Excessive basal nitrogen (N) inputs and improper water management limit both wheat yields and N use efficiency. Thus, a field experiment was conducted for two years to evaluate whether optimizing water and N management could reduce basal N inputs, improve N uptake and utilization efficiencies (NUpE and NUtE), and achieve high yields. A split-plot design was employed with water and N management as the main plots (conventional water and N management, CM; and drip fertigation, DF) and basal N rates as the sub-plots (150, 125, 100, 75, 50, 25, and 0 kg ha(-1), designated as B150, B125, B100, B75, B50, B25, and B0, respectively), while maintaining a fixed topdressing N rate of 150 kg ha(-1). The results showed that DF increased the average yield by 12.7-15.9% compared with CM due to improvements in N absorption, tillering ability, ear and grain numbers, leaf area index, and biomass production. More importantly, DF reduced the sensitivity of yield to the basal N rate. Halving the basal N rate from B150 to B75 reduced the yield by 4.1-4.3% under DF (P > 0.05), but the yield loss was 10.9-11.4% under CM (P < 0.05). Under DF, the increased grain weight compensated for the reduced grains m(-2), but under CM, the 17.3-17.8% reduction in grains m(-2) was not fully offset by the increase of 8.4-9.9% in the grain weight. In addition, the increased NUpE and NUtE also contributed to relatively high yield at B75 under DF. Furthermore, the NO3--N residue under DF was 7.9-9.8% lower at B75 than at B150. In conclusion, DF combined with a reduced basal N rate is effective for increasing wheat production, while decreasing soil nitrate residual levels to mitigate environmental impacts.

To address the issue of inefficient soil water utilization in dryland wheat fields, caused by a mismatch between summer fallow precipitation and crop growth periods, implementing fallow-period tillage was crucial for conserving water and enhancing yield. However, there was a lack of comprehensive evaluations of the impact of different tillage practices on soil functional quality based on multidimensional indicators, and the relationship between yield and soil functional quality remained unclear. This study established three treatments during the summer fallow period: no tillage (FNT), subsoiling tillage (FST) and plowing tillage (FPT). We determined the soil water-stable aggregates particle size distribution and stability, aggregate organic carbon (AOC) content, soil organic carbon (SOC) content and storage (SOCs), as well as winter wheat yield. Using the Z-score method, we integrated the soil's physical and chemical indicators to perform a comprehensive evaluation of different tillage practices. The results showed that FNT significantly enhanced soil aggregate stability in the 0-30 cm soil depths compared to FST and FPT (p < 0.05), which was primarily attributed to a substantial increase in the content of >2 mm aggregates. Meanwhile, FNT resulted in significantly higher SOCs within the 0-50 cm profile, with increases of 8.1% and 5.8% compared to FST and FPT (p < 0.05), respectively. This was primarily due to elevated SOC content and higher AOC contents within the 2-0.25 mm and >2 mm aggregates in the topsoil layer. In contrast, FST significantly increased grain yield compared to FNT and FPT, by 16.7% and 15.0% (p < 0.05), respectively, which was associated with higher ear number and ear grains. A comprehensive evaluation using the Z-score method revealed that FNT achieved the highest soil functional quality score across the five layers. Therefore, no tillage during the summer fallow can enhance soil functional quality, primarily due to its positive impact on soil structure and carbon sequestration, but may not immediately increase crop yield.

Context: Green manure (GM) can potentially increase crop yields by enhancing the soil properties to solve the contradiction between soil degradation and food security. However, the effects of GM on the soil properties and crop yields in variable environments, and the relationships between them remain unclear, and the key factors need to be identified. Moreover, global prediction are lacking of the effects of GM on crop yields. Objectives and methods: Therefore, we conducted a meta-analysis using 5125 pairs of data observations to study the overall effects of GM and environmental variability on the soil properties and subsequent crop yields, and to establish their relationships by introducing the soil quality index (SQI). In addition, we used a machine learning model to predict the global changes in SQI and the yields of maize, wheat, and rice under GM. Results: GM significantly increased the soil C, N, P, and K contents, and enzyme activities by 5.34-40.02 %, 8.81-32.39 %, 4.54-10.02 %, 1.18-8.74 %, and 9.49-19.76 %, respectively, increasing SQI by 16.96 %. The fundamental physical and chemical features of soil, duration of GM application, and climatic conditions significantly affected the improvements in the soil properties under GM. The initial total nitrogen (TN) content of the soil and duration of GM application were the two main factors associated with the effect of GM on SQI. When the initial soil TN content was lower than 0.75 g kg-1 and the GM application duration exceeded 15 years, SQI increased by 26.60 % and 19.94 %, respectively. GM significantly increased SQI by enhancing the soil properties to eventually increase the crop yield by 3.48 %. GM duration was the most important factor associated with the crop yield, and GM significantly increased the crop yield by 18.72 % when the duration exceeded 15 years. However, when the application duration is less than 5 years, the increase is only 2.10 %. The global machine learning model predicted that GM can potentially increase the SQI and crop yield by 23.98 % and 6.35 %, respectively. Conclusion: Therefore, we conclude that applying GM as a green fertilization strategy can increase crop yields by enhancing SQI, and its effects on increasing yields are greater in areas with insufficient soil fertility and longterm planting. Implication: This study highlights the importance of GM for farmland production. SQI was used to establish the relationship between soil quality and crop productivity, and we predicted the potential of GM for improving the global SQI and crop yields.

Delayed sowing of winter wheat is increasingly common in the winter wheat-summer maize rotation system of northern China, yet whether its yield penalty can be mitigated without increasing seasonal water and nitrogen (N) inputs remains unclear. A three-year field experiment was conducted to test whether stage-specific drip fertigation could mitigate yield loss in winter wheat sown 20 d late without increasing total seasonal water and N inputs. Delaying sowing by 20 d under conventional management reduced grain yield by 21.0% relative to wheat sown at the conventional date (CK). The optimized regime (DF4) achieved a yield recovery rate of 100.7%. Grain number per unit area in DF4 was partly restored but remained 5.6% lower than in CK, indicating incomplete sink recovery. Yield recovery was therefore supported by post-anthesis source compensation, evidenced by a 17.0% increase in post-anthesis dry matter accumulation relative to CK and associated with higher post-anthesis N uptake and radiation use efficiency. Although root penetration depth under DF4 remained lower than in CK, root length in the 0-40 cm soil layer was restored to the CK level. DF4 also improved water use efficiency by 11.1% relative to CK while soil water consumption was only 56.4% of that in CK. These findings indicate that stagespecific timing and placement of water-N supply through drip fertigation can mitigate yield loss in winter wheat sown 20 d late by coordinating partial sink recovery with stronger post-anthesis source compensation, without increasing seasonal water or N inputs.

Green manure (GM) is promising for use in sustainable agriculture, but its impacts on nitrogen emissions from farmland and crop productivity are unclear. Thus, we conducted a meta-analysis based on 2,616 data pairs from 218 studies to clarify the effects of GM. GM enhanced soil nitrogen retention to increase the crop yield and nitrogen use efficiency (NUE) by 3.71 % and 24.41 %, respectively, and reduce ammonia (NH3) emissions by 9.09 %, but with no significant impact on nitrous oxide (N2O) emissions. GM was most effective in low-quality soil and warm, humid climates, especially legume GM. Combining GM with high nitrogen fertilizer use may further reduce NH3 emissions. Machine learning models showed that GM could increase global maize and rice yields by 9.78 % and 11.10 %, respectively, and reduce NH3 emissions from major crops by 9.92 %, but increase N2O emissions from paddy fields by 9.45 %. In general, GM can enhance crop productivity and reduce agricultural environmental costs to promote green development.

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.

The application of controlled-release urea or deep fertilization is effective for increasing crop yields. However, more research is needed to determine whether the deep placement of controlled-release and common urea can increase crop productivity and reduce environmental pollution. Between 2019 and 2021, we conducted field experiments in semi-humid and drought prone areas of the Loess Plateau region in China to study the effects of different controlled-release and common urea fertilization methods on maize productivity. Further experiments were conducted in semi-arid areas in 2022 and 2023 to verify the research results. We used the traditional fertilization strategy with common urea (TFC) as the control, deep placement of common urea (DFC), traditional fertilization with controlled-release and common urea (TFB), and deep placement with controlled-release and common urea (DFB) as optimized fertilizer management strategies. The results showed that the deep placement of controlled release and common urea changed the temporal and spatial distributions of the soil NO3--N and NH4+-N, which affected the N2O and NH3 emissions. The NH3 emissions under DFC, TFB, and DFB were lower by 29.78%, 32.77%, and 59.08% than TFC, and N2O emissions were lower by 38.21%, 40.96%, and 72.89%, respectively. Compared with TFC, the maize yields under DFC, TFB, and DFB were 7.91 %, 8.41 %, and 15.11 % higher, respectively, and the nitrogen use efficiencies were 14.23%, 15.60%, and 27.83% higher, whereas the yield-scaled N2O emissions were 38.21 %, 40.96%, and 72.89% lower, and the yield-scaled NH3 emissions were 29.78%, 32.77%, and 59.08% lower. Overall, DFB obtained the highest maize yield (12013.35 kg ha-1) and nitrogen use efficiency (47.15 %), as well as the lowest gaseous nitrogen loss intensity (1.13 g N kg-1 grain), global warming potential (323.08 kg CO2-eq ha-1), and greenhouse gas emission intensity (GHGI, 27.13 g CO2-eq kg-1 grain). Therefore, deep placement of controlled-release and common urea is an effective fertilizer management strategy that can balance maize productivity and environmental pollution in the Loess Plateau region of China.

No-tillage (NT) has been widely recognized for significantly enhancing crop yield and nitrogen (N) use efficiency in dryland agricultural systems globally. However, in irrigated fields, NT has demonstrated adverse effects on wheat yield, and limited information is available regarding its impact on N uptake and use efficiencies, and grain protein characteristics. Previous studies concluded that drip fertigation (DF) achieved superior yield gain over the conventional N fertilizer broadcasting with flood irrigation (BF) under NT compared to rotary tillage (RT) and intensive tillage (PRT; first plowing followed by rotary tillage). This study measured tissue N concentration, grain protein content and composition, dough processing quality traits, and the activities of N metabolism enzymes in flag leaves and developing grains. The objectives were to (1) evaluate the response of N use traits and grain quality to DF, and (2) elucidate the relationship between gains in yield and N uptake across varying tillage methods. Results revealed that DF significantly increased N uptake by 35.4–38.0%, 22.1–22.2%, and 16.0–16.6% over BF under NT, RT, and PRT, respectively. This boosted N uptake predominantly contributed to enhanced N use efficiency (grain production per unit of total soil mineral and fertilizer N input). Regression analysis indicated that increased N pre-anthesis uptake was the primary driver of yield improvement by DF (r2 > 0.99, P < 0.01). Furthermore, NT demonstrated superior improvements by DF in N nutrition index, grain protein content, gliadin content, wet gluten content, and water absorption rate compared to RT and PRT. In conclusion, wheat N use and grain protein under NT responded greater to DF than intensive tillage. Therefore, our findings emphasize that transitioning from conventional water and N management to DF is an effective and practical strategy for enhancing N uptake, achieving high yield, improving N use efficiency, and enriching grain protein content, particularly under NT conditions.

Closing the yield gap in smallholder farming systems requires precise identification of key limiting factors. This study addresses this need by applying boundary line analysis (BLA) to diagnose primary soil constraints to winter wheat (Triticum aestivum L.) yield across 95 smallholder farms in the Loess Plateau of China. The BLA approach effectively delineates optimum nutrient ranges amidst inherent field variability, offering a novel methodological advantage for heterogeneous agricultural landscapes. The results showed that, regarding variability, the coefficients of variation for productive spike number and grain yield were considerably greater than those for kernels per spike and thousand-kernel weight. Soil available phosphorus showed the highest coefficient of variation (67.1%), 1.8–2.2 times greater than that of soil organic matter, alkali-hydrolyzed nitrogen, and available potassium. Boundary line models identified significant (p < 0.05) parabolic relationships, defining optimal ranges of 18.5–21.7 g kg−1 for soil organic matter, 10.4–49.0 mg kg−1 for alkali-hydrolyzed nitrogen, 40.5–61.6 mg kg−1 for available phosphorus, and 218.3–284.1 mg kg−1 for available potassium. Crucially, maintaining soil organic matter and available phosphorus within their respective optimal ranges was fundamental for maximizing yield. These findings provide a scientific basis for site-specific nutrient management and offer direct implications for designing targeted agricultural extension services and fertilization policies to enhance productivity in smallholder systems.

Waxy maize (Zea mays L. ceratina) is extensively cultivated and exhibits substantial market demand in China; however, its yield and quality improvement remain constrained by relatively underdeveloped cultivation techniques. Optimizing plant density and row spacing is critical to improving the yield and nutritional quality of waxy maize, yet their combined effects remain insufficiently explored. A split-plot design evaluated two plant densities, i.e., 5.25 × 104 plants ha−1 (PD5.25) and 6.75 × 104 plants ha−1 (PD6.75), and three row configurations, i.e., 80 + 40 cm wide–narrow rows (RS8-4), 100 + 20 cm wide–narrow rows (RS10-2) and conventional 60 + 60 cm equal rows (RS6-6). This study aims to identify the optimal cultivation configuration for waxy maize in the Loess Plateau region. Results showed that the RS8-4 configuration maximized agronomic traits, dry matter accumulation, and yield relative to RS6-6 and RS10-2 treatments. Specifically, RS8-4 reduced the insertion angle of the lower ear leaf by 12.4% (p < 0.05) and ear height by 8.3% while increasing yield by 19.86–20.00% compared to RS6-6 and RS10-2 treatments. At fresh-market maturity, dry matter accumulation under RS8-4 treatment increased significantly by 34.0% with higher plant density. Under PD6.75, RS8-4 boosted dry matter by 29.8% and 39.4% versus RS6-6 and RS10-2, respectively. Under the RS8-4 and PD6.5 configurations, dry matter accumulation reached 13.56 t ha−1 and a yield of 9.94 t ha−1 was achieved in 2022. In summary, the combination of the PD6.75 density and the RS8-4 row spacing configuration achieved the optimal yield for the ‘Jinnuo 20’ cultivar in the Loess Plateau region. This approach provides a scalable planting framework for high-yield waxy maize production in the area, while demonstrating that optimized plant density and row spacing represent not only a key technical measure for enhancing productivity but also a core agronomic strategy for improving resource-use efficiency.

Waxy maize (Zea mays L. sinensis kulesh) contains a lot of nutrients, and has a long history of cultivation and extensive consumption. In this study, six waxy maize varieties of white (J18 and W2000), yellow (J41 and J7), and black (J10 and J20) were selected as experimental materials, and the functional nutrients and the differences in anthocyanin anabolic pathways in maize kernels at 14, 18, 22, and 26 days after pollination were determined. The result show that the varieties and kernel development stages had significant effect on the carotenoid, soluble sugar, vitamin C, anthocyanin, and mineral element content. The black waxy maize varieties had a higher anthocyanin content, which plays an important role in maize kernel coloration, whereas the yellow and black waxy maize varieties exhibit a greater abundance of mineral elements. Furthermore, the phenylalanine content, as well as the activities of phenylalanine ammonia lyase (PAL), chalcone isomerase (CHI), dihydroflavonol reductase (DFR), and flavonoid 3-glucosyltransferase (UFGT), played a significant role in the anthocyanin biosynthetic pathway. In conclusion, the comprehensive functional quality of waxy maize decreased with the delay of kernel development stage, and the black waxy maize varieties demonstrated superior functional quality. The PAL and CHI played a primary role in the initial phase of anthocyanin accumulation, while UFGT gradually assumed control in the subsequent stages.

Effective agricultural management in maize production operations starts with the early quantification of seedlings. Accurately determining plant presence allows growers to optimize planting density, allocate resources, and detect potential growth issues early on. This study provides a comprehensive analysis of the performance of various object detection models in maize production, with a focus on the effects of planting density, growth stages, and flight altitudes. The findings of this study demonstrate that one-stage models, particularly YOLOv8n and YOLOv5n, demonstrated superior performance with AP50 scores of 0.976 and 0.951, respectively, outperforming two-stage models in terms of resource efficiency and seedling quantification accuracy. YOLOv8n, along with Deformable DETR, Faster R-CNN, and YOLOv3-tiny, were identified for further examination based on their performance metrics and architectural features. The study also highlights the significant impact of plant density and growth stage on detection accuracy. Increased planting density and advanced growth stages (particularly V6) were associated with decreased model accuracy due to increased leaf overlap and image complexity. The V2–V3 growth stages were identified as the optimal periods for detection. Additionally, flight altitude negatively affected image resolution and detection accuracy, with higher altitudes leading to poorer performance. In field applications, YOLOv8n proved highly effective, maintaining robust performance across different agricultural settings and consistently achieving rRMSEs below 1.64% in high-yield fields. The model also demonstrated high reliability, with Recall, Precision, and F1 scores exceeding 99.00%, affirming its suitability for practical agricultural use. These findings suggest that UAV-based image collection systems employing models like YOLOv8n can significantly enhance the accuracy and efficiency of seedling detection in maize production. The research elucidates the critical factors that impact the accuracy of deep learning detection models in the context of corn seedling detection and selects a model suited for this specific task in practical agricultural production. These findings offer valuable insights into the application of object detection technology and lay a foundation for the future development of precision agriculture, particularly in optimizing deep learning models for varying environmental conditions that affect corn seedling detection.

The optimized winter wheat sowing method comprising wide-belt sowing (WBS) can improve the ears number and biomass to increase the grain yield, compared with conventional narrow-drill sowing (NDS). The seed rate and the interaction between the sowing method and seed rate also affect yield formation. However, the effects of the sowing method and seed rate, as well as their interaction on biomass production, particularly the interception of solar radiation (ISR) and radiation use efficiency (RUE), are unclear. A field experiment was conducted for two seasons in southern Shanxi province, China, using a split-plot design with sowing method as the main plot (WBS and NDS) and seed rate as the sub-plot (100–700 m−2). Our results showed that while WBS had a significant and positive effect, increasing the yield by 4.7–15.4%, the mechanism differed between seed rates. Yield increase by WBS was mainly attributed to the increase in total biomass resulting from both the promoted pre- and post-anthesis biomass production, except that only the increase in post-anthesis biomass mattered at the lowest seed rate (100 m−2). The higher biomass was attributed to the increased ISR before anthesis. After anthesis, the increased ISR contributed mainly to the increased biomass at low seed rates (100 and 200 m−2). In contrast, the increased RUE, resulting from the enhanced radiation distribution within canopy and LAI, contributed to the higher post-anthesis biomass at medium and high seed rates (400 to 700 m−2). The greatest increases in total biomass, pre-anthesis ISR, and post-anthesis RUE by WBS were all achieved at 500 seed m−2, thereby obtaining the highest yield. In summary, WBS enhanced grain yield by increasing ISR before anthesis and improving RUE after anthesis, and adopting relatively higher seed rates (400–500 m−2) was necessary for maximizing the positive effect of WBS, and thus the higher wheat yield.

IntroductionNitrogen (N) plays a pivotal role in the growth, development, and yield of maize. An optimal N application rate is crucial for enhancing N and carbohydrate (C) accumulation in waxy maize grains, which in turn synergistically improves grain weight.MethodsA 2-year field experiment was conducted to evaluate the impact of different N application rates on two waxy maize varieties, Jinnuo20 (JN20) and Jindannuo41 (JDN41), during various grain filling stages. The applied N rates were 0 (N0), 120 (N1), 240 (N2), and 360 (N3) kg N ha-1.ResultsThe study revealed that N application significantly influenced nitrogen accumulation, protein components (gliadin, albumin, globulin, and glutelin), carbohydrate contents (soluble sugars, amylose, and amylopectin), and activities of enzymes related to N and C metabolism in waxy maize grains. Notable varietal differences in these parameters were observed. In both varieties, the N2 treatment consistently resulted in the highest values for almost all measured traits compared to the other N treatments. Specifically, the N2 treatment yielded an average increase in grain dry matter of 21.78% for JN20 and 17.11% for JDN41 compared to N0. The application of N positively influenced the activities of enzymes involved in C and N metabolism, enhancing the biosynthesis of grain protein, amylose, and amylopectin while decreasing the accumulation of soluble sugars. This modulation of the C/N ratio in the grains directly contributed to an increase in grain dry weight.ConclusionCollectively, our findings underscore the critical role of N in regulating kernel N and C metabolism, thereby influencing dry matter accumulation in waxy maize grains during the grain filling stage.

Context or problem: There is an urgent need to address the contradiction between food security and climate change, and achieve the highest crop productivity at the lowest environmental cost. Scientific fertilization is the key to solving this problem. Objective or research question: Deep placement of fertilizer (DPF) is an effective fertilization strategy for improving crop productivity and reducing gaseous N losses, but its effectiveness varies among agricultural systems and appropriate fertilization depths have not yet been determined. Methods: In this study, we synthesized 99 global studies (120 locations) and conducted a three-year field experiment to evaluate the effects of DPF on the crop yield, nitrogen use efficiency (NUE), and nitrous oxide (N2O), and ammonia (NH3) emissions, and explored their responses to different climates, field management practices, and environmental factors. Results: DPF could increase the grain yield by 13.5%, and NUE by 33.8%, and reduce N2O emission by 16.2%, and NH3 emissions by 86.6%, respectively. Random forest analysis showed that the fertilization depth and nitrogen application rate were the most important factors that determined the impacts of DPF on the crop yield, NUE, and N2O and NH3 emissions, but their effects also depended on the climate conditions, field management practices, and soil environmental factors. Meta-regression modeling showed that the effects of DPF on the crop yield and NUE increased but then decreased as the fertilizer application depth and nitrogen application rate increased, and the effects on N2O and NH3 emissions tended to increase gradually. The meta-analysis also demonstrated that under DPF, the emission factors for N2O and NH3 decreased by 35.8% and 84.5%, respectively. According to the meta-analysis, the global N2O and NH3 emissions under DPF can be reduced by 0.23 and 5.46 Tg N & sdot;year-1 respectively. Conclusions: The results obtained based on global meta-analysis and a three-year experiment demonstrated that DPF obtained higher grain production with lower environmental costs, and the most suitable fertilization depth was identified as 15-25 cm. Implications or significance: The results obtained in this study provide valuable insights into food security and environmental costs under effective fertilization management.

Waxy corn is a special type of maize primarily consumed as a fresh vegetable by humans. Nitrogen (N) plays an essential role in regulating the growth progression, maturation, yield, and quality of waxy maize. A reasonable N application rate is vital for boosting the accumulation of both N and carbon (C) in the grains, thereby synergistically enhancing the grain quality. However, the impact of varying N levels on the dynamic changes in N metabolism, carbohydrate formation, and anthocyanin synthesis in purple waxy corn kernels, as well as the regulatory relationships among these processes, remains unclear. To explore the effects of varying N application rates on the N metabolism, carbohydrate formation, and anthocyanin synthesis in kernels during grain filling, a two-year field experiment was carried out using the purple waxy maize variety Jinnuo20 (JN20). This study examined the different N levels, specifically 0 (N0), 120 (N1), 240 (N2), and 360 (N3) kg N ha−1. The results of the analysis revealed that, for nearly all traits measured, the N application rate of N2 was the most suitable. Compared to the N0 treatment, the accumulation and content of anthocyanins, total nitrogen, soluble sugars, amylopectin, and C/N ratio in grains increased by an average of 35.62%, 11.49%, 12.84%, 23.74%, 13.00%, and 1.87% under N2 treatment over five filling stages within two years, respectively, while the harmful compound nitrite content only increased by an average of 30.2%. Correspondingly, the activities of related enzymes also significantly increased and were maintained under N2 treatment compared to N0 treatment. Regression and correlation analysis results revealed that the amount of anthocyanin accumulation was highly positively correlated with the activities of phenylalanine ammonia-lyase (PAL) and flavanone 3-hydroxylase (F3H), but negatively correlated with anthocyanidin synthase (ANS) and UDP-glycose: flavonoid-3-O-glycosyltransferase (UFGT) activity, nitrate reductase (NR), and glutamine synthetase (GS) showed significant positive correlations with the total nitrogen content and lysine content, and a significant negative correlation with nitrite, while soluble sugars were negatively with ADP-glucose pyrophosphorylase (AGPase) activity, and amylopectin content was positively correlated with the activities of soluble starch synthase (SSS), starch branching enzyme (SBE), and starch debranching enzyme (SDBE), respectively. Furthermore, there were positive or negative correlations among the detected traits. Hence, a reasonable N application rate improves purple waxy corn kernel nutritional quality by regulating N metabolism, as well as carbohydrate and anthocyanin biosynthesis.

Conventional water and nitrogen (N) management practice in north China, comprising flood irrigation and N fertilizer broadcast (FB), limits sustainable wheat production. Drip fertigation (DF) has been widely adopted in wheat production in recent years and has effectively improved yields. However, the responses of the yield and quality to the N topdressing rate (NTR) under DF are still unclear. This study determined the responses of the wheat yield and quality to NTR under DF, as well as assessing whether DF could synergistically increase the yield and quality. A field experiment was conducted in north China for two seasons (2021–2023) using a split-plot design with three replicates. The main plot used the management practice (FB and DF) and the sub-plot had N treatment (no N applied, and NTRs of 0, 40, 80, 120, and 160 kg ha−1 with 150 kg N ha−1 as basal fertilizer, denoted as N0, T0, T40, T80, T120, and T160, respectively). Our results showed that high and saturated wheat yields (12.08 and 11.46 t ha−1) were obtained under DF at T80, and the highest yields were produced at T160 (11.71 and 11.30 t ha−1) under FB. Compared with FB, the greatest yield increase of 10.4–12.6% was achieved at T80 under DF. A higher spike number due to the increased effective stem percentage and a greater grain weight because of enhanced post-anthesis biomass production (BPpost) explained the improved yield under DF. The enhanced post-anthesis radiation use efficiency (RUE) led to the greater BPpost under DF. The enhanced specific leaf N, antioxidant capacity, and stomatal conductance under DF explained the higher light-saturated photosynthesis rate of flag leaves, which partly led to the increased post-anthesis RUE. NTR higher than 80 kg ha−1 did not enhance the yield, but it significantly improved the gliadin and glutelin contents, thereby leading to a higher total protein content, better gluten characteristics, and superior processing quality. Therefore, drip fertigation is a practical strategy for increasing both yield and quality with reduced water input and appropriate N input in irrigated winter wheat in north China. Applying 80 kg ha−1 of NTR under drip irrigation produces a high yield, but further gain in grain quality needs a higher NTR.

Selenium (Se) is a micronutrient known for its essential role in human health and plant metabolism. Waxy maize (Zea mays L. sinensis kulesh)—known for its high nutritional quality and distinctive flavor—holds significant consumer appeal. Therefore, this study aims to assess the effects of foliar Se spraying on the nutritional quality of waxy maize grains, with a focus on identifying varietal differences and determining optimal Se dosage levels for maximizing nutritional benefits. We employed a two-factor split-plot design to assess the nutritional quality, trace elements, and pigment content of jinnuo20 (J20) and caitiannuo1965 (C1965) at the milk stage after being subjected to varying Se doses sprayed on five leaves. Our findings indicate superior nutrient content in J20 compared to C1965, with both varieties exhibiting optimal quality under Se3 treatment, falling within the safe range of Se-enriched agricultural products. JS3 (0.793) demonstrated the highest overall quality, followed by JS2 (0.606), JS4 (0.411), and JS1 (0.265), while CS0 had the lowest (−0.894). These results underscore the potential of foliar biofortification to enhance the functional component contents of waxy maize grains.

Conservation tillage, particularly no tillage (NT), has been recognized as an efficient farming practice, particularly in dryland agriculture, as it significantly enhances crop yields, improves soil health, and contributes to environmental sustainability. However, the influence of NT on winter wheat radiation interception and utilization, biomass, and yield under NT in irrigated fields, especially under drip fertigation, is unclear. A field experiment was carried out for two growing seasons in Shandong province, China, using a split-plot design with the tillage method as the main plot (no tillage, NT; rotary tillage, RT; and first plowing the soil and then conducting rotary tillage, PRT), and water–nitrogen management as the sub-plot (N fertilizer broadcasting and flood irrigation, BF and drip fertigation, DF). Our results showed that DF increased yield by 11.0–28.5%, but the yield response to DF depended on the tillage methods. NT had the highest response in yield of 26.3–28.5%, followed by RT of 14.6–15.1% and PRT of 11.0–11.9%. Both increased grains per ear and ear number, a result of the greater maximum stems number donating to the yield gain by DF under NT. This gain was also due to the substantially promoted post-anthesis biomass (36.7–47.3%), which resulted from the increased interception of solar radiation and radiation use efficiency after anthesis. In addition, the extended post-anthesis duration also benefited biomass and yield. To conclude, our findings underscore the critical need to optimize water and nitrogen management strategies to maximize yield under conservation tillage systems.

This study aimed to understand the variations in soil organic carbon(SOC)pools,soil temperature and water content and their relationships to mitigate climate change.Therefore,a field experiment was conducted to investigate the seasonal dynamics of SOC,permanganate oxidizable organic carbon(POxC)concentrations,as well as their relationships with soil temperature and water content under different tillage practices during the summer fallow in the drylands of the Loess Plateau in China.The experiment included three tillage practices,i.e.,no tillage,plough tillage and subsoiling tillage during the summer fallow.Results showed that the seasonal changes in the SOC concentrations increased and then decreased at both 0-5 and 5-10 cm depths under plough tillage and subsoiling tillage treatments during the growth period of winter wheat.While the seasonal changes in POxC concentration,soil water content and soil temperature fluctuated.Regression analysis revealed that the soil water content at the 5-10 cm depth had a linear relationship with the SOC concentrations and a quadratic polynomial relationship with the POxC concentrations(P＜0.05),with a better fit under the plough tillage treatment compared to the no tillage and subsoiling tillage treatments.The SOC concentrations showed no significant response to variations in soil temperature at both the 0-5 and 5-10 cm depths.In contrast,the POxC concentrations demonstrated a negative correlation with daily maximum temperature,daily mean temperature and daily minimum temperature.In summary,the findings of our study demonstrated that the seasonal changes in the POxC concentration at 0-10 cm depth were closely related to variations in soil temperature and water content,while seasonal changes in the SOC concentrations were less sensitive to soil temperature under summer fallow tillage treatments in the drylands.This study provides a theoretical basis for the scientific management of SOC pools in dryland wheat fields.