The increasing use of nitrogen (N) fertilizers is essential for plant productivity, but may induce physiological and nutritional constraints when applied at excessive rates, particularly under acidic substrate conditions. Our study evaluated the effects of increasing N supply on substrate chemistry, growth, N partitioning, N-use efficiency (NUE), and physiological performance of young Macadamia tetraphylla trees grown under acidic conditions. Increasing N rates elevated substrate nitrate–N concentrations and intensified substrate acidification, whereas ammonium–N remained relatively stable. An excessive N supply reduced root dry mass and NUE in leaves and roots, despite increasing tissue N concentration across all organs. High N availability did not enhance total biomass production or N accumulation, indicating a decoupling between N uptake and growth. Chlorophyll fluorescence responses revealed early photochemical stress at elevated N rates. Multivariate analyses further separated low and high N treatments, highlighting contrasting associations among substrate pH, root development, NUE, and N-related variables. Overall, excessive N fertilization under acidic conditions promoted N accumulation rather than efficient biomass production, constraining root growth, physiological performance, and NUE. These results show the importance of balanced N management to optimize growth and resource-use efficiency in young macadamia trees.

The agroecological transition offer opportunities to reduce agriculture's environmental impacts by reducing reliance on synthetic fertilisers and pesticides. Crop diversification, in both time and space, is a key strategy including extended crop rotations, intercropping, and cover crops. Yet, relationships between reduced input use and associated environmental impacts remain insufficiently quantified. We assessed the environmental performance of six innovative low-input cropping systems that used cover crops, cultivar mixture and intercropping in term of nitrogen fertiliser and pesticide use, as well as nitrate and pesticide losses. From 2010 to 2016, cropping systems were monitored for input use and drainage water was collected with tension plate lysimeters at 1 m depth. Nitrate and up to 44 pesticide compounds were analysed annually. Nitrogen fertiliser application varied across systems, with more diversified systems applying less thanks to legumes. Pesticide use remained similar among systems but reduced by over 50% compared to conventional rates. Cover crops played a key role in reducing pollution. Nitrate leaching reduced by 42–56% in systems with cover crops. More originally, pesticide leaching decreased by 53–82% for these systems with S-metolachlor representing more than 50% of the quantity of pesticide losses. These results demonstrate that diversifying cropping systems, particularly through cover cropping, can reduce agriculture's environmental footprint greatly. When combined with reducing input use, such strategies provide a promising pathway towards more sustainable and resilient farming systems, with clear benefits for water quality and agroecosystem functioning. • Six low-input diversified arable cropping systems were tested for six years. • Nitrate and pesticide leaching were collected over the six years of monitoring. • Cover crops cut nitrate leaching by 42–56% under field conditions. • First evidence that cover crops reduce pesticide leaching by 53–82%. • S-metolachlor loss is the main driver of the pesticide leaching pattern observed.

Engineering of Azotobacter chroococcum enables potential replacement of synthetic nitrogen fertilizer and mitigation of nitrogen pollutants release under medium-fertility field conditions.

Relay intercropping (RI) involves cultivating two crops in overlapping growth cycles to enhance land use efficiency and optimize resource utilization. While RI systems can increase overall productivity, their success depends on effectively managing interspecific interactions that influence crop establishment, development, and yield potential. This study aimed to evaluate how nitrogen (N) fertilization and winter canola plant population density influence crop establishment, development and yield in a winter canola–soybean RI system compared to sole cropping (SC). Field experiments were conducted across multiple environments in Ontario, Canada during the 2022 and 2023 growing seasons. Treatments included two N levels and varying winter canola densities. Crop growth, yield components, and physiological traits such as internode elongation and harvest index (HI) were measured. When spring N was applied, total seed yield in the RI system was comparable to SC soybean, with a 40% increase in winter canola yield offsetting an 18% decline in soybean yield. However, soybean yield alone declined by 58–61% in RI compared to SC. Despite these reductions, LER values consistently exceeded 1.0 (0.93–1.67), confirming that RI improved land-use efficiency across environments and N levels. In contrast, TOI values were generally below 1.0 (0.68–1.30), indicating that combined intercrop yield rarely surpassed the most productive sole crop, except in environments where SC soybean yields were very low. RI soybeans exhibited significantly greater epicotyl elongation, particularly under N fertilization, indicating a strong shade avoidance response. This was accompanied by reduced biomass, lower yield, and increased variability in reproductive partitioning. While mean HI was similar between systems (0.58), RI soybeans showed a 45% wider range and 76% higher coefficient of variation in HI. The results demonstrate that increased winter canola productivity in RI systems can intensify interspecific interference, primarily through canopy shading and N-mediated effects, limiting soybean yield potential. Despite reduced soybean yield, the overall productivity and land equivalence ratio (LER) of the RI system suggest that winter canola is a viable intercrop partner. These findings underscore the need for refined agronomic strategies, such as optimized row spacing and fertility recommendations, to mitigate interspecific interference and enhance system-level performance in RI systems. • Relay intercropping matched sole crop yield when spring nitrogen was applied. • Yield losses in soybean coincided with early-season shade avoidance responses. • Epicotyl elongation explained 25% of yield variation in intercropped soybean. • Intercropped soybeans showed greater variability in reproductive partitioning.

This study explores how hyperspectral sensors mounted on unmanned aerial vehicles (UAVs) may assist in maize nitrogen status monitoring and yield prediction using traditional regression and machine learning models. Three field experiments were conducted with three soil types (alluvial soil, black soil, and aeolian sand soil) and various nitrogen (N) fertilizer treatments (0, 168, 240, 270 and 312 kg N/ha) in Lishu County, Northeast China. Hyperspectral images obtained from sensors mounted on UAVs were collected to monitor the nitrogen nutrition index (NNI) at the jointing, silking, and maturity stages and the grain yield of maize in 2019 and 2020. In comparison to the prediction performance of the partial least squares regression (PLSR) and random forest (RF) regression models, 13 narrowband vegetation indices (VIs) and N application rates were employed as predictors to determine N status at the field scale. The results revealed that most VIs were significantly correlated with the NNI and yield at different stages and that the Maccioni index was the most influential predictor for both the NNI and yield estimation based on the relative importance calculation results of the different predictors. Compared with the PLSR model, the NNI and yield were better estimated by the RF model, except for yield estimation at the jointing and silking stages. The best performance for maize NNI and yield estimation was achieved at the silking stage and maturity stage, respectively. Based on the relationships between the NNI and yield, the NNI intervals were 0.91–1.30 for alluvial and black soil and 0.67–0.72 for aeolian sandy soil, with the goal of achieving the target yield. This study highlights the significance of introducing UAV technologies in providing a field-scale data-driven approach for crop nitrogen monitoring and yield prediction information to farmers and policy-makers for better precision crop management.

• We evaluated Nellore steers’ muscle development and meat quality traits as well as the methane (CH 4 ) emissions intensity per kg of carcass. • Five tropical pasture-based beef cattle production systems were analyzed. • Carcass and meat quality traits observed are positively influenced by well-managed intensified systems. • This increased efficiency allows CH 4 emission intensities, confirming their potential as a viable sustainability system to avoid pasture degradation processes. This study evaluated the effects of five pasture-based production systems on the carcass and meat quality traits, as well as the methane (CH 4 ) emissions intensity of male Nellore steers per kg of carcass under tropical conditions. Over two years (2019-2021), uncastrated male steers (three/year/experimental spatial unit) were randomly assigned to five treatments (with two replicates): 1) degraded pasture without nitrogen (N) fertilization (DP0); 2) silvopastoral with 200 kg N ha -1 (SP200); 3) rainfed pasture with 200 kg N ha -1 (RP200); 4) rainfed pasture with 400 kg N ha -1 (RP400); and 5) irrigated pasture with 600 kg N ha -1 (IP600). Animals grazed exclusively, receiving water and mineral-protein supplement ad libitum until being stunned by the Brazilian-approved method cranial concussion, followed by exsanguination, without electrical stimulation. The carcass and meat quality traits observed are positively influenced by intensification. Specifically, IP600, RP400 and RP200 demonstrate a clear benefit in improving RA, BFT, LCCW, CEP and FT (including HEP, FEP and spareribs), and Bones (expressed as kg carcass -1 and %); while SP200 and DP0 restricted the growth rates and muscle development of the animals due to the competition between the trees and the pasture and lack of fertilization, respectively. For CH 4 emission intensities (per kg of carcass), SP200 and DP0 exhibited the highest emissions without proportional production gains, while IP600, RP400, and RP200 showed the lowest values. Well-managed intensified pasture-based systems consistently achieved lower CH 4 emission per unit of product than those observed in DP0, confirming their potential as a viable sustainability system.

Plasticity and compensatory mechanisms of the yield components of triticale in response to reduced nitrogen fertilization

Unlocking the potential of Rhodopseudomonas palustris as a biofertilizer: Soil factors and microbial partnerships governing enhanced free-living nitrogen fixation.

Nitrogen fertilization shapes rhizosphere microbiome to boost peanut yield: A two-year field study

Raised-bed planting enables reduced nitrogen fertilizer input without compromising peanut yield in a peanut–wheat double cropping system

Optimizing drip irrigation and nitrogen fertilization to increase net ecosystem carbon budget and economic benefits with reduced carbon footprint in maize agroecosystems

A hybrid centralized-distributed green ammonia system for cost-effective decarbonization of China's nitrogen fertilizer production

Nitrogen fertilizer weakens spider predation on rice planthoppers via altered prey quality

Long-term straw substitution for chemical fertilizers promotes an increase in phosphorus availability in greenhouse soils by modulating the microbial community structure

Optimizing organic fertilizer nitrogen substitution to enhance growth, nutrient uptake, and use efficiency in Zanthoxylum armatum

Biochar co-application with nitrogen and phosphorus fertilizers modulates maize growth and physiological performance by reshaping soil P pools.

Abstract Species of the genus Stylosanthes show great potential for use in mixed pastures and as green manure due to their symbiotic potential in symbiosis with diazotrophic bacteria, particularly Bradyrhizobium . These herbaceous legumes can improve pasture quality and contribute to sustainability. This study evaluated performance of Stylosanthes cv. Campo Grande when inoculated with Bradyrhizobium strains isolated from Oxisols in Roraima, Brazil, versus standard strains. A greenhouse experiment tested 18 new Bradyrhizobium strains isolated from soil alongside two recommended strains, including uninoculated and nitrogen‐fertilized controls. Also, two field experiments were conducted using the best‐performing greenhouse strain, the recommended strains, and absolute control and nitrogen fertilization (30 kg ha − 1 of N). Variables measured included nodule number and dry nodule mass, root and shoot biomass, and total nitrogen in shoot biomass. The proportion of nitrogen derived from biological nitrogen fixation (percentage of N derived from the atmosphere) was estimated by the 1 5 N natural abundance method, with Urochloa brizantha as the reference plant. In the greenhouse, strains ERR 917, ERR 922, ERR 942, ERR 1110, and ERR 1173 present great nodulation and dry matter production, identifying ERR 917 as optimal for field testing. Inoculation significantly increased both shoot and root biomass of cv. Campo Grande. Standard strain BR 446 T and ERR 917 enabled plants to obtain 38%–44% of their total nitrogen from biological nitrogen fixation, with inoculated plants accumulating about twice as much nitrogen and biomass versus the uninoculated control (averaging 1900 and 3900 kg ha − 1 of dry biomass for control and inoculated treatments, respectively).

Annual crop yield losses due to plant diseases and weeds can be substantial. In the northern Great Plains, Bromus tectorum (L.) (also known as cheatgrass or downy brome) and Fusarium pseudograminearum (causing crown rot) form a multi-trophic pest complex threatening wheat production sustainability. This study assessed the impact of these pests on the wheat rhizosphere bacterial community. Field trials were conducted over four site-years in plots inoculated with F. pseudograminearum using a randomized split-plot design with two seeding and nitrogen fertilizer rates and B. tectorum presence/absence. A seed fungicide treatment was also used to evaluate its effect on F. pseudograminearum abundance. Rhizosphere bacterial communities were analyzed using full-length 16S rRNA sequencing on the Oxford Nanopore platform, followed by diversity analysis, structural equation modeling (SEM), and co-occurrence network analysis. Alpha and beta diversity were significantly different between location-years. The SEM results showed a negative relationship (β = -0.180, p = 0.002) between F. pseudograminearum presence and rhizosphere bacterial community alpha and beta diversity. Effects of B. tectorum presence, seeding rate, nitrogen fertilizer, and fungicide treatment were not significant. Correlation analysis identified specific bacterial taxa responsive to F. pseudograminearum presence, including putatively beneficial species belonging to the genera Massilia, Bacillus, and Neobacillus, which were positively correlated with pathogen presence, suggesting a stress response mechanism. Network analysis revealed that F. pseudograminearum presence reduced network cohesion, and connectivity measures compared to treatments with lower pathogen load. These findings demonstrate that fungal pathogen presence can impact rhizosphere bacterial networks even when overall diversity metrics show minimal changes, highlighting the importance of network-based approaches in understanding plant-microbe-pathogen interactions in agricultural systems.

Abstract In this study, we investigated the characteristics of ammonium nitrogen and nitrate nitrogen in soil and groundwater under different nitrogen application rates through a field experiment in a maize-growing area in Northwest China. The experiment set four nitrogen application rates: CK (0 kg · hm − 2 ), F1 (100 kg · hm − 2 ), F2 (200 kg · hm − 2 ), and F3 (300 kg · hm − 2 ). The results showed that nitrogen application significantly increased the nitrogen concentration in soil and groundwater, and the high nitrogen application treatment (F3) showed a stronger effect at most growth stages. The results showed that nitrogen application significantly increased the nitrogen concentration in soil and groundwater, and the high nitrogen application treatment (F3) showed a stronger effect at most fertility periods. 0–40 cm shallow soil nitrogen was strongly affected by nitrogen application and fertility period, while 60–80 cm deep soil content was lower and stable. Correlation analysis revealed the synergistic effects of environmental factors on nitrogen transformation. Soil water content was positively correlated with ammonium nitrogen and negatively correlated with nitrate nitrogen. The ammonium nitrogen of groundwater was negatively correlated with nitrate nitrogen, and nitrate nitrogen was positively correlated with dissolved oxygen (DO) and oxidation reduction potential (ORP). Ammonium nitrogen of soil and groundwater showed positive correlation, nitrate nitrogen of soil and groundwater showed positive correlation, and soil water content and ORP of groundwater showed negative correlation. This study reveals the dynamic influence mechanism of nitrogen application on soil and groundwater nitrogen, which provides a theoretical basis for optimizing nitrogen fertilizer management and preventing and controlling groundwater nitrogen pollution. It has important scientific significance for the study of agricultural nitrogen fertilizer management and groundwater environmental protection in arid areas.

Nitrogen and sulphur are among the most important plant nutrients (along with C, H, and O) and the main elements comprising the organic substance of plants. In this study, it is assumed that light soils (Cambisols) do not naturally meet the nitrogen and sulphur needs of spring wheat and, consequently, impact the phosphorus and silicon content in the plant biomass. Therefore, to determine the effect of N and S on the content and uptake of these elements at specific growth stages (BBCH 30–31: in leaves, BBCH 55–59: in whole plants, BBCH 89–90: in grain and straw), a three-year field experiment was conducted using different doses of nitrogen (0, 40, 80, and 120 kg ha−1) and sulphur (0, 50 kg ha−1). The results show that fertilisation with N and S had a significant effect on increasing the content and uptake of P and Si by phytomass in the phenostages studied. In general, as the N fertilisation dose increased, the yields of phytomass and grain increased. A beneficial effect of S on increases in green weight, straw, and spring wheat grain was found. A significant effect of N and S fertilisation on the growth of the Si:P ratio in individual parts of plants in the studied stages was also observed. A significant positive correlation between P and Si content was proven, indicating that the two elements do not act antagonistically towards each other. In contrast, a negative correlation was observed between the P content in plants and their Si uptake. Si is taken up more strongly by plants under conditions of N and S fertilisation, as evidenced by the increase in the Si:P ratio and the fact that plants accumulated on average 3.5 times more Si than P. The highest Si content was found in the green parts of plants in the BBCH 30–31 and BBCH 55–59 stages, while in BBCH 89–92, straw had nearly half that amount and grain contained a thousand times less silicon.