Nitrogen Supply Research Articles

Ежа сборная (Dactylis glomerata L.) - кормовая культура универсального использования в адаптивном лугопастбищном хозяйстве (обзор )

The review summarizes the results of domestic and foreign literature on the biological and ecological characteristics and use of orchardgrass in forage production. In Russia and the world, the orchardgrass is one of the most widespread species in natural and seeded meadows. With a sufficient supply of nitrogen, it surpasses other grasses in terms of competitiveness and yield, producing 5 to 12 t/ha of dry matter in different regions of Russia. Under optimal conditions of use, its productive longevity is 8 to 10 years or more. Orchardgrass provides 3 to 5 cuttings per season and is resistant to animal grazing. It provides the earliest fodder in the spring in the green mowing system. Orchardgrass is highly aggressive and will quickly displace other grasses from a sward, so it is often grown in monoculture. It has good foliage and accumulates 15 to 25% crude protein when used before the heading phase. Orchardgrass is superior to meadow fescue, perennial ryegrass, and timothy in terms of drought resistance, but like ryegrass it can be thinned out in the winter-spring period under unfavorable overwintering conditions, and has poor resistance to flooding and near groundwater. Its high shade tolerance makes it suitable for interrow sowing in turf-humus orchards. This improves soil fertility and fruit quality. Under conditions of climate warming, orchardgrass may expand its range in Russia.

Impact of nitrogen fertilizer type and application rate on growth, nitrate accumulation, and postharvest quality of spinach.

A balanced supply of nitrogen is essential for spinach, supporting both optimal growth and appropriate nitrate (NO3 -) levels for improved storage quality. Thus, choosing the correct nitrogen fertilizer type and application rate is key for successful spinach cultivation. This study investigated the effects of different nitrogen (N) fertilizer type and application rates on the growth, nitrate content, and storage quality of spinach plants. Four fertilizer types were applied at five N doses (25, 50, 200, and 400 mg N kg-1) to plants grown in plastic pots at a greenhouse. The fertilizer types used in the experiment were ammonium sulphate (AS), slow-release ammonium sulphate (SRAS), calcium nitrate (CN), and yeast residue (YR). Spinach parameters like Soil Plant Analysis Development (SPAD) values (chlorophyll content), plant height, and fresh weight were measured. Nitrate content in leaves was analyzed after storage periods simulating post-harvest handling (0, 5, and 10 days). The application of nitrogen fertilizer significantly influenced spinach growth parameters and nitrate content. The YRx400 treatment yielded the largest leaves (10.3 ± 0.5 cm long, 5.3 ± 0.2 cm wide). SPAD values increased with higher N doses for AS, SRAS, and CN fertilizers, with AS×400 (58.1 ± 0.8) and SRAS×400 (62.0 ± 5.8) reaching the highest values. YR treatments showed a moderate SPAD increase. Fresh weight response depended on fertilizer type, N dose, and storage period. While fresh weight increased in all fertilizers till 200 mg kg-1 dose, a decrease was observed at the highest dose for AS and CN. SRAS exhibited a more gradual increase in fresh weight with increasing nitrogen dose, without the negative impact seen at the highest dose in AS and CN. Nitrate content in spinach leaves varied by fertilizer type, dose, and storage day. CNx400 resulted in the highest NO3 - content (4,395 mg kg-1) at harvest (Day 0), exceeding the European Union's safety limit. This level decreased over 10 days of storage but remained above the limit for CN on Days 0 and 5. SRAS and YR fertilizers generally had lower NO3 - concentrations throughout the experiment. Storage at +4 °C significantly affected NO3 - content. While levels remained relatively stable during the first 5 days, a substantial decrease was observed by Day 10 for all fertilizers and doses, providing insights into the spinach's nitrate content over a 10-day storage period. For rapid early growth and potentially higher yields, AS may be suitable at moderate doses (200 mg kg-1). SRAS offers a more balanced approach, promoting sustained growth while potentially reducing NO3 - accumulation compared to AS. Yeast residue, with its slow nitrogen release and consistently low NO3 - levels, could be a viable option for organic spinach production.

Transcriptome analysis of differentially expressed genes in rice seedling leaves under different nitrate treatments on resistance to bacterial leaf blight.

Nitrogen (N), as one of the most abundant mineral elements in rice, not only is the primary limiting factor for rice yield, but also impacts plant disease resistance by modulating plant morphology, regulating biochemical characteristics, as well as enhancing metabolic processes. Bacterial blight, a severe bacterial disease caused by Xanthomonas oryzae pv. oryzae (Xoo), significantly impairing rice yield and quality. Previous studies have shown that moderate application of nitrate nitrogen can improve plant disease resistance. However, further exploration is urgently required to investigate the involvement of the nitrate nitrogen signaling pathway in conferring resistance against bacterial leaf blight. In this study, we employed transcriptome sequencing to analyze the differentially expressed genes under various concentrations of nitrate supply duringrice bacterial blight infection. Our research reveals that nitrate nitrogen supply influences rice resistance to bacterial leaf blight. Through transcriptomic profiling of rice leaves inoculated under different nitrate nitrogen concentrations, we identified 4815 differentially expressed genes (DEGs) among four comparison groups, with notable differences in DEG enrichment between low and high nitrate nitrogen conditions, with some members of the NPF family implicated and we preliminarily elucidated the molecular regulatory network in which nitrate nitrogen participates in bacterial leaf blight resistance. Our findings provide a novel insight into a mechanism involving the nitrate nitrogen drive wider defense in rice.

Chemical composition and quality of rapeseed meal as affected by genotype and nitrogen fertilization

Rapeseed meal (RSM) is known for its high nutritional quality as animal feed. However, there has been little studies on the effect of nitrogen fertilization on RSM chemical composition, mainly neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and ash content. Therefore, this study was carried out to evaluate the effect of nitrogen application rate on chemical composition of RSM in interaction with different spring rapeseed varieties (Brassica napus L). A field experiment was conducted during 2018/19 cropping season at the experimental station of the Ecole Nationale d’Agriculture de Meknès” according to a split-plot design with three replications, using six nitrogen application rates, as main plot, and six rapeseed varieties, as subplot. After seeds harvest and oil extraction, meals derived from the different treatments were used in this study. Results showed that increasing nitrogen rate from 0 to 120 kg N ha−1 led to a significant rise in meal yield up to 74.58%. A positive effect of nitrogen fertilization was observed on dry matter, protein content and ash content, recording the highest values at 120 kg N ha−1 treatment. However, cellulose and lignin content were affected negatively by nitrogen fertilization. The nitrogen supply of 150 kg N ha−1 resulted in a reduction of ADF and ADL contents by 23% and 28%, respectively, compared to the unfertilized control (N0). Variability within rapeseed varieties for all parameters except dry matter and ADL content was highlighted.

Electron repulsion tuned electronic structure of TiO2 by fluorination for efficient and selective photocatalytic ammonia generation.

The photocatalytic conversion of nitrogen into high-value ammonia products holds tremendous potential in the global nitrogen cycle. However, the activation of N2 and competition of hydrogen evolution limit the improvement of nitrogen fixation performance. In this study, we developed a fluorinated TiO2 (F-TiO2) using a hydrothermal-annealing method. The incorporation of F dopants not only enhances the adsorption and activation of N2 through electronic structure regulation, but also facilitates an in situ increase in active sites via the electron repulsion effect between F and Ti atoms. In addition, the presence of F on the surface effectively improved the nitrogen supply problem and optimized the nitrogen fixation selectivity for its hydrophobic modulation. The NH3 yield of the F-TiO2 photocatalyst reached 63.8 μmol h-1 g-1, which was 8.5 times higher than that of pure TiO2. And the selectivity experiment showed that the electronic ratio of NH3 to H2 production reached 0.890. This research offers valuable insights for the design of highly efficient and selective nitrogen-fixing photocatalysts.

Synthetic data generation methods for training neural networks in the task of segmenting the level of crop nitrogen status on UAV images of agricultural fields

This study is devoted to the automatization of the image masks’ construction of large sized agricultural objects in precision farming tasks for training neural network methods for crop’s nitrogen status analysis using georeferenced images. The scientific direction is extremely relevant because it allows to automate and replace the manual process of data labeling, significantly reducing the cost of preparing training samples. In the paper, four new synthetic data generation methods are proposed for training neural networks aimed at UAV image segmentation by the level of crop nitrogen supply on an agricultural field. In particular, the paper gives a description of synthetic data generation algorithms based on nitrogen covering with lines, parabolas, and areas. Experiments were carried out to test and evaluate the quality of these algorithms using eight modern image segmentation methods: two classical machine learning methods (Random Forest and XGBoost), four convolutional neural network methods based on U-Net architecture, and two transformers (TransUnet and UnetR). The results showed that two algorithms based on areas gave the best accuracy for convolutional neural networks and transformers — 98–100 %. Classical machine learning methods showed very low values for all quality metrics — 27–44 %.

LNG 기화열을 이용한 수조 수온 냉각성능에 관한 실험적 연구

In this study, a heat transfer performance experiment was conducted by experimentally testing the vaporization process of liquefied natural gas (LNG) using a seawater vaporizer and the process of supplying cooled seawater to the aquaculture tank. By using liquid nitrogen instead of LNG, we experimentally analyzed changes in tank water temperature according to changes in liquid nitrogen supply mass flow rate, water supply mass flow rate, and injection angle of the aquaculture tank nozzle. When testing was conducted by fixing the water mass flow rate at 0.05 kg/s and changing the liquid nitrogen mass flow rate to 0.0058 kg/s, 0.0075 kg/s, and 0.0092 kg/s, the target temperature of 17°C was reached under the experimental condition of 0.0092 kg/s.
 When the water supply mass flow rate was set to 0.05 kg/s, 0.07 kg/s, 0.08 kg/s, and 0.10 kg/s at the constant mass flow rate of liquid nitrogen of 0.0092 kg/s, the target temperature of 17°C was reached under the experimental condition of 0.07 kg/s. When the angle of the water nozzle was adjusted to 0°, 30°, and 60°, the fastest way to reach the target temperature of 17°C was the 0° experimental condition in which water was injected tangentially to the water tank.

Maize residue input rather than cover cropping influenced N2O emissions and soil–crop N dynamics during the intercrop and cash crop periods

The well-known benefits of cover cropping for mitigating climate change and improving soil quality could be threatened by increased greenhouse gas emissions. Therefore, such practices could have negative consequences in the context of global climate change. The present year-long field experiment, carried out under irrigated semiarid conditions, evaluated the effect of returning maize crop residues at two topsoil input levels in combination with bare fallow, a cereal (barley, Hordeum vulgare L.) and a legume (vetch, Vicia sativa L.) as cover crops as part of an annual cover crop–cash crop (maize, Zea mays L.) rotation. In addition, control plots, without the addition of nitrogen fertilizer (either in the previous cropping season or during the experiment), were established following the same experimental design in order to assess the carry-over impact of residual nitrogen from prior crops. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes were measured together with soil mineral nitrogen and crop yields and nitrogen use efficiency. The significant effect of maize residue input on N2O emissions during the cover crop phase (this was 43% greater for the lower maize residue input than for the higher) was offset after subsequent maize fertilization (there was a 170% increase following the higher maize residue input compared to the lower). Although no differences in soil mineral nitrogen content were reported between treatments before maize fertilization, N2O emissions were 72% higher on the fertilized plots than on the control plots. Before maize fertilization, N2O emissions were increased by the incorporation of cover crop residues and soil rewetting after irrigation, with the highest N2O fluxes being reported for the cereal crop. Cumulative CO2 fluxes were higher in the plots with cover crops (cereal and legume) than in bare fallow plots, while CH4 sink was not affected by cover cropping or maize residue input. The grain yield penalty for maize production (a 7% decrease) with the legume cover crop on the nitrogen fertilized plots (the opposite of what was observed in the control area) highlights the need for an accurate estimation of the nitrogen supply from the mineralization of legume residues. Overall, cover crop and maize residue input did not have any significant effect on annual cumulative N2O emissions, so the positive effects of these practices should be considered to recommend them under semiarid conditions for climate change mitigation and adaptation.

Unclenching the potentials of global core germplasm for root nodulation traits for increased biological nitrogen fixation and productivity in chickpea (Cicer arietinum L.)

Chickpea being an important food legume crop is able to fix the atmospheric nitrogen and form root nodules that support biologicalnitrogen fixation- a sustainable alternative for nitrogen supply to agriculture worldwide. In order to support findings on nodule formation in chickpeas, a diverse core set of 300 chickpea genotypes, including four checks, was evaluated for morphological and nodulation traits in four different environments. The maximum genotypic and phenotypic coefficient of variation was observed for a number of nodules, nodule fresh weight, shoot fresh weight, and number of seeds per plant. The heritability for most of the characters ranged from 26.56 for days to 50% flowering to 99.61 for a number of pods per plant. The genotypic and phenotypic correlation coefficient analysis revealed that the number of nodules was positively correlated with seed yield. Further, seed yield was partitioned into direct and indirect effects at genotypic and phenotypic levels through path coefficient analysis. Significant genotypic correlations and direct positive effects were exhibited by a number of nodules and number of pods per plant on grain yield. Based on the D2 statistics, the number of seeds per plant, number of pods per plant, shoot fresh weight and number of nodules have been identified as top-ranking yield contributing traits. The genotypes ICC1013 and ICC16569 for a number of nodules and ICC1049 for the trait number of seeds per plant were identified as potential stable donors for the respective traits with high mean yield, heritability and genetic advance across the locations and can be used as donors in the chickpea breeding programs for increasing biological nitrogen fixation and enhancement of the crop productivity.

The influence of gas heating on the calculated supersonic parameters of gas-powder flow at slag blower in the converter. Message 2

The article presents the results of numerical modeling of the interaction of a supersonic non-calculated gas-powder jet with the surrounding strongly heated environment of the converter cavity, including slag particles ejected by the jet. The method of determining the depth of penetration of the jet into the melt is the subject of many years of discussion, but it has not been solved analytically. A new approach to solving this problem is proposed, which consists in the fact that in this work the structure is considered not according to the laws of subsonic turbulent flow, but as supersonic, not calculated. In this paper, there is a task - to increase the stability of the slag crust, nitrogen supply of MgO powder is provided, which, in turn, enters the jet and slows it down. To solve this problem, the solution of many parametric equations is proposed to establish the effect of heating on the qualitative characteristics of the slag crust on the surface linings. A physical model has been created that predicts the outflow of a gas-powder jet (N2 + powder) from a Laval nozzle. The formation outside the jet nozzle is established, which becomes a supersonic non-computational structure with a shock wave. The most important hydro-gas-dynamic characteristic of the gas jet flow is its momentum, which depends on a number of factors and physical effects. The scheme for solving a fairly high-tech problem involves the following: calculation of the parameters of the gas-powder flow at the exit from the nozzle; calculation of the amount of added gas mass from the environment; temperature: pulse speed; jet power, etc. It was established that in some cases, when a chemical connection between the slag and the lining is ensured (when there is an optimal value of MgO and CaO in the slag), it is possible to stop the supply of refractory powder and then the slag will be inflated only with a nitrogen jet. Using the law of constancy of momentum in different cross-sections of the jet (for example, in the outlet cross-section of the nozzle and in the fixed cross-section of the XX stream), it is possible to calculate: total momentum, average mass velocity of the nitrogen-powder jet, average mass temperature of the jet. It is shown that the power of the gas-powder jet flowing into the melt is most significantly affected by the heating of the gas-dispersed flow to the temperature before the nozzles. It was established that an increase in temperature from 50°C to 600°C leads to an increase in momentum by almost 2.75 times. The joint solution of almost 50 equations (messages 1 and 2) makes it possible to visually present the picture of the interaction of the supersonic jet with shock waves and melt, as well as to develop recommendations for improving the energy efficiency of slag-blowing technology. Since conducting an experiment in the converter cavity is difficult, the results of numerical calculations are verified by the method of special cases

Diversified molecular adaptations of inorganic nitrogen assimilation and signaling machineries in plants.

Plants evolved sophisticated machineries to monitor levels of external nitrogen supply, respond to nitrogen demand from different tissues and integrate this information for coordinating its assimilation. Although roles of inorganic nitrogen in orchestrating developments have been studied in model plants and crops, systematic understanding of the origin and evolution of its assimilation and signaling machineries remains largely unknown. We expanded taxon samplings of algae and early-diverging land plants, covering all main lineages of Archaeplastida, and reconstructed the evolutionary history of core components involved in inorganic nitrogen assimilation and signaling. Most components associated with inorganic nitrogen assimilation were derived from the ancestral Archaeplastida. Improvements of assimilation machineries by gene duplications and horizontal gene transfers were evident during plant terrestrialization. Clusterization of genes encoding nitrate assimilation proteins might be an adaptive strategy for algae to cope with changeable nitrate availability in different habitats. Green plants evolved complex nitrate signaling machinery that was stepwise improved by domains shuffling and regulation co-option. Our study highlights innovations in inorganic nitrogen assimilation and signaling machineries, ranging from molecular modifications of proteins to genomic rearrangements, which shaped developmental and metabolic adaptations of plants to changeable nutrient availability in environments.

Optimizing One-Time Nitrogen Fertilization for Rice Production Using Controlled-Release Urea and Urease Inhibitors

One-time fertilization with controlled-release urea (CRU) is a research hotspot for its lower labor cost and stability of nitrogen (N) supply for rice growth. Yet the fertilizer formulation needs to be further improved to better adjust the N supplement to meet the demand of rice plants and obtain a higher grain yield. Therefore, the effects of novel fertilizer formulations composed of CRU, urease inhibitor (UI) and nitrification inhibitor (NI) on the rice growth and photosynthetic characteristics as well as high-yield formation were tested through a two-year field experiment. The result indicated that the combined use of CRU and UI treatment can achieve higher yields than with CRU at the same N application level. Meanwhile, with a 20% reduction of N use, one-time application of CRU + UI can obtain the same high yield as the conventional split application of urea. Compared with conventional fertilization and CRU treatment, the CRU + UI treatment had suitable leaf area and biomass accumulation at the vegetative growth stage and high effective stem tiller rate. More post-anthesis dry matter accumulation, higher net photosynthesis rate and low senescence rate were guaranteed for its high yield and nitrogen agronomic efficiency.

Effects of Nitrogen Reduction at Different Growth Stages on Maize Water and Nitrogen Utilization under Shallow Buried Drip Fertigated Irrigation

A field experiment of drip fertigated nitrogen reduction was set up in a typical Maize planting area in the Xiliao River Basin in 2018 and 2019. Different phased nitrogen reductions were set up under shallow buried drip irrigation during the growth period to explore ways to improve nitrogen use efficiency (NUE) by understanding the Maize regulation of nitrogen absorption and utilization. The recommended nitrogen application in the early stage (Nopt, total nitrogen 240 kg·hm−2) had the highest grain nitrogen uptake and total nitrogen uptake, followed by nitrogen reduction before the maximum canopy mulching (Nde-I, total nitrogen 180 kg·hm−2), nitrogen reduction after the maximum canopy mulching (Nde-II, total nitrogen 180 kg·hm−2) and no nitrogen application (N0). Without nitrogen application, the leaves were thin, green and yellow. The total nitrogen uptake was 38.54~41.31% lower than the recommended nitrogen application in the early stage. When nitrogen fertilizer was reduced in the maximum canopy mulching, grain nitrogen absorption was affected. Grain nitrogen absorption fell by 15.07% to 17.51% when nitrogen was reduced in the maximum canopy mulching compared to the recommended nitrogen application. The harvest index of nitrogen reduction before the maximum canopy coverage was 9.65~11.52% higher than that in the later stage, indicating that the nitrogen absorption between Maize grain, stem, and leaf was better regulated. Maize evapotranspiration water consumption was reduced throughout the growth cycle when nitrogen was reduced at various stages. Nitrogen reduction before maximum canopy mulching boosted water use efficiency (WUE) by 3.44% to 6.12% compared to the recommended nitrogen application in the early stage. The nitrogen fertilizer agronomic efficiency increased by 11.17% to 13.87%. The nitrogen use efficiency rose by 10.99~3.15% (5.24~6.60 percentage points). A total of 25% of nitrogen fertilizer was saved with the yield declining by only about 5%, resulting in increased NUE while maintaining the yield stability. Under shallow buried drip fertigated irrigation, the appropriate reduction in nitrogen fertilizer during the period from Maize sowing to the maximum canopy development ensured the nitrogen supply during tasseling–silking stage and filling stage, which can be used as a regulation method and a way to improve the Maize fertilizer use efficiency.

MODERN ASSESSMENT OF FERTILITY OF DARK CHESTNUT SOILS OF KAMYSTINSKY DISTRICT OF KOSTANAY REGION

The article presents the results of a study on the morphological, nutritional characteristics of arable dark chestnut soils in the Kamystinsky district of the Kostanay region. According to the structure of the morphological profile, dark chestnut soils belonged to medium and low thickness types, where the thickness of the humus horizon A + B1 is noted within the range of 29 - 45 cm in depth. The accumulation of carbonates and ready soluble salts depends on the parent rocks and the grain-size distribution of dark chestnut soils. In dark chestnut immature soil, there are no carbonates along the soil profile, but gypsum is found at a depth of 36 cm. The line of bubbling from hydrochloric acid is different in ordinary and carbonate genus of dark chestnut soil. The humus content is low, in the plough-layer of soils it ranges 1.10 - 3.05%, the supply of nitrate nitrogen is very low, moving forms of phosphorus are medium and low, while potassium content is very high and elevated.

Applying Nitrogen Fertilizer at the Full Heading Stage Has the Potential to Decrease Brown Rice Cd Accumulation

Soil contamination by cadmium (Cd) has presented a major challenge in China. The objective of the field experiments in this study was to examine the influence of nitrogen fertilizer application at the full heading and milky stages on minimizing the absorption of Cd in rice. This was achieved by affecting the distribution of Cd in root plaques and subcellular compartments of the root and flag leaf. The hydroponic culture experiments aimed to examine the effect of nitrogen and Cd interaction or deficiency on Cd accumulation in rice during the late growth stage. The findings revealed that adequate nitrogen supply during the early growth stage, coupled with nitrogen application during the full heading and milky stages, led to a notable increase in Fe concentration in the root plaques during the milk and mature stages. Furthermore, it elevated the Cd proportion in the soluble fraction of the flag leaves at the milky stage. Conversely, nitrogen deficiency during the early growth stage resulted in a significant increase in Fe concentration in the root plaques, along with a decrease in Cd concentration. Additionally, the proportion of Cd in the flag leaf cell walls increased significantly, while the proportion in the soluble fraction decreased notably. Irrespective of nitrogen supply during the early growth stage, applying nitrogen at the full heading stage significantly reduced Cd transport from shoots to brown rice, leading to a considerable reduction in the Cd concentration in brown rice. Under hydroponic culture conditions, combined Cd exposure with nitrogen supply significantly increased the Cd concentration in brown rice. Nitrogen supply had no impact on the Cd concentration in brown rice in the absence of Cd. The study showed that applying nitrogen fertilizer at the full heading stage effectively decreased the brown rice Cd concentration. This was achieved by elevating the concentration of Fe in the root plaque, thereby influencing the adsorption of Cd by the roots. Additionally, nitrogen application at the full heading stage can influence the distribution of Cd in flag leaf cells during the filling stage. Ensuring ample nitrogen supply in the early stage of rice growth is crucial, and nitrogen application at the full heading stage can effectively reduce the Cd concentration in brown rice.

Long-term straw returning improved soil nitrogen sequestration by accelerating the accumulation of amino acid nitrogen

Straw incorporation has been widely recommended as an effective management practice to increase soil nitrogen stocks in agroecosystems worldwide. However, the overall trend and magnitude of changes in various soil organic nitrogen fractions in response to crop residue return and their contribution to soil nitrogen sequestration remain uncertain. Here, we show through a long-term experiment (12 years) that straw return increased soil total nitrogen and soil nitrogen sequestration rate by 20.01% and 120.95%, respectively. Ammonia nitrogen, amino acid nitrogen, and amino sugar nitrogen were affected by straw and its interaction with year, and increased by 43.08%, 27.70%, and 46.56%, respectively, with the highest growth rate in amino acid nitrogen (10.51 mg kg−1 yr−1). Furthermore, redundancy analyses showed that soil total organic carbon and C:N ratio were the major factors explaining the variations in soil organic nitrogen fractions, which increased by 46.22% and 21.75%, respectively. The structural equation model further revealed that amino acid nitrogen was a pivotal driver of soil nitrogen sequestration, because the soil C:N ratio indirectly influenced soil nitrogen sequestration via affecting the accumulation of amino acid nitrogen. Our results suggest that long-term straw return can improve nitrogen sequestration by accelerating the accumulation of amino acid nitrogen and that soil nitrogen storage and supply capacity may be improved by adopting straw incorporation and other appropriate management practices to regulate soil stoichiometry.

Storage protein activator controls grain protein accumulation in bread wheat in a nitrogen dependent manner

The expression of cereal grain storage protein (GSP) genes is controlled by a complex network of transcription factors (TFs). Storage protein activator (SPA) is a major TF acting in this network but its specific function in wheat (Triticum aestivum L.) remains to be determined. Here we generated an RNAi line in which expression of the three SPA homoeologs was reduced. In this line and its null segregant we analyzed GSP accumulation and expression of GSP and regulatory TF genes under two regimes of nitrogen availability. We show that down regulation of SPA decreases grain protein concentration at maturity under low but not high nitrogen supply. Under low nitrogen supply, the decrease in SPA expression also caused a reduction in the total quantity of GSP per grain and in the ratio of GSP to albumin-globulins, without significantly affecting GSP composition. The slight reduction in GSP gene expression measured in the SPA RNAi line under low nitrogen supply did not entirely account for the more significant decrease in GSP accumulation, suggesting that SPA regulates additional levels of GSP synthesis. Our results demonstrate a clear role of SPA in the regulation of grain nitrogen metabolism when nitrogen is a limiting resource.

Nutrient intake, digestibility, and utilization in goats fed graded levels of hempseed cake finisher diets

Globally, the price of soybean meal, the most common proteinaceous ingredient in livestock diets, has become highly expensive prompting a search for alternative ingredients. Hemp seed cake is a promising alternative but could be limited by its high neutral detergent fiber and ether extract contents which impede nutrient intake and digestibility. However, some ruminant species such as goats have superior ability to digest high fiber and ether extract diets. Thus, the current research evaluated nutrient intake and digestibility, rumen fermentation, and microbial protein synthesis of goats fed hempseed cake as a substitute for soybean meal in finisher diets. A total of 25 Kalahari Red castrates (27 ± 3 kg, 4–5 months old) were assigned to five dietary treatments (5 goats/ diet) in a completely randomized design. A maize-lucerne-based finishing diet was formulated with hempseed cake substituting soybean meal as the primary protein ingredient at 0, 25, 50, 75, or 100 g/kg dry matter. Ether extract intake exhibited a positive linear trend (P ≤ 0.05) while crude protein intake and microbial nitrogen supply exhibited a negative linear trend (P ≤ 0.05) with dietary inclusion of hempseed cake. However, feeding hempseed cake did not influence (P > 0.05) apparent nutrient digestibility, rumen fermentation parameters and nitrogen use efficiency. In conclusion, the substitution of soybean meal for hempseed cake decreased crude protein intake and microbial nitrogen supply in goat finisher diets without compromising nutrient digestibility and nitrogen use efficiency. The study recommends partial or full replacement of soybean meal with hempseed cake in goat finisher diets.

The exceptional form and function of the giant bacterium Ca. Epulopiscium viviparus revolves around its sodium motive force.

Epulopiscium spp. are the largest known heterotrophic bacteria; a large cigar-shaped individual is a million times the volume of Escherichia coli. To better understand the metabolic potential and relationship of Epulopiscium sp. type B with its host Naso tonganus, we generated a high-quality draft genome from a population of cells taken from a single fish. We propose the name Candidatus Epulopiscium viviparus to describe populations of this best-characterized Epulopiscium species. Metabolic reconstruction reveals more than 5% of the genome codes for carbohydrate active enzymes, which likely degrade recalcitrant host-diet algal polysaccharides into substrates that may be fermented to acetate, the most abundant short-chain fatty acid in the intestinal tract. Moreover, transcriptome analyses and the concentration of sodium ions in the host intestinal tract suggest that the use of a sodium motive force (SMF) to drive ATP synthesis and flagellar rotation is integral to symbiont metabolism and cellular biology. In natural populations, genes encoding both F-type and V-type ATPases and SMF generation via oxaloacetate decarboxylation are among the most highly expressed, suggesting that ATPases synthesize ATP and balance ion concentrations across the cell membrane. High expression of these and other integral membrane proteins may allow for the growth of its extensive intracellular membrane system. Further, complementary metabolism between microbe and host is implied with the potential provision of nitrogen and B vitamins to reinforce this nutritional symbiosis. The few features shared by all bacterial behemoths include extreme polyploidy, polyphosphate synthesis, and thus far, they have all resisted cultivation in the lab.

OPTIMIZATION OF NITROGEN FERTILIZATION FOR AGRICULTURAL CROPS UPON ADDITIONAL APPLICATION OF FRESH ORGANIC MATTER TO THE SOIL

Objective. Using biological testing, determine the environmental appropriate rates of mineralnitrogen, applied in the background of effect and aftereffect of straw and biomass of intermediatelupine green manure, in the fertilization system of potatoes and spring barley. Methods. Field experiment (growing crops in crop rotation in the conditions of a long-term (since 2009) stationaryexperiment on leached chornozem); gas chromatographic (to determine the potential nitrogenfixing (nitrogenase) and potential denitrifying activities in the rhizosphere soil of plants dependingon the fertilizer); statistical. Results. With the systematic application of fresh organic matter to thesoil in the form of 5.0 t/ha of straw and 5.3 t/ha of dry biomass of intermediate lupine green manure, the excess of nitrogen mineral compounds is metabolically bound (immobilized) by microorganisms, the process of nitrogen fixation is restored, the emission of N2O decreases, and the ratesof mineral fertilizers not exceeding N80P80K80 become environmentally appropriate when growingpotatoes. At the same time, the introduction of straw does not require additional provision of mineral nitrogen to optimize the C/N ratio. The highest rate of mineral fertilizers N120P120K120 in theexperiment, even when combined with organic matter for a long time is environmentally inappropriate — only at the end of the growing season, the studied indicators demonstrate its acceptability.When growing spring barley on leached chornozem, the optimization of the processes of biologicaltransformation of nitrogen compounds is achieved if mineral fertilizers are applied on the background of aftereffect of organic matter in a rate not exceeding N60P60K60. Systemic application ofN90P90K90 suppresses the activity of nitrogen fixation and ensures significant losses of nitrous oxide.This rate of fertilizers should be applied only on the condition that it is applied against the background of the aftereffect of straw and green manure mass, which contributes to the mitigation ofenvironmental consequences. Conclusion. The use of mineral fertilizers against the backgroundof systematic application of winter wheat straw and intermediate lupine green manure biomass tothe soil contributes to the optimization of the biological state of the leached chornozem. The improvement of environmental indicators contributes to the growth of the yield of agricultural crops.