Nitrogen Loss Research Articles

Impact of cellulolytic nitrogen-fixing composite inoculants on humification pathways and nitrogen cycling in kitchen waste composting.

Low humification and nitrogen loss pose substantial challenges to the resource utilization in kitchen waste composting. This study investigated the effects of brown-rot fungi (BRF), cellulolytic nitrogen fixing bacteria (CNFB), and their composite microbial inoculants (CMI) during composting. Results indicated that microbial inoculants extended the thermophilic phase and enhanced cellulose degradation. Compared with the control, the degree of polymerization (HA/FA) in BRF, CNFB, and CMI was 2.28, 1.85, and 2.68 times higher, respectively, while increasing total nitrogen by 11.15%, 15.50%, and 19.73%. BRF and CMI primarily enhanced the Maillard humification pathway, while CNFB promoted the polyphenol humification pathway. Additionally, BRF enhanced nitrification and reduced denitrification, whereas CNFB and CMI improved nitrification, nitrogen fixation, and ammonification while reducing denitrification. Overall, BRF primarily promoted humification, while CNFB excelled in nitrogen retention. The CMI achieved optimal humification and nitrogen retention, indicating a potential sustainable solution for kitchen waste composting.

Optimized agricultural management reduces global cropland nitrogen losses to air and water.

Nitrogen (N) losses from croplands substantially contribute to global N pollution. Assessing the reduction in N losses through improved N management practices is complex due to varying site conditions, such as land use, climate, soil properties and local farming methods. In this Article, we conducted a meta-analysis to evaluate the effects of improved practices on N loss reduction, analysing data from 1,065 studies with 6,753 pairs of observations comparing standard and optimized practices. Without considering site-specific conditions, optimized management practices can reduce N2O emissions by 3-39%, NH3 emissions by 15-68%, N run-off by 21-37% and N leaching by 19-52%. After considering local conditions and current practices, average reductions on a global scale were 31% for N2O, 23% for NH3, 18% for N run-off and 17% for N leaching. The effectiveness of N loss reduction was mainly influenced by optimized management practices and, to a lesser extent, site conditions. The results of this study underscore the importance of implementing optimized, site-specific management to effectively reduce N losses from global croplands.

A Perspective on Powder Metallurgy and Additive Manufacturing of High‐Nitrogen Alloyed Stainless Steels

Incorporating nitrogen as an alloying element in stainless steels can significantly enhance their mechanical and chemical properties. However, the limited solubility of nitrogen, particularly in the liquid phase, presents challenges. This perspective article explores an innovative powder metallurgical approach to producing high‐nitrogen steels (HNS) by utilizing a mixture of stainless steel and Si3N4. This mixture undergoes hot isostatic pressing (HIP) followed by direct quenching, facilitating diffusion alloying, and solution annealing in a single step. The article also examines adapting this method to powder bed fusion of metals using a laser beam (PBF‐LB/M) to overcome nitrogen solubility limits, which currently constrain the achievable nitrogen content in PBF‐LB/M‐manufactured stainless steels. The approach aims to retain Si3N4 particles within the matrix during PBF‐LB/M to enrich the steel with nitrogen during subsequent HIP. However, laser interaction with Si3N4 can lead to nitrogen loss, prompting an alternative strategy: a shell–core structure based on a gas‐tight shell enclosing loose Si3N4 particles. These particles dissolve during HIP, enriching the matrix with nitrogen and enabling the production of HNS. This article highlights the potential for extending this approach to other stainless steel groups, broadening the possibilities for HNS production through both conventional HIP and PBF‐LB/M manufacturing routes.

Drill‐seeding rice reduces global warming potential but increases nitrogen loss potential compared to water‐seeding

AbstractFlooded rice (Oryza sativa L.) systems are critical for global food security but contribute significantly to anthropogenic greenhouse gas (GHG) emissions due to high methane (CH4) emissions from anaerobic soils. Drill‐seeding (DS) rice, which in California includes early‐season irrigation flushes to establish the rice, has been shown to reduce CH4 emissions compared to water‐seeded (WS) systems. The effect of these early‐season flushes on nitrogen (N) fertilizer losses and nitrous oxide (N2O) emissions, however, is not well understood. In a 2‐year study, we quantitatively compared DS to WS systems with respect to their global warming potential (GWP) (CH4 + N2O in CO2 eq.), nitrate (NO3−) accumulation during flushes, and crop N‐uptake. Despite 0.68 kg ha−1 more N2O–N emissions in the DS system, GWP was 3700 CO2 eq. kg ha−1, a 42% reduction compared to 6340 CO2 eq. kg ha−1 in the WS system. This was due to a 46% reduction in CH4 in the DS (94.5 CH4–C kg ha−1) relative to the WS (175.7 CH4–C kg ha−1) system. Nitrate accumulation in the DS system amounted to 26.2 kg NO3–N ha−1, and subsequent N losses via denitrification likely contributed to the 22.4 kg N ha−1 less crop N‐uptake in the DS system. These results suggest that DS rice has potential for improved environmental impact via GWP reductions but will require increased N inputs. Future efforts should focus on reducing N losses, which have a negative economic impact for the farmer and contribute to N2O emissions.

Augmented Renal Clearance: Prevalence, Risk Factors and Underlying Mechanism in Critically Ill Patients with Subarachnoid Hemorrhage.

Augmented renal clearance (ARC) is an increase in the measured creatinine clearance (CLCR), the cause of which remains poorly understood. ARC may be associated with drug underdosing and appears to be more frequent in patients with brain damage, such as subarachnoid hemorrhage (SaH), although the incidence of ARC remains poorly understood. The aim of this study was to investigate the prevalence of ARC in patients with SaH in a neurointensive care unit (neuro-ICU) and to identify factors associated with ARC. All consecutive patients hospitalized in the neuro-ICU of Bordeaux University Hospital between June 2018 and June 2019 for SaH treatment were retrospectively included. CLCR was measured daily via 24-h urine collection. ARC was defined as a CLCR ≥ 130mL/min/1.73 m2. The effects of different covariates on the time course of CLCR were investigated using a linear mixed model. Of the 205 included study participants, 168 developed ARC during their neuro-ICU stay; the estimated ARC prevalence was 82% (95% confidence interval 76-87) with a median of 4days (range 3-6days) after hemorrhage; ARC persisted for a median of 5days (range 2-8days). Patients with ARC were younger and had a lower BMI and lower mortality rate. In multivariate analysis, younger patients with a higher mean arterial pressure, no history of hypertension, and greater nitrogen loss were more likely to have ARC. Augmented renal clearance is very common in critically ill patients with SaH, persists over time, and seems to lack specific risk factors. Daily CLCR measurements could be essential.

Simulating Agricultural Water Recycling Using the APEX Model

Irrigation plays a vital role in many agricultural crop production regions. Drainage water recycling (DWR) is a popular irrigation water management system that collects excess water drained from cropland fields and stores it in on-site reservoirs for reuse. The efficacy of these systems varies by location, climate, irrigation frequency, and crop demands. Simulating this system would be beneficial for assessing the impact of water and land management practices on agriculture and natural resources. This study presents the development of computational algorithms for DWR simulation with the Agricultural Policy Environmental eXtender (APEX) model, along with the results for 39 testing sites where both reservoir and drainage systems are adopted. Simulating a DWR system with the revised reservoir module, the APEX model simulates irrigation water reuse ranging between 29% and 93%; sediment reduction of around 66%; nitrogen loss reduction of 23% and 73% for the mineral and organic forms, respectively; and phosphorus loss reduction of 22% and 79% for the soluble and sediment-transported forms, respectively. In conclusion, the results provided by the APEX model for sediment loss reduction align with field data, but discrepancies for nitrogen and phosphorus losses emerged from this test.

Low protein diet influences mineral absorption and utilization in medium-growing yellow-feathered broilers from 1 to 30 days of age

Reduced-protein diet can save protein ingredients and reduce nitrogen (N) losses. However, the effect of low protein diet on the mineral uptake and utilization in broilers needs to be explored. The aim of this study was to investigate the effect of low-protein diet on the growth performance, N deposition, mineral contents in serum, tissues and excreta, and the activities and gene expression of related enzymes in tissues of medium-growing yellow-feathered broilers, so as to elucidate the relationship between dietary protein level and the absorption and utilization of minerals in broilers. A total of 72 1-d-old Spotted-Brown male broilers were randomly allotted to 1 of 2 treatments with 6 replicate cages of 6 birds per cage for each treatment. The dietary crude protein (CP) levels for the two treatments were 21 % (the control treatment) and 19 % (low protein treatment), respectively. The experimental period was 30 d. The results showed that no differences (P > 0.05) were detected in average daily gain, average daily feed intake and feed: gain ratio of broilers during 1 to 30 d between the two treatments. However, low protein intake increased (P < 0.05) N retention rate, serum P, Cu and Mn, and excreta Cu, Mn and Zn, and decreased (P < 0.05) liver P and excreta P. In addition, birds fed low protein diet had higher (P < 0.05) manganese superoxide dismutase, and total superoxide dismutase activities in liver, and total antioxidant capacity and malondialdehyde content in heart, and lower (P < 0.05) copper-zinc superoxide dismutase (CuZnSOD) and succinate dehydrogenase activities in liver and CuZnSOD mRNA level in heart. In conclusion, the reduction of dietary CP content from 21 % to 19 % improved N retention, the absorption of P, Cu and Mn, as well as the antioxidant ability of liver and heart, and influenced metabolic utilization of P, Cu, Zn, Fe and Mn in medium-growing yellow-feathered broilers from 1 to 30 d of age.

Estimating the effect of biological nitrification inhibition-enabled sorghum on nitrogen fertilizer consumption, life cycle GHG emissions, farmer's benefit and fertilizer subsidy from Indian sorghum production

Biological nitrification inhibition (BNI) effectively curtails nitrogen (N) loss and enhances N utilization efficiency. BNI is increasingly important as a technology for mitigating greenhouse gas emissions and water pollution in countries with high N fertilizer consumption. This study aimed to evaluate the potential impacts of BNI-enabled sorghum varieties with a 30 % soil nitrification inhibition rate for a major sorghum-growing state (Maharashtra, India). We analysed the farm survey data collected for Rabi sorghum in 2020–2021 (n = 250) and for Kharif sorghum in 2022 (n = 209). Life cycle greenhouse gas (LC-GHG) emissions were estimated using a life cycle assessment with a cradle-to-farm gate perspective. The results showed that adoption of BNI-enabled sorghum reduced N fertilizer application in the Rabi and Kharif seasons by 8.0 % and 7.4 % and area-scaled/yield-scaled LC-GHG emissions by 15.6 % and 11.2 %, respectively, while increasing farmers' benefits slightly. These changes could reduce the government's expenditure on urea fertilizer subsidies by 9.1 %. However, many farmers indicated that they would not change N fertilizer application even if the yield per N fertilizer application increased. Even under these circumstances, area-scaled/yield-scaled LC-GHG emissions will be decreased by 11.3 % and 13.5 % in the Rabi season and 8.1 % and 10.2 % in the Kharif season, respectively. The yield and farmers' benefit will increase by 2.5 % and 4.9 % in the Rabi season and by 2.4 % and 6.5 % in the Kharif season, respectively, but the government's expenditure on fertilizer will not decrease. These results indicate that BNI-enabled sorghum can be introduced into countries where fertilizer use is low. This study shows the potential impacts of BNI-enabled sorghum under two scenarios; N fertilizer consumption is reduced or maintained. Discussions on the N fertilizer consumption under BNI-enabled sorghum are needed to establish a sustainable food system, especially in countries with high N fertilizer consumption.

Newly Established Blueberry Plants: The Role of Inorganic Nitrogen Forms in Nitrogen and Calcium Absorption

Efficient nitrogen (N) management is crucial for maximizing the growth of young blueberry plants (Vaccinium corymbosum). This study evaluates the effects of the N fertilization form (ammonium, NH4+; nitrate, or NO3−) and application timing on the blueberries’ establishment, N and Ca absorption, and N distribution. The experiment was conducted in the southern hemisphere, in Chile, from October 2023 to January 2024. Six-month-old blueberry cv. Blue Ribbon plants were cultivated in pots. NH4+ and NO3− were used as full or split-dose applications using the 15N isotopic dilution technique. Plant leaves, stems, root growth, and biomass, as well as their N and Ca contents, were measured. Our results showed that 90 days after nitrogen application, blueberry plants obtained the lowest biomass in their leaves, stems, and roots when NO3− was applied in T1 or T1T2. The same pattern was observed for N and Ca contents, hence for N recovery. During the first period (T1) of application, heavy rain (100 mm) was registered over the course of a few days and caused leaching. Therefore, applying nitrate to young blueberry plants cultivated in areas with spring rainfall and low temperatures would not be recommended because the leaching losses and lower growth conditions, such as low temperatures and high precipitation, led to reduced transpiration, resulting in lower calcium and nitrogen contents. These confirm that N fertilization management (form and timing) can ensure a better establishment for young blueberry plants, optimizing their growth and sustainable production by minimizing nitrogen losses.

Heterologous biosynthesis of betanin triggers metabolic reprogramming in tobacco

Engineering of a specialized metabolic pathway in plants is a promising approach to produce high-value bioactive compounds to address the challenges of climate change and population growth. Understanding the interaction between the heterologous pathway and the native metabolic network of the host plant is crucial for optimizing the engineered system and maximizing the yield of the target compound. In this study, we performed transcriptomic, metabolomic and metagenomic analysis of tobacco (Nicotiana tabacum) plants engineered to produce betanin, an alkaloid pigment that is found in Caryophyllaceae plants. Our data reveals that, in a dose-dependent manor, the biosynthesis of betanin promotes carbohydrate metabolism and represses nitrogen metabolism in the leaf, but enhances nitrogen assimilation and metabolism in the root. By supplying nitrate or ammonium, the accumulation of betanin increased by 1.5–3.8-fold in leaves and roots of the transgenic plants, confirming the pivotal role of nitrogen in betanin production. In addition, the rhizosphere microbial community is reshaped to reduce denitrification and increase respiration and oxidation, assistant to suppress nitrogen loss. Our analysis not only provides a framework for evaluating the pleiotropic effects of an engineered metabolic pathway on the host plant, but also facilitates the development of novel strategies to balance the heterologous process and the native metabolic network for the high-yield and nutrient-efficient production of bioactive compounds in plants.

Feedstock optimization with low carbon to nitrogen ratio during algal sludge aerobic composting: Quality and gaseous emissions

This study investigated compost quality and gaseous emissions during the algal sludge composting. The experiment explored the feasibility of low initial carbon to nitrogen (C/N) ratio composting by using different volume ratios of algal sludge and spent mushroom substrates (1:1, 1:2, 1:3, and 1:4, corresponding to C/N ratios of 9.5, 12.3, 14.6, 16.0, respectively). The results showed that increasing the proportion of algal sludge in the initial material led to a longer maturation time and higher nitrogen losses but also enhanced the mineralization of organic nitrogen (converted to NH4+ and NO3-) and reduced carbon losses. The addition of carbon-rich bulking agents within a certain range improved the diversity and interactions of bacterial communities during algal sludge composting. In conclusion, considering the nitrogen and carbon lost, retained, and made available across the four treatments, treatment 3 (C/N = 14.6) appears to be the optimal choice for low C/N composting.

Unprecedented N2O production by nitrate-ammonifying Geobacteraceae with distinctive N2O isotopocule signatures.

Dissimilatory nitrate reduction to ammonium (DNRA), driven by nitrate-ammonifying bacteria, is an increasingly appreciated nitrogen-cycling pathway in terrestrial ecosystems. This process reportedly generates nitrous oxide (N2O), a strong greenhouse gas with ozone-depleting effects. However, it remains poorly understood how N2O is produced by environmental nitrate-ammonifiers and how to identify DNRA-derived N2O. In this study, we characterize two novel enzymatic pathways responsible for N2O production in Geobacteraceae strains, which are predominant nitrate-ammonifying bacteria in paddy soils. The first pathway involves a membrane-bound nitrate reductase (Nar) and a hybrid cluster protein complex (Hcp-Hcr) that catalyzes the conversion of NO2- to NO and subsequently to N2O. The second pathway is observed in Nar-deficient bacteria, where the nitrite reductase (NrfA) generates NO, which is then reduced to N2O by Hcp-Hcr. These enzyme combinations are prevalent across the domain Bacteria. Moreover, we observe distinctive isotopocule signatures of DNRA-derived N2O from other established N2O production pathways, especially through the highest 15N-site preference (SP) values (43.0‰-49.9‰) reported so far, indicating a robust means for N2O source partitioning. Our findings demonstrate two novel N2O production pathways in DNRA that can be isotopically distinguished from other pathways.IMPORTANCEStimulation of DNRA is a promising strategy to improve fertilizer efficiency and reduce N2O emission in agriculture soils. This process converts water-leachable NO3- and NO2- into soil-adsorbable NH4+, thereby alleviating nitrogen loss and N2O emission resulting from denitrification. However, several studies have noted that DNRA can also be a source of N2O, contributing to global warming. This contribution is often masked by other N2O generation processes, leading to a limited understanding of DNRA as an N2O source. Our study reveals two widespread yet overlooked N2O production pathways in Geobacteraceae, the predominant DNRA bacteria in paddy soils, along with their distinctive isotopocule signatures. These findings offer novel insights into the role of the DNRA bacteria in N2O production and underscore the significance of N2O isotopocule signatures in microbial N2O source tracking.

Impact of low crude protein diets containing animal byproducts on growth performance, nitrogen excretion, meat yield and quality in broiler chickens

This study examined the impact of a low crude protein (CP) diet incorporating meat and bone meal (MBM) as an alternative (AD) to standard diet, on broiler performance, nitrogen intake, excretion, and meat quality. A total of 846 male Ross 308 chicks were assigned to two diets in a randomized complete block design with 9 replicates of 47 birds/replicate. The diets were a plant-based control (20.4 and 19.5% CP) and an AD diet (-2.0% CP, +2.5% MBM) in the grower and finisher phases. Compared to the control, the AD diet reduced nitrogen intake (P = 0.01) and excretion (P &lt; 0.01) while improving nitrogen retention efficiency (P &lt; 0.001) without affecting body weight, feed conversion, or carcass yield. Breast yield was higher in the AD group (P &lt; 0.001). In the AD group, the ultimate pH of breast meat increased slightly (P = 0.07), cooking loss decreased (P = 0.002), sarcoplasmic protein solubility tended to increase (P = 0.09), while muscle protein emulsifying properties remained unchanged. Breast meat proximate composition was not affected by the AD diet. In conclusion, the AD diet can reduce nitrogen loss and emissions without negatively impacting broiler production, provided that amino acid requirements are met.

Assessment of nitrogen and phosphorus losses due to erosion in compost-treated and non-treated vineyard soils: effect of rainfall intensity

Vineyards in Mediterranean areas suffer from significant soil degradation through erosion, due to rainfall and soil characteristics, as well as soil management practices. Previous studies pointed out the nutrient losses produced by erosion and the benefits that some management practices could have on reducing erosion. This research tried to evaluate the effect of events of different intensities and to assess whether the beneficial effect of compost amendment may pose a potential risk of nutrient loss and environmental pollution in particular under high-intensity events. The study compared soil and nutrient losses in compost-treated and non-treated vineyard soils after rainfall events of different intensities analyzed over 2 years in two vineyards. Runoff samples were collected by triplicate in treated and non-treated soils. Sediment and nitrogen and phosphorous concentrations in the runoff samples were analyzed. The results reveal a reduction in runoff rates and an increase in soil water content in compost-treated soils, which represents a benefit for rainfed vineyards. Both nitrogen and phosphorus losses depended on rainfall characteristics. Although for low intensities there were no significant differences in the amount of nutrient lost by runoff in both treated and non-treated soils, nitrogen and phosphorus losses were higher after high-intensity rainfall events in compost-treated soils. With the expected increase in high-intensity rainfall events associated with climate change in the Mediterranean region, organic amendments should be applied in several splits or incorporated into the soil to avoid increased nutrient loss to water bodies.

The dynamic relation between fertilization, precipitation and the diffusion of agricultural non-point pollution in Hainan Island

With the increasing demand for crops, the excessive application of fertilizers has gradually become a significant factor affecting water quality. Therefore, studying the relationship between agricultural fertilizer runoff and water quality is crucial for the sustainable development of agricultural production. The present study sets up a new dynamic model of nitrogen fertilizer loss, introducing variables such as precipitation, fertilization application during dry and rainy seasons, and their lagged and interaction terms. The paper analyzed the issue of fertilizer runoff under the complex interactions of various factors, including spatial and temporal scales and climatic conditions, and explored the relationship between agricultural activities and water quality changes in the context of sustainable development. Due to Hainan Island’s independent river system, which is free from transboundary pollution, and its low level of industrial pollution, it provides an excellent sample for assessing the impact of agricultural non-point source pollution on water quality. Based on watershed monitoring data from Hainan Island, this study draws the following conclusions: 1. Precipitation exhibits a pronounced seasonal influence on total nitrogen concentration. 2. Nitrogen fertilizer enters into water bodies through precipitation, resulting in a lag effect on total nitrogen concentration. 3. The influence of grain and tropical crops on nitrogen loss is less significant, while cash crops will trigger the nitrogen overloading of rivers in scenarios where they account for a high proportion of the planting structure of the sown area.

Application of Nitrate–Ammonium Nitrogen Fertilization Reduced Nitrogen Loss in Surface Runoff and Infiltration by Improving Root Morphology of Flue-Cured Tobacco

Nitrogen loss in water from farmland has become an environmental issue. Nitrogen fertilizer is the main cause of agricultural non-point source pollution in the Lake Basin, Yunnan. However, it is unclear how different nitrogen fertilizer forms affect water loss from farmland and how the root systems of crops respond. We established five nitrogen fertilizer treatments (100–0% [T1], 75–25% [T2], 50–50% [T3], 25–75% [T4], and 0–100% [(T5)] nitrate–ammonium) and performed an investigation to determine nitrogen loss in water and root morphological parameters of tobacco in Mile County and Chengjiang County. Compared with in the T1, T4, and T5 treatments, the total nitrogen loss in surface runoff was reduced by 4.67%, 11.85% and 9.56% in the T2 treatment and 27.32%, 23.20%, and 31.43% in the T3 treatment, respectively. Similar results were observed for the nitrogen loss due to infiltration. The root biomass was negatively correlated with nitrogen loss. There was greater root biomass, root surface area, and root spatial distribution in T2 and T3 compared with in T1, T4, and T5. These results indicate that 50–50% nitrate–ammonium nitrogen fertilizer can facilitate the root growth of tobacco and reduce nitrogen loss, which provides a reference for agricultural sustainable development.

Synthesis and Evaluation of Starch-Grafted-Poly[(Acrylic Acid)-Co-Acrylamide] Based Nanoclay Polymer Composite Fertilizers for Slow Release of Nitrogen in Soil.

Nitrogen (N) losses from conventional N fertilizers contribute to environmental degradation and low N use efficiency. Highlighting the need for slow-release fertilizers (SRFs) to mitigate these problems, this study aims to develop slow-release N fertilizers using starch-grafted-poly[(acrylic acid)-co-acrylamide] based nanoclay polymer composites (NCPCs) and investigate their efficacy for slow N delivery in soil. Three types of NCPCs, NCPC(A) (poly [(acrylic acid)-co-acrylamide]), NCPC(W) (wheat starch-grafted-poly[(acrylic acid)-co-acrylamide), and NCPC(M) (maize starch-grafted-poly[(acrylic acid)-co-acrylamide) were prepared and characterized using FTIR spectroscopy and X-ray diffraction techniques. N-release behaviour of the products was assessed under two distinct soils, i.e., Assam (Typic Hapludults, pH 4.2) and Delhi (Typic Haplustepts, pH 7.9) soils. Additionally, the effects of varying soil moisture and temperature levels on N release were studied in the Assam soil. The N-release kinetics of the synthesized fertilizers were assessed using zero-order, first-order, Higuchi, and Korsmeyer-Peppas models. Degradability of the NCPCs was evaluated by measuring evolved CO2-C under various soil conditions as an indicator of microbial degradation. The results indicated that NCPC fertilizers significantly slowed down the release of N compared to urea. According to the R2 values obtained, it was evident that the first-order kinetic model most accurately describes the N release from both urea and NCPC-based N fertilizers in the studied soils. Among the formulations, NCPC(A) exhibited the lowest N release (42.94-53.76%), followed by NCPC(M) (51.05-61.70%), NCPC(W) (54.86-67.75%), and urea (74.33-84.27%) after 21 days of incubation. The rate of N release was lower in the Assam soil compared to the Delhi soil, with higher soil moisture and temperature levels accelerating the release. Starch addition improved the biodegradability of the NCPCs, with NCPC(W) showing the highest cumulative CO2-C evolution (18.18-22.62 mg g-1), followed by NCPC(M) (15.54-20.97 mg g-1) and NCPC(A) (10.89-19.53 mg g-1). In conclusion, NCPC-based slow-release fertilizers demonstrated a more gradual N release compared to conventional urea and the inclusion of starch enhanced their degradability in the soil, which confirms their potential for sustainable agricultural applications. However, soil properties and environmental factors influenced the N release and degradation rates of NCPCs.

Selecting an optimal sorghum cultivar can improve nitrogen availability and wheat yield in crop rotation.

Sorghum (Sorghum bicolor L. Moench) is a cereal crop known for its biological nitrification inhibition (BNI) capacity, a plant-mediated activity limiting nitrification pathway. The use of BNI-producing plants represents an environmentally friendly and cost-effective approach to reduce nitrogen (N) losses, such as nitrate (NO3 -) leaching and nitrous oxide (N2O) gas emissions. The present study aimed to test the effectiveness of different S. bicolor cultivars in rotation to retain ammonium (NH4 +) in soils and promote N availability for the subsequent wheat crop. A two-year field rotation was established with four sorghum cultivars followed by winter wheat (Triticum aestivum L.). Urea alone or combined with the urease inhibitor N-(n-butyl) thiophosphoric triamide was applied to promote a NH4 +-based fertilization regimes. AddingN-(n-butyl) thiophosphoric triamide maintained higher soil NH4 + content and reduced ammonia-oxidizing bacteria population during sorghum cultivation. However, the benefits of the inhibitor on sorghum growth were cultivar-dependent. Notably, the further reduction in ammonia-oxidizing bacteria abundance for sorghum Voyenn and the increased soil NH4 + content for Vilomene suggested a BNI potential for these cultivars. Importantly, the Vilomene precedent enhanced wheat yield for both fertilization regimes. Overall, the present study confirms that sorghum is a suitable catch crop and emphasizes the importance of selecting the proper sorghum cultivar to maximize the yield of the target wheat crop, at the same time as minimizing N losses. Furthermore, developing combined strategies with selected sorghum cultivars and the application of urease inhibitors enables to enhance sorghum productivity as forage, achieving added value to the rotation. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Temporal variations of N and P losses via surface runoff from Chinese farmland after fertilisation

The loss of nitrogen (N) and phosphorus (P) via surface runoff induced by fertilisation leads to water pollution and aggravates water scarcity. Studies estimating N and P losses from farmland have focused on the efficacy of agricultural management actions at reducing the amount of N and P lost. However, a gap remains in understanding the dynamics of N and P losses from farmland, especially differences among types of farmland, crop and fertiliser. Thus, the temporal variations of N and P losses via surface runoff from farmland induced by fertilisation were estimated using 5530 groups of paired observations collected in China. The results showed that N and P losses via surface runoff from paddy fields associated with fertilisation were greater than losses from upland fields. However, after > 90 days post-fertilisation, the effects of fertilisation on N and P loss from paddy fields were non-significant, while the effects of fertilisation on N and P losses from upland fields remained significant. Organic fertilisation decreased N losses from upland and paddy fields, but at more than 60 days post-fertilisation, N and P losses from upland fields were greater with organic than chemical or combined fertilisation. Increasing the fertilisation rate led to higher N and P losses from upland and paddy fields and extended the occurrence time of N and P loss from paddy fields. Overall, this study demonstrates the dynamic processes associated with fertilisation underlying N and P losses from farmland via surface runoff.

Warming exacerbates global inequality in forest carbon and nitrogen cycles

Forests are invaluable natural resources that provide essential services to humanity. However, the effects of global warming on forest carbon and nitrogen cycling remain uncertain. Here we project a decrease in total nitrogen input and accumulation by 7 ± 2 and 28 ± 9 million tonnes (Tg), respectively, and an increase in reactive nitrogen losses to the environment by 9 ± 3 Tg for 2100 due to warming in a fossil-fueled society. This would compromise the global carbon sink capacity by 0.45 ± 0.14 billion tonnes annually. Furthermore, warming-induced inequality in forest carbon and nitrogen cycles could widen the economic gap between the Global South and Global North. High-income countries are estimated to gain US$179 billion in benefits from forest assets under warming, while other regions could face net damages of US$31 billion. Implementing climate-smart forest management, such as comprehensive restoration and optimizing tree species composition, is imperative in the face of future climate change.