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Background: Nitrogen fertilization in broccoli is very important for plant growth and productivity. However, it is known that the nitrogen source of the nitrogen fertilizer is also effective on quality parameters. In this study we investigated the effects of different nitrogen sources (ammonium sulphate and calcium nitrate) on bioactive compounds and leaf nutrients of broccoli cultivars (Monet, Italian and Karadede). Results: The highest total phenolic content was 0.24 mg g− 1 fw in cultivar Monet. Nitrate-based fertilizer treatments provided higher total phenolic (0.28 mg g− 1 fw) and flavonoid (0.56 mg g1 fw) contents and FRAP (0.24 mmol g− 1 fw) values compared to ammonium-based fertilizer treatments. On the other hand, DPPH (0.77 mmol g− 1 fw) values were higher in the ammonium nitrogen treatments. Among the cultivars, Monet had the highest total phenolics, flavonoids and FRAP values. When leaf nutrient concentrations were analyzed, ammonium sulfate application resulted in higher sulfur (0.86%), zinc (20.72 mg kg− 1) and manganese (28.80 mg kg− 1) concentrations compared to calcium nitrate. Calcium nitrate treatment provided the highest calcium (2.09%) and iron (37.50 mg kg− 1) concentration in Monet cultivar. Phosphorus (0.31–0.35%) and magnesium (0.073–0.084%) concentrations differed among cultivars. Conclusions: In conclusion, the choice of nitrogen source and cultivar in broccoli cultivation plays an important role in the bioactive compound profile and nutrient composition of the broccoli crop. The results provide useful information for the improvement of broccoli quality. [ABSTRACT FROM AUTHOR]

AbstractThis study presents a novel approach to the production dynamics of rose-scented pelargonium for pot cultivation as an ornamental plant. It investigates how nitrogen supply affects plant growth, development, quality attributes, and biochemical properties to provide insights for enhanced commercial viability. Nitrogen concentrations (0, 50, 100, 200, and 400 mg l−1) were applied weekly for 3 months. Results show that increased nitrogen levels raised nitrogen concentrations in shoots (1.32%–2.57%) and roots (0.39%–1.27%). Periodic morphological evaluations indicated that the effects of nitrogen doses on growth started to appear after the second month of the experiment. By the end of the experiment (90th day), it was determined that increased nitrogen application resulted in reduced plant height, stem length, internode length, total phenolic compound (TPC) antioxidant capacity (DPPH) and malondialdehyde (MDA). In contrast, increases were observed in the number and length of lateral branches, stem thickness, leaf count, shoot biomass, chlorophyll (Clfs) levels and total carotenoid. MDA, TPC, and Clfs can be considered important biochemical indicators of nitrogen deficiency stress, defense mechanism, and plant quality in rose-scented pelargonium, respectively. It was determined that a minimum nitrogen concentration of 100 mg l−1 is required to obtain healthy, high-quality plants with strong visual appeal for the presentation of rose-scented pelargonium as potted ornamental plants. Higher concentrations may offer an advantage for more compact plant formation. To enhance the market value of rose-scented pelargonium as potted ornamental plants, future studies could include different pot sizes and pinching practices alongside nitrogen fertilization. [ABSTRACT FROM AUTHOR]

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A peat substrate is made from peat from drained peatlands, which is a limited resource. A realistic estimate is that 50% of the world's wetlands have been lost. Peat is used in horticulture, especially for the cultivation of vegetables in greenhouses. The consequences of peatland exploitation are an increase in the greenhouse effect and a decrease in carbon stocks. Wood fiber can be used as an alternative to peat. The chemical properties of growing media interact and change continuously due to the small volume of growing media, which is limited by the growing container. This study aims to gain new knowledge on the impact of nutrient changes in the microbial degradation of carbon compounds in wood fiber and mixtures with a peat substrate on the content and uptake of nutrients required by plants. The cucumber (Cucumis sativus L.) variety 'Dirigent H' developed in the Netherlands was cultivated in growing media of a peat substrate and wood fiber: (1) peat substrate (PS); (2) wood fiber (WF); (3) wood fiber and peat substrate 50/50 v/v (WF/PS 50/50); (4) wood fiber and peat substrate 25/75 v/v (WF/PS 25/75). The rates of fertilization were the following: (1) conventional fertilization (CF); (2) 13 g N per plant (N13); (3) 23 g N per plant (N23); (4) 30 g N per plant (N30). The experiment was carried out with three replications. As the amount of wood fiber increased, the humidity and pH of the growing media increased. The fertilization of the cucumbers with different quantities of nitrogen influenced the nutrient uptake. The plants grown in the 50/50 and 25/75 growing media had the best Cu uptake when fertilized with N23. When the plants grown in the wood fiber media and the 50/50 media were fertilized with N13, N23, and N30, the Mn content in the growing media at the end of the growing season was significantly lower than the Mn content in the media with conventional fertilization. Thus, nitrogen improved the uptake of Mn by the plants grown not only in the wood fiber, but also in the combinations with a peat substrate. Growing plants in wood fiber and fertilizing them with N13 can result in the optimum uptake of micronutrients. The number and biomass of cucumber fruits per plant were influenced by the amount of wood fiber in the growing media and the application of nitrogen fertilizer. The highest number of fruits and biomass of fruits per plant obtained were significantly higher when the cucumbers were grown in WF/PS 50/50 growing media with additional N13 fertilization. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen fertilization is one of the most important practices for improving of crop yield and soil quality, which also affects soil CO2 emission. CO2 emission is strongly influenced by soil bacterial communities. It is still unknown precisely how nitrogen fertilization affects soil bacterial communities in the semiarid Loess Plateau and how its effects are related to CO2 emissions. Methods: A field experiment was conducted with four nitrogen fertilization rates (0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg N ha–1). Nitrogen fertilization effects soil bacterial communities, CO2 emission, carbon emission efficiency (CEE), and their relationships were investigated. Results: As a result of nitrogen fertilization, soil bacterial abundance increased, and the bacterial community composition and network changed. Soil CO2 emission under N1, N2, and N3 were increased by 17.3%, 24.8%, and 28.9% compared to the N0 treatment, respectively. N2 and N3 exhibited the highest maize grain yield and CEE. CEE under N2 and N3 increased by 96.9%-140.9% compared to the N0 treatment. Soil bacterial abundance had a positive correlation with CO2 emission. CO2 emission were also affected by the bacterial composition and network, which were related to the Actinobacteria. Multiple regression analysis further suggested that CO2 emission was jointly regulated by the abundance, composition, and network modules of the bacterial community. Conclusion: Overall, our results indicated that nitrogen fertilization promoted CO2 emission via increasing bacterial abundance and altering the composition of their community, and provided a new insight into the connection between soil microorganisms and agricultural CO2 emission in the semi-arid region. [ABSTRACT FROM AUTHOR]

Organic amendments and nitrogen fertilization are common practices in agriculture, which have complex influences on the carbon cycle. To evaluate the effects of nitrogen‐organic carbon combination on CO2 efflux, we conducted a field incubation experiment with control, N fertilization without and with straw/biochar amendments for 20 months in a typical soil of North China Plain. CO2 efflux was measured every ~3–4 weeks, and water‐extractable organic carbon and soil microbial biomass carbon were analyzed in spring, summer, and autumn. Our results showed an asymmetric seasonality (slow increase in spring but rapid decrease in fall) in the control and biochar treatments, but a symmetric seasonality under straw treatments. Organic amendments with N fertilization caused an increase of CO2 efflux in most seasons (comparing without N fertilization), with a much greater increase in spring–summer of the first year (22%–35%) than the second year (1%–3%). Nitrogen fertilization caused a much greater increase in cumulative CO2 efflux with biochar (7%–13%) and with straw treatment (20%) than without organic amendments (3%) over the period of 20 months. SIC content showed an increase under organic amendments, with a greater increase under biochar amendments than straw amendments. The increases of CO2 efflux under nitrogen‐biochar and nitrogen‐straw combinations could be explained mainly by enhanced decomposition of SOC, biochar, and straw rather than SIC dissolution. Our study indicated that biochar amendments were more effective for carbon sequestration than straw amendments and nitrogen fertilization with organic amendments could cause changes in various processes of CO2 production in the cropland of north China. [ABSTRACT FROM AUTHOR]

Introduction: The stay-green (SG) or delayed leaf senescence enables crop plants to maintain their green leaves and photosynthetic capacity for a longer time after flowering. It is considered an important trait in maize breeding, which has contributed to gain in grain yield of modern varieties. It has been also used to improve the tolerance to drought and deficiencies in nitrogen fertilization (NF). However, the objective of this study is to evaluate the influence of water irrigation (WI), NF, and plant density (PD) on SG and the effect of SG on agronomic traits in maize. Methods: Four SG lines and four non-stay-green (NSG) lines were evaluated in four contrasting environments under two WI, three NF, and two PD levels. Results and discussion: As expected, the chlorophyll content of leaves at 45 days after flowering (Chlo45) was, on average, higher in the SG group of lines. The difference in Chlo45 between the SG and NSG genotypes was consistent across WI, NF, and PD and the environments. This is indicative that internal or developmental factors were more important than external signals in controlling the senescence. The effect of SG increasing thousand-kernel weight, stover yield at harvest, or moisture was not influenced by WI, NF, or PD but was altered by the background environment. Our results have implications for the application of SG as a secondary trait for enhancing abiotic stress tolerance. Future studies could consider a wider range of environmental conditions to assess the performance of SG traits under different climatic and soil conditions. [ABSTRACT FROM AUTHOR]

C, N, and P concentrations and stoichiometric ratios of the leaf are important for adaptive plant growth and nutrient utilization. However, our knowledge of how these traits change with N fertilization in intercropping systems remains limited. Hence, a 2‐year experiment was conducted with four cropping patterns, including two‐row common vetch (Vicia sativa L.) intercropping with one‐row oat (Avena sativa L.), one‐row common vetch intercropping with two‐row oat as well as sole oat and common vetch cropping with 0, 50, and 100 kg N/ha fertilization. Leaf total nitrogen (LTN) and phosphorus (LTP) concentrations and C:N:P stoichiometric ratios were measured and their linkages with soil nutrient availability were analysed. N fertilization significantly increased LTN, N:P, and C:P, while significantly decreasing LTP and C:N. Intercropping affected leaf nutrient concentrations and stoichiometric ratios, which were affected by N fertilization, basic soil fertility, and crop species. Intercropping and N fertilization affected soil nitrate nitrogen (SNN), available phosphorus (SAP) content, and dry matter (DM) yield. There were strong correlations between the leaf nutritional traits of oats and SNN, SAP, and DM, but few correlations were observed with common vetch. In conclusion, intercropping led to contrasting changes in leaf nutrient concentrations and stoichiometric ratios, which varied with N fertilization and crop species. We failed to reveal solid and direct effects of intercropping ratio on leaf nutritional traits. These findings contribute to a better understanding of crop nutritional traits and the link between leaves and soil in response to intercropping and N fertilization. [ABSTRACT FROM AUTHOR]

Introduction: Plant growth-promoting bacteria (PGPB) have been primarily studied for atmospheric nitrogen (N) fixation but they also have the capacity to improve nutrition and yield of crop plants. Methods: Therefore, the objective of this research was to investigate the effects of inoculation with PGPB in association with different N rates on N uptake, grain yield, and oil concentration of dwarf castor beans in succession to legumes and grasses in Ilha Solteira, Brazil. The treatments consisted of N rates (0 to 180 kg ha-1 of N) and inoculation with three plant growth-promoting bacteria (Azospirillum brasiliense, Bacillus subtilis, and Pseudomonas fluorescens, applied by leaf) and a control with no-inoculation. Results: The grain and oil yields of castor beans were increased by 20 and 40% at a rate of 103 kg ha-1 of N in succession to grasses as compared to without N application. In addition, the grain yield of castor bean after legumes was increased by 28, 64, and 40% with estimated rates of 97, 113, and 92 kg ha-1 of N in combination with inoculations of A. brasilense, B. subtilis, and P. fluorescens as compared to without N application, respectively. Shoot, grain, and total N uptake were improved with foliar inoculation of A. brasilense, B. subtilis, and P. fluorescens at the N rates of 45, 90, and 135 kg ha-1, respectively. Discussion and conclusions: Topdressing of N at the rate of 103 kg ha-1 and foliar inoculation in succession to grasses and 180 kg ha-1 of N without the effect of foliar inoculation in succession to legumes are recommended for higher grain and oil yield of castor beans. Foliar inoculations with A. brasilense, B. subtilis, and P. fluorescens increased grain yield under reduced use of N fertilizer by 44, 37, and 49% in dwarf castor cultivation in succession to legumes, potentially contributing to sustainable agriculture. INSET: C. [ABSTRACT FROM AUTHOR]

Water and nitrogen are widely used agricultural inputs in potato production areas. However, the excessive and inappropriate use of these significant inputs may lead to the rapid depletion of water resources and inappropriate nitrogen leakage. In potato production, insight into the effects of water and nitrogen on the physiological properties will help to overcome these difficulties. This study was therefore conducted to determine the effects of different nitrogen and irrigation levels on the physiological (photosynthesis rate, leaf area index, leaf chlorophyll content, and leaf temperature) characteristics of potato. Field experiments were conducted during the 2021–2022 and 2022–2023 primary potato cropping seasons to select the suitable combination of irrigation and fertilization levels for potato production in the Nigde Province of the Central Anatolia Region of Turkey. Employing a factorial design, the study encompassed six nitrogen fertilization rates and three irrigation levels. Measurements were systematically recorded at five distinct intervals (40, 50, 60, 70, and 80 days) post-emergence. The outcomes underscored that nitrogen treatments augmented physiological traits, manifesting in heightened photosynthetic rates, chlorophyll content, and leaf area indices, barring leaf temperature, in comparison to the control group (devoid of nitrogen treatments). Full irrigation (I1) yielded the utmost values for both photosynthesis and leaf area index, with I1N3 (full irrigation and intermediate nitrogen supply) was identified as the most efficacious treatment for these parameters. This study identifies the most appropriate nitrogen and irrigation application for optimum physiological yield of the potato for crop producers. However, it is important to note that the study focused solely on one commercial potato cultivar (Agria), and further research on various potato cultivars is recommended for more conclusive results. [ABSTRACT FROM AUTHOR]

The aim of this study was to economically estimate the effect of inoculation with Azospirillum brasilense (A. brasilense) associated with enhanced efficiency nitrogen fertilizers on corn yield cultivated in the Brazilian Amazon. The experimental design used was completely randomized, in a 2 × 3 × 5 factorial scheme, resulting from the combination of the presence and absence of seeds inoculated with A. brasilense, three sources of N (conventional urea, urea with NBPT, N-(n-butyl)thiophosphoric triamide, and polymer-coated urea), and five doses of N (0; 50; 100; 150; and 200 kg ha−1 of N), with six replications. Inoculation with A. brasilense promoted profit in corn, regardless of dose and the source of N applied. The urea with NBPT provided better economic return compared to polymer-coated urea and conventional urea sources, and doses of N applied in topdressing that promoted the highest economic return were 100 and 150 kg ha−1 of N, with an estimated increase of 62.33 and 135.53 bags ha−1 and increase of BRL 3253.76 and BRL 7074.88 respectively, compared to the control treatment. [ABSTRACT FROM AUTHOR]

Abstract Background Nitrogen fertilization in broccoli is very important for plant growth and productivity. However, it is known that the nitrogen source of the nitrogen fertilizer is also effective on quality parameters. In this study we investigated the effects of different nitrogen sources (ammonium sulphate and calcium nitrate) on bioactive compounds and leaf nutrients of broccoli cultivars (Monet, Italian and Karadede). Results The highest total phenolic content was 0.24 mg g− 1 fw in cultivar Monet. Nitrate-based fertilizer treatments provided higher total phenolic (0.28 mg g− 1 fw) and flavonoid (0.56 mg g1 fw) contents and FRAP (0.24 mmol g− 1 fw) values compared to ammonium-based fertilizer treatments. On the other hand, DPPH (0.77 mmol g− 1 fw) values were higher in the ammonium nitrogen treatments. Among the cultivars, Monet had the highest total phenolics, flavonoids and FRAP values. When leaf nutrient concentrations were analyzed, ammonium sulfate application resulted in higher sulfur (0.86%), zinc (20.72 mg kg− 1) and manganese (28.80 mg kg− 1) concentrations compared to calcium nitrate. Calcium nitrate treatment provided the highest calcium (2.09%) and iron (37.50 mg kg− 1) concentration in Monet cultivar. Phosphorus (0.31–0.35%) and magnesium (0.073–0.084%) concentrations differed among cultivars. Conclusions In conclusion, the choice of nitrogen source and cultivar in broccoli cultivation plays an important role in the bioactive compound profile and nutrient composition of the broccoli crop. The results provide useful information for the improvement of broccoli quality.

In 2021 - 2023, in the region of South Central Bulgaria, the influence of three sowing rates (10, 15 and 20 kg/ha) and four levels of nitrogen fertilization (0, 30, 60 and 90 kg/ha) on the productivity of teff (Eragrostis tef (Zucc.) Trotter) in two stages of development (milk and dough maturity) has been studied. The experiment was based on the method of fractional plots, with the size of the harvest plot 10 m2, under non-irrigated conditions. The statistical processing was carried out with the ANOVA LSD test and the MS Excel software package - 2010. Fertilization with 90 kg/ha of nitrogen resulted in the highest yields (up to 56.7% more green mass and up to 55.5% more dry matter) in all tested sowing rates (10, 15, 20 kg/ha) and harvesting phases (milk and dough maturity). The increase in the sowing rate from 10 to 15 kg/ha increased the yield of green mass and dry matter by up to 5.9% and 3.6%, respectively in the dough maturity phase. Teff productivity is positively correlated with the amount of vegetation precipitation (r = 0.745 – 0.766) and nitrogen fertilization (r = 0.535 – 0.541) and negatively correlated (r = -0.526 – -0.543) with vegetation temperatures. The conditions of the year (68.58 – 72.18%) and nitrogen fertilization (20.25 – 22.81%) have the main influence on the teff productivity. The influence of the sowing rate is weaker - 1.73 - 2.62% of the total variation. The harvesting phase has been shown to affect dry matter yield.

BACKGROUND: Vegetal‐derived protein hydrolysates (PHs) have been recognized as sustainable biostimulant products due to their beneficial effects on crops. However, most studies on PHs have been conducted at a fixed ratio of nitrate‐to‐ammonium (NO3−:NH4+) without considering other N application scenarios, leading to inconsistent results among the studies. This study compared the influences of N levels (2 or 10 mM N), NO3:NH4 ratios (100:0, 75:25, 50:50, or 25:75), and PH application methods – control, foliar spray (PH‐F) or root application (PH‐R) – on the yield, morphology, nutrients, and nutraceutical quality of hydroponic lettuce. RESULTS: Nitrogen level, NO3:NH4 ratio, and PH application affected plant growth, morphology, and quality significantly, highlighting the importance of the interactions among these factors. Shoot growth was influenced by NO3:NH4 ratios, PH, and their interactions. Similar trends were observed in chlorophyll content. The interactions among all three factors significantly influenced root growth and morphology. Root application (PH‐R) protected lettuce from yield loss caused by low NO3:NH4 ratios and from reduced antioxidant compounds caused by high N levels. Vegetal‐derived protein hydrolysates improved nutrient uptake through two‐way and three‐way interactions although neither PH nor any interactions affected nitrate concentrations. CONCLUSION: This study demonstrated that PH interacts with N level and NO3:NH4 ratio, affecting hydroponic lettuce yield and quality. In particular, the root application of PH was the most effective method for enhancing yield (shoot fresh weight), quality (chlorophylls, carotenoids, flavonoids, and phenols), and nutrient uptake in hydroponically grown lettuce in relation to N form and level. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Purpose: This research aims to develop a meta-machine learning model to optimize soil and nitrogen management for durum wheat in Italy. It addresses the challenges of increased food production on limited land amidst rising input costs, geopolitical changes, and climate change. The goal is to aid decision-makers in achieving maximum crop yield and income margins through effective agronomic strategies. Methods: The study developed a meta-machine learning model, integrating classification and regression models, and tested it at four sites in Marche and Basilicata, Italy, over several years. The model incorporated data from remote sensing, crop phenology, soil chemical properties, weather data, soil management, and nitrogen levels. A Random Forest model was used to classify crop phenology, while a Neural Network model predicted yield. Eleven nitrogen levels were compared across these sites. Results: The Random Forest model achieved an accuracy of 0.98, kappa of 0.96, and recall of 0.98 for predicting crop phenology. The Neural Network model for yield prediction had an R squared of 0.90 and a Root Mean Square Error of 0.59 t ha-1. Key factors identified for model accuracy were temperature, precipitation, NDVI, and nitrogen input. Simulations of 30 soil management and fertilization combinations revealed that no-tillage management increased grain yield. The Marginal Fertilizer Yield Index determined optimal nitrogen application. Conclusions: The meta-machine learning model accurately predicted durum wheat yield and identified effective agronomic strategies, demonstrating the potential for broader application in field conditions. The model offers a promising approach to sustainable agriculture and climate change mitigation by utilising publicly available spatial datasets. [ABSTRACT FROM AUTHOR]

This study presents a method based on retrofitted low-cost and easy to implement tracking devices, used to monitor the whole harvesting process in viticulture, to map yield and harvest quality parameters in viticulture. The method consists of recording the geolocation of all the machines (harvest trailers and grape harvester) during the harvest to spatially re-allocate production parameters measured at the winery. The method was tested on a vineyard of 30 ha during the whole 2022 harvest season. It has identified harvest sectors (HS) associated with measured production parameters (grape mass and harvest quality parameters: sugar content, total acidity, pH, yeast assimilable nitrogen, organic nitrogen) and calculated production parameters (potential alcohol of grapes, yield, yield per plant) over the entire vineyard. The grape mass was measured at the vineyard cellar or at the wine-growing cooperative by calibrated scales. The harvest quality parameters were measured on grape must samples in a commercial laboratory specialized in oenological analysis and using standardized protocols. Results validate the possibility of making production parameters maps automatically solely from the time and location records of the vehicles. They also highlight the limitations in terms of spatial resolution (the mean area of the HS is 0.3 ha) of the resulting maps which depends on the actual yield and size of harvest trailers. Yield per plant and yeast assimilable nitrogen maps have been used, in collaboration with the vineyard manager, to analyze and reconsider the fertilization process at the vineyard scale, showing the relevance of the information. [ABSTRACT FROM AUTHOR]

Abstract Background Straw incorporation serves as an effective strategy to enhance soil fertility and soil microbial biomass carbon (SMBC), which in turn improves maize yield and agricultural sustainability. However, our understanding of nitrogen (N) fertilization and straw incorporation into soil microenvironment is still evolving. This study explored the impact of six N fertilization rates (N0, N100, N150, N200, N250, and N300) with and without straw incorporation on soil fertility, SMBC, enzyme activities, and maize yield. Results Results showed that both straw management and N fertilization significantly affected soil organic carbon (SOC), total N, SMBC, soil enzyme activities, and maize yield. Specifically, the N250 treatment combined with straw incorporation significantly increased SOC, total N, and SMBC compared to lower fertilization rates. Additionally, enzyme activities such as urease, cellulase, sucrose, catalase, and acid phosphatase reached their peak during the V6 growth stage in the N200 treatment under for both straw management conditions. Compared to N250 and N300 treatments of traditional planting, the N200 treatment with residue incorporation significantly increased yield by 8.30 and 4.22%, respectively. All measured parameters, except for cellulase activity, were significantly higher in spring than in the autumn across both study years, with notable increases observed in 2021. Conclusions These findings suggest that optimal levels of SOC, soil total N (STN), and SMBC, along with increased soil enzyme activities, is crucial for sustaining soil fertility and enhancing maize grain yield under straw incorporation and N200 treatments.

The aim of this study was to economically estimate the effect of inoculation with Azospirillum brasilense (A. brasilense) associated with enhanced efficiency nitrogen fertilizers on corn yield cultivated in the Brazilian Amazon. The experimental design used was completely randomized, in a 2 × 3 × 5 factorial scheme, resulting from the combination of the presence and absence of seeds inoculated with A. brasilense, three sources of N (conventional urea, urea with NBPT, N-(n-butyl)thiophosphoric triamide, and polymer-coated urea), and five doses of N (0; 50; 100; 150; and 200 kg ha−1 of N), with six replications. Inoculation with A. brasilense promoted profit in corn, regardless of dose and the source of N applied. The urea with NBPT provided better economic return compared to polymer-coated urea and conventional urea sources, and doses of N applied in topdressing that promoted the highest economic return were 100 and 150 kg ha−1 of N, with an estimated increase of 62.33 and 135.53 bags ha−1 and increase of BRL 3253.76 and BRL 7074.88 respectively, compared to the control treatment.

Previous research has demonstrated the ability of isolate Pseudomonas thivervalensis SC5 to express the enzyme 1-aminocyclopropane-1-carboxylate deaminase (ACC), which regulates ethylene levels, one of the most important phytohormones in the regulation of plant growth and development. Thus, the present study evaluated the agronomic efficiency of a biological conditioner based on P. thivervalensis SC5 in the growth and productivity increases of corn in Brazil. It was found that corn was highly responsive to the inoculation of P. thivervalensis SC5, with increments ranging from 10.1 to 40.6% in the production of dry shoot biomass (DSB) compared to the control, while for grain yield the increments ranged from 9.0 to 27.8%. The increments are related to the levels and accumulations of N and P in the shoots of the plants. This suggested the participation of P. thivervalensis SC5 in mechanisms of soil modulation and nutrient acquisition. The inoculation of P. thivervalensis SC5 provided average increments in FDA hydrolysis ranging from 16.7 to 47.4% compared to the control, confirming the ability of this strain to increase the supply of nutrients to plants. Therefore, it is concluded that Pseudomonas thivervalensis SC5 participates in key mechanisms in the soil-plant system, with a consequent improvement in soil quality and other plant-related parameters. [ABSTRACT FROM AUTHOR]

This research aimed to assess the effect of applying digestate fractions and conventional mineral nitrogen (N) fertilizers on plant and soil properties, as well as potential nitrate leaching, in acidic soil over two consecutive years (2018 and 2019). The digestate fractions were obtained after the anaerobic co-digestion of maize silage and liquid cattle manure (LCM). Seven different treatments were applied to the maize crop in four replicates: unfertilized control (C), mineral fertilizer (MF), LCM, solid fraction of digestate (SFD), liquid fraction of digestate (LFD) and a mixture of SFD and LFD with MF (50% of total N from digestate fractions + 50% of total N from MF). The highest maize yields were achieved on average in 2018. Statistically, the highest dry grain yield was observed in the MF treatment (12.1 t ha−1) and in the mixtures of MF+SFD (11.0 t ha−1) and MF+LFD (11.8 t ha−1), while the lowest yield was achieved in both years in the C treatment (7.9 t ha−1). The N fertilizer replacement value was statistically highest on average in the MF treatment (100%) and in the mixtures of MF+LFD (80.5%) for both years. The experiment results could inform legal guidelines and standardize digestate application on agricultural land in Croatia and the European Union (EU). [ABSTRACT FROM AUTHOR]

Background: Straw incorporation serves as an effective strategy to enhance soil fertility and soil microbial biomass carbon (SMBC), which in turn improves maize yield and agricultural sustainability. However, our understanding of nitrogen (N) fertilization and straw incorporation into soil microenvironment is still evolving. This study explored the impact of six N fertilization rates (N0, N100, N150, N200, N250, and N300) with and without straw incorporation on soil fertility, SMBC, enzyme activities, and maize yield. Results: Results showed that both straw management and N fertilization significantly affected soil organic carbon (SOC), total N, SMBC, soil enzyme activities, and maize yield. Specifically, the N250 treatment combined with straw incorporation significantly increased SOC, total N, and SMBC compared to lower fertilization rates. Additionally, enzyme activities such as urease, cellulase, sucrose, catalase, and acid phosphatase reached their peak during the V6 growth stage in the N200 treatment under for both straw management conditions. Compared to N250 and N300 treatments of traditional planting, the N200 treatment with residue incorporation significantly increased yield by 8.30 and 4.22%, respectively. All measured parameters, except for cellulase activity, were significantly higher in spring than in the autumn across both study years, with notable increases observed in 2021. Conclusions: These findings suggest that optimal levels of SOC, soil total N (STN), and SMBC, along with increased soil enzyme activities, is crucial for sustaining soil fertility and enhancing maize grain yield under straw incorporation and N200 treatments. [ABSTRACT FROM AUTHOR]

Background and aims: Long-term nitrogen (N) and phosphorus (P) fertilization could immensely alter plant-soil-microbial properties, thereby impacting the priming effect (PE). However, previous studies mostly simulated PE responses to fertilization by adding nutrient in the laboratory, which could not represent PE changes under long-term fertilization-induced ecosystem alteration. Our aim is to clarify the PE alteration in soils with long-term fertilization history in an alpine meadow. Methods: Soil samples (0–10 cm) were collected from a 9-year field fertilization experiment (including four treatments: control, + N with urea, + P with triple superphosphate, + NP with both fertilizers), and incubated for 30 days with 13C-labeled glucose amendment (2% SOC). Plant-soil-microbial properties were measured before/after incubation. Results: Glucose addition induced a positive PE in all soils with a range from 0.56 to 1.37 mg C g−1 soil. N fertilization did not affect PE intensity due to the microbial adaptation and fast utilization of the added glucose for metabolic needs. P fertilization caused P accumulation in soils, and decreased available N and pH. Such changes inhibited microbes, and glucose activated microbial activities, causing higher PE intensity. Conclusion: Long-term N fertilization did not significantly affect PE, while P fertilization stimulated PE intensity. Overall, we highlight that P fertilization may induce higher risk of CO2 release, which deserves more attention when applying P fertilizers in this alpine meadow. [ABSTRACT FROM AUTHOR]

There are doubts about nitrogen (N) management and the use of growth regulator in wheat. Thus, the objective was to evaluate the wheat performance as a function of topdressing N applied at different phenological stages of crop, and the use of trinexapac-ethyl (TE) growth regulator associated with N fertilization in subtropical regions in southern Brazil. In each environment, two experiments were carried out, all with an experimental design in 2 × 4 factorial scheme. The factors in experiment 1 were topdressing N application at seedling emergence and tillering stages and N rates (0, 40, 80, and 120 kg N ha−1); and in experiment 2: use of TE (with and without) and N rates (0, 40, 80, and 120 kg N ha−1) applied at tillering. The augment of N in topdressing increases the lodging. The use of TE minimizes the lodging. In environment with irrigation, the application of intermediate N rates at crop emergence reduces lodging. The yield components are altered by the rates and stages of N application, with variable responses according to the cultivation environment. The stage of application does not affect grain yield. N fertilization increases the yield, being that in Ponta Grossa the wheat is more responsive to higher N input. In certain environments, TE reduces the number of spikes m−2 and increases the number of grains per spike. TE impairs yield when associated with N non-application in topdressing. On the other hand, it maximizes the effect of N fertilization on yield, when using higher N rates in topdressing. [ABSTRACT FROM AUTHOR]

Maize plays a significant global role as a food source, feed, and as a raw material in industry. However, it is affected by toxin-producing fungi, mainly Fusarium graminearum, Fusarium verticillioides, and Aspergillus flavus, which compromise its quality. This study, conducted in 2022 and 2023 at the Látókép long-term research site of the University of Debrecen, Hungary, investigated the effects of different nitrogen fertilization rates (0, 90 and 150 Kgha−1 N) on mycotoxin contamination (DON vs. FB vs. AFB1) in the kernels of three (3) maize hybrids: DKC4590 (tolerant), GKT376 (sensitive), and P9610 (undefined). The results showed a significant (p = 0.05) influence of nitrogen fertilization and maize genotype on mycotoxin levels. Sole nitrogen impacts were complex and did not define a clear trend, contrary to the hybrids selected, which followed superiority to resistance. Increased nitrogen fertilization was associated with higher DON production, while hybrid selection demonstrated a clearer trend in resistance to mycotoxins. Therefore, to maximize yield and minimize mycotoxin contamination, future research should focus on optimizing nitrogen application rates and breeding for resistance to balance yield and mycotoxin management. These results suggest that while nitrogen fertilization is crucial for maximizing yield, selecting less susceptible maize hybrids remains vital for minimizing mycotoxin contamination. [ABSTRACT FROM AUTHOR]

Background and Objectives: Field experiments were conducted to assess the influence of in‐season split application of nitrogen (N) on grain protein, protein digestibility, and amino acid dynamics in grain sorghum, in three different environments. Treatments included a zero N check and eight treatments with varying N application timings and amounts. Findings: The five high N treatments had significantly greater grain protein content than all the lower N treatments. As the total protein increased, the kafirin portion of the protein increased, whereas the albumin‐globulin levels decreased. Nitrogen treatment had a significant effect on 13 of the 18 amino acids. High N applications significantly increased amino acids on a protein basis including alanine, glutamic acid, leucine, proline, and phenylalanine. Conclusions: Treatment N92 with N applied at 92 kg N ha−1 as split application at three different growth stages including planting, panicle initiation, and booting emerged as the optimum N treatment for increasing protein and amino acid concentration in grain sorghum. Significance and Novelty: The ideal N application approach identified can be used to screen a wide range of sorghum hybrids under varying levels of irrigation and the same N treatments can be adopted by producers to enhance grain protein in sorghum. [ABSTRACT FROM AUTHOR]

In 2021 - 2023, in the region of South Central Bulgaria, the influence of three sowing rates (10, 15 and 20 kg/ha) and four levels of nitrogen fertilization (0, 30, 60 and 90 kg/ha) on the productivity of teff (Eragrostis tef (Zucc.) Trotter) in two stages of development (milk and dough maturity) has been studied. The experiment was based on the method of fractional plots, with the size of the harvest plot 10 m2, under non-irrigated conditions. The statistical processing was carried out with the ANOVA LSD test and the MS Excel software package - 2010. Fertilization with 90 kg/ha of nitrogen resulted in the highest yields (up to 56.7% more green mass and up to 55.5% more dry matter) in all tested sowing rates (10, 15, 20 kg/ha) and harvesting phases (milk and dough maturity). The increase in the sowing rate from 10 to 15 kg/ha increased the yield of green mass and dry matter by up to 5.9% and 3.6%, respectively in the dough maturity phase. Teff productivity is positively correlated with the amount of vegetation precipitation (r = 0.745 - 0.766) and nitrogen fertilization (r = 0.535 - 0.541) and negatively correlated (r = -0.526 - -0.543) with vegetation temperatures. The conditions of the year (68.58 - 72.18%) and nitrogen fertilization (20.25 - 22.81%) have the main influence on the teff productivity. The influence of the sowing rate is weaker - 1.73 - 2.62% of the total variation. The harvesting phase has been shown to affect dry matter yield. [ABSTRACT FROM AUTHOR]

Grazing lands can be considered a conservation land use providing value to farmers and society. An underappreciated value of these lands may be in C and N storage and cycling. However, soil organic C (SOC) and total soil N (TSN) storage under humid‐temperate zone pastures have not been well characterized. A survey of 31 farms in Virginia USA characterized SOC and TSN depth distributions under a diversity of grassland management scenarios, as well as in comparison with long‐term no‐till cropland and woodland uses on the same farms. Root‐zone enrichment calculations separated management‐controlled SOC and TSN stocks from a baseline condition characterized at 30‐cm depth. Total stock of SOC at 0–30‐cm depth varied from 46 to 88 Mg C ha−1 (5%–95% range from 304 soil profiles) across all land uses. Root‐zone enrichment of SOC was maximized under mature pastures (≥20 years old) at 38.3 ± 1.6 Mg C ha−1, which was not different from that under woodland (39.8 ± 1.2 Mg C ha−1), but was greater than under no‐till cropland (28.3 ± 1.3 Mg C ha−1) and conventional‐till cropland (15.1 ± 5.1 Mg C ha−1). Root‐zone enrichment of TSN was optimized at stocking rate of ~1 Mg live weight ha−1, but was not affected by stocking method, N fertilization history, or low levels of hay feeding. These results suggest that grazed pastures in Virginia are storing significant amounts of SOC and TSN, with at least half due to management‐induced compared with pedogenic‐controlled accumulation. [ABSTRACT FROM AUTHOR]

This five-year study (2016–2021) in Morocco's Mediterranean climate investigated the effect of nitrogen fertilization and genotypic selection on wheat yield and associated components. Utilizing a split-plot design, the study assessed five wheat genotypes—'Faraj', 'Luiza', 'Itri', 'Karim' and 'Nassira'—under three nitrogen application rates (120, 60 and 0 kg/ha) across thirty plots with two replicates. Interactions between nitrogen and year showed marked significance in yield (p = 0.001), biomass (p = 0.002), TKW (p = 0.003) and Spk/m2 (p = 0.001), underscoring the variability in optimal nitrogen application rates across different years. Additionally, significant interactions between variety and year were observed for biomass (p = 0.001) and G/m2 (p = 0.001), indicating variability in the performance of different varieties across years. The 'Itri' genotype showed the highest yield in 2017, while 'Luiza' was pre-eminent in 2018, with 'Itri' producing the most biomass. 'Faraj' demonstrated consistent superiority in yield and biomass during 2019 and 2020. Our integrated principal component analysis and quadratic models elucidated that an intermediate nitrogen rate of 60 kg/ha (N2) was particularly advantageous for the 'Faraj' and 'Karim' genotypes. These findings highlight the substantial impact of informed nitrogen level adjustment and genotypic selection on yield optimization. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the phytoremediation potential of fiber flax (Linum usitatissimatum L., var. Calista) cultivated in a soil contaminated with multiple metals, under real field conditions. A two-year (2022 and 2023) field experiment was conducted in a site contaminated with elevated concentrations of Cd, Ni, Cu, Pb, and Zn due to mining and metallurgical activities. Three different nitrogen fertilization levels were tested (N0: 0 kg N ha−1, N1: 30 kg N ha−1, N2: 60 kg N ha−1), and both spring and winter sowings were conducted. At full maturity, growth parameters and yields were measured. The phytoremediation potential of flax was assessed in terms of the metal concentrations in the above-ground biomass and of the metal uptake (i.e., the potential removal of the soil metals in g ha−1 and per year). Flax demonstrated a shorter growth cycle, with shorter and thicker plants and higher yields when sown in spring compared to winter sowing. Plant growth and productivity were not evidently influenced by additional nitrogen fertilization during plant growth. The cadmium bioaccumulation factor was 1.06, indicating that flax accumulates this metal. For Ni, Cu, Pb, and Zn, the corresponding values were 0.0, 0.04, 0.004, and 0.02, suggesting that this crop excludes these metals. The order of the higher uptake in plant tissues was as follows: Zn > Pb > Cd > Cu > Ni. In conclusion, flax demonstrated tolerance to heavy metals in the soil, effectively supporting soil restoration through cultivation. Additionally, flax showed potential as a cadmium accumulator while excluding nickel, copper, lead, and zinc. [ABSTRACT FROM AUTHOR]

Nitrogen, as one of the important elements affecting the growth and development of fruit trees, leads to slowed protein synthesis and reduced photosynthesis, resulting in yellowing of the leaves, poor tree growth, and decreased yield under nitrogen-deficient conditions. In order to minimize losses and maximize fruit yield, there is often an occurrence of excessive fertilization, soil structure degradation, and water pollution. Therefore, accurate and real-time monitoring of nitrogen content in fruit trees has become the fundamental prerequisite for precision management of orchards. Furthermore, precision orchard management is crucial for enhancing fruit quality by maintaining the optimal growth conditions necessary for trees. Moreover, it plays a vital role in safeguarding the ecological environment by mitigating the overuse of fertilizers and pesticides. With the continuous development and application of spectral remote sensing technology in agricultural monitoring and land management, this technology can provide an effective method for monitoring nitrogen content. Based on a review of relevant literature, this paper summarizes a research framework for monitoring and inversion of nitrogen content in fruit trees, which provides help for further research. Firstly, based on different remote sensing platforms, the application was discussed, on spectral remote sensing technology in the acquisition of nitrogen content in fruit trees. Secondly, the index parameters that can reflect the nitrogen content of fruit trees are summarized, which provides practical guidance for remote sensing monitoring. Additionally, the regression algorithms and application situations based on spectral data for nitrogen content were introduced. In conclusion, in response to the current issues and technological limitations, future research should focus on studying the nitrogen content characteristics of fruit trees during different phenological periods, integrating multi-type data information, and thereby improving the universality of the nitrogen content inversion model for fruit trees.

IntroductionThe stay-green (SG) or delayed leaf senescence enables crop plants to maintain their green leaves and photosynthetic capacity for a longer time after flowering. It is considered an important trait in maize breeding, which has contributed to gain in grain yield of modern varieties. It has been also used to improve the tolerance to drought and deficiencies in nitrogen fertilization (NF). However, the objective of this study is to evaluate the influence of water irrigation (WI), NF, and plant density (PD) on SG and the effect of SG on agronomic traits in maize.MethodsFour SG lines and four non–stay-green (NSG) lines were evaluated in four contrasting environments under two WI, three NF, and two PD levels.Results and discussionAs expected, the chlorophyll content of leaves at 45 days after flowering (Chlo45) was, on average, higher in the SG group of lines. The difference in Chlo45 between the SG and NSG genotypes was consistent across WI, NF, and PD and the environments. This is indicative that internal or developmental factors were more important than external signals in controlling the senescence. The effect of SG increasing thousand-kernel weight, stover yield at harvest, or moisture was not influenced by WI, NF, or PD but was altered by the background environment. Our results have implications for the application of SG as a secondary trait for enhancing abiotic stress tolerance. Future studies could consider a wider range of environmental conditions to assess the performance of SG traits under different climatic and soil conditions.

In the forest-steppe of the Euro-North-East of the Russian Federation (The Republic of Mordovia), the research has been carried out to optimize methods for cultivating spring barley of the Zazersky 85 cultivar, which allow to increase yield and improve grain quality. The experiment was carried out in 2020–2022 on leached medium-humic heavy loamy chernozem. There were studied seeding rates (4.5; 5.0; 5.5 million germinating seeds/ha) and doses of fertilizers (Ν0Р0К0; Ν32Р32К32 – before sowing (background); background + Ν30-60-90 – in top dressing). It has been established that increasing the seeding rate from 4.5–5.0 to 5.5 million significantly reduced the barley grain yield by 0.61–0.70 t/ha, respectively, on average over the years of the research. The crop yield increased significantly under the influence of mineral fertilizers – by 1.62–3.42 t/ha compared to the control (2.68 t/ha). In general, the highest grain yield (6.29–6.47 t/ha) was obtained when sowing barley at rates of 4.5 and 5.0 million germinated seeds/ha by the application of Ν32P32K32 before sowing and Ν60-90 as a top dressing in the tillering phase. Under the influence of fertilizers, the quality parameters of grain changed: the grain unit increased by 15–33 g/l, the weight of 1000 grains – by 0.63–1.53 g, the protein content – up to 13.2 %; the film content decreased by 0.3–0.7 abs.%. The highest grain uniformity (93.0–94.8 %) was observed at the seeding rate of 4.5 and 5.0 million germinated seeds/ha in the variants with nitrogen fertilizers (Ν60-90) against the background of Ν32P32K32. The highest profitability of grain production of the Zazersky 85 barley cultivar (103,18 %) was obtained at the seeding rate of 4.5 million germinated seeds per 1 ha with the application of Ν32P32K32 before sowing and N60 as a top dressing in the tillering phase.

Abstract Background Nitrogen (N) is essential for plant growth and development. In Lithocarpus polystachyus Rehd., a species known for its medicinal and food value, phlorizin is the major bioactive compound with pharmacological activity. Research has revealed a positive correlation between plant nitrogen (N) content and phlorizin synthesis in this species. However, no study has analyzed the effect of N fertilization on phlorizin content and elucidated the molecular mechanisms underlying phlorizin synthesis in L. polystachyus. Results A comparison of the L. polystachyus plants grown without (0 mg/plant) and with N fertilization (25, 75, 125, 175, 225, and 275 mg/plant) revealed that 75 mg N/plant fertilization resulted in the greatest seedling height, ground diameter, crown width, and total phlorizin content. Subsequent analysis of the leaves using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detected 150 metabolites, including 42 flavonoids, that were differentially accumulated between the plants grown without and with 75 mg/plant N fertilization. Transcriptomic analysis of the L. polystachyus plants via RNA sequencing revealed 162 genes involved in flavonoid biosynthesis, among which 53 significantly differed between the N-treated and untreated plants. Fertilization (75 mg N/plant) specifically upregulated the expression of the genes phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), and phlorizin synthase (PGT1) but downregulated the expression of trans-cinnamate 4-monooxygenase (C4H), shikimate O-hydroxycinnamoyltransferase (HCT), and chalcone isomerase (CHI), which are related to phlorizin synthesis. Finally, an integrated analysis of the transcriptome and metabolome revealed that the increase in phlorizin after N fertilization was consistent with the upregulation of phlorizin biosynthetic genes. Quantitative real-time PCR (qRT‒PCR) was used to validate the RNA sequencing data. Thus, our results indicated that N fertilization increased phlorizin metabolism in L. polystachyus by regulating the expression levels of the PAL, PGT1, 5-O-(4-coumaroyl)-D-quinate 3’-monooxygenase (C3’H), C4H, and HCT genes. Conclusions Our results demonstrated that the addition of 75 mg/plant N to L. polystachyus significantly promoted the accumulation of flavonoids, including phlorizin, and the expression of flavonoid synthesis-related genes. Under these conditions, the genes PAL, 4CL, and PGT1 were positively correlated with phlorizin accumulation, while C4H, CHI, and HCT were negatively correlated with phlorizin accumulation. Therefore, we speculate that PAL, 4CL, and PGT1 participate in the phlorizin pathway under an optimal N environment, regulating phlorizin biosynthesis. These findings provide a basis for improving plant bioactive constituents and serve as a reference for further pharmacological studies.

This five-year study (2016–2021) in Morocco’s Mediterranean climate investigated the effect of nitrogen fertilization and genotypic selection on wheat yield and associated components. Utilizing a split-plot design, the study assessed five wheat genotypes—’Faraj’, ‘Luiza’, ‘Itri’, ‘Karim’ and ‘Nassira’—under three nitrogen application rates (120, 60 and 0 kg/ha) across thirty plots with two replicates. Interactions between nitrogen and year showed marked significance in yield (p = 0.001), biomass (p = 0.002), TKW (p = 0.003) and Spk/m2 (p = 0.001), underscoring the variability in optimal nitrogen application rates across different years. Additionally, significant interactions between variety and year were observed for biomass (p = 0.001) and G/m2 (p = 0.001), indicating variability in the performance of different varieties across years. The ‘Itri’ genotype showed the highest yield in 2017, while ‘Luiza’ was pre-eminent in 2018, with ‘Itri’ producing the most biomass. ‘Faraj’ demonstrated consistent superiority in yield and biomass during 2019 and 2020. Our integrated principal component analysis and quadratic models elucidated that an intermediate nitrogen rate of 60 kg/ha (N2) was particularly advantageous for the ‘Faraj’ and ‘Karim’ genotypes. These findings highlight the substantial impact of informed nitrogen level adjustment and genotypic selection on yield optimization.

Regulating planting density and nitrogen (N) fertilization could delay chlorophyll (Chl) degradation and leaf senescence in maize cultivars. This study measured changes in ear leaf green area (GLAear), Chl content, the activities of Chl a-degrading enzymes after silking, and the post-silking dry matter accumulation and grain yield under multiple planting densities and N fertilization rates. The dynamic change of GLAear after silking fitted to the logistic model, and the GLAear duration and the GLAear at 42 d after silking were affected mainly by the duration of the initial senescence period (T1) which was a key factor of the leaf senescence. The average chlorophyllase (CLH) activity was 8.3 times higher than pheophytinase activity and contributed most to the Chl content, indicating that CLH is a key enzyme for degrading Chl a in maize. Increasing density increased the CLH activity and decreased the Chl content, T1, GLAear, and GLAear duration. Under high density, appropriate N application reduced CLH activity, increased Chl content, prolonged T1, alleviated high-density-induced leaf senescence, and increased post-silking dry matter accumulation and grain yield.

Abstract Soybean, belonging to legumes, has a specific ability to biological nitrogen fixation, which can be reinforced by seeds inoculation. However, support with a starter dose of mineral nitrogen fertilizer may be necessary to achieve high seed yields. A four-year field experiment was conducted to determine the effect of mineral N fertilization (0, 30, 60 kg ha−1), seed inoculation with two commercial inoculants and combinations of these treatments on yield components and yielding of soybean in conditions of south-western part of Poland. The synergistic effect of mineral fertilization at dose 30 kg ha−1 and inoculation on soybean productivity was the most beneficial. Similar effects were observed when 60 kg N ha−1 was applied both separately and with inoculation. However, due to the environmental impact of mineral fertilizers and to promote plants to biological nitrogen fixation (BNF), it is advisable to use lower doses of N fertilizer (at 30 kg ha−1) and inoculate soybean seeds in agro- climatic conditions of south-western Poland. Therefore, based on this study we recommend to apply starter dose of N and inoculation.

Abstract Organic forms of phosphorus (P) prevail in soils and their quantification is vital to better understand global biogeochemical cycles. P speciation in soil is commonly assessed by 31P NMR spectroscopy of sodium hydroxide‐EDTA (NaOH‐EDTA) extracts. A liquid chromatography‐inductively coupled plasma‐mass spectrometry (LC‐ICP‐MS) method that employs NaOH‐EDTA is described. Comparison with 31P NMR shows that LC‐ICP‐MS is up to three orders of magnitude more sensitive. It allows measurement in samples as small as 1 mg. We reveal variation of inositol phosphate distribution in Swedish boreal forest soil and identify myo‐ and scyllo‐inositol hexakisphosphates and other isomers including scyllo‐inositol pentakisphosphate. Speciation of the major inositol phosphates was not altered by long‐term nitrogen fertilization.

Background: Nitrogen (N) is essential for plant growth and development. In Lithocarpus polystachyus Rehd., a species known for its medicinal and food value, phlorizin is the major bioactive compound with pharmacological activity. Research has revealed a positive correlation between plant nitrogen (N) content and phlorizin synthesis in this species. However, no study has analyzed the effect of N fertilization on phlorizin content and elucidated the molecular mechanisms underlying phlorizin synthesis in L. polystachyus. Results: A comparison of the L. polystachyus plants grown without (0 mg/plant) and with N fertilization (25, 75, 125, 175, 225, and 275 mg/plant) revealed that 75 mg N/plant fertilization resulted in the greatest seedling height, ground diameter, crown width, and total phlorizin content. Subsequent analysis of the leaves using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detected 150 metabolites, including 42 flavonoids, that were differentially accumulated between the plants grown without and with 75 mg/plant N fertilization. Transcriptomic analysis of the L. polystachyus plants via RNA sequencing revealed 162 genes involved in flavonoid biosynthesis, among which 53 significantly differed between the N-treated and untreated plants. Fertilization (75 mg N/plant) specifically upregulated the expression of the genes phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), and phlorizin synthase (PGT1) but downregulated the expression of trans-cinnamate 4-monooxygenase (C4H), shikimate O-hydroxycinnamoyltransferase (HCT), and chalcone isomerase (CHI), which are related to phlorizin synthesis. Finally, an integrated analysis of the transcriptome and metabolome revealed that the increase in phlorizin after N fertilization was consistent with the upregulation of phlorizin biosynthetic genes. Quantitative real-time PCR (qRT‒PCR) was used to validate the RNA sequencing data. Thus, our results indicated that N fertilization increased phlorizin metabolism in L. polystachyus by regulating the expression levels of the PAL, PGT1, 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase (C3'H), C4H, and HCT genes. Conclusions: Our results demonstrated that the addition of 75 mg/plant N to L. polystachyus significantly promoted the accumulation of flavonoids, including phlorizin, and the expression of flavonoid synthesis-related genes. Under these conditions, the genes PAL, 4CL, and PGT1 were positively correlated with phlorizin accumulation, while C4H, CHI, and HCT were negatively correlated with phlorizin accumulation. Therefore, we speculate that PAL, 4CL, and PGT1 participate in the phlorizin pathway under an optimal N environment, regulating phlorizin biosynthesis. These findings provide a basis for improving plant bioactive constituents and serve as a reference for further pharmacological studies. [ABSTRACT FROM AUTHOR]

The global agriculture industry is facing never before faced issues in the form of soil degradation, water scarcity, rising greenhouse gas emissions, and climate change. Among the possible remedies, applying biochar to the soil has drawn interest as a viable strategy. Although a great deal of literature has been written about the benefits and drawbacks of applying biochar initially, there is still a significant amount of research on the effects of using biochar repeatedly. This study seeks to address this gap by examining the varied effects of both the initial application (at rates of 0 t.ha−1, 10 t.ha−1, and 20 t.ha−1) and the reapplication of biochar (at rates of 0, 10, and 20 t.ha−1), especially when combined with different levels of nitrogen fertilizer (0, 108, and 162 kg.ha−1). The investigation focuses on soil properties and CO2 emissions from Haplic Luvisol in the temperate climate zone (Slovakia). The results showed that biochar generally improved soil properties, such as soil pH (KCl) (p <0.05), shifting it from acidic towards moderately acidic, and generally led to a decrease in ammonium (NH4+) and nitrate (NO3-) content. The second level of fertilization, combined with different biochar treatments, yielded the most efficient results in physical properties such as soil temperature, bulk density (BD), and soil water content (SWC) compared to control treatments without biochar. Biochar application contributed to the reduction of both average daily CO2 emissions and cumulative CO2 emissions during the study period (April – October) in 2022 compared to the control without biochar application. [ABSTRACT FROM AUTHOR]

Background and Aims: Root exudations play a crucial role in plant nutrient uptake; however, studies on their response to different forms of nitrogen (N) are lacking. To bridge these gaps, we examined the effect of different N forms on the root exudation rates among tree species. Methods: NO3−-N, NH4+-N, and organic N were added to the soil at identical concentrations for three months. Root exudate, fine root, and soil samples were collected from the seedlings of four temperate tree species to determine the root exudation rate, aboveground biomass, root characteristics (morphological, physiological, and nutrient traits), and soil characteristics (soil physicochemical properties and enzymatic activity). The differences in all variables among different N forms and tree species were investigated to explore the causative factors for the variations in root exudation. Results: All three forms of N addition reduced the root exudation rate (up to 43.8%), which was consistent across all species and was positively correlated with root morphological traits and negatively correlated with soil total N concentration. The effect of N addition on root exudation was not affected by N form. Conclusion: For four temperate tree species, inorganic and organic N additions increased soil N availability and reduced root exudation rates, and the effects were not varied with N form. The results indicated that, in the short-term, temperate tree species do not show a preference in utilizing different N resources. These findings provide new insights into the effect of different N form additions on belowground C dynamics and root-soil interactions. [ABSTRACT FROM AUTHOR]

This study explored the effects of soil acidification on degradation of Chinese hickory forest under field experimental conditions. Responses of plant nutrient absorption and non-targeted metabolomics based on LC-MS were analyzed to understand the mechanisms of Chinese hickory plant to acid resistance and susceptibility. In this field experiment, Chinese hickory plants were treated with CK (T1, control), nitrogen application (urea) (T2), and aluminum application (aluminum sulfate) (T3). Results showed that Al is the key toxic factor of acidification of soils planted with Chinese hickory. T2 and T3 treatments significantly inhibited absorption of nutrient elements (N, P, K, Ca, Mg, Cu, B and Zn) by Chinese hickory (except N in T2). The metabolomics data analysis showed that there were differences in plant metabolites between the experimental group (T2 and T3) and the control (T1), including p-coumaroyl quinic acid, chlorogenic acid, catechin, (+) germacrene A, myricetin 3-galactoside, and neoglucobrassicin. These metabolites may be the main regulators of Chinese hickory to soil acid stress or related to the effect of soil acidification on Chinese hickory resistance. KEGG metabolic pathway enrichment analysis showed that these differential metabolites were mainly enriched in four metabolic pathways: Flavonoid biosynthesis, Phenylpropanoid biosynthesis, Tyrosine metabolism, Stilbenoid, diarylheptanoid, and gingerol biosynthesis. This study provides a reference for metabolomics studies in Chinese hickory. [ABSTRACT FROM AUTHOR]

Background and Objectives: Research in crop science is usually conducted in studies with a small number of plants and crops. The aim of this project was to investigate whether near‐infrared spectroscopy (NIRS) can contribute to the analysis of such small data sets. For this purpose, NIR spectra of a small sample set of whole‐grain wheat flours of two winter wheat cultivars harvested from greenhouse and field experiments with different fertilization management were analyzed. Findings: Principal component analysis (PCA) facilitated the discrimination of samples based on fertilization, baking volume, and growing conditions for each wheat cultivar. In addition, PCA allowed the differentiation of wheat cultivars in a data set containing both cultivars. Spectra–structure relationships were also established. Accurate calibrations with R2 of.98,.98, and.54 were obtained for fertilization, crude protein concentration, and baking volume, respectively, even for a small data set of 10 samples of wheat cultivar Discus. Conclusion: The NIR spectra of whole‐grain wheat flour samples provided high‐resolution information on various parameters such as fertilization, baking volume, wheat cultivar, and growing site. This study demonstrates that NIRS is a valuable and efficient tool for the analysis of small data sets in crop science. This illustrates the effectiveness of the elegant NIRS method. Significance and Novelty: In this study, small data sets of whole‐grain wheat flour from crop science experiments were analyzed by NIRS. Characteristic changes of the NIR spectra based on applied fertilizer amount, crude protein concentration, baking volume, growing site, and wheat cultivar were revealed. The detection of cause‐and‐effect relationships between spectra and chemical properties of samples contributes to a better understanding of NIR spectra of wheat flours in an interpretative way. [ABSTRACT FROM AUTHOR]

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