Nitrogen

The objective of this study was to treat groundwaters with a high initial nitrate (NO₃⁻) content (125 mg/L, and 177 mg/L) by adsorption onto a local bentonite in its raw state (RB), treated with a ratio of H₂SO₄/bentonite = 0.2 (B0.2), and another treated with a ratio of H₂SO₄/bentonite = 0.6 (B0.6). Non-linear modelling of the nitrate adsorption kinetics of two water samples showed the pseudo-first-order model was the best fit, confirming that nitrate retention on each adsorbent was due to chemisorption. The intra-particle diffusion curves were multi-linear, indicating that there are other mechanisms influencing nitrate ion adsorption on bentonite than intra-particle diffusion. The effectiveness of the adsorbents tested was in the following order: B0.6 > B0.2 > RB. This finding demonstrates that acid activation of the clay improves its characteristics. The optimal adsorbent dose was found to be 1 g/L after changing the bentonite dose from 0.1 to 4 g/L. The pH of the treatment affects nitrate removal rates. The greatest results are achieved at pH levels close to 6. It also appears that the treatment was more effective for water with low initial nitrate levels. Full article

Understanding how transport and storage conditions affect enzymatic activity is essential for accurate biomonitoring of nitrogen metabolism in plants. This study evaluated the effects of transport conditions and low-temperature storage on the enzymatic activities of nitrate reductase (NR), glutamine synthetase (GS), and phosphomonoesterase (PME) for Chloris gayana, Fraxinus uhdei, and Trifolium repens. Enzymatic activities were measured for leaf samples immediately after collection, after 18 h at room temperature, or after 18 h on ice. Additionally, samples were stored at −16 °C or −45 °C for up to 28 days. NR activity decreased to near-zero levels under all storage conditions, indicating that this enzyme is unsuitable for delayed analysis. In contrast, GS and PME activities showed species-dependent responses to storage, with increased activity observed for T. repens and C. gayana, potentially reflecting tissue degradation processes. F. uhdei exhibited greater stability in enzyme activities, suggesting a higher resilience to storage. These findings highlight the importance of minimizing storage time to preserve enzymatic integrity, particularly for NR, while providing insight into the potential for delayed analysis of GS and PME in specific species. This work offers practical recommendations for future biomonitoring efforts in nitrogen deposition studies. Full article

Climate change and anthropogenic nitrogen addition alter the soil physicochemical properties and microbial activity in oligotrophic forest soil. Unbalanced and non-selective nitrogen fertilizer application is lost as gas emissions (N₂O, NO) and also contributed to eutrophication through NO₃⁻ leachate. Similarly, NO₃⁻ infiltrates and contaminated drinking water sources lead to human thyroid dysfunction. In order to protect depleting timber growth due to nitrogen deficiency and increasing ecological concerns from nitrogen misapplication, we reviewed the effects of different synthetic nitrogen forms and levels on the biogeochemical process. In this review, we focused on the most recent findings from research articles, review articles, and meta-analyses on forest soil and also followed the complementary insights from agricultural soil so that we may be able to highlight how these observations contribute to the understanding of the forest soil nitrogen cycle. Firstly, we elaborated the role of nitrification and denitrification in the nitrogen transformation process. Secondly, we discussed the effect of different nitrogen forms and levels on nitrification and denitrification functional gene abundances. Thirdly, we analyzed the possible effect of gene abundances on the nitrogen conversion process. Finally, we revealed that different forms and levels of synthetic nitrogen not only alter the nitrogen conversion pathways by increasing the gene abundances through substrate availability but also shift the gene dominance, thereby modifying soil physicochemical properties, such as pH. This collectively changes the conditions, which are critical for gene expression potential involved in the nitrogen conversion process. These findings may create a direction for sustainable and eco-friendly fertilizer application in nitrogen-deficient soil. Full article

Nutrient management in coupled aquaponic systems presents significant challenges due to competing requirements between fish and plant production within a single-loop framework. These challenges often result in suboptimal nutrient concentrations, compromised system efficiency, and reduced yields. This critical review examines the Decoupled recirculating aquaponics system (DRAPS) as an innovative solution that separates fish and plant nutrient cycles while maintaining water recirculation benefits. This study provides a comprehensive review of DRAPS, emphasizing how its decoupled structure enhances nutrient management and promotes sustainable production. It specifically evaluates the ability of DRAPS to optimize macronutrient and micronutrient levels, control agronomic factors independently, and improve both nutrient and water use efficiency. Additionally, this review highlights the advantages of using urea as a nitrogen source, which can enhance plant productivity without compromising fish health. The findings indicate that the loops of DRAPS facilitate customized nutrient concentrations, fostering optimal growth conditions for both plants and fish. By safely incorporating urea as a nitrogen source, DRAPS increases plant productivity while reducing the risk of ammonia toxicity for fish. Furthermore, independent control over agronomic factors enhances nutrient uptake, nutrient use efficiency, and water use efficiency. This approach minimizes the risks of cross-toxicity and enables higher levels of essential micronutrients, such as iron and nickel, which are beneficial for plant health but can be toxic in coupled systems. DRAPS signifies a significant advancement in sustainable agriculture, particularly in regions with limited water and land resources. By optimizing nutrient management and supporting the high-density production of plants and fish, DRAPS presents a scalable, resource-efficient model that aligns with sustainable development goals. Its capacity for precise nutrient control with minimal environmental impact positions it as a valuable solution for sustainable, high-yield food production in resource-constrained settings. Full article

This study presents the results of two on-farm trials evaluating the efficacy of a nitrogen (N)-fixing inoculant (Methylobacterium symbioticum) applied as a foliar spray to provide N to hazelnut (Corylus avellana L.) and walnut (Juglans regia L.) trees. In the hazelnut trial, a factorial design was employed with soil N application at three levels [0 (N0), 40 (N40), and 80 (N80) kg ha⁻¹] and foliar application of the inoculant (Yes and No). The walnut trial was arranged as a completely randomized design with three treatments: the N-fixing microorganism, a seaweed extract, and a control. Soil N application significantly increased hazelnut yield in 2021 (1.99, 2.49, and 2.65 t ha⁻¹ for N0, N40, and N80, respectively) but not in 2022 (average values ranging from 0.28 to 0.33 t ha⁻¹). The inoculant application did not significantly affect hazelnut yield. In the walnut trial, no significant differences were observed among the treatments in either year. The average yields ranged from 1.72 to 2.38 t ha⁻¹ in 2021 and 0.66 to 0.84 t ha⁻¹ in 2022. Soil N application in hazelnuts tended to increase leaf N concentration and significantly increased kernel N concentration. The inoculant increased leaf N concentration in one of the three sampling dates but did not affect kernel N concentration. In walnuts, the inoculant did not increase leaf N concentration but significantly increased kernel N concentration in one of the two years. The seaweed extract did not influence walnut yield or leaf N concentration. None of the treatments in either trial consistently affected the concentration of other macronutrients and micronutrients in the leaves. Therefore, while the inoculant showed some potential to improve the N nutritional status of the trees, it did not affect the yield. Overall, the results of the inoculant application were not sufficiently compelling, indicating the need for further studies on these species before the commercial product can be confidently recommended to farmers. Full article

The application of nitrogenous fertilizer in reduced (“split”) doses of its total is suggested as a means to increase nitrogen use efficiency and rice productivity whilst reducing its environmental impact. Field trials conducted in 2022 and 2023 aimed to assess the impact of split nitrogen fertilizer applications on the productivity and nitrogen use efficiency of rice. This experiment included three nitrogen treatments (N1: control (no nitrogen); N2: 50% basal + 25% at tillering stage + 25% at panicle initiation stage (conventional method); N3: 33.33% basal + 33.33% at tillering stage + 33.33% at panicle initiation stage (equal split of nitrogen)) and four high-yielding rice varieties (V1: Super Gold 2019; V2: Super Basmati 2019; V3: Noor Basmati 2017; V4: Kissan Basmati 2016). The results indicated that the N3 treatment, with an equal split of nitrogen, combined with the V4 variety (Kissan Basmati 2016) produced the most favorable outcomes. The results indicated that the N3 treatment, particularly when applied to Kissan Basmati (V4), produced, statistically, the highest leaf area index (32.98%, 29.59%), 1000-grain weight (32.84%, 46.97%), grain yield (30.02%, 38.09%), agronomic nitrogen use efficiency (9.21%, 11.63%), and partial factor productivity (29.98%, 38.11%) compared to the control for the study periods of 2022 and 2023, respectively. Moreover, the grain yield demonstrated a strong positive correlation with growth traits and other yield components, except for plant height. The results showed that the application of three equal nitrogen doses significantly increases rice production, and therefore, in this yield context, improves nitrogen use efficiency. Full article

Drought and low nitrogen stress are the leading cause of low crop production and productivity worldwide. Developing drought-tolerant wheat germplasm resilient to low nitrogen conditions is essential through genetic enhancement and selection for novel traits. The objective of the research was to investigate genetic diversity, parameters, and trait relationships within a wheat genotype panel to inform drought- and low-N-tolerant variety selection. This study evaluated 50 wheat genotypes under drought-stressed and non-stressed conditions, with varying nitrogen (50 kg ha⁻¹, 100 kg ha⁻¹, and 200 kg ha⁻¹) levels across four testing sites during the 2019/2020 growing season. Statistical analysis (combined ANOVA) revealed substantial genetic variation (p < 0.05) for the majority of tested traits. High heritability and substantial genetic gain for KPS (97.49%, 28.10% GAM) and SE (96.48%, 14.28% GAM) were determined under drought and low nitrogen stress. Under drought-stressed and non-stressed (at 200 kg N ha⁻¹), grain yield expressed high heritability estimates of 80.43% and 75.68% and genetic advance at 21.90% and 21.56%, respectively. Positive and significant correlations (r > 0.5; p < 0.001) were measured between grain yield and yield components, implicating simultaneous direct and indirect selection of desired traits. The positive relationship between grain yield and yield components suggests that further quantitative trait loci analysis and progeny testing are crucial to guide genotype selection and breeding for drought and low-N stress-tolerant wheat genotypes. Full article

Wildfires in the western U.S. have increased in severity and duration in recent decades. Severe wildfires can enhance the rates of nutrient mineralization, causing large exports of inorganic nitrogen and other ions from forests to streams. Measuring the degree to which streams respond to severe, stand-replacing wildfires is critical to estimate in ecosystems prone to disturbance. In 2003, two severe crown wildfires burned in Yellowstone National Park, WY, USA. We studied the extent to which these fires increased nitrogen (ammonium, nitrate and nitrite), sulfate, chloride, and total dissolved phosphorus concentrations and export in three watersheds prior to and during the first four years post-fire. We measured higher concentrations of most ions after wildfire, and nitrate and chloride concentrations increased the most, increasing > 1000 µg/L. Concentrations of nitrate (≤146 times pre-fire concentrations), total dissolved nitrogen (≤11 times), chloride (≤9 times), and total dissolved phosphorus (≤7 times) were higher four years post-fire than before the wildfires burned. Exports of nitrate (≤1392 times), sulfate (≤14 times), and chloride (≤37 times) were also higher after wildfire, while nitrite (≤2.9 times) and ammonium (≤6.4 times) increased to a lesser degree. Stream concentrations of most ions were higher in watersheds that had a larger percent of the area burned. Comparing ion concentrations in streams before and after severe wildfires provides critical information to managers as the climate warms and the frequency of fire-conductive weather increases. Full article

Abiotic factors, such as drought, can significantly impact the vegetative growth and productivity of maize. To investigate the effects of the combined foliar application of zinc (Zn) and iron (Fe) nanoparticles with the recommended nitrogen dose (RND) on maize production and grain chemical composition under different water regimes, two field experiments were conducted in El-Ayyat city, Giza, Egypt, during the summer seasons of 2022 and 2023. This study utilized a split-split-plot experimental design with three replications. The main plots were designated to different water regimes (100, 80, 60, and 40% of estimated evapotranspiration), while the sub-plots were randomly distributed with Zn and Fe nanoparticle concentrations (0, 100, and 200 mg/L). The sub-sub-plots were randomly allocated to three maize cultivars (SC-P3062, SC-32D99, and SC-P3433). The results revealed that exposure to drought conditions resulted in a significant decline in the yield and yield-related attributes across all maize cultivars examined. Grain yield decreased by 10–50% under drought conditions. However, the foliar application of Zn and Fe nanoparticles was found to significantly improve grain yield, protein content, oil content, starch content, crude fiber, ash, and macro- and micronutrient concentrations in the maize cultivars under control and drought stress conditions. The foliar application of Zn and Fe nanoparticles at a concentration of 200 mg/L to the SC-P3433 maize cultivar led to the greatest grain yield per hectare, reaching 11,749 and 11,657 kg under the irrigation regimes with 100 and 80% total evapotranspiration, respectively. According to the assessment using the relative drought index, the SC-P3062 maize cultivar demonstrated tolerance (T) to water stress conditions. In conclusion, the foliar application of Zn and Fe nanoparticles (100–200 mg/L) effectively mitigated the negative effects of drought stress on maize plants. This approach can be recommended for farmers in arid and semi-arid regions to maintain and improve maize yield and grain quality under water-deficit conditions. Full article

Sustainable agricultural practices are pivotal for environmental preservation and enhancing crop quality. Understanding soil nutrient levels is crucial in determining appropriate fertilizer application in agriculture production systems. In the 2022/23 agricultural season, an experiment that aimed to investigate the spatial distribution of nitrogen (N₂) fixation or absorption in fields cultivated with diverse crops was carried out in Mozambique. Three experimental fields were established, and the following crops were used—maize (local variety), soybean (SAN-BEIB variety), and cotton (ALBAR SZ9314 variety)—each measuring 83.35 m × 30 m. A sampling grid of 13.9 m × 10 m facilitated the collection of 24 composite soil samples per field, consisting of 5 sub-samples within 12 cells, taken at a depth of 0.0–0.20 m before planting and after harvesting, totaling 12 samples per period per field. Laboratory analysis employed the Kjeldahl method to determine total soil nitrogen levels. The Inverse Distance Weighted (IDW) method was used for mapping the spatial total soil nitrogen distribution. The results revealed distinct total soil nitrogen credit and debit patterns. Variations were notable between pre-planting and post-harvest analyses in maize and cotton, showcasing high absorption and minimal fixation. Contrary to expectations, soybeans exhibited high absorption and low fixation, challenging the determination of optimal crop rotation intervals. Quantitative results identified specific total soil nitrogen debit efficiencies of approximately 1692.29 kg ha⁻¹ in cotton and 1081.5 kg ha⁻¹ in maize, respectively, and a credit of 459.215 kg ha⁻¹ in soybeans. Despite discrepancies, this study serves as a foundational platform for future research. As the findings of this study advocate for continued crop rotation practices to bolster soil health and enhance nutrient utilization, it provides the first novel insights into nitrogen dynamics of global key crops in Mozambique, revealing significant variations in nitrogen fixation and absorption across different crop types and fields, which is crucial for informing tailored agricultural practices and soil fertility management strategies. Full article

Commercial mango growers commonly spray potassium nitrate (KNO₃) solution to enhance flowering and fruit quality, yet there is limited information on the uptake efficiency of nitrogen (N) by mango cultivars through leaf cuticles. The study aimed to assess N uptake efficiency (NUpE) from foliar application of KNO₃ solution and compare NUpE among mango varieties. Mango cultivars were ‘Kensington Pride’ (‘KP’), ‘B74’ (‘Calypso^®’), and ‘NMBP 1201’ (‘AhHa!^®’), ‘NMBP 1243’ (‘Yess!^®’), and ‘NMBP 4069’ (‘Now^®’) grafted onto ‘KP’ seedlings. Leaves of six-month-old seedlings were dipped in ¹⁵N-enriched KNO₃ solution and analyzed for total N and ¹⁵N contents. A significant correlation was observed between the leaf area and the amount of solution retained after dipping the leaves in the KNO₃ solution. Moreover, leaves treated with the KNO₃ solution had higher ¹⁵N levels than the natural ¹⁵N abundance, indicating successful N uptake from the KNO₃ solution. The NUpE ranged from 27% to 44% and varied with variety. Cultivar ‘NMBP 4069’ had the highest NUE (44%) which was comparable with that of ‘B74’ (40%). ‘NMBP 1201’ showed the lowest (27%) NUpE which was comparable with that of ‘NMBP 1243’ (30%) and ‘KP’ (33%). These data on ¹⁵N uptake through the mango leaf cuticle demonstrates the effectiveness of foliar application as a method of supplying N to mango trees, highlighting important varietal differences in foliar ¹⁵N uptake efficiency. Considering these differences in NUpE among mango varieties will help in making informed decisions about cultivar selection and N management strategies for sustainable mango production. Full article

Prolonged inoculation of soya bean (Glycine max L.) farms with exotic strains of Bradyrhizobium species starting in the 1960s resulted in the establishment of populations of Bradyrhizobium strains in the soils of several soya bean farms in South Africa. With the increasing number of new soya bean genotypes in the country, it is challenging to determine which genotypes are highly compatible with a given rhizobium strain. In this study, we investigated the symbiotic compatibility of native rhizobial isolates and the strains from the South African Rhizobium Culture Collection (SARCC) on ten selected locally available soya bean genotypes. A glasshouse soil trap experiment using soil samples collected from Lothair, Bothaville, and Standerton was performed on five cultivars. The trapped rhizobial strains were further screened in the glasshouse to authenticate their nodulation compatibility with the different soya bean cultivars. The rhizobial strains showed significant nodulation compatibility with the selected cultivars. These strains were also tested for beneficial traits in vitro and characterized using DNA sequencing methods to elucidate their taxonomic identity. Some of the most nodulation-compatible strains characterized as Bradyrhizobium and Sinorhizobium species exhibited significant symbiotic performance in terms of plant biomass, nodule number, and nodule dry weight. The study generated valuable data that provide information on the extent of symbiotic compatibility of some of the existing cultivars used in South Africa with native rhizobia and whether inoculation of soya bean with commercial products is vital on some soya bean farms. Full article

Substituting soybean meal (SM) with other protein sources can be advantageous in reducing production costs without increasing nitrogen losses in the environment. Peanut cake (PC) might be a strategy in ruminant herds to result in a performance similar to that observed in animals fed SM. This study assessed the PC inclusion at rates of 0, 250, 500, 750, and 1000 g/kg on intake and digestibility, performance, nitrogen balance, microbial protein synthesis, and carcass traits of lambs. Forty-five entire, crossbreed Dorper × Santa Inês lambs (average age = five months and 24.49 ± 5.27 kg of BW) were distributed in a completely randomized design. Only the ether extract intake was not affected by the PC inclusion, and only the crude protein digestibility was affected by the diets. The total weight and average daily gains decreased, and the feed conversion increased. Hot carcass yield was influenced quadratically, the leg depth increased and the loin-eye area decreased. The total replacement of soybean meal with peanut cake in diets for lambs did not compromise nutrient digestibility, microbial protein synthesis, and carcass characteristics. Nevertheless, peanut cake as a protein source in the diet had adverse effects on nutrient intake and growth performance of feedlot lambs. Full article

Nitrogen fertilizers have a significant impact on the growth of rice. The overuse and inappropriate application of nitrogen fertilizers have resulted in environmental pollution, in addition to subjecting both humans and livestock to negative health hazards. Finding a viable substitute for traditional nitrogen fertilizers is crucial and essential to help improve crop yield and minimize environmental damage. Nano-nitrogen fertilizers offer a possible alternative to traditional fertilizers due to a slow/controlled release of nitrogen. The present work aimed to study the effect of a slow-release urea nanofertilizer on soil ammonical (NH₄-N) and nitrate-N (NO₃-N) content, culturable soil microflora, and soil enzyme activities in three different soil samples procured from Ludhiana and Patiala districts through a soil column study. Seven treatments, including 0, 50 (75 kg/ha N), 75 (112.5 kg/ha N), and 100% (150 kg/ha N) of the recommended dose (RD) of conventional urea and nano-urea fertilizer were applied. The leachate samples collected from nano-urea treatment exhibited NH₄-N for the first two weeks, followed by NO₃-N appearance. The higher NH₄-N and NO₃-N contents in the leachate were recorded for light-textured soil as compared to medium- and heavy-textured soil samples. The soil microbial counts and enzyme activities were recorded to be maximum in light-textured soils. Therefore, this slow-release formulation could be more useful for light-textured soils to decrease applied N-fertilizer losses, as well as for improving the soil microbial viable cell counts and soil enzyme activities. The effect of urea nanofertilizer on the growth and yield of direct-seeded rice (Oryza sativa L.) was also evaluated under field conditions. Both studies were performed independently. Numerically, the highest shoot height, fresh and dry shoot weight, and significantly maximum total chlorophyll, carotenoid, and anthocyanins were recorded in the T2 (100% RDF through nano-urea) treatment. The yield-attributing traits, including the number of filled grains and thousand-grain weight, were also recorded to have increased in T2 treatment. A numerical increase in NPK for plant and grain of rice at 100% RDN through nano-urea was recorded. The soil application of the product exhibited no negative effect on the soil microbial viable cell count on different doses of nano-urea fertilizer. The soil nitrogen fixer viable counts were rather improved in nano-urea treatments. The results reflect that nano-urea fertilizer could be considered as a possible alternative to conventional fertilizer. Full article

High nitrogen (N) losses and low nitrogen utilisation efficiency (NUE) of conventional-nitrogen fertilisers (CNFs) are due to a mismatch between N-delivery and plant demand; thus, slow-release N fertilisers (SRNFs) are designed to improve the match. A quantitative synthesis is lacking to provide the overall assessment of SRNFs on pasture. This meta-analysis analyses application rate and type of SRNFs on N losses and agronomic performances with 65 data points from 14 studies in seven countries. Standardized mean difference of SRNFs for nitrate leaching losses and N₂O emission were −0.87 and −0.69, respectively, indicating their effectiveness in controlling losses. Undesirably, SRNFs had a more negative impact on dry matter (DM) yield and NUE than CNFs. Subgroup analysis showed that SRNF type and application rate had an impact on all tested parameters. The biodegradable coating-type of SRNF outperformed other types in controlling N losses and improving agronomic performances. High application rates (>100 kg N ha⁻¹) of SRNFs are more effective in controlling N losses. In conclusion, SRNFs are more conducive to controlling N losses, but they showed a negative impact on yield and NUE in pasture. Further studies are recommended to assess the efficacy of SRNFs developed using advanced technologies to understand their impact on pastoral agriculture. Full article

Fertigation practices in soilless crop cultivation often rely on predetermined recipes, which may lead to suboptimal nutrient concentrations due to inherent human error or environmental fluctuations. To address this challenge, the integration of in situ real-time nutrient analyzers becomes imperative for ensuring the delivery of high-quality supply solutions. This study assesses the effectiveness of a real-time nitrate (NO₃⁻) analyzer in optimizing the mineral composition of the nutrient solution for fertigating a decoupled aquaponic cucumber crop. The analyzer was integrated into the programmable logic controller of the greenhouse’s hydroponic system. The NO₃⁻ analyzer was activated during solution preparation, dynamically adjusting the NO₃⁻ concentration based on real-time measurements from either the aquaculture or drainage solution by adding the necessary water or/and nutrients in order to prepare a solution to meet the needs of the crop. Four treatments were evaluated: hydroponics (HP), coupled aquaponics (CAP), decoupled aquaponics (DCAP) with EC adjustment, and decoupled aquaponics with NO₃⁻ adjustment (DCAP_N). Results indicated that the DCAP_N treatment, with NO₃⁻ adjustment, yielded the highest crop productivity, outperforming DCAP, HP, and CAP treatments by 7.4%, 21.2%, and 56.1%, respectively. Additionally, DCAP_N demonstrated superior water use efficiency (WUE) and fertilizer use efficiency (FUE), exhibiting a 21.5% and 52.5% increase over the HP treatment, respectively. These findings align with the European Green Deal’s objectives by enhancing nutrient management practices, which are crucial for minimizing nutrient loss and ensuring the sustainable and efficient use of fertilizers. Full article

Nitrogen is essential for plants’ growth, yield, and crop quality, and its deficiency limits food production worldwide. In addition, excessive fertilization and inefficient use of N can increase production costs and cause environmental problems. A possible solution to this problem is the application of biofertilizers, which improve N assimilation and increase biomass and yield. Therefore, the objective of this research was to evaluate the impact of the application of a combination of green and red algae (Ulva lactuca and Solieria spp.), Rhizobium sp., Trichoderma asperellum, and the combination of the above three biofertilizers on N assimilation. A completely randomized design was performed, with 10 plants per treatment and five treatments: T1 = control; T2 = algal extracts; T3 = Rhizobium sp.; T4 = T. asperellum; T5 = T2 + T3 + T4. Our analyses showed that the biofertilizers’ application was better than the control. The application of Rhizobium sp. had the best performance amongst all of the biofertilizers, with the highest nitrate reductase activity in maize leaves, which enhanced photosynthesis, increasing biomass and yield. The use of Rhizobium sp. showed increases in biomass (13.4%) and yield (11.82%) compared to the control. This research shows that biofertilizers can be a key component for sustainable agricultural practices. Full article

Excessive nitrate loading from agricultural runoff leads to substantial environmental and economic harm, and although hydrological models are used to mitigate these effects, the influence of various satellite precipitation products (SPPs) on nitrate load simulations is often overlooked. This study addresses this research gap by evaluating the impacts of using different satellite precipitation products—ERA5, IMERG, and gridMET—on flow and nitrate load simulations with the Soil and Water Assessment Tool Plus (SWAT+), using the Tar-Pamlico watershed as a case study. Although agricultural activities are higher in the summer, this study found the lowest nitrate load during this season due to reduced runoff. In contrast, the nitrate load was higher in the winter because of increased runoff, highlighting the dominance of water flow in driving riverine nitrate load. This study found that although IMERG predicts the highest annual average flow (120 m³/s in Pamlico Sound), it unexpectedly results in the lowest annual average nitrate load (1750 metric tons/year). In contrast, gridMET estimates significantly higher annual average nitrate loads (3850 metric tons/year). This discrepancy underscores the crucial impact of rainfall datasets on nitrate transport predictions and highlights how the choice of dataset can significantly influence nitrate load simulations. Full article

Oilseed rape is one of many crops with high nutritional requirements, particularly for nitrogen (N) and sulphur (S). Both macronutrients affect important physiological plant functions and are essential for the proper growth and development of oilseed rape. The objective of the experiment was to investigate the impact of nitrogen and sulphur fertilization on the yield of the winter oilseed rape cultivar LG Absolut. The experiment was conducted during the 2019/2020, 2020/2021, and 2022/2023 growing seasons on Haplic Cambisol soil formed from loess, with medium levels of mineral nitrogen and sulphur. In the experiment, two nitrogen fertilization treatments (150 and 200 kg ha⁻¹) were compared in combination with three additional sulphur fertilization rates (20, 40, and 60 kg ha⁻¹). The results demonstrated that the effectiveness of N and S fertilization varied between individual years. On average, the highest seed yields were obtained with the application of 200 kg N ha⁻¹ combined with sulphur, regardless of the rate. This was attributed to a significant increase in soil–plant analysis development (SPAD) values, the number of pods per plant, and the thousand-seed weight. The increase in seed yield with the higher nitrogen rate without sulphur ranged from 0.36 to 0.57 t ha⁻¹ compared to the lower rate (control 150 N kg ha⁻¹). Supplementary sulphur fertilization increased seed yield ranging from 0.22 to 0.76 t ha⁻¹. The protein content in the seeds increased, while the fat content decreased, following the application of the higher nitrogen rate. The decrease in fat content was mitigated by higher rates of sulphur. The application of 60 kg S ha⁻¹ yielded similar results of the tested parameters to the lower rates. Therefore, for soils with moderate levels of mineral nitrogen and sulphur, it is recommended to fertilize winter oilseed rape with 200 kg N ha⁻¹ combined with 20 or 40 kg S ha⁻¹. Full article