【Objective】 To evaluate the contributions of source, flow and sink traits to soybean yield, clarify the relationships among these traits during yield formation, reveal the key physiological mechanisms underlying soybean yield formation, and provide a theoretical basis for soybean breeding. 【Method】 Qihuang 34, Lindou 9, Weidou 9, and Hedou 12 were investigated during the pod-setting and seed-filling stages. The photosynthetic performance, assimilate partitioning, and dry matter accumulation were analyzed throughout plant development by using ¹³C isotope labeling. Source-flow-sink traits were comprehensively evaluated, and radar chart analysis was applied to characterize the coordination of these traits among cultivars during yield formation.【Result】 (1) The correlations between source, flow and sink traits and yield varied considerably. The contributions of these traits to yield ranked as follows: leaf area index > 100-seed weight > net photosynthetic rate > palisade tissue thickness > effective quantum yield of PSII (ΦPSII) > glutamine synthetase activity > glutamate synthase activity > mean sieve tube diameter > stomatal conductance > midrib diameter. (2) Significant interactions were observed among source, flow and sink traits. Source-sink interactions were reflected by positive correlations of net photosynthetic rate, stomatal conductance and transpiration rate with 100-seed weight. Source-flow interactions were indicated by positive correlations of palisade tissue thickness and leaf thickness with net photosynthetic rate, whereas flow-sink interactions were represented by a positive correlation between mean sieve tube diameter and 100-seed weight. (3) Source, flow and sink traits differed markedly among cultivars. Qihuang 34 exhibited higher leaf area index, palisade tissue thickness, leaf thickness, net photosynthetic rate, ΦPSII, sustained dry matter accumulation in main stem pods, yield, 100-seed weight, glutamine synthetase activity, glutamate synthase activity, 3-day assimilate translocation to main stem pods and sustained assimilate translocation than the other three cultivars. Hedou 12 showed the largest midrib diameter, Weidou 9 had the highest seed number per plant, and Lindou 9 exhibited the greatest carbon assimilation capacity of branch pods. These results indicate that high soybean yield depends on the coordinated regulation of source, flow and sink traits rather than on any single trait.【Conclusion】 Among the four cultivars, Qihuang 34 achieved the highest yield owing to its larger leaf area index, stronger assimilate transport capacity, and greater 100-seed weight. Breeding high-yield soybean cultivars with coordinated source, flow and sink characteristics should prioritize germplasm with high photosynthetic efficiency based on ΦPSII, net photosynthetic rate and leaf area index, followed by evaluation of assimilate transport efficiency using leaf and vascular bundle anatomical traits and assessment of yield potential through nitrogen metabolism enzyme activities and sink capacity.

【Objective】 Seed vigor is one of the key determinants of seed quality in maize, directly influencing emergence rate, seedling growth, and stand uniformity, thereby affecting final yield formation. This study aimed to identify high-vigor inbred lines and hybrids, uncover key genes involved in regulating seed germination, and provide a theoretical basis for breeding high-vigor maize varieties.【Method】 Twenty-two maize inbred lines from two heterotic groups, Shaan A Group and Shaan B Group, were used to produce 104 F₁ hybrids following an NC-Ⅱ mating design. Seed vigor was evaluated under both the standard germination test and the cold soaking germination test. Nine traits were recorded, including germination energy (GE), germination percentage (GP), germination index (GI), seedling length (SL), root length (RL), dry weight (DW), vigor index I (VIⅠ), vigor index Ⅱ (VIⅡ), and vigor index Ⅲ (VIⅢ). Genotypic and phenotypic data were combined to perform a genome-wide association study (GWAS) for major traits. Quantitative trait nucleotides (QTNs) significantly associated with seed vigor were identified. Public transcriptome data were further used to screen potential candidate genes and to predict their possible functions. 【Result】 Significant genetic variation was observed for seed vigor-related traits in both inbred lines and hybrids. Compared with the standard germination test, cold soaking treatment reduced GE, GP, and GI, and increased the range of phenotypic variation among genotypes. Most traits showed significant effects of genotype, treatment, and their interaction, indicating that seed vigor is mainly controlled by genetic factors. Germination traits were positively correlated with seedling growth traits and vigor indices. Several materials showed stable performance under different germination conditions and low sensitivity to cold soaking. Hybrids derived from KA105, KA088, KA085, and KA205 of the Shaan A Group, and KB088, KB060, KB168, KB076, and KB021 of the Shaan B Group maintained relatively high seed vigor under cold soaking conditions. Some inbred lines with moderate seed vigor were able to improve hybrid performance in specific combinations. GWAS detected 43 QTNs significantly associated with seed vigor, including seven loci that were shared by two or more traits under cold soaking conditions. Based on transcriptome data, 11 candidate genes were identified, of which eight had functional annotation and were mainly related to stress response and transcription regulation.【Conclusion】 Maize seed vigor is a quantitative trait under genetic control, and genetic variation is the main source of phenotypic differences. Seed vigor is regulated by multiple loci, with key genomic regions involved under low-temperature conditions. The accumulation of favorable alleles can improve seed vigor in hybrids, and hybrid performance is also influenced by specific genetic interactions between parents.

【Objective】 Ethylene and gibberellin are key phytohormones regulating rice coleoptile elongation, however, the interaction of ethylene and gibberellin in coleoptile elongation remains unclear. This study aimed to investigate the molecular mechanism of ethylene and gibberellin in regulating coleoptile elongation.【Method】 This study utilized transgenic rice lines of the core components of ethylene and gibberellin signaling pathways as experimental materials. The coleoptile lengths were examined with or without different phytohormone treatments. The expression levels of downstream genes of OsEIN2/OsEIL2 were detected by RT-qPCR. Yeast two-hybrid and pull-down assays were further employed to verify the interaction between OsSLR1 and OsEIL2. 【Result】 Exogenous phytohormones treatment revealed that both ethylene and gibberellin promoted coleoptile elongation, and they exhibited a synergistic effect. Paclobutrazol (PAC, a GA biosynthesis inhibitor) treatment or overexpression of the gibberellin inactivation gene OsGA2ox3 weakened the promoting effect of ethylene on coleoptile elongation, whereas exogenous application of gibberellin partially relieved the 1-MCP (1-Methylcyclopropene) inhibited coleoptile elongation, indicating that ethylene and gibberellin shared a common regulatory pathway in controlling coleoptile elongation. Further studies revealed that OsSLR1, a negative regulator of gibberellin signaling, interacted with OsEIL2. Moreover, OsEIN2/OsEIL2-regulated genes, such as OsERF63, OsERF73, OsHKT2; 1 and OsGY1 were also regulated by OsSLR1. The OsSLR1 loss-of-function mutant slr1 exhibited a long coleoptile phenotype, and the promoting effect of ethylene on coleoptile elongation was further enhanced in slr1, suggesting that OsSLR1 was involved in ethylene-mediated coleoptile elongation and signal transduction. 【Conclusion】 In summary, this study revealed that OsSLR1 served as a crosstalk node for the synergistic regulation of coleoptile elongation by ethylene and gibberellin, and it interacted with OsEIL2 to co-regulate downstream signaling pathways and coleoptile elongation. This study not only enriched the understanding of the phytohormone interaction network in coleoptile growth, but also provided a theoretical basis and useful genes for the breeding of rice varieties suitable for direct seeding cultivation.

【Objective】 This study aimed to elucidate the differentiation patterns of aroma metabolism during fruit development across distinct peach flesh types, and identify key regulatory genes governing cultivar-specific aroma profiles, so as to provide a theoretical basis for flavor improvement in stony hard peaches. 【Method】 The melting-flesh cultivar Chunmei and the stony hard cultivar Zhongtao 9 were utilized as experimental materials. Seven critical sampling stages were established throughout the fruit development cycle. Volatile compounds were profiled using headspace solid-phase microextraction combined with gas chromatography- mass spectrometry (HS-SPME-GC-MS). Transcriptome sequencing was performed to identify differentially expressed genes (DEGs), and Pearson correlation analysis was employed to pinpoint core genes significantly associated with key aroma compounds.【Result】 A total of 57 volatile compounds were identified, with significant variation in composition and content across cultivars and developmental stages. The stony hard cultivar Zhongtao 9 exhibited no detectable ethylene production throughout development, maintained high levels of C6 aldehydes (e.g., 2-hexenal) at the mature stage, and showed almost no accumulation of esters and lactones. In contrast, the melting-flesh cultivar Chunmei exhibited a typical ethylene climacteric peak at the S3 to S4 transition, accompanied by a 3.1-3.8 fold increase in ester content and a marked decrease in C6 compounds. Transcriptome analysis identified 2 806 DEGs, with clear separation between the two cultivars at all developmental stages based on clustering analysis. KEGG enrichment analysis indicated that these DEGs were significantly involved in plant hormone signal transduction, α-linolenic acid metabolism, and carotenoid biosynthesis pathways. Correlation analysis identified 16 candidate genes associated with ester/lactone biosynthesis. Among them, BSK2 (Prupe.2G110200) and PpYUC11 (Prupe.6G157400/6G157500) showed strong positive correlations with hexyl acetate and γ-decalactone, respectively.【Conclusion】 Ethylene was a key regulatory factor underlying aroma quality divergence between the two peach flesh types. Impaired ethylene signaling in Zhongtao 9 likely restricted fatty acid metabolism at the C6 aldehyde stage, preventing downstream esterification and lactone biosynthesis. Candidate genes, such as BSK2 and PpYUC11, together with hormone signaling pathways, were identified as potential regulators of aroma formation.

Wheat (Triticum aestivum) remains vital to global food security, yet diverse pathogens constantly threaten its stable production. To address these threats, the identification and utilization of resistant genetic resources is the most effective and eco-friendly approach to manage disease epidemics. Based on a systematic review of the molecular mechanisms of wheat immunity, this paper compares the infection strategies of biotrophic and necrotrophic pathogens and elucidates the evolutionary arms race between wheat and its pathogens. Particular emphasis is placed on key immune regulatory mechanisms, including resistosome assembly and allele-specific evolution, modular cooperation mediated by kinase-integrated immune receptors, and host physiological homeostasis reprogramming driven by non-canonical resistance genes. In addition, the molecular basis by which pathogen effectors promote susceptibility through hijacking host immune pathways or exploiting hypersensitive response-associated cell death is discussed. Building upon these mechanistic insights, we summarize current strategies for resistance resource discovery and precision improvement, including the construction of panoramic resistance-gene atlases, the exploitation of novel resistance resources from wild relatives, and receptor optimization through targeted editing of key genetic loci. In response to the continuing evolution of pathogen populations and the increasing prevalence of multiple concurrent diseases, we further propose several emerging directions for resistance improvement, including the decoupling of immune activation from cell death, the evolution-guided design of universal immune receptors, and the establishment of multi-kingdom immune ecological barriers. These concepts provide a theoretical framework and technical foundation for the rational design of broad-spectrum and durable disease resistance in wheat.

【Objective】 This study aimed to reveal the spatiotemporal variation in characteristics of soil chemical properties and their relationship with sugarcane yield under long-term continuous cropping, identify the key soil factors limiting sugarcane productivity, and provide a scientific basis for sustainable soil management in sugarcane fields.【Method】 A space-for-time substitution approach was adopted with five continuous cropping duration treatments: CK (0 a), T1 (1 a), T2 (10-19 a), T3 (20-29 a), and T4 (>35 a). Sugarcane yield and soil chemical properties within the 0-60 cm profile (stratified into 0-20, 20-40, and 40-60 cm layers) were systematically analyzed, including pH, soil organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP), available potassium (AK), and available micronutrients contents. The integrated fertility index (IFI) was calculated using factor analysis combined with correlation coefficient analysis and the Nemerow composite index method. Two machine learning algorithms-Extreme Gradient Boosting (XGBoost) and Random Forest (RF)-were employed to quantify the relative contribution of individual soil chemical indicators to sugarcane yield.【Result】 (1) Long-term continuous cropping significantly reduced sugarcane yield (P<0.05), with a 13.68% decline observed in the T4 treatment（>35 years）compared with the CK, and induced deterioration in soil chemical properties. (2) Soil acidification was intensified under continuous cropping, exhibiting significant layer-specific characteristics. Compared with the control (CK), the mean soil pH decreased to 4.60 after more than 20 years of continuous cropping. The subsurface layer (20-40 cm) exhibited the most severe acidification, with pH values significantly lower than the CK in the T3 and T4 treatment groups. (3) Soil nutrients exhibited obvious surface enrichment and accumulation of certain elements. The contents of soil organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, and available phosphorus in the surface layer (0-20 cm) were significantly higher than in deeper layers. Prolonged continuous cropping led to significant accumulation of available potassium and available zinc, increasing by 320.47% and 164.13%, respectively, in the surface layer. (4) The soil integrated fertility index (IFI) decreased significantly with soil depth. Although long-term continuous cropping improved average fertility in the surface layer, it exacerbated the variability and spatial heterogeneity of fertility in deeper soil layers. (5) Both XGBoost and RF analyses consistently identified soil pH in the 20-40 cm layer as the primary limiting factor determining sugarcane yield, with a relative importance contribution substantially greater than that of surface available nutrients and other soil indicators.【Conclusion】 Under long-term continuous sugarcane cultivation, soils exhibited a spatiotemporal soil pattern characterized by surface nutrient enrichment and severe subsurface acidification. Acidification in the 20-40 cm soil layer constitutes the core obstacle restricting sugarcane productivity. In practical production, management strategies should shift from surface-oriented nutrient application to deep amelioration targeting subsurface acidification.

【Objective】 This study aimed to clarify the regulatory effects of the reduced nitrogen combined with controlled water, biochar, and the nitrification inhibitor dicyandiamide (DCD) on nitrogen losses within a facility soil-tomato system, so as to provide a scientific basis for efficient nitrogen use and sustainable green development in facility vegetable production.【Method】 A field plot experiment was conducted using facility tomato as the research object, with two irrigation treatments including traditional drip irrigation (TD) and reduced drip irrigation (CD). Based on this, eight nitrogen treatments were designed, including no nitrogen (TDN0, and CDN0), traditional nitrogen (TDN1, and CDN1), reduced nitrogen (TDN2, and CDN2), and reduced nitrogen combined with biochar and dicyandiamide (DCD) (TDN2+BD, and CDN2+BD). During the topdressing period, soil N₂O emission and NH₃ volatilization, NO₃^--N accumulation in the 0-100 cm soil profile, and tomato nitrogen uptake, yield, and fruit quality indicators were systematically monitored to quantitatively evaluate the synergistic regulatory effects of biochar and DCD under reduced nitrogen and controlled water conditions. 【Result】 Nitrogen application significantly increased soil N₂O emissions and NH₃ volatilization, with peak fluxes occurring 2-3 days after topdressing. Nitrogen reduction effectively suppressed gaseous nitrogen losses, and the combined application of biochar and the nitrification inhibitor DCD further enhanced the mitigation effect on N₂O emissions. Although biochar and DCD posed a potential risk of increasing NH₃ volatilization, this adverse effect was substantially alleviated by reduced nitrogen and controlled water conditions. Compared with conventional nitrogen application, nitrogen reduction significantly decreased total gaseous nitrogen losses by 45.7%-56.6% and reduced NO₃^--N accumulation in the 0-100 cm soil profile by 13.7%-16.2%. When biochar and DCD were applied on the basis of nitrogen reduction, total gaseous nitrogen losses further declined by 49.4%-59.0%, while the reduction in NO₃^--N accumulation expanded to 27.4%-30.0%, with a clear suppression of deep leaching. Both irrigation methods enhanced the synergistic mitigation effects of water nitrogen regulation. However, controlled drip irrigation demonstrated superior performance compared with conventional drip irrigation. Under controlled irrigation, the CDN2+BD treatment reduced total nitrogen losses by 30.0% compared with CDN1, with decreasing the net nitrogen loss rate from 3.3% to 2.5%. This treatment also significantly inhibited deep NO₃^--N accumulation and increased NO₃^--N retention in the 20-40 cm soil layer by 27.1%. In addition, biochar and DCD increased the apparent nitrogen use efficiency under controlled irrigation to 28.9%; TDN2+BD and CDN2+BD improved nitrogen use efficiency by 53.0% and 30.2%, respectively, compared with their corresponding nitrogen-reduction treatments (TDN2 and CDN2) (P<0.05). Furthermore, the controlled irrigation with biochar and DCD (CDN2+BD) achieved the highest tomato yield (115.93 t·hm^-2), while significantly enhancing fruit vitamin C content and improving soluble protein, soluble sugar, and total soluble solid levels.【Conclusion】 Reduced nitrogen application combined with controlled water, biochar, and the nitrification inhibitor dicyandiamide (DCD) significantly decreased gaseous and leaching nitrogen losses, optimized soil nitrogen distribution, and improved nitrogen use efficiency and tomato quality, representing an optimal technical approach for nitrogen reduction and efficiency enhancement in facility vegetable production.

【Objective】 Intercropping maize with leguminous green manure can achieve fertilizer conservation and efficiency improvement. Biochar application is an effective measure to mitigate gaseous nitrogen loss form farmland. However, the impacts of nitrogen reduction under intercropping green manure combined with the biochar application on gaseous nitrogen loss and the system’s nitrogen footprint remain unclear. This study aimed to evaluate this comprehensive practice to provide a technical approach for the green maize production in oasis irrigation areas of Northwest China. 【Method】 A two-factor field experiment was set up in 2021 at Wuwei Oasis Agricultural Experimental Station in Gansu Province. The experiment employed a two-factorial design. The main factor was nitrogen application system, including conventional nitrogen application (N100), 30% nitrogen reduction (N70), and 30% nitrogen reduction combined with sesbania biochar (N70S). The second factors were cropping patterns, including maize monoculture (MM) and maize intercropping with common vetch (IMC). Six treatments were formed: N100-MM, N100-IMC, N70-MM, N70-IMC, N70S-MM, and N70S-IMC. From 2024 to 2025, maize yield, nitrogen absorption and soil physicochemical properties were measured, nitrous oxide emission and ammonia volatilization were monitored, and the nitrogen footprint of the system was quantified by life cycle assessment method. 【Result】 Compared with N100, N70 decreased maize grain yield, aboveground biomass and nitrogen absorption by 7.9%, 6.1% and 4.7%, respectively. In contrast, N70S increased grain yield and biomass by 8.6% and 2.7%, respectively. IMC increased the yield by 3.8% compared with MM. Notably, N70S-IMC increased grain yield, aboveground biomass and nitrogen absorption by 12.6%, 4.3% and 4.0%, respectively, compared with N100-MM. The N70 reduced cumulative N₂O emissions and NH₃ volatilization by 16.0% to 25.2% and 9.9% to 24.7%, respectively, relative to N100. The N70S further reduced these emissions by 24.8% to 27.7% and 17.6% to 43.9%, respectively. Compared with N100-MM, N70-IMC and N70S-IMC reduced cumulative N₂O emissions by 12.1% to 20.1% and 20.1% to 35.8% and NH₃ volatilization by 15.3% to 24.3% and 11.2% to 20.1%, respectively. Soil analysis showed that, compared with N100-MM, N70-IMC decreased soil ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), and microbial nitrogen (MBN) by 17.6%, 15.6%, and 9.6%, respectively. While N70S-IMC decreased NH₄⁺-N and soluble organic nitrogen (DON) by 15.6% and 7.3%, respectively, but increased total nitrogen (TN) and MBN by 3.9% and 25.0%, respectively. Random forest analysis indicated that soil NO₃^--N, NH₄⁺-N, MBN and DON were the key factors driving N₂O emissions, while NH₃ volatilization was mainly driven by NO₃^--N, NH₄⁺-N and TN. Life cycle assessment indicated that the nitrogen footprint under N70-IMC and N70S-IMC was decreased by 28.9% and 39.7%, respectively, compared with the N100-MM. Furthermore, the nitrogen footprint of the N70S-IMC treatment was 10.4% lower than that under N70-MM. 【Conclusion】 The combination of maize-green manure intercropping, 30% nitrogen reduction, and sesbania biochar application increased grain yield and nitrogen absorption, improved key soil properties, and lowered N₂O emissions, NH₃ volatilization, and the system’s nitrogen footprint, which was an effective path for green and sustainable maize production in the Northwest Oasis Irrigation District.

【Objective】 This study investigated differences in flavonoid-related gene expression and metabolite profiles in the flesh of red-fleshed grape berries and their self-pollinated progenies, aiming to elucidate the metabolic accumulation characteristics of flavonoid biosynthesis, and provide insights into transcriptional regulation, so as to lay a theoretical foundation for improving flavonoid contents in grape berries and breeding new grape varieties. 【Method】 The red-fleshed grape germplasm Zhongshanhongyu (ZSHY), its self-pollinated progenies Nan 19 (N19) and Nan 30 (N30), and Muscat (MGX) were used as materials. Four pairwise comparison groups (ZSHY_vs_MGX, N30_vs_ZSHY, N19_vs_MGX, and N30_vs_N19) were established for targeting flavonoid metabolomics alongside transcriptome sequencing (RNA-seq) of berry flesh. Enrichment analyses were subsequently conducted to characterize flavonoid metabolites accumulation, identify key structural genes, and dissect the transcriptional regulatory networks involved in flavonoid biosynthetic pathway. 【Result】 Based on targeted flavonoid metabolomics technology, a total of 104 differentially accumulated flavonoid metabolites were detected, and 62 core metabolites exhibiting significant differences were further identified. Notably, most flavonols and flavanols accumulated to substantially higher levels in ZSHY and N19 than in N30 and MGX. KEGG enrichment analysis revealed that these differential metabolites were predominantly enriched in flavonoid biosynthesis pathways, particularly responsible for anthocyanin, flavone, and flavonol biosynthesis. Transcriptome profiling identified 758 differentially expressed genes (DEGs), which were significantly overrepresented in flavonoid and phenylpropanoid biosynthesis pathways. Furthermore, 30 core DEGs directly involved in flavonoid biosynthesis were screened, whose expression patterns were broadly consistent with the metabolite accumulation profiles, showing high transcript abundance in ZSHY and N19, but low expression in N30 and MGX. In addition, 22 transcription factors (TFs) significantly correlated with flavonoid structural genes were identified, mainly belonging to the WRKY, MYB, and ERF families. 【Conclusion】 Significant differences existed in flavonoid metabolism between the red-fleshed grape and its self-pollinated progenies. The elevated flavonoid accumulation in the flesh of ZSHY and N19 was closely associated with the upregulation of the key structural genes in the flavonoid pathway, and the identified TFs might play important regulatory roles in this process.

【Objective】 The composition of soil nitrogen pool is an important indicator reflecting the sustainable productivity of soil. By quantifying the response relationship between changes in soil nitrogen pool components and the application rate of organic and chemical fertilizers, the cultivation characteristics of different nitrogen components in soil by organic and chemical fertilizers were clarified, so as to provide a theoretical basis for soil fertilization and optimizing nitrogen management in farmland soil.【Method】 This study used a long-term location monitoring experiment with different dosages of organic fertilizer and chemical fertilizer (starting in 2006) as a platform. Both organic fertilizer and chemical fertilizer were set at 10 nitrogen fertilizer levels (calculated as N, with crop nitrogen application rates of 0, 60, 120, 180, 240, 300, 360, 420, 500, and 600 kg·hm^-2 per season). The planting system was a double cropping system of winter wheat and summer maize per year. Plant samples were taken during the maturity period of maize in the summer of 2024 to determine nitrogen content, biomass, and maize grain yield. After the summer maize harvest, soil samples were collected in 0-20 cm depth to determine the total nitrogen and inorganic nitrogen content of the soil. The Bremner method was used to determine the organic nitrogen component content of the soil. 【Result】 (1) The total nitrogen content of the soil in both fertilization treatments showed a linear increase with the increase of nitrogen application rate. Compared with the no fertilization treatment, the increase in soil total nitrogen content in organic fertilizer and chemical fertilizer treatments was 19.1%-273.5% and 8.8%-25.0%, respectively. For soil inorganic nitrogen, with the increase of nitrogen application rate, the soil nitrate nitrogen content significantly increased under both fertilization treatments. Under the same nitrogen content, the nitrate nitrogen content in soil treated with organic fertilizer was significantly higher than that of chemical fertilizer, ranging from 1.44 to 5.17 times, but the difference in ammonium nitrogen was not significant. (2) For soil organic nitrogen components, the content of total acid hydrolyzable nitrogen (THN) and non-acid hydrolyzable nitrogen (NHN) in organic fertilizer treatment increased with the increase of nitrogen application rate. The THN content of fertilizer treatment also increased with the increase of nitrogen application rate, but there was no significant difference between the treatments. In the components of acid hydrolyzed nitrogen, the content of acid hydrolyzed ammonium nitrogen (AN), amino acid nitrogen (AAN), and amino sugar nitrogen (ASN) increased with the increase of nitrogen application rate in both organic and chemical fertilizer treatments. However, the trend of changes in the content of acid hydrolyzed unknown nitrogen (HUN) was opposite, with organic fertilizer treatment increasing with increasing nitrogen application, while chemical fertilizer treatment showed a decreasing trend. The linear fitting results indicated that there was no significant correlation between NHN and nitrogen application rate in fertilizer treatment. Under both fertilization treatments, the content of various organic nitrogen components showed a significant linear positive correlation with nitrogen application rate. Among them, the HUN of fertilizer treatment showed a significant linear negative correlation with nitrogen application rate. Long term application of organic and chemical fertilizers has changed the proportion of various acid hydrolyzed nitrogen components to total soil nitrogen. The distribution ratio of chemical fertilizer treatment was AN (28.3%-32.5%)>AAN (25.1%-29.5%)>HUN (5.9%-10.0%)>ASN (2.6%-3.5%); the allocation ratio for organic fertilizer treatment was AAN (23.7%-31.4%)>AN (19.6%- 27.6%)>HUN (7.9%-12.6%)>ASN (2.3%-3.2%). (3) Correlation analysis showed that AN, AAN, and ASN were significantly positively correlated with nitrogen uptake in the aboveground parts of summer maize (P<0.01). 【Conclusion】 Under the winter wheat-summer maize rotation system in the North China Plain, the long-term application of chemical fertilizer and long-term application of organic fertilizer could significantly increase the soil nitrogen pool capacity. In acid hydrolyzed organic nitrogen, compared with the application of chemical fertilizers, organic fertilizer treatment significantly increased the content of AN, AAN, ASN, and HUN, thereby improving soil nitrogen supply capacity. AN, AAN, and ASN exhibited a highly significant positive correlation with the nitrogen absorption in the aboveground parts of summer maize, making them potential effective nitrogen sources for the absorption and utilization by summer maize.