Silicon (Si) has been proven to enhance the stress resistance of rice, but its effect on the lodging resistance of rice under dry cultivation (DCR) is still unclear. The purpose of this experiment is to clarify the appropriate amount of silicon fertilizer for DCR to resist lodging and to elucidate how it coordinates lodging resistance and yield. This experiment used the ‘Suigeng 18’ cultivar as the material and set six silicon fertilizers (SiO₂) with dosages of 0, 15, 30, 45, 60, and 75 kg·ha⁻¹ (Si0, Si1, Si2, Si3, Si4, Si5). Analyze the effects and key indicators of silicon on lodging resistance of DCR from the perspectives of plant weight distribution, stem structure and composition, and root architecture. The results showed that the Si3 treatment had the highest yield and the lowest lodging index (LI). Si3 increases the weight of the upper three leaves and 4–5 internodes, thereby promoting panicle weight and yield. An increase of 13.38% in 2/3PWSI (weight of the 4th–5th stems and upper three leaves/weight of the 1st–3rd stems and lower leaves) can reflect the promoting effect of silicon on stem and leaf development near the panicle. Si3 reduces the GA/IAA value, shortens the length of the second internode, and increases the diameters of the major and minor axes, thereby increasing culm thickness and section modulus (SM), achieving the effect of “short and thick”. Si3 also increases the content of silicon and non-structural carbohydrates (NSCs) in the second internode, and increases lignin and cellulose content by upregulating the expression levels of CAD7, PAL, COMT, and CesA4 genes, thereby increasing fullness and flexural strength (M), achieving “short, thick, and strong” and reducing LI. The 38.95% reduction in IFL (second internode length/fullness) reflects the positive effect of silicon on the “short, thick, and strong” stem. In the underground part, adding silicon reduces the CTK/IAA value of roots, and increases root length, root tip number, root surface area, and root weight. The key to coordinating the lodging resistance and yield of DCR with appropriate silicon dosage is to reduce the IFL in the second internode and increase 2/3 PWSI and root growth. The key to DCR and breeding is to focus on the relationship between basal internode length and fullness, as well as stem and leaf growth near the panicle.

Straw return has important impacts on black soil protection, food security, and environmental protection. One year of straw return (S1) reduces rice yield and increases greenhouse gas (GHG) emissions. However, the effects of successive years of straw return on rice yield, soil nutrients, and GHG emissions in the northeast rice region are still unclear. Therefore, we conducted four successive years of straw return (S4) in a positional experiment to investigate the effects of different years of straw return on rice yield, soil nutrients, and GHG emissions in the northeast rice region. The experimental treatments included the following: no straw return (S0), a year of straw return (S1), two successive years of straw return (S2), three successive years of straw return (S3), and four successive years of straw return (S4). Compared with S1, the rice yields of S2, S3, and S4 increased by 10.89%, 15.46%, and 16.98%, respectively. But only S4 increased by 4.64% compared to S0, while other treatments were lower than S0. S4 increased panicles per m² and spikelets per panicle by 9.34% and 8.93%, respectively, compared to S1. Panicles per m² decreased by 8.06% at S4 compared to S0, while spikelets per panicle increased by 13.23%. Compared with S0, the soil organic carbon, total nitrogen, NH₄⁺-N, NO₃⁻-N, available phosphorus, and available potassium of S4 increased by 11.68%, 10.15%, 24.62%, 21.38%, 12.33%, and 13.35%, respectively. Successive years of rice straw return decreased GHG intensity (GHGI). Compared with S1, the GHGI of S4, S3, and S2 decreased by 16.2%, 11.84%, and 9.36%, respectively. Thus, S4 increased rice yield and soil nutrients, reducing GHGI.

Combining straw return with nitrogen fertilizer application is an effective strategy to enhance farmland productivity, improve soil structure, and mitigate climate change. Although straw return practices are widely recommended in agricultural ecosystems targeting sustainable agriculture, few studies have investigated the combined effects of consecutive years of straw return and nitrogen-fertilizer interactions on rice yield, nitrogen use, and lodging resistance, as well as the potential interactions among these variables. To investigate the effects of consecutive years of rice straw return and nitrogen fertilizer inputs on rice growth, a straw return experiment was conducted in 2021–2022 in Northeast China. The test crop was rice (cv. Jinongda No. 667), with four nitrogen fertilizer levels: 0 kg/ha (N0), 125 kg/ha (N1), 150 kg/ha (N2), and 175 kg/ha (N3). Five straw-return treatments were applied: no straw (S0), straw return to the field for one year (S1), continuous straw return to the field for two years (S2), continuous straw return to the field for three years (S3), and continuous straw return to the field for four years (S4). Results indicated that under the same straw return year, the N3 yield, nitrogen accumulation, nitrogen use efficiency, and apparent utilization were the highest. Under the same nitrogen treatment condition, S1 significantly reduced yield, nitrogen accumulation, nitrogen use efficiency, apparent nitrogen utilization, and lodging index compared to S0. However, under N3 conditions, S3 did not significantly differ from S0. Both S3 and N3 enhanced nitrogen uptake, translocation, and accumulation in rice. Their significant interactive effect increased yield while simultaneously enhancing the lodging resistance and stem strength. The study findings highlighted the effects of years of straw return and nitrogen fertilizer application on crop yield and resistance traits. They further demonstrated that the combination of straw return and optimized nitrogen fertilizer inputs could improve resource utilization and result in a high-yielding and efficient crop population.

Background: In Northeast China’s cold rice (Mollisol) regions, low temperatures slow straw decomposition, causing early microbial nitrogen (N) immobilization that competes with crop demand. Delayed N release from slow-release fertilizer (SRF) exacerbates this deficit, hindering high yield and grain quality. Methods: A two-year (2024–2025) pool planting experiment was conducted on rice ‘Jinongda 667’ with a total N application rate of 150 kg ha⁻¹. Six treatments were established: a 7:3 blend of slow-release fertilizer and urea, alongside controls of conventional urea and slow-release fertilizer alone, under both straw removal and incorporation conditions. Results: This blend increased grain yield by 6.64–7.75% over conventional urea, achieving the highest yield among all treatments, whereas SRF alone under straw incorporation reduced yield by 7.57% relative to N + S. The 30% urea (45 kg N ha⁻¹) alleviated immobilization deficit (15–30 kg N ha⁻¹) during the tillering-to-jointing stage, promoting root growth and panicle formation, while 70% SRF sustained N supply during mid-to-late stages, delaying senescence and enhancing photosynthesis. At peak grain filling, SSS and SBE activities increased by 94.01% and 10.53–11.08%, respectively. Under straw incorporation, it reduced chalky grain rate by 4.56–35.55% and chalkiness by 1.77–41.86%, increased protein content by 0.47–6.95% and gel consistency by 43.59–52.99%, decreased amylose by 2.2–5.77%, and optimized RVA profiles. Conclusions: The 7:3 blend synchronizes N supply with crop demand through temporal complementarity with straw nutrient dynamics, offering a one-time fertilization strategy for achieving high yield and quality under straw incorporation. However, given inter-annual variation (2024–2025) in tillering and N accumulation, its performance may be sensitive to climatic fluctuations, warranting further validation under diverse conditions.

This study used DIA-based proteomics to elucidate how foliar application of glycine betaine (GB) and zinc (Zn) synergistically regulates quality formation in dry-cultivated rice. GB and Zn effectively improved both the appearance and eating quality of rice through multi-level coordinated actions. GB primarily enhanced drought tolerance and quality by regulating key protein expression: upregulated RRM domain proteins potentially directly regulated starch and protein synthesis; increased disease resistance proteins activated immune priming, establishing a dual "drought tolerance-immunity" protective system; SNF2 chromatin remodeling proteins participated in epigenetic reprogramming; and amino acid transporters optimized nitrogen allocation. Zn induced functional proteins that enhancedmetabolic homeostasis: Pyridoxal 5-phosphate synthase promoted antioxidant synthesis; dCTP pyrophosphatase and tRNA pseudouridine synthase ensured genomic stability and accurate protein synthesis; and 3-isopropylmalate dehydratase promoted the accumulation of flavor precursors. The combined application of GB and Zn produced significant synergistic effects: upregulated Hexosyltransferase served as a key node, likelystabilizing osmolytes and antioxidants via glycosylation modifications and participating in zinc ligand synthesis to facilitate zinc transport and grain enrichment. Persistent upregulation of Receptor-like serine/threonine-protein kinase (RLK) enhanced signal perception and transduction, thereby initiating drought-resistance defense pathways. Physiologically, combined foliar application significantly enhanced photosynthetic, promoted osmolyte accumulation, and increased antioxidant enzyme activities. Overall, GB stabilizes functional proteins, while Zn servesas a cofactor to activate enzymatic activity. Together, they create a"signal perception-defense activation-nutrition optimization" pathway that mitigates oxidative damage while enhancing stress resistance and quality in dry-cultivated rice, providing a theoretical foundationfor cultivating stress-resistant and high-quality crops.