percentage in the trait of grain yield, which amounted to 6.259.

Linking the ecological roles of Jania adhaerens and Ulva reticulata in seagrass meadows based on variations of tissue δ13C and δ15N

The capacity of macroalgae to absorb, hold, and release the relative amounts of carbon (C) and nitrogen (N) in its environment varies. C and N stable isotopes can be used to gain a better understanding of the ecosystem services of nutrient cycling by quantifying its usage in macroalgae. In this study, we conducted an in situ δ13C and δ15N tracer study of the macroalgae Ulva reticulata and Jania adhaerens in the seagrass meadows of Sungai Pulai estuary, Johor. Bulk tissues were labelled with enriched sodium bicarbonate (NaH13CO3) and ammonium chloride (15NH4Cl). Within 1 to 18 days post-enrichment, the macroalgae were measured for C N contents and stable isotope signatures. U. reticulata showed more bulk losses for excess 13C and 15N compared to J. adhaerens. J. adhaerens tended to retain greater %C and %N incorporated in its tissues. There was a clear distinction between the amount of C and N retained and lost in the tissues of each species. The amount of nutrients, especially C, that remained at the end of the experiment demonstrated that both macroalgae species are capable of short-term carbon sequestration, with implications for meadow-scale nutrient subsidies. Higher N uptake and retention in the biomass of the macroalgae, especially in U. reticulata, suggest their relatively high growth capacity. Understanding the C and N dynamics and loss rate of the whole plant provides an estimation of the nutrient uptake and retention capacity of the macroalgae. Such insights are important as a means to formulating steps in preserving the ecological balance of marine ecosystems.

The importance of time and space in biogeochemical heterogeneity and processing along the reservoir ecosystem continuum

Globally significant quantities of carbon (C), nitrogen (N), and phosphorus (P) enter freshwater reservoirs each year. These inputs can be buried in sediments, respired, taken up by organisms, emitted to the atmosphere, or exported downstream. While much is known about reservoir-scale biogeochemical processing, less is known about spatial and temporal variability of biogeochemistry within a reservoir along the continuum from inflowing streams to the dam. To address this gap, we examined longitudinal variability in surface water biogeochemistry (C, N, and P) in two small reservoirs throughout a thermally stratified season. We sampled total and dissolved fractions of C, N, and P, as well as chlorophyll-a from each reservoir’s major inflows to the dam. We found that heterogeneity in biogeochemical concentrations was greater over time than space. However, dissolved nutrient and organic carbon concentrations had high site-to-site variability within both reservoirs, potentially as a result of shifting biological activity or environmental conditions. When considering spatially explicit processing, we found that certain locations within the reservoir, most often the stream–reservoir interface, acted as “hotspots” of change in biogeochemical concentrations. Our study suggests that spatially explicit metrics of biogeochemical processing could help constrain the role of reservoirs in C, N, and P cycles in the landscape. Ultimately, our results highlight that biogeochemical heterogeneity in small reservoirs may be more variable over time than space, and that some sites within reservoirs play critically important roles in whole-ecosystem biogeochemical processing.

Technology of storage of bee pollen and its effects on the development of honey bees

The article presents data on changes in the protein content of bee pollen due to different storage methods. In May, during the collection of bee pollen by bee colonies, in the conditions of the farm located in the Stryi district of the Lviv region, more than 30 types of flower pollen entered the nest. At the same time, for species identification, acetolysis of seven types of flower pollen was carried out, which differed in the maximum amount of arrival: apple (Malus), dandelion (Taráxacum), winter rape (Brassica napus), buckwheat (Fagopyrum esculentum), clover (Trifolium pratense), chestnut (Castánea) and raspberry (Rúbus idáeus). To study the nitrogen content according to the Kjeldahl method, all pollen was divided into three groups according to the storage method. Bee pollen of the first group was considered fresh. In it, the nitrogen content was determined immediately after determining the species. Calculations showed the maximum crude protein content in this group. Of all types of bee pollen that were determined to be fresh, the maximum amount of protein was found in bee pollen collected during the flowering of winter rape (Brassica napus) and apple (Malus). Its average content is 24.9 ± 2.09 and 23.4 ± 1.77 %, respectively. As a result of freezing at a temperature of 18 ºС and its storage for 8–12 months, the protein content practically did not change and decreased by only 0.3–0.9 %. A slight tendency to decrease the amount of nitrogen in bee honey was also found when stored in a dried state. Bee pollen, stored for 8–12 months under different conditions, was fed to newborn honey bees and kept in entomological boxes. It was found that bee pollen storage conditions affect honey bees' food consumption rate. The minor attractiveness of the feed was found in the dried bee pollen. The absence of a connection between the content of crude protein in feed and the rate of its consumption by bees was investigated.

The inhibition of high ammonia to in vitro rumen fermentation is pH dependent.

Ammonia is an important rumen internal environment indicator. In livestock production, feeding a large amount of non-protein nitrogen to ruminants will create high ammonia stress to the animals, which increases the risk of ammonia toxicity. However, the effects of ammonia toxicity on rumen microbiota and fermentation are still unknown. In this study, an in vitro rumen fermentation technique was used to investigate the effects of different concentrations of ammonia on rumen microbiota and fermentation. To achieve the four final total ammonia nitrogen (TAN) concentrations of 0, 8, 32, and 128 mmol/L, ammonium chloride (NH4Cl) was added at 0, 42.8, 171.2, and 686.8 mg/100 mL, and urea was added at 0, 24, 96, and 384 mg/100 mL. Urea hydrolysis increased, while NH4Cl dissociation slightly reduced the pH. At similar concentrations of TAN, the increased pH of the rumen culture by urea addition resulted in a much higher free ammonia nitrogen (FAN) concentration compared to NH4Cl addition. Pearson correlation analysis revealed a strong negative correlation between FAN and microbial populations (total bacteria, protozoa, fungi, and methanogens) and in vitro rumen fermentation profiles (gas production, dry matter digestibility, total volatile fatty acid, acetate, propionate, etc.), and a much weaker correlation between TAN and the above indicators. Additionally, bacterial community structure changed differently in response to TAN concentrations. High TAN increased Gram-positive Firmicutes and Actinobacteria but reduced Gram-negative Fibrobacteres and Spirochaetes. The current study demonstrated that the inhibition of in vitro rumen fermentation by high ammonia was pH-dependent and was associated with variations of rumen microbial populations and communities.

Optimizing the Amount of Nitrogen and Seed Inoculation to Improve the Quality and Yield of Soybean Grown in the Southeastern Baltic Region

The cultivation of soybeans, especially where this species has not been grown in large areas, requires the determination of the optimal mineral nitrogen fertilization and seed inoculation with Bradyrhizobium japonicum. The purpose of the study was to determine the optimal dose of mineral N fertilization and seed inoculation treatments with B. japonicum under field conditions in the southeastern Baltic region. The objective of this study was to achieve nitrogen supply and/or inoculation with B. japonicum: check-0 kg N ha−1, 30 kg N ha−1, 60 kg N ha−1, HiStick® Soy + 0 kg N ha−1, Nitroflora + 0 kg N ha−1, HiStick® Soy + 30 kg N ha−1, HiStick® Soy + 60 kg N ha−1, Nitroflora + 30 kg N ha−1, Nitroflora + 60 kg N ha−1. Higher yields of seeds, protein and fat were found after application HiStick® Soy compared to Nitorflora. The inoculation with B. japonicum together with nitrogen fertilization improved crude protein content in seeds, biometrical features, yield components and especially the seed yield of ‘Aldana’ soybean. The highest seed yield was found after the application of HiStick® Soy and nitrogen fertilization in doses 30 kg N ha−1 or 60 kg N ha−1. Compared to the control, combined B. japonicum inoculation and nitrogen fertilization in soybean cultivation proved to be a significant factor in improving the productivity of this species in southeastern Baltic conditions.

Anaerobic Digestion of Solid Agricultural Biomass in Leach-Bed Reactors.

This study focuses on the feasibility of the dry anaerobic digestion of solid agricultural biomass for efficient renewable-energy production and nutrient recycling. Methane production and the amount of nitrogen in the digestates were measured in pilot- and farm-scale leach-bed reactors. In the pilot scale, with a digestion time of 133 days, the methane production of a mixture of whole crop fava bean and horse manure corresponded to 94% and 116%, respectively, of the methane potentials of the solid substrates. The mono-digestion of fava beans resulted in relatively low methane production (production/potential ratios of 59% and 57%). In two full-scale experiments, the methane production of mixtures of clover-grass silage, chicken manure, and horse manure corresponded to 108% and 100% of their respective methane potentials with digestion times of 117 and 185 days. In co-digestion, the production/potential ratios were similar in the pilot and farm experiments. High nitrogen loss was observed in the farm scale when the digestate was stored in a stack covered with a tarpaulin during summertime. Thus, although the technology seems promising, attention needs to be paid to management practices to minimise nitrogen losses and greenhouse gas emissions.

Carbon sink potential and environmental benefits of seaweed: A case study of the seaweed cultivation industry on China coast

Initiatives to mitigate climate change have recently aroused great interest in the role of natural carbon sinks in coastal ecosystems. Seaweeds are widely distributed in the world and represent a large biomass. Since they are part of the global carbon reserves, they remove carbon dioxide and influence climate change. Using the recent 20 years of seaweed mariculture in China's coastal areas as a case, this paper quantifies the carbon storage in cultivated seaweed biomass, and evaluates the carbon sink potential, the remediation ability of nitrogen and phosphorus and other environmental benefits. The carbon sink potential of cultivated seaweeds exhibits a rising trend from 2000 to 2019. The total carbon, nitrogen, and phosphorus removal amount of seaweed were 3,551,754.9 ± 177,587.75, 297,772.25 ± 14,888.61, 39,967.15 ± 1998.36 tons according to the seaweed cultivation yield in China coast. The total benefit of carbon sequestration was 22,405.67 ± 259.59 million CNY, and the average benefit was 1120.28 ± 263.27 million CNY, with the average annual growth rate of 4.00%. The total environmental benefit was 1,962,020.88 ± 22,747.42 million CNY, and the average benefit was 98,103.04 ± 23,073.08 million CNY, with the average annual growth rate of 4.00%. The present study illustrates distinctly the ecological value of large-scale cultivated seaweeds in increasing marine carbon sequestration and resolving offshore environmental issues, which is an efficient approach and comparable to other key marine ecosystems. Based on the carbon sink role of seaweed mariculture, and with the goal of global carbon neutrality, more attention should be paid to the carbon sink capacity of large-scale seaweed cultivation industry and be vigorously developed worldwide.