High Nitrogen Levels Research Articles

Hydrothermal-Induced Formation of Well-Defined Hollow Carbons with Curvature-Activated N-C Sites for Zn-Air Batteries.

Metal-free carbons have been regarded as one of the promising materials alternatives to precious-metal catalysts for oxygen reduction reaction (ORR) due to their high activity and stability. In this paper, well-defined N-doped hollow carbons (NHCs) are firstly synthesized by using an ammonia-based hydrothermal synthesis that is environmentally friendly and suitable for mass production in industry and a commercial black carbon as raw material. Moreover, the shell thickness of the NHCs can be easily tuned by this hydrothermal strategy. Zn-air battery test results reveal shell thickness-dependent activity and durability for ORR over the NHCs, which exceeds that obtained by commercial Pt/C (20 wt %). The enhanced battery performance can be attributed to the curvature-activated N-C moieties on the hollow carbon surface, which served as the main active sites for ORR as evidenced by DFT calculations. The proposed approach may open a way for designing curved hollow carbons with high graphitization degree and dopant nitrogen level for metal-air batteries or fuel cells.

Impact of levels of nitrogen fertilizer and types of irrigation water on yield and yield components of barley crop

A pot experiment was carried out at the Experimental Farm, Faculty of Agriculture, South Valley University, Qena, Egypt during the 2015-2016 and 2016-2017 seasons to study the effect of nitrogen fertilizer levels and types of irrigation water (W1; Tap water only, W2; manipulated wastewater with sandy filter, W3; manipulated wastewater with nano-titanium dioxide + sandy filter and W4; a mixture of treated wastewater with nano-titanium dioxide and sandy filter + tap water) on growth, yield and its attributes of barley cv. Giza 2000. A randomized complete block design (RCBD) using a split-plot arrangement with four replications was used. The main plot was four different levels of nitrogen fertilizer and the sub-plot were four different types of irrigation water. The seeds of above mentioned variety were used in the pot experiments. The highest mean values of plant height, number of tillers plant-1, spike length, number of grains spike-1, spike weight, biological yield plant-1 and grain yield plant-1 were obtained from high level of nitrogen (60 kg N fed-1). Also, the highest values of above traits were obtained from irrigation with treated wastewater with nano-titanium dioxide and sandy filter + tap water (W4). It could be concluded that under the conditions of the experiment, application of high levels of nitrogen (N60) under irrigation with treated wastewater with nano-titanium dioxide and sandy filter+ tap water (W4) is recommended.

Gluten Protein Compositional Changes in Response to Nitrogen Application Rate

Field trials were conducted to evaluate the effect of nitrogen level on wheat protein content and composition in 16 cultivars over two years at three locations. The nitrogen treatment comprised two nitrogen levels, 0 kg ha−1 as low and 100 kg ha−1 as high nitrogen, applied as top dressings of 50 kg nitrogen per ha at tillering and stem extension growth stages. Increased nitrogen level generally enhanced grain protein by 11.3% (11.5% vs. 12.8%). Considering protein composition determined by reversed phase–high-pressure liquid chromatography, higher nitrogen supply generally enhanced the proportion of total gliadins, α-gliadins, γ-gliadins and high-molecular-weight glutenin subunits by 1.1%, 2.0%, 3.7%, 0.6% and 0.9%, respectively, and reduced albumins and globulins, ω-gliadins, total glutenins and low-molecular-weight glutenin subunits by 1.1%, 1.7%, 1.9% and 3.2%. Under a high nitrogen level, the historical cultivars Libellula, San Pastore and U-1 had a higher protein content (13.1–15.2%) with significantly higher total gliadins, which resulted in a significantly higher gliadin/glutenin ratio (1.68–1.92). In the modern cultivars, protein content varied between 11.4% and 14.6% with a well-balanced gliadin/glutenin ratio (1.08–1.50), except for cultivar MV Nemere which had a high gliadin/glutenin ratio at both nitrogen levels (1.81 vs. 1.87). In summary, increasing nitrogen level enhanced grain protein content while the composition of gliadin and glutenin fractions was changed to a lesser extent and was largely cultivar specific and therefore should be considered for wheat baking quality assessment and breeding purposes.

Tolerance of Tetraselmis tetrathele to High Ammonium Nitrogen and Its Effect on Growth Rate, Carotenoid, and Fatty Acids Productivity.

Microalgae can use either ammonium or nitrate for its growth and vitality. However, at a certain level of concentration, ammonium nitrogen exhibits toxicity which consequently can inhibit microalgae productivity. Therefore, this study is aimed to investigate the tolerance of Tetraselmis tetrathele to high ammonium nitrogen concentrations and its effects on growth rate, photosynthetic efficiency (Fv/Fm), pigment contents (chlorophyll a, lutein, neoxanthin, and β-carotene), and fatty acids production. Experiments were performed at different ammonium nitrogen concentrations (0.31–0.87 gL−1) for 6 days under a light source with an intensity of 300 μmol photons m−2 s−1 and nitrate-nitrogen source as the experimental control. The findings indicated no apparent enhancement of photosynthetic efficiency (Fv/Fm) at high levels of ammonium nitrogen (-N) for T. tetrathele within 24 h. However, after 24 h, the photosynthetic efficiency of T. tetrathele increased significantly (p < 0.05) in high concentration of -N. Chlorophyll a content in T. tetrathele grown in all of the different -N levels increased significantly compared to nitrate-nitrogen (NO3-N) treatment (p < 0.05); which supported that this microalgal could grow even in high level of -N concentrations. The findings also indicated that T. tetrathele is highly resistant to high ammonium nitrogen which suggests T. tetrathele to be used in the aquaculture industry for bioremediation purpose to remove ammonium nitrogen, thus reducing the production cost while improving the water quality.

LED Light Quality of Continuous Light before Harvest Affects Growth and AsA Metabolism of Hydroponic Lettuce Grown under Increasing Doses of Nitrogen.

To study the effects of light quality of continuous light before harvest on the growth and ascorbic acid (AsA) metabolism of lettuce (Lactuca sativa L.) grown under relative high nitrogen level, lettuce plants grown under different nitrogen levels (8, 10 and 12 mmol·L−1) were subjected to continuous light with different red: blue light ratios (2R:1B and 4R:1B) before harvest. The results showed that the shoot fresh weight of lettuce under 12 mmol·L−1 nitrogen level was significantly higher than that under other treatments. There were no significant differences in shoot dry weight, root fresh weight, root dry weight, soluble sugar content, nitrate content and AsA content in leaves among the treatments at different nitrogen levels. The content of AsA in leaves was significantly higher than that in petioles before and after continuous light. Under the same nitrogen level, the fresh weight of lettuce under continuous light quality 4R:1B was significantly higher than that under other treatments. The content of AsA in lettuce leaves increased in different degrees after continuous light before harvest. High yield and AsA content could be obtained by 72 h continuous light with red and blue light 4R:1B at 12 mmol·L−1 nitrogen level. After continuous light, the content of AsA increased significantly due to the increase of the ratio of red light and nitrogen level, which increased the activities of L-galactono-1,4-lactone dehydrogenase (GalLDH) and dehydroascorbic acid reductase (DHAR) involved in AsA synthesis and in the recycling of DHAR to AsA respectively.

Physicochemical Characteristics and Microbial Communities in Gochujang, a Traditional Korean Fermented Hot Pepper Paste.

Gochujang is a Korean fermented hot pepper paste beneficial to human health by providing various nutrients. In this study, its physicochemical characteristics were identified, and its microbial communities were analyzed by high-throughput sequencing. The interrelationship between physicochemical characteristics and microbial composition was investigated to reveal the properties of gochujang before and after fermentation. After fermentation, all samples showed decreased salt concentration, pH, and reducing sugar content, while the acidity and amino-type nitrogen increased. The water content, salt concentration, amino-type nitrogen, and reducing sugar differed according to the batches of samples. Bacillus, Aerosakkonema, and Enterococcus were identified as the predominant bacterial genera. Furthermore, Aerosakkonema was the most abundant genus before fermentation; however, it was replaced by Bacillus as it decreased after fermentation. For the fungi, Aspergillus dominated before fermentation, whereas Zygosaccharomyces and Millerozyma dominated after fermentation. The high level of amino-type nitrogen in gochujang was related to the relative abundance of B. haynesii/B. licheniformis before fermentation. Additionally, the high abundance of Z. rouxii after fermentation was related to the flavor of gochujang. This comprehensive analysis of the microbial community associated with the physicochemical properties of gochujang could help in understanding the factors affecting the quality of the product.

The mechanisms underlying melatonin improved soybean seedling growth at different nitrogen levels

To investigate the function of melatonin (MT) on nitrogen uptake and metabolism in soybean, six groups of treatments, with and without 100μM melatonin were conducted at low, normal, and high nitrogen levels (1.5, 7.5, and 15mM, respectively). The related indexes of nitrogen metabolism and the antioxidant system of seedlings were measured and analysed. Results indicated that MT could enhance the level of nitrogen metabolism by upregulating the coding genes of enzymes related to nitrogen metabolism and increasing total nitrogen content, especially under low nitrogen levels. Under high nitrogen conditions, the addition of MT not only accelerated ammonium assimilation and utilisation by enhancing the activity of glutamine synthetase involved in ammonium assimilation, but also reduced the extent of membrane lipid peroxidation to alleviate the degree of damage by improving the activity of antioxidant enzymes. In addition, MT enhanced soybean growth with positive effects in morphological changes at different nitrogen levels, including significantly increased stem diameter, total leaf area, and root nodule number, and biomass accumulation. Finally, biomass accumulation increased under low, normal, and high nitrogen levels by 9.80%, 14.06%, and 11.44%, respectively. The results suggested that MT could enhance the soybean tolerance to low and excessive N treatments.

Producción de girasol en función del tipo de suelo, nitrógeno y densidad de población

El nitrógeno es el nutrimento que limita en mayor medida la producción de girasol (Helianthus annuus L.). El objetivo del estudio fue determinar la producción de biomasa y rendimiento en el cultivo de girasol en función del tipo de suelo, nitrógeno y densidad de población. Los tratamientos fueron tres tipos de suelo donde se aplicaron tres niveles de nitrógeno (0, 50 y 100 kg ha-1), así como tres densidades de población (4, 8 y 12 plantas por m2). El diseño fue bloques completos al azar con arreglo de parcelas subdivididas y cuatro repeticiones. Se evaluó la fenología de la planta, biomasa, índice de cosecha, rendimiento y sus componentes. Como resultado se obtuvo que las condiciones climáticas fueron favorables para el desarrollo del cultivo cuando la temperatura osciló entre 8 a 31°C. De los tres sitios donde se estableció el estudio, el que presentó las mejores condiciones para el crecimiento del cultivo fue en el suelo con pH de 7.1 y CE de 0.49 dS m-1 con la aplicación de 100 kg ha-1 de nitrógeno y una densidad de 12 plantas m-2. Por ello, la mejor producción de biomasa y rendimiento se encontró en el suelo con pH neutro, sin salinidad con textura franco arenoso en combinación con el más alto nivel de nitrógeno y densidad de población.

Анализ пространственного распределения сообществ макрозообентоса в равнинной реке полупустынной зоны

Анализ пространственного распределения сообществ макрозообентоса в равнинной реке полупустынной зоны

Macrophytes restoration and its effects on eutrophication control in rehabilitated lakeshore zone of Gonghu Bay, Lake Taihu

以太湖贡湖湾人工湖滨带为对象，研究湖滨水生植物修复过程及其富营养化控制效果.人工湖滨区域内的消浪带、岸上护坡措施为水生植物修复提供了良好的生境条件，形成了包括荇菜（Nymphoides peltatum（Gmel.）Kuntze）、睡莲（Nymphaea tetragona Georgi）、菱（Trapa bispinosa Roxb.）为主的浮叶植物群落，以及以黑藻（Hydrilla verticillata（Linn.f.）Royle）、狐尾藻（Myriophyllum verticillatum L.）、小眼子菜（Potamogeton pusillus L.）、竹叶眼子菜（Potamogeton malaianus）为主的沉水植物群落.通过设置研究区、对照区，持续监测溶解氧、总氮、总磷、氨氮、叶绿素a浓度等水体指标，烧失量、氮含量、磷含量等沉积物指标，水生植物生物量、覆盖度，浮游藻类等指标.不同时期、不同区域间的时空分布显示：随着水生植物的恢复，水体营养状态指数（TLI）、沉积物生物生产力指数（BPI）显著下降，水体透明度显著提升；较高浓度的总氮（>3.0 mg/L）、氨氮（>0.6 mg/L）环境不利于浮叶植物的生长，沉水植物对其则表现出更好的适应性，同时水生植物在成长过程中直接从水体/沉积物中吸收氮；颤藻（Cyanophyta oscillatoria）、直裂藻（Cyanophyta merismopedia）等浮游藻类吸收了水体磷，水生植物利用了沉积物磷，共同缓解了磷在湖滨区域的累计.总结以上，湖滨带的水文水质条件可以影响水生植物群落结构，进而决定氮、磷的控制效果，所以在湖滨带修复中构建合适的生境条件是水生植物发挥氮磷控制效果的重要前提.水生植物在恢复过程中对浮游藻类群落结构的影响是显著的，并且以此影响到湖滨水体中磷的分布.;A rehabilitated lakeshore zone in Gonghu Bay, Lake Taihu, China was chosen to study macrophytes restoration and its effects on eutrophication control. The facilities including wave-weakening belts and bank revetment in rehabilitated lakeshore provided habitat for floating-leaved macrophytes, like Nymphoides peltatum (Gmel.) Kuntze, Nymphaea tetragona Georgi, Trapa bispinosa Roxb., etc. and submerged macrophytes, like Hydrilla verticillate, Myriophyllum verticillatum L., Potamogeton pusillus L., Potamogeton malaianus, etc.. The continuously monitoring on dissolved oxygen, total nitrogen, total phosphorus, ammonia, chlorophyll-a concentrations of water, ignition loss, nitrogen, phosphorus contents of sediment, macrophytes' coverages and biomass, phytoplankton's density were performed between two study areas and reference area. The space-time distribution of different areas and stages indicated that the trophic level index (TLI) of water and the bioproduction index (BPI) of sediment were remarkedly reduced, the water transparency was significantly increased as the macrophytes restored. The relatively high levels of total nitrogen (>3.0 mg/L) and ammonia (>0.6 mg/L) were the condition unfavorable for the floating-leaved macrophytes but not for the submerged macrophytes, in the meanwhile nitrogen of water and sediment were utilized directly during the macrophytes' restoration. Phytoplankton like Cyanophyta oscillatoria, Cyanophyta merismopedia and etc. absorbing phosphorus from water directly and macrophytes utilizing phosphorus in sediment collaboratively alleviated the phosphorus accumulation in lakeshore. Overall, it is concluded that the hydrological condition and water quality have impact on structure of macrophyte communities in the restoration, thus affecting the efficiency of nitrogen and phosphorus control. The macrophytes restoration had significant influences on planktonic communities, of which were directly correlated with phosphorus distribution in lakeshore water.

Influence of nitrogen fertilizer levels on growth and quality of barley (Hordeum vulgare) varieties

Nitrogen is the most important essential nutrient that comes under macronutrient category as it plays vital role in various physiological processes in plant as it produce rapid early growth, improve fruit quality, protein content in fodder crops, vegetative growth in plants, leaves, stem growth and imparts dark green color to plants. When different level of nitrogen applied in Barley(Hordeum vulgare L.) at different sowing dates, it resulted in increased rate of growth parameters like plant height, number of tillers per hill, CGR(Crop Growth Rate), RGR(Relative Growth Rate), plant dry weight and yield attributes like grain yield, straw yield, number of effective tillers. When nitrogen is given to barley at different concentration (60, 75, 90 kg per ha) maximum nitrogen content in grain and straw yield was found with the application of 90 kg per ha and protein content in grain and grain yield was found to be increased with increased level of nitrogen in Barley in sodic soils. When different levels of nitrogen (i.e. 0, 20, 40, 60, 80 and 100 kg per ha) in different varieties of Barley was applied, it affect yield attributes like grain weight, grain spike, straw yield, grain yield, biological yield, plant and grain nitrogen differently like maximum grain spike, grain and grain yield was recorded in sterling varieties while highest biological yield, straw yield, grain and plant nitrogen was observed in local varieties and nitrogen applied at rate of 60 kg per ha resulted in maximum grain spike, grain weight, biological yield, grain yield and grain and plant N. nitrogen applied at once showed minimum days to emergence of crop and maximum plant height while when applied in three split doses it results good yield with maximum emergence m-2, fresh and dry biomass, tillers and leaves plant-1, tillers and spike m-2, grain spike, grain weight and minimum days to spike and maturity in dual purpose Barley. Regarding nitrogen fertilizer application at rates 0, 30, 60, 90, 120and 150kg ha-1 yield was increase upto 90 kg ha-1 later on it remains steady. Nitrogen accumulation in crops, green fodder yield, vegetative growth of plants is found to be increased upto a certain level of nitrogen applied beyond that limit some parameters are going to stay steady and some going to decline. Along with different nitrogen levels, number of cuttings and timing of cutting also affects parameters as late cutting have positive impact on enhancement of yield of green fodder and lack of cutting enhanced grain yield and most of yield components and high level of nitrogen led to increase in green fodder and grain yield.

Chemical composition of the wood of Juglans neotropica Diels.,and its relationship with the chemical properties of the soil in Valladolid parish, Zamora Chinchipe province, Ecuador

This research evaluated the chemical composition of the wood of Juglans neotropica D ie ls (Walnut) and its relationship with the chemical properties of the soil, ina humid forest ecosystem of the Valladolid parish in southern Ecuador. For this purp os e , w o od s a m ple s were taken from five walnut trees and soil samples around each individual within a ra d iu s of two meters. Later, in the laboratory, the chemical characterization of the woodwas carried out, as well as the edaphic analysis. For statistical analysis between variables, we used the non-parametric test of Kruskal-Wallis and Spearman. The results showed th a t th e wood of Walnut has greater percentage of holocellulose (78.91%), followed by lignin (13.39%), and in smaller proportions of extractive (5.76%) and ashes (1.94%). The soil presented an average pH of 5.21 (acid), high levels of nitrogen (159.39 ppm) and phosphorus (57.33 ppm). It was evidenced that among the variables of soiland wood th e re are two significant negative relationships (nitrogen-holocellulose and phosphorus-extractants), and a positive relationship (nitrogen-lynogen). However, the p H a n d th e a s h did not present any relation with the components and properties analyzed.Key word:Extractives, ash, lignin, holocellulose, pH.

Chemical composition of the wood of Cedrela odorataL. andits relationship with the chemical properties of the soil of the Zumba parish province of Zamora Chinchipe, Ecuador

The research had the objective of determining the chemical composition of the wood o f Cedrela odorataL. and its relationship with the chemical properties of the soil in a forest ecosystem; for this purpose, five trees were taken as samples, from which a branch of one meter long of 10 to 20 centimeters in diameter was obtained and the analyses of ash, extracts, lignin and holocellulose of each sample were carrie d o ut; th e analysis of the level of pH, phosphorus and nitrogen of the soil was made. For statistical analysis, the non-parametric Kruskal-Wallis test was used with the Dunn test, and a bivariate correlation of Spearman was applied. In general, it was obtained that the holocellulose (62,97 %), is the most abundant component, followed by lignin (30,15 %) and with a lower percentage the content of extractable (5,64) and Ashes (1,24 % ). Th e soil where the individuals grew is very acidic (pH of4,70) with a medium p h os p ho rus level (33,74 ppm), and a high level of nitrogen (165,24 ppm). The relationship betw ee n the chemical properties of the wood and each of the chemical properties of the soil resulted in four relationships, two positive (phosphorus -lignin with a s ign if ic a n c e o f 0.1 and nitrogen -holocellulose with a significance = 0,01) and two negative (p H -a s h with a significance of 0,01 and nitrogen -lignin with a significance value of 0,04). Key words: Chemical composition, wood, Cedrela odorata

Effect of Nitrogen Levels on Spring Maize in Relation to Mulching Materials in Central Inner Tarai of Nepal

The effect of different mulching materials and varying nitrogen fertilizer levels on growth, yield attributes, and yield of open-pollinated maize variety aiming at yield improvement was studied in inner Terai of Nepal through a field experimentation in 2019. The treatments included were the combinations of three mulching materials, (a) plastic mulch, (b) straw mulch, and (c) no mulching; and four nitrogen levels (0, 50, 100, and 150 kg ha-1) arranged in a split-plot design with four replications. Data on growth, yield attributes, and yield were taken and analyzed by using R Studio. The higher (p&lt;0.05) heat use efficiency was recorded under plastic mulch and the higher levels of nitrogen application. The number of kernels per cob and thousand kernel weight were higher (p&lt;0.05) in mulch treatments and higher nitrogen levels. Both the barrenness and sterility percentage were higher (p&lt;0.05) for the 0 kg N ha-1 and reduced (p&lt;0.05) by the nitrogen application of ≥100 kg ha-1. Increased tasseling-silking interval increased (p&lt;0.05) the sterility and grain filling duration and increased (p&lt;0.05) the grain yield. Due to the better yield attributes, the grain yield of mulch applied treatments and application of ≥100 kg N ha-1 were higher (p&lt;0.05) than the no mulch and ≤50 kg N ha-1, respectively. The yield was hampered more by barrenness than by sterility. The effect of nitrogen levels on grain yield followed the quadratic relationship; 104 kg and 129-130 kg N ha-1, respectively for no mulch and mulching treatments which are estimated as economic levels of nitrogen fertilizers for open-pollinated spring maize under the central inner Terai environment.

Status and Properties of Soils under Some Woody Species of Degraded Glacis in Northern Burkina Faso

Land degradation is a threat to biodiversity and has negative impacts on agricultural communities by aggravating food insecurity. The objective of this study was to examine the responses of native woody species and soil variables to different levels of glacis degradation in the Sahelian zone of Burkina Faso. Field investigations were performed according to the degradation gradient outlined in the Braun-Blanquet method. Soil samples were collected and analyzed in the laboratory. The results indicate that the diversity and diametric structure of woody species are functions of the glacis degradation stage. A total of eight (08) woody species were recorded on the glacis (7 species in non-degraded glacis, 7 species in moderately-degraded glacis and only 1 species in degraded glacis). Acacia raddiana is the only local woody species present in all three glacis degradation stages. It is recommended to rehabilitate degraded glacis in the Sahel in response to desertification. The high levels of sand, nitrogen (N) and carbon (C) characterize the non-degraded and moderately-degraded glacis, whereas the high levels of silt, clay, bulk density, pH-H20 and pH-Kcl indicate degraded glacis. This study can inform the future rehabilitation and management of Sahelian glacis.

Unraveling membrane fouling in anoxic/oxic membrane bioreactors treating anaerobically digested piggery wastewater

Anaerobically digested piggery wastewater (ADPW) draws increasing attention due to the high nitrogen and carbon level. In this study, four parallel lab-scale anoxic-oxic membrane bioreactors were applied to treat ADPW with the hydraulic retention time (HRT) of 75, 60, 45 and 30 h, respectively. Reactor performance and membrane fouling mechanisms also have been systematically evaluated. The results demonstrated a decline in chemical oxygen demand and total nitrogen biodegradation (from 65.8 ± 2.5% and 62.2 ± 5.5% to 38.6 ± 3.6% and 26.2 ± 5.7%, respectively) and a rise in membrane resistance (from 37.34 × 1012 m−1 to 51.69 × 1012 m−1) as the HRT decreased. The decline of HRT didn’t affect the functional group types of cake layer extracellular polymeric substances (EPS) and tightly bound EPS (TB-EPS) of activated sludge, but led to the increased concentrations of protein (PN) and polysaccharide (PS) in loosely bound EPS (LB-EPS) and soluble microbial products (SMP) of activated sludge and a decreased PN/PS ratio in SMP. These changes in SMP and EPS accelerated the formation of cake layer and aggravated the membrane fouling. Proteobacteria and Bacteroidetes were the predominant phyla on membrane surface. The abundant Proteobacteria in the reactor with longer HRTs was beneficial to mitigate membrane fouling while the relative abundance of Bacteroidetes remained stable in all reactors. The enrichment of Thauera was the primary reason for membrane fouling at genus level in the reactors. This study provides scientific insights on the practical application of membrane bioreactors in terms of membrane fouling control.

No tillage and previous residual plastic mulching with reduced water and nitrogen supply reduces soil carbon emission and enhances productivity of following wheat in arid irrigation areas

Abstract No tillage, optimal nitrogen and irrigation supply levels, and crop rotation are promising strategies for reducing soil carbon emission, and plastic mulching is an important measure to improve crop productivity in arid regions. However, the effect of no tillage and plastic mulching combined with optimum management of water and nitrogen on soil carbon emission has not been tested. A field experiment was carried out in 2016–2018, to evaluate how no tillage, reduced the levels of irrigation and nitrogen affect crop yield, water use, and soil carbon emission of following spring wheat after plastic-mulched maize. A sustainability evaluation index was analyzed via integrating key parameters related to yield performance, water use, and soil carbon emission characteristics. Our results show that no tillage with previous residual plastic mulching, reduced irrigation, and reduced nitrogen application increased yield and water use efficiency of following wheat, but decreased soil carbon emission. From the 3-year average, no tillage and previous residual plastic mulching combined with the reduction of 20 % in both irrigation and nitrogen levels (i.e., the integrated system), increased grain and energy yields of following wheat by 13.7 and 7.8 %, respectively, compared to conventional tillage with conventional high levels of irrigation and nitrogen (i.e., the control). Also, the integrated system improved grain and energy yields for water use efficiency by 7.2 and 4.0 %, respectively. The soil carbon emission with the integrated system was 31.7 % lower than that with the control treatment, and the integrated system reduced soil carbon emission for water use efficiency by 33.8 % compared to the control treatment. However, the integrated system had 65.1 % greater carbon emission efficiency than the control treatment. The integrated system had the highest sustainability index among all treatments. Therefore, no tillage with previous residual plastic mulching from the previous maize combined with a 20 % reduction in both irrigation and nitrogen levels is an optimal strategy for sustainable and effective production of wheat in arid Oasis irrigation regions.

Can crop management reduce the negative effects of warm nights on wheat yield?

Abstract In wheat, warmer nights during the critical period reduce grain yield due to a diminished grain number per unit area, associated with lower spike number. Previous studies have evaluated the impact of increased night temperatures, but only under potential growing conditions. The aims of this study were to: (i) evaluate the impact of warmer nights during the critical period (i.e. from third detectable node to 10 days after anthesis) on grain yield and its numerical components, under contrasting nitrogen (N) and water levels and (ii) determine whether plant density could be useful as a management strategy to reduce yield losses caused by warmer nights. Two sets of experiments were conducted in Buenos Aires, the first in 2015 and 2016. In both years trials were carried out combining (i) two levels of nitrogen availability (60 and 200 kg N ha−1), (ii) two levels of water availability (rainfed and irrigated) and (iii) two conditions of night temperature (increased night temperature from third visible node to 10 days after anthesis and unheated crops during the whole crop cycle). The second experiment was performed in 2017 and combined: (i) three plant densities (ca. 100, ca. 150 and 300 plants m−2) and (ii) two-night temperature regimes (increased night temperature from third visible node to 10 days after anthesis and unheated crops during the whole crop cycle). Night temperatures were increased by heating systems, during the critical period average night temperatures ranged from 10.7 °C to 15.1 °C. Yield losses occurred when plants were exposed to warmer nights at high nitrogen levels (ca. 7% - i.e. 550 g m−2 - loss per °C of increase) but no effects were apparent under lower nitrogen availability. Warmer nights increased tiller mortality only under high nitrogen availability. No conclusions could be reached concerning water supply management or the convenience of this strategy to reduce the impact of warmer nights due to the lack of response of grain yield or grain number to modifications in water availability. Grain yield was significantly reduced by increases in night temperature only under higher nitrogen supply mostly due to a reduction in grain number per unit area, associated with reductions in spike dry weight; however, crops under high nitrogen levels yielded significantly more than those grown under low nitrogen, even when exposed to warmer nights. For all three densities, warmer nights reduced grain yield similarly (on average ca. 15 %).

Correlation and Path Coefficient Analysis of Yield Attributes in Grain Sorghum (Sorghum bicolor L.) Genotypes

Path coefficient was computed to estimate the contribution of individual traits to yield in grain sorghum .An investigation was carried out with 24 restorer lines of sorghum and one check variety Doradoto asses association of grain yield components and their direct and indirect effects on grain yield/plant during 2019 and 2020 growing seasons at Shandweel Agric. Res. Station, Egypt under four levels of nitrogen fertilization (60, 80 .100 .120 kg N / fed). Results of combined analysis of variance showed that significant or highly significant variations were recorded for environments, genotypes, and their location for various studied morphological and yield traits. The results of correlation analysis indicated that 1000-grain weight, panicle length, panicle width and plant height positive and significant correlation with grain yield. Plant height had maximum positive direct effect on grain yield/plant followed by 1000-grain weight. The best genotype was Rsh-19 for grain yield / plant , Rsh-22 for 1000-grain weight , Adv-44 for panicle width , Rsh-20 for panicle length , Sel pop- 13 for earliness and Rsh-12 for plant height . The highest mean values for all traits except days to 50% flowering were obtained under high nitrogen level (120 Kg N/fed) in both two seasons while the reverse was obtained under low nitrogen level (60 Kg N/ fed) in both two growing seasons.

19 Assessment of Nitrogen Intake, Excretion and Deposition in lipopolysaccharide-Challenged Pigs

Abstract This study was conducted to assess the effect of E. Coli lipopolyssacharide challenge (IC) on Nitrogen Balance (NB) in growing pigs (19 kg). Three NB trials were performed in a complete RBD, with six nitrogen levels (NL), two sanitary status (control and IC) and two individual replicates per treatment (6 x 2 x 6). Pigs were intramuscular injected with 30 and 34 μg LPS/kg for two consecutive days. Dietary NL ranged from 1.06 to 4.48 % (dry matter), with lysine being limiting in all diets. NB trials lasted 11 days in which feces and urine were collected at the last four days to determine N intake (NI), N excretion (NEX) and N deposition (ND). Data were analyzed as two-way ANOVA and polynomial contrasts were used. Body weight were unaffected by the factors under study (P &amp;gt;0,05). LPS-challenged pigs had a lower (P&amp;lt; 0,05) feed intake compared with control group (372,98 vs. 417,82). Interaction between NL and IC were observed (P&amp;lt; 0,05) for NI, NEX and ND. NL linearly increased NI, NEX and ND, with different equations for both groups (P&amp;lt; 0,05): ND = 127,86 + 246,95 NL in control group whereas ND = 150,66 + 155,4 in LPS group. LPS-challenged pigs fed the three highest NL exhibited a decrease in NI compared with control group (P&amp;lt; 0,05). From NL2 to NL6, ND was also impaired in LPS-challenged pigs compared with control. Nitrogen excretion was higher in LPS-challenged pigs fed the two highest NL compared with pigs from control group (P&amp;lt; 0,05). In conclusion, LPS challenge impairs nitrogen retention in growing pigs by 37%. These outcomes can be used further for modelling procedures to estimate lysine requirements of pigs in different sanitary status.