Search Results (121)

Nitrogen (N) fertilizer management in winter wheat production faces challenges from volatilization losses and sub-optimal application strategies. This is particularly problematic in the Southern Great Plains, where environmental conditions during top-dressing periods favor N losses. This study evaluated the effects of a fertilizer placement method, enhanced-efficiency fertilizers, and application timing on grain yield and protein concentration (GPC) across six site-years in Oklahoma (2016–2018). Treatments included broadcast applications of untreated urea and SuperU^® (urease/nitrification inhibitor-treated urea). These were compared with subsurface placement using single-disc and double-disc drilling systems, applied at 67 kg N ha⁻¹ during January, February, or March. Subsurface placement increased the grain yield by 324–391 kg ha⁻¹ compared to broadcast applications at sites with favorable soil conditions. However, responses varied significantly across environments. Enhanced-efficiency fertilizers showed limited advantages over untreated urea. Benefits were most pronounced during February applications under conditions favoring volatilization losses. Application timing effects were more consistent for GPC than for the yield. Later applications (February–March) increased GPC by 0.8–1.2% compared to January applications. Treatment efficacy was strongly influenced by soil pH, equipment performance, and post-application environmental conditions. This indicates that N management benefits are highly site-specific. These findings demonstrate that subsurface placement can improve nitrogen use efficiency (NUE) under appropriate conditions. However, success depends on matching application strategies to local soil and environmental factors rather than adopting universal recommendations. Full article

Choosing appropriate tillage methods and nitrogen application are important steps in the management of wheat production for obtaining high-yield and high-quality products, as well as managing the level of weed infestation. The aim of this research was to examine the impacts of three different tillage practices (conventional tillage—CT, mulch tillage—MT, and no tillage—NT), and two top dressing fertilization nitrogen levels (rational—60 kg ha⁻¹ and high—120 kg ha⁻¹) on the grain yield and quality of winter wheat, as well as on weed infestation. The present study was carried out in field experiments on chernozem luvic type soil at the Faculty of Agriculture Belgrade-Zemun Experimental field trial “Radmilovac”, in the growing seasons of 2020/2021–2022/2023. The C/N ratio in the soil was also assessed on all plots. The results showed that the number of weeds and their fresh and air-dry weights were higher on the MT and NT plots, compared to the CT plots. Therefore, the CT system has better effects on the yield (5.91 and 5.36 t ha⁻¹) and the protein content (13.3 and 13.1%). Furthermore, the grain weight per spike and the 1000-grain weight were higher in the wheat from the CT system (41.83 and 42.75 g) than from the MT (40.34 and 41.49 g) and NT (40.26 and 41.08 g) systems. Also, the crops from the CT system had higher values of grain density and grain uniformity compared to the crop from the MT and NT systems. Fertilization with a high nitrogen level (120 kg ha⁻¹) causes higher grain yield and more weediness compared with the rational level (60 kg ha⁻¹). Top dressing fertilization in each tillage system resulted in an increase in the number of weeds, but, at the same time, it also resulted in stronger competitive ability of the wheat crop against weeds. The most favorable C/N ratio occurred on the NT plots, and the least beneficial one on the CT ones. A correlation analysis showed strong negative correlations of number (r = −0.82) and fresh weed mass (r = −0.72) with yield. It is concluded that the conventional tillage practice with a low nitrogen dose manifests its superior performance in minimizing weed infestation and maximizing crop productivity. Full article

With the increase in prices of correctives and fertilizers, the investigation of the interactions between plants and plant growth-promoting bacteria shows an economically viable and sustainable alternative, and the use of Azospirillum brasilense has shown an increase in efficiency of nitrogen use and increased pasture yield. This study, conducted in the Brazilian Amazon, aimed to evaluate the effect of different inoculation techniques of Azospirillum brasilense associated with the dose of nitrogen topdressing on the productive performance of Brachiaria brizantha cv. Paiaguás is a grass species commonly cultivated in this region. The experiment was conducted in the Experimental Forage Sector of the Federal Rural University of the Amazon, Parauapebas city, Brazil. The experimental design was a randomized block design in a 3 × 3 factorial arrangement, with three inoculation methods (control, seed, and foliar) and three nitrogen fertilization doses (0, 75, and 150 kg ha⁻¹ of N), with four replicates. An effect was observed in interaction between inoculation and nitrogen fertilization (p ≤ 0.05) for the variables total forage green mass, total forage dry mass, dry mass of leaf blade, dry stem mass, and number of tillers m⁻². The dose of 150 kg ha⁻¹ of N promoted a positive effect of N on the total forage dry mass and LAI (leaf area index). Inoculation with Azospirillum brasilense, especially foliar application, efficiently increased Brachiaria brizantha cv. Paiaguás yield, potentially reducing the use of nitrogen fertilizers, promotes greater sustainability in pasture management. Full article

The critical nitrogen dilution curve (CNDC) model enables precise nitrogen management by quantifying the threshold of nitrogen deficiency in crops, thereby enhancing both crop productivity and nitrogen use efficiency. However, its applicability to perennial crops remains unclear. In this study, alfalfa (Medicago sativa L.), a perennial leguminous forage, was used as the model crop. Based on two years of field experiments, CNDC models of aboveground biomass were constructed under two nitrogen fertilizer regimes: urea (0, 80, 160, and 240 kg·ha⁻¹, applied in a 6:2:2 basal-to-topdressing ratio) and controlled-release urea (CRU; 0, 80, 160, and 240 kg·ha⁻¹, applied as a single basal dose). Using these models, the nitrogen nutrition index (NNI) and cumulative nitrogen deficit (N_and) models were developed to diagnose alfalfa nitrogen status, and the optimal nitrogen application rates were determined via regression analysis. The results showed that critical nitrogen concentration and aboveground biomass followed a power function relationship under both fertilizer types. For CRU treatments, parameters a and b were 3.41 and 0.20 (first cut), 3.15 and 0.12 (second cut), and 2.24 and 0.40 (third cut), respectively. For urea treatments, a and b were 3.13 and 0.35 (first cut), 2.21 and 0.16 (second cut), and 1.75 and 0.73 (third cut). The normalized root mean square error (n-RMSE) of the models ranged from 3.1% to 13%, indicating high model reliability. Based on the NNI, N_and, and yield response models, the optimal nitrogen application rates were 175.44~181.71 kg·ha⁻¹ for urea and 145.63~153.46 kg·ha⁻¹ for CRU, corresponding to theoretical maximum yields of 14.76~17.40 t·ha⁻¹ and 16.76~20.66 t·ha⁻¹, respectively. Compared to urea, CRU reduced nitrogen input by 18.41~20.47% while achieving equivalent or higher theoretical yields. This study provides a scientific basis for nitrogen status diagnosis and precision nitrogen application in alfalfa cultivation. Full article

The increased frequency of extreme heat stress events due to climate change is adversely impacting rice yield. Nitrogen (N) is an essential element in the synthesis of chlorophyll in rice, contributing substantially to the achievement of spikelet fertility and addressing the high yields. Two experiments were conducted in Japan and Afghanistan in 2020 and 2022, respectively, utilizing IR64 and Nipponbare (NPB) varieties to elucidate the efficacy of N top-dressing on spikelet fertility and yield of rice under heat stress conditions. In experiment I, the treatments involved were based on N application before panicle emergence in pots, including (1) control (fertilized at the tillering stage), (2) control + N topdressing, (3) heat stress (fertilized at the tillering stage), and (4) heat stress + N topdressing. Experiment II consisted of (1) control (basal dressing at the tillering stage) and (2) control + N topdressing, which was conducted under field conditions. Results showed that N application significantly (p < 0.05) increased SPAD values and spikelet fertility rates in both experiments. A positive correlation (range; r = 0.83–0.98) was observed between enhanced SPAD values and spikelet fertility rates in IR64 and NPB rice varieties under both ambient and heat stress conditions. Moreover, there were notable increases in photosynthetic rate (7.4% to 52.6%) and leaf transpiration. N top dressing significantly (p < 0.05) increased the panicle length, panicle weight, number of secondary branches/panicle, filled grain/panicle, total spikelets/panicle, and yield/plant. However, there was no significant difference in the number of primary branches per panicle and 1000-grain weight. In addition, the number of unfilled grains/panicle decreased from 5.5 to 49.7% with N top dressing in both experiments. Applying N as a top dressing improved the spikelet fertility percentage and other yield components, resulting in a high yield/plant. Full article

Applying a top dressing of nitrogen fertilizer before harvesting spring tea is vital for producing high-quality spring tea. However, the interaction between the sprouting phenological characteristics of various cultivars and the timing of top dressing remains unclear. A field trial was conducted to investigate such interaction. Urea enriched with ¹⁵N was applied to soil of the early-sprouting cultivar Jia-ming-1 (JM1) and the late-sprouting cultivar Tie-guan-yin (TGY) on 29 January (early application, EApp) or 10 March (late application, LApp), respectively. The bud density and yield of young spring shoots were significantly decreased in LApp compared to EApp. Such differences were more remarkable in the early-sprouting cultivar (JM1) than in the late-sprouting cultivar (TGY). The N_dff (N derived from ¹⁵N-enriched urea) in mature leaves and young spring shoots as well as the amount of ¹⁵N in young spring shoots were all higher in EApp than in LApp. N_dff in both mature leaves (R² = 0.99, p < 0.001) and young spring shoots (R² = 0.61–0.89, p < 0.01) could be well predicted by the growing degree days of the duration between the N fertilization and sampling. N_dff and ¹⁵N concentrations in mature leaves were significantly correlated with the content of nitrate and the ratio of ammonium to total inorganic nitrogen. Partial least squares path modeling revealed that thermal condition directly affected soil N supply and soil pH and thereby affected N_dff in mature leaves and young spring shoots. Our findings highlight the importance of early pre-spring topdressing of N fertilizer to improve the yield and N use efficiency of spring tea in both early- and late-sprouting tea cultivars. The work identified a synergistic effect of N uptake by tea plants, N transformation, and soil pH related to the thermo-conditions of early and late N topdressing. Full article

The precision estimation of N fertilizer application according to the nitrogen nutrition index (NNI) using unmanned aerial vehicle (UAV) multi-spectral measurements remains to be tested in different rice cultivars and planting areas. Therefore, two field experiments were conducted using varied N rates (0, 60, 120, 160, and 200 kg N ha⁻¹) on two rice cultivars, Yunjing37 (YJ-37, Oryza sativa subsp. Japonica Kato., the Institute of Food Crops at the Yunnan Academy of Agricultural Sciences, Kunming, China) and Jiyou6135 (JY-6135, Oryza sativa subsp. indica Kato., Hunan Longping Gaoke Nongping seed industry Co., Ltd., Changsha, China), in southwest China. The rice canopy spectral images were measured by the UAV’s multi-spectral remote sensing at three growing stages. The NNI was calculated based on the critical N (Nc) dilution curve. A random forest model integrating multi-vegetation indices established the NNI inversion, facilitating precise N topdressing through a linear platform of NNI-Relative Yield and the remote sensing NNI-based N balance approaches. The Nc dilution curve calibrated with aboveground dry matter demonstrated the highest accuracy (R² = 0.93, 0.97 for shoot components in cultivars YJ-37 and JY-6135), outperforming stem (R² = 0.70, 0.76) and leaf (R² = 0.80, 0.89) based models. The RF combined with six vegetation index combinations was found to be the best predictor of NNI at each growing period (YJ-37: R² is 0.70–0.97, RMSE is 0.02~0.04; JY-6135: R² is 0.71–0.92, RMSE is 0.04~0.05). The RF surpassed BPNN/PLSR by 6.14–10.10% in R² and 13.71–33.65% in error reduction across the critical rice growth stages. The topdressing amounts of YJ-37 and JY-6135 were 111–124 kg ha⁻¹ and 80–133 kg ha⁻¹, with low errors of 2.50~8.73 kg ha⁻¹ for YJ-37 and 2.52~5.53 kg ha⁻¹ for JY-6135 in the jointing (JT) and heading (HD) stages. These results are promising for the precise topdressing of rice using a remote sensing NNI-based N balance method. The combination of UAV multi-spectral imaging with the NNI-nitrogen balance method was tested for the first time in southwest China, demonstrating its feasibility and offering a regional approach for precise rice topdressing. Full article

Previous research on soil bacteria focused on refining the nitrogen (N) rates during the wheat (Triticum aestivum L.) growth cycle. Studies concerning how additional and split N topdressing applications can affect wheat rhizobacteria are limited. To address this, a two-year field experiment took the cultivar ‘Gaoyou 2018’ of winter wheat as the experimental material from October 2020 to June 2022. Six nitrogen application regimes were established, including no nitrogen application (T1), single topdressing applications of 120 kg ha⁻¹ (T2) and 80 kg ha⁻¹ (T3) at the jointing stage, and split topdressing applications combining 80 kg ha⁻¹ at jointing with 40 kg ha⁻¹ at the booting stage (T4), the flowering stage (T5), and 10th day post-anthesis (T6). The delayed impacts of the split topdressing time on the rhizobacteria diversity were observed in the second year, with T4 exhibiting a 10.5% higher Chao1 index and 2% greater Shannon diversity than T6. Results from both years indicated that the dominant bacterial phylum compositions in the winter wheat rhizosphere were similar across the nitrogen treatments. The additional N treatments fostered 22.9–27.9% Bacteroidita abundance but diminished 24.0–35.9% Planctomycetota, compared to the thenon-fertilized control (T1). T6 increased the α-Proteobacteria abundance by 15.7–22.0% versus T4, while the N topdressing redistribution to the booting stage increased the MND1 genus abundance in Proteobacteria by 31.3–62.5% compared to T2. Redundancy analysis identified that the rhizosphere pH and soil moisture content were the predominant environmental drivers shaping the winter wheat rhizobacteria. Preliminary findings revealed that split nitrogen application during the jointing and booting stages of winter wheat improved the edaphic micro-environment and modulated the proliferation of beneficial rhizobacteria. However, this change was not transmitted to the yield variation. These results suggest that short-term N management strategies may enhance ecological benefits by intensifying soil–plant–microbe interactions, yet they lack direct agronomic yield advantages. Long-term trials are required to establish causality between rhizosphere microbial community dynamics and crop productivity under split N management regimes. Full article

This study developed a nitrogen management framework that simultaneously addresses photosynthetic limitations and water scarcity challenges, providing a scalable solution for sustainable wheat production in arid farming systems. Focusing on Xinjiang’s arid region, we investigated how different ratios of basal to topdressed nitrogen fertilization affect photosynthetic mechanisms in drip-irrigated spring wheat. We implemented a split-plot design during the 2020–2021 growing seasons, using two wheat cultivars as main plots: strong-gluten Xinchun 37 (XC37) and medium-gluten Xinchun 6 (XC6). The subplots consisted of five N application treatments: N00: (no nitrogen application, control), N28 (base fertilizer 20%, top dressing 80%, and so on), N37 (3:7), N46 (4:6), and N55 (5:5). The vast majority of indicators performed best under N37 treatment. And LAI, RuBPC (ribulose-1,5-diphosphate ribulose carboxylase) activity, net photosynthetic rate (P_n), yield, and its composition were higher than the rest of the treatments by 0.21~31.75%, 6.94~25.21%, 7.42~40.78%, 0.86~25.44%, and 0.44~12.02%. And intercellular CO₂, concentration (C_i) was lower than other treatments by 7.63~50.60%. Yield showed q highly significant positive correlation with P_n, G_s, T_r, Φ_PSⅡ, and chlorophyll fluorescence parameters, but a negative correlation with C_i. Stepwise regression analysis showed that LAI, P_n, C_i, and RuBPC activity had a significant impact on yield and its compositions. In addition, all index performances of XC37 were better than XC6. Under drip irrigation in arid zones, allocating 30% basal + 70% topdressed N optimally enhances photosynthetic capacity and yield formation in spring wheat, offering a practical pathway for sustainable intensification in water-limited agroecosystems. Full article

The observation time and water background can affect the remote sensing estimates of the nitrogen (N) content in rice crops. This makes the use of vegetation indices (VIs) for N status monitoring and topdressing recommendations challenging, as the timing of panicle initiation and the water level in bays usually differ between farms even when managed using the same irrigation technique. This study aimed to investigate the influence of standing water levels (from 0 to 20 cm) and the time of image acquisition on a set of N-sensitive VIs to identify those less affected by these factors. The experiment was conducted using a split-plot experimental design with two side-by-side bays (main plots) where rice was grown ponded for most of the growing season and aerobically (not permanently ponded), each with four fertilization N rates. The SCCCI and SCCCI² were the only indices that did not vary depending on the time of the day when the multispectral images were collected. These indices showed the lowest variation among water layer treatments (5%), while the Clg index showed the highest (20%). All VIs were significantly correlated with N uptake (average R² = 0.73). However, the SCCCI² was the index that showed the lowest variation in N-uptake estimates resulting in equal N-fertilizer recommendations across water level treatments. The consistent performance of SCCCI² across different water levels makes this index of interest for different irrigation strategies, including aerobic management, which is gaining increasing attention to improve the sustainability of the rice industry. Full article

Nitrogen fertilization greatly affects the development of sugar beet leaf and photosynthetic activity. This study aimed to evaluate the dynamics of leaf SPAD index, chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids (Caro), and the macronutrient status (N, P, K, Na, Mg) in different N fertilization rates in sugar beet production. This study set up a two-year field experiment in Eastern Croatia. The N fertilization rate was applied as: N0—control, N1—only presowing fertilization (45 kg/ha), and N2—presowing with topdressing (99 kg/ha in 2014 and 85.5 kg/ha in 2015). In general, N fertilization has a significant (p ≤ 0.05) influence on leaf pigments, except for Chl b. With the highest N dose (N2), the Chl content in the leaves increased by 12% compared to the control treatment (0.75 mg/g FW). The Caro dynamics in the leaves of vegetative growth were significantly different (p ≤ 0.05); leaves in the younger growth stage at the end of May had the highest Caro content (0.011 mg/g FW). In general, the SPAD index was significantly different (p ≤ 0.05), among N fertilization, whereas the lowest SPAD was found at the control treatment (38.7) and the highest at the N2 treatment (40.8). In general, regarding nitrogen fertilization, the lowest SPAD readings had sugar beet leaves at the control treatment (38.7), whereas the highest was determined at the N2 treatment (40.8). A strong positive relationship (p ≤ 0.01) was determined for Chl a, Chl b, Chl a + b, and Chl a + b/Caro with the SPAD index, whereas an inverse relationship with the SPAD index was determined for Caro and Chl a/b. The results demonstrate that nitrogen application, particularly at higher rates, positively influences chlorophyll and carotenoid content, as well as overall plant health, which can inform agricultural practices for more sustainable and efficient sugar beet cultivation. Full article

Several countries around the world are facing the issue of freshwater availability, where agriculture is highly dependent on irrigation, consuming 70% of this vital resource. Water availability is the most limiting factor for the crop production sector and one of the main regulators of the spatial distribution of plants. It is noted that in recent years, the methods of irrigation water application have been improved. Currently, research is directed towards irrigation strategies that reduce water applications. A partial root drying (PRD) technique involves irrigating one-half of the root zone while leaving the other half in relatively dry soil. This method is used in the production of various crops, such as potatoes and cotton. However, the mechanism of PRD, including the physiological and molecular biological processes involved, is not fully understood. In this study, tomato plants were treated with PRD and nitrogen (N) top-dressing. The results showed that PRD could significantly increase the fruit yield, photosynthetic activities, nitrate reductase activity, and fruit quality in the tomato plants, and PRD could also promote the concentrations of oxygen species (O₂⁻), malondialdehyde (MDA) and proline contents, and activities of antioxidant enzymes. In addition, PRD could enhance stress resistance by increasing disease resistance and NP1 and DRED3 antioxidant enzyme activity. Tomato plants treated with PRD compared to the control showed high photosynthetic activity, high yield, better quality of production, and low leaf blight incidence. Overall, the results indicate that PRD is a feasible approach that could be effectively utilized in tomato fields to improve plant growth and production compared with the control. Full article

The imbalanced use of fertilizers, particularly the inefficient application of nitrogen (N), has led to reduced nitrogen use efficiency (NUE), lowered crop yields and increased N losses in Nepal. This study aimed to enhance yields, NUE and farm profitability by optimizing N fertilizer rates, application timing and methods through multilocation trials and demonstrations. In 2017, 57 field trials were conducted in two mid-hill districts using a completely randomized block design. The treatments included control (CK), NPK omission (N0, P0 and K0), variable N rates (60, 120, 180 and 210 kg N ha⁻¹) and top-dressing timings (120 kg N ha⁻¹ applied at knee height and shoulder height, V6, V10 and V8 stages). A full dose of recommended P (60 kg ha⁻¹) and K (40 kg ha⁻¹) were applied at planting, while N was top-dressed in two equal splits at knee-height and shoulder-height growth stages for P and K omission treatments, as well as for treatment with variable N rates. Grain yields responded quadratically, with optimum N rates ranging from 120 to 180 kg ha⁻¹ across the districts. N applied at 120 kg ha⁻¹ and top-dressed at V6 and V10 increased maize yield by 20–25%, partial factor productivity of nitrogen (PFPN) by 12%, agronomic efficiency of nitrogen (AEN) by 21% and gross margin by 10% compared to conventional knee and shoulder height application. In 2018 and 2019, fertilizer BMPs, including V6 and V10 top-dressing and the urea briquette deep placement (UDP) were demonstrated on 102 farmers’ fields across five mid-hill districts to compare their agronomic and economic significance over traditional farmers’ practice (FP). UDP, validated in 2018 field trials, increased yields by 34% (8.8 t ha⁻¹) and urea top-dressing at V6 and V10 increased yield by 33% (8.7 t ha⁻¹) compared to FP (5.8 t ha⁻¹), reducing the average yield gap by 3.0 t ha⁻¹. Moreover, the gross margin was increased by 39% (V6 and V10) and 40% (UDP) over FP. The findings highlight the need for widespread adoption of fertilizer BMPs to close the yield gap and maximize profitability with minimal nitrogen footprint. Full article

The Jianghuai region in China is well known for its high-quality and high-yielding maize production, but there is inadequate analysis about the N management in this region (especially the topdressing ratio). To evaluate the suitable topdressing ratio for maize nitrogen application, the effects of different nitrogen topdressing ratios on soil nitrogen and summer maize growth were studied in 2022–2023. In each treatment, a total of 250 kg N/hm² was applied, i.e., 50 kg N/hm² was applied as the base fertilizer, and the rest of the nitrogen fertilizer (200 kg N/hm²) was applied at the jointing and filling stages at different ratios, including 3:7 (60 and 140 kg N/hm² were applied at the jointing and filling stages, respectively, T1 treatment), 7:3 (T2 treatment), and 1:1 (CK treatment). Compound fertilizer (N:P:K = 18%:12%:5%) was used as the base fertilizer, and urea was used as the topdressing fertilizer. The results showed that in 2022 (dry year), compared with values in the T1 treatment, the nitrate-nitrogen accumulation in the 0–100 cm soil layer at maize harvest under the T2 and CK treatments decreased by 33.8% and 14.7%, respectively; compared with values in CK treatment, the T2 treatment could significantly increase the ear length of maize by 9.4%. In 2023 (wet year), compared with values in the T1 treatment, the 100-grain weight, maize yield, N partial factor productivity (NPFP), and N uptake efficiency (NUPE) of T2 treatment significantly increased by 13.4%, 17.2%, 20.1%, and 21.5%, respectively; compared with values in the CK treatment, ear length, maize yield, and NPFP of T2 treatment significantly increased by 6.15%, 14.0%, and 15.8%, respectively. Therefore, for this study, a topdressing ratio of 7:3 between the jointing and filling stages (T2 treatment) was beneficial to reduce nitrogen accumulation in dry years and increase maize yield and nitrogen partial factor productivity in wet years. Full article

Drip fertigation (DF) can improve yield, water use efficiency (WUE), and nitrogen use efficiency (NUE, grain production per unit of the sum of soil inherent mineral N and fertilizer N), as well as reduce the risk of environmental pollution compared with flood irrigation and N fertilizer broadcast (FB). Previously, we showed that DF enhanced the response of the yield to the N topdressing rate (NTR), but the underlying mechanisms associated with the soil N supply, root architecture, and N uptake remain unclear. We conducted a field experiment by testing six N treatments (no N applied, and NTRs of 0, 40, 80, 120, and 160 kg ha⁻¹, denoted as N0, T0, T40, T80, T120, and T160, respectively) under DF and FB from 2021 to 2023. Compared with FB, the NUE and WUE were 4.8–4.9% and 10.0–10.5% higher under DF. The higher NUE was due to an improvement in N uptake efficiency (6.1–7.7%) resulting from the enhanced aboveground N uptake (AGN). The greater AGN under DF was attributed to the higher soil N availability at the soil depth of 0–40 cm. DF decreased the residual soil NO₃⁻-N at a depth of 40–200 cm but increased the NO₃⁻-N at a depth of 0–40 cm. In addition, DF combined with T80 achieved high root length density, surface density, and dry weight density and improved NUE and WUE. DF combined with T80 achieved high yield and efficient utilization of water and N, and the NTR threshold was 61.75–119.50 kg ha⁻¹, in which the production conditions were similar to those of the experimental site. Our results provide a reference for high-efficiency water and N fertilizer usage for irrigated winter wheat production in North China. Full article