The paddy soils in coastal saline areas are high in salt content, which may potentially slow down the decomposition rate of straw, thereby affecting rice yield and nitrogen fertilizer use efficiency. We investigated the appropriate amounts of straw return, nitrogen application rates, and the effects of using straw decomposition agents, aiming to provide reasonable technical approaches for soil fertility improvement, high rice yield, and efficient nitrogen fertilizer utilization in coastal saline paddy fields.

Field experiments were conducted in 2022 and 2023 in Caofeidian District, Tangshan City, Hebei Province. A split-split plot design was employed. Under the conditions of no application decomposition agent HT20 (D0) and an application rate of 45 kg/hm² (D1), treatments with half amount of straw return (HS, 5250 kg/hm²) and full straw return (S, 10500 kg/hm²) were set up respectively. For each straw return amount, three nitrogen application levels were established: a 40% reduction in nitrogen fertilizer (N1), a 20% reduction (N2), and the conventional nitrogen rate (375 kg/hm², N3). Additionally, two control treatments were included: a blank control (CK), and a control with only the conventional nitrogen rate applied (F). Soil samples (0−20 cm) and aboveground plant samples were collected during the rice tillering, full heading, grain filling, and maturity stages. Soil physicochemical properties, plant biomass, and nitrogen content were analyzed. Yield and its component factors were measured at maturity, and N accumulation, translocation characteristics, and nitrogen fertilizer use efficiency were calculated.

At rice maturity stage, compared to the F control, the D0HSN3, D1HSN3, and D1SN3 treatments increased the average soil total N over two years by 2.11%−7.59%; all the 12 combined treatments increased soil alkali-hydrolyzable N by 11.76%−28.71%; D1N2 and D1N3 treatments increased NH₄⁺-N by 26.21%−42.68%; D0N3, D1N2, and D1N3 treatments increased NO₃⁻-N by 32.94%−74.76%; all the 12 treatments increased soil organic carbon by 1.83%−15.95%; D0N2, D0N3, D1SN2, and D1SN3 treatments increased soil EC by 4.20%−7.29%; all the 12 treatments increased CEC by 4.43%−12.23%. There were no significant differences in pH values among different treatments during various rice growth stages. Compared to the F treatment, eight N2 and N3 combined treatments increased nitrogen accumulation in the aboveground parts of rice from the heading to maturity stages by 0.93%−2.78%; four N2 treatments improved the apparent nitrogen recovery rate by 11.16%−12.95% and the nitrogen agronomic efficiency by 23.50%−27.11%, with the D1HSN2 treatment showing the highest values. Random forest analysis indicated that N accumulation, thousand-grain weight, soil NH₄⁺-N, and soil organic carbon (SOC) content were important factors affecting rice yield. Removing these four variables respectively led to decreases in model prediction rates of 41.39%, 23.43%, 22.94%, and 11.83%. N accumulation, soil NH₄⁺-N, and CEC were important factors affecting the apparent nitrogen recovery rate. Removing these three variables respectively led to decreases in model prediction rates of 62.83%, 28.06%, and 13.86%. TOPSIS comprehensive evaluation showed that the D1HSN2 combination was the optimal treatment, followed by the D0HSN2 combination.

Reducing the conventional nitrogen application rate by 20% while returning straw to the field significantly increased the contents of organic carbon, available N, EC, and CEC in coastal saline paddy soils. Applying a straw decomposition agent further improved soil physicochemical properties. Under a 20% reduction in the conventional nitrogen application rate, returning half the amount of straw was more beneficial for increasing rice yield and achieving a higher apparent nitrogen recovery rate compared to full straw return. Applying a straw decomposition agent further enhanced the apparent nitrogen recovery rate. Based on the comprehensive evaluation results, a nitrogen application rate of 300 kg/hm² combined with 5250 kg/hm² of straw return, along with either applying 45 kg/hm² of the decomposition agent HT20 or not applying any decomposition agent, can be recommended as the fertilization mode for current coastal saline paddy fields.

This study aimed to investigate the optimum combination of nitrogen (N), phosphorus (P), and potassium (K) fertilizers for the growth and effective component accumulation of Astragalus membranaceus var. mongholicus in northern Shaanxi.

A field experiment was conducted in Zizhou County, Yulin City, Shaanxi Province, using two-year-old A. membranaceus var.mongholicus. A three-factor quadratic saturation D-optimal design was employed, and 10 NPK combination treatments were used in the experiment. The seedlings were transplanted in August 2021, and plant samples of A. membranaceus var.mongholicus were collected on July 25, August 14, September 3, September 23, and October 13, 2023 for the investigation of plant height, root length, root diameter, aboveground and underground biomass, and the content of the effective component astragaloside IV. The effects of fertilization treatments were evaluated using the membership function method and frequency analysis.

Significant differences were observed in the plant height, root length, root diameter, and above-ground and below-ground biomass of Astragalus membranaceus (Huangqi) across 10 fertilization treatments. The highest values for all final growth indices of Astragalus membranaceus (measured on October 13th) were achieved under the N4P4K2 treatment. Compared with the N1P1K1 treatment(no N, P, and K fertilizers) , N₄P₄K₂ (with application rates of N 150 kg/hm², P₂O₅ 225 kg/hm², and K₂O 79.41 kg/hm²) led to notable increases of 51%, 69%, and 52% in plant height, root diameter, and root length, respectively. The accumulation of dry matter in the above-ground and under-ground parts increased by 117% and 120%, respectively, and the root thickening was also significantly greater than that under all treatments except N₄P₂K₄ (with application rates of N 150 kg/hm², P₂O₅ 79.41 kg/hm², and K₂O 225 kg/hm²). The overall promoting effects of fertilizer combinations on the growth indices and the astragaloside IV content at the five harvest stages of Huangqi followed the order: combined application of N, P, and K fertilizers > combined application of any two of these fertilizers > single application of one fertilizer. The astragaloside IV content in the roots of Huangqi increased significantly with growth duration across all treatments. By integrating four indicators—root length, root diameter, below-ground biomass, and astragaloside IV content—with weights of 24%, 26%, 20%, and 30% respectively to calculate the comprehensive membership function values for each treatment, the N₄P₄K₂ treatment emerged with the highest score.

The optimal fertilizer ratio for the rapid growth and high astragaloside IV content in Huangqi is N: 103.4−128.3 kg/hm², P₂O5 143.9−172.8 kg/hm², and K₂O 149.2−164.1 kg/hm², with a ratio of N﹕P₂O₅﹕K₂O as 1﹕1.35−1.39﹕1.28−1.44.

This study evaluated the feasibility of substituting conventional field nitrogen (N) fertilization with bowl seedling tray application, examining its impact on seedling quality, rice nutrient uptake, grain yield, and nutrient runoff into paddy surface water. The aim was to inform optimized N management strategies that minimize N and phosphorus (P) losses.

A field trail was conducted in Guangxi Academy of Agricultural Sciences, with rice cultivar "Guiyefeng" as test materials. Three treatments were applied, CK: conventional seedling-raising and N fertilizer application rate (CK); T1: bowl seedlings, with 30% reduced N applied at a 4:6 ratio between nursery and tillering stages using coated urea (180-day release); T2: bowl seedlings, with 30% reduced N (coated urea) applied entirely within the bowls. Seedling quality (stem base width, leaf number, root length/number, aboveground biomass, N/P/K content) was assessed 17 days post-transplanting. Surface water samples were collected post-fertilization to measure N and P concentrations. At harvest, grain yield, yield components, and N/P/K accumulation in rice and straw were analyzed.

Both T1 and T2 significantly enhanced stem base width, leaf number, max. root length, root traits, aboveground biomass, and N content compared to CK. T2 outperformed T1 in most metrics, indicating superior seedling vigor. Compared to CK, T2 increased grain yield by 24.9% through increased panicle length and effective panicle number, enhanced N content of rice stalk, gain, and root by 20.4%, 16.0%, 31.2%, thus increased N accumulation rate of rice stalk and grain by 13.5% and 44.8%, respectively. T2 also surpassed T1 in grain yield (+18.1%), N content in rice stalk, rice and root (11.1%, 14.2%, 18.0%, respectively), and N accumulation rate of in grain (34.8%). T1, T2 and CK exhibited comparable P content in seedlings and P accumulation rate in rice straw and grain. T1 and T2 reduced total N and ammonium in surface water within 7 days after nursery fertilizer (vs. CK), T2 further reduced the total N and ammonium concentrations within 5 days after tiller fertilization (vs. CK and T1). Both T1 and T2 treatments reduced the cumulative loss of total N, ammonium, nitrate and total P by 84.3%−86.8%, 93.7%−95.7%, 51.5%−57.4% and 14.0%−30.2% in seedling stage, and the cumulative loss of total N and ammonium by 23.2%−68.6% and 32.2%−65.9% in tillering stage, with T2 treatment demonstrating the higher decrease.

Applying 30% reduced N via coated urea entirely within bowl seedling trays effectively enhanced seedling quality, rice yield, and N uptake while minimizing surface water N concentrations throughout the growing season. This approach significantly curtails nutrient runoff, thereby reducing eutrophication risks and promoting sustainable rice cultivation.

To clarify the effects of fertilization on soil moisture and crop yield in dryland will provide a scientific basis for improving resource use efficiency in dryland.

The field trial was conducted in Shouyang, Shanxi Province since 2018, the crropping system is single spring maize. In the experiment, three fertilizer types were set up with no fertilization as the control (CK), and three fertilizer types were set up with organic fertilizer alone (O), chemical fertilizer alone (F) and organic and inorganic combined application (T), and three fertilizer rates (calculated as N) were set under each fertilizer type, including low fertilizer (50 kg/hm²), medium fertilizer (150 kg/hm²) and high fertilizer (250 kg/hm²), a total of 10 treatments. Before maize harvest in 2022 and 2023 and after maize harvest in 2023, the soil water storage efficiency and evaporation of farmland, the water consumption of farmland during the growth period, and the yield and components of maize were investigated.

Chemical fertilizer treatment (F) exhibited no significant differences in fallow-period soil water storage, evaporation, or storage efficiency compared to CK. In contrast, organic fertilizer treatment (O) significantly enhanced fallow-period water storage efficiency increased by 89.1% (O) and integrated treatment (T) significantly enhanced fallow-period water storage by 49.1 mm , respectively, while reducing evaporation by 50.7 mm (average). And water storage efficiency increased by 157.6% (T) relative to CK. Notably, O improved water storage efficiency only at the low fertilization rate, whereas T demonstrated consistent benefits across all N rates. Both F and T treatments boosted maize yield by 107.5% and 121.7%, respectively, over CK, with corresponding increases in 100-grain weight (23.9% and 29.1%) and spike number (23.2% and 22.6%). WUE improved by 96.5% (F) and 104.3% (T). Under medium and high N rates, F and T yielded comparable results for yield, grain weight, spike number, WUE, and rainfall use efficiency (RUE), surpassing O in all parameters.

Chemical fertilization is capable of enhancing yield and WUE but failed to improve fallow-period soil water storage efficiency, suggesting limited long-term moisture retention benefits. Organic fertilization could improve water storage efficiency but underperformed in yield and WUE, even at high N rates, highlighting its inefficiency for immediate productivity gains. Integrated application of organic and chemical fertilizers could optimize water-fertilizer synergy, ensuring stable, high yields and superior WUE under medium and high N inputs. This strategy is recommended as the optimal fertilization regime for dryland maize, balancing productivity with sustainable resource management.

Nebkhas, which are widely distributed in desert ecosystems, play a pivotal role in sustaining regional ecological stability by mitigating wind erosion, enhancing soil fertility, and fostering biodiversity. Soil stoichiometric characteristics serve as critical indicators of nutrient cycling dynamics and ecosystem resilience within nebkha systems. This study focuses on the Nitraria tangutorum nebkhas, a dominant shrub species in arid regions, aiming to elucidate soil stoichiometric patterns and their underlying drivers.

Field sampling was conducted across five spatially distinct nebkhas in the eastern Qaidam Basin, China. Soil samples were collected from three microhabitats: within nebkha mounds, the subsurface zone beneath nebkhas, and the inter-nebkha substrate. Vertical profiles (0−135 cm) were analyzed for total nitrogen (TN), total phosphorus (TP), organic carbon (SOC), available nitrogen (AN), available phosphorus (AP), and available potassium (AK). Stepwise regression analysis identified key soil factors influencing stoichiometric ratios, while Spearman correlation analysis assessed relationships between nutrient ratios and environmental variables. Structural equation modeling (SEM) quantified the direct and indirect effects of soil physicochemical properties (e.g., cation exchange capacity, bulk density, soil moisture, root biomass, and litter accumulation) on stoichiometric dynamics.

1) The average contents of TN, TP and SOC in Nitraria tangutorum nebkhas were 0.11−0.13 g/kg, 0.38−0.43 g/kg, and 1.48−1.76 g/kg, respectively, lower than other deserts in TN and SOC. TP content in nebkhas was significantly depleted compared to underground section of inter-nebkhas (P<0.05). AN, AP and AK contents are in range of 2.98−4.31 mg/kg, 2.67−3.93 mg/kg, and 68.68−87.03 mg/kg, respectively, at the levels of extreme deficiency, deficiency and slight deficiency. AP content in nebkhas was significantly higher than in underground section (P<0.05), and AK content in nebkhas was significantly higher than underground section beneath (P<0.05) and inter-nebkhas (P<0.001). The mean Stoichiometric ratios values (C/N: 14.64−15.45, C/P: 3.86−4.48, and N/P 0.25−0.32) revealed the deficiency degree of nutrients in order of N>C>P. C/N ratios exceeded those in natural deserts but were lower than in oasis plantations, while C/P and N/P ratios were universally lower than in other desert soils. N/P in nebkha mounds surpassed subsurface values (P<0.05). 2) TN, SOC, AN, AP, AK, C/P, and N/P exhibited a "decrease-increase-decrease" trend with depth, whereas TP declined uniformly and C/N increased. Nutrient accumulation peaked in surface (0−5 cm) and deep (110−130 cm) layers. Root volume, diameter, biomass, and litter weight as well as soil moisture varied significantly across soil layers (P<0.05), with the 100−135 cm layer harboring dense root networks and elevated moisture. 3) Soil stoichiometry was jointly influenced by nutrient availability (AN, TP, SOC) and physicochemical factors (cation exchange capacity, bulk density, moisture, root biomass, litter mass). SEM highlighted root distribution and litter accumulation as primary mediators of moisture heterogeneity, thereby regulating nutrient cycling and stoichiometric ratios.

The Nitraria tangutorum nebkhas exhibit pronounced nutrient scarcity (TN, TP, SOC, AN, AP), with nitrogen emerging as the primary growth-limiting factor. Vertical nutrient dynamics reveal a stratified pattern: subsurface P depletion, surface and deep nutrient enrichment, and mid-profile minima. The heterogeneous distribution of roots and litter, coupled with soil moisture gradients, drives these stoichiometric shifts. These findings underscore the vulnerability of nebkha ecosystems to nutrient stress and emphasize the need for conservation strategies that prioritize soil fertility restoration and belowground biodiversity protection.

We investigated the impacts of returning wheat straw combined with distinct tillage practices on the annual productivity and nitrogen (N) utilization efficiency of a wheat-maize rotation system, as well as on soil N storage dynamics. The objective was to identify an optimal straw management strategy for this system.

A long-term field trial was established in Jinan City, Shandong Province, in 2012, employing a winter wheat-summer maize rotation. The conventional practice (CK) served as the control, involving the return of both wheat and maize straw post-harvest, followed by rotary tillage before wheat sowing and no-tillage before maize planting. The experimental treatments included returning only wheat straw with deep tillage (DT), rotary tillage (RT), or no-tillage (NT). During the 2021−2023 harvest seasons, plant samples were collected to assess biomass, N content, and yield. Soil samples were simultaneously obtained across the 0−100 cm profile at 20 cm intervals to determine total N content, enabling calculations of apparent N loss and N use efficiency (NUE).

Compared to CK, the RT treatment significantly enhanced wheat, maize, and annual yields over two years, with increases of 4.4%, 5.4%, and 5.1%, respectively. Conversely, the DT treatment reduced yields in 2021 but had no significant impact in 2022, while the NT treatment had no significant effect on wheat yield but decreased maize and annual yields by 3.8% and 4.7%, respectively. Returning only wheat straw reduced soil N input by 33.1% compared to returning straw in both seasons. The RT treatment significantly increased annual crop N uptake by 5.2% relative to CK, whereas DT and NT treatments decreased it by 5.3% and 5.1%, respectively. Soil N storage under RT was 51.9% lower in the 0−20 cm layer but 34.7% and 56.7% higher in the 20−40 cm and 40−60 cm layers compared to CK. Moreover, RT exhibited 36.2% and 63.5% higher N storage in the 0−20 cm layer than DT and NT, respectively, while being 31.3% and 45.7% lower in the 20−40 cm layer. Annual N loss under DT, RT, and NT was significantly lower than CK, with RT showing the greatest reduction (67.6% over two years), followed by DT (43.9%) and NT (42.0%). RT increased aboveground N uptake by 10.4% compared to CK, whereas DT and NT decreased it by 5.3% and 5.1%, respectively. Under single-season straw return, DT, RT, and NT treatments significantly improved aboveground NUE compared to CK, with RT demonstrating the highest increase (37.0%), significantly exceeding DT (16.2%) and NT (12.6%).

Returning wheat straw in combination with rotary tillage enhances the annual yield of wheat and maize, promotes plant N uptake, increases soil N storage, and reduces N loss in farmland, thereby achieving a synergistic improvement in annual yield and N utilization efficiency. This practice is recommended as an effective annual straw management strategy for intensive wheat-maize cropping systems in the Huang-Huai-Hai region.

Light intensity and nitrogen supply heavily affect the growth of Cunninghamia lanceolata seedlings. We measured the growth and physiological indices of Cunninghamia lanceolata seedlings under different light intensity and nitrogen application rates.

Awith two-factor randomized block design pot experiment was conducted in the state owned Cunninghamia lanceolata seedling forest, located in Shunping City, Fujian Province, one-year-old seedlings was used as test materials. Four shading levels were applied to simulate natural light reduction: 0% shading (L0, full sunlight), 25% shading (L1), 55% shading (L2), and 80% shading (L3). Three N levels were administered per seedling: N 0 g (N0, control), N 4 g (N1, moderate), and N 6 g (N2, high). The seedlings were exposed to the experimental conditions for one year, with regular maintenance to ensure consistent growth conditions. Then seedling height and ground diameter were measured, the antioxidant indices in leaves were analyzed to calculate the resistance to stress, and the endogenous hormone contents in apical buds were measured as well. The promotion effects of treatments was screened by subordination function method.

Compared with L₀N₀, suitable shading promoted the height and ground diameter growth of C. lanceolata seedlings, nitrogen application further enhanced the promoting effect of shading. L₂N₁ was recorded the most suitable light-nitrogen combination, with seedling height and ground diameter increased by 139.54% and 89.84%, compared to L₀N₀. Both shading and nitrogen application increased the activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD), reduced the accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) in the leaves C. lanceolata seedlings, thereby enhancing the seedlings' total antioxidant capacity. L₂N₁ and L₂N₂ were tested higher CAT, SOD, POD activities and total antioxidant capacities, with the increment in L₂N₁ by 131.67%, 24.26%, 625.70%, and 141.84%, and decline in H₂O₂ and MDA contents by 72.71% and 66.42% as compared with L₀N₀, respectively. Shading impacted led to lower CTK and ABA content in the buds and GA and ABA content in the stems of C. lanceolata, but higher ratios of CTK/GA, GA/ABA, and IAA/ABA. N application offset the inhibition of hormones by shading, and significantly improved the contents of IAA, GA and ABA, as well as the ratios of CTK/GA, GA/ABA and IAA/ABA in buds and stems of C. lanceolata seedlings (P<0.01), and the effect were not significantly different between N₁ and N₂. The subordination function analysis results showed that the most suitable light-nitrogen combination treatment for the growth of C. lanceolata seedlings was L₂N₁ treatment.

An appropriate light-nitrogen combination can effectively increase the IAA and GA contents and the IAA/ABA and GA/ABA ratios, decrease the CTK/GA ratio in buds, and enhance the antioxidant enzyme activity, which resulting high scavenging capacity, as a consequencece promoting the growth of C. lanceolata seedlings. Under the test conditions, the suitable light intensity and nitrogen application rate are 542.68 μmol/(m²·s) and 4 g/seedling for high quality C. lanceolata seedling production.

We analyzed the filling capacities and the starch synthesis activities at different positions of rice grains under different N and P supply levels, so as to provide a theoretical basis for balanced of nitrogen and phosphorus fertilization in japonica rice cultivation in northern China.

In 2021 and 2022, field trials were conducted at the Kalima Rice Experimental Station of Shenyang Agricultural University using the japonica Beigeng 3. Three N and P application levels were used to compose 9 treatments, conventional level N 210 kg/hm² and P₂O₅ 105 kg/hm² (N3, P3), 15% reduction (N2, P2), and 30% reduction (N1, P1). From flowering (flower appeared on the top spikelets of rice) to maturing stage, 15 panicles samples were collected in a 5-days frequency, and the superior, medium and inferior grains were separately picked, and part of them were dried to weight biomass, then using Richards formula to fit the filling process and calculated the initial growth potential (R₀), maximum grain filling rate (Gmax), the time reaching maximum filling rate (Tmax.G) and the biomass (Wmax.G), and calculate the mean filling rate (Gmean) and vigital filling days (D). The other part were used for determination of starch synthesis enzyme activities. At harvest, rice yield, effective panicles, and spikelets per panicle, seed setting rate, 1000-grain weight of superior, medium and inferior grains were investigated.

The P levels required to achieve high yields varied among the N levels, N3P2 N3P2, and N2P1 treatments were recorded similar yields, which were significantly higher than the other treatments. Under N3 level, P2 achieved similar yield components, but P1 achieved significantly lower effective panicles, spikelets per panicle and seed setting rate. Under N2 level, P3 significantly decreased the effective panicles and spikelets per panicle, P2 significantly decreased the spikelets per panicle, while P1 increased the spikelets per panicle, and maintained similar 1000-grain weight. Compared the N3 level, N1 significantly decreased the yield and yield components of rice. Among the three high yield treatments, N2P1 resulted higher spikelets per panicle of superior, medium, and inferior grains, similar seed-setting rate of superior and medium grains, but significantly lower seed setting rate of inferior grains, compared to N3P3 and N3P2 treatments. The 1000-grain weight was most affected by the medium grains, followed by the inferior grains. P level was beneficial to increase the 1000-grain weight of all the superior, medium and inferior grains. Within the range of nitrogen and phosphorus fertilizers tested, reducing N and P reduced the Gmax, Gmean and Wmax.G, prolonged the Tmax.G and D. The D for the N3P2 and N2P1 treatments of superior, medium and inferior grains were extended by 3.6, 2.3, 2.3 d, and 3.8, 3.3, 2.3 d, respectively. Compared with N3, N2 suppressed AGPP activity in superior and inferior grains, but the difference in the activities of SSS, SBE and GBSS were minimal; N1 reduced the activity of these enzymes. Reducing P inhibited the activities of AGPP and GBSS in superior grains and the GBSS activity in inferior grains. Correlation analysis showed that the Gmean of superior grains was mainly regulated by the activities of AGPP, SSS and GBSS, and the grain weight was mainly positively affected by the activities of SSS. There was a significant positive correlation between the grain weight of inferior grain and its AGPP and SSS activities.

P level significantly influences the Gmax, Gmean, and Wmax in superior grains and the Tmax.G in medium grains, and N level significantly affect the Wmax in medium grains and Tmax.G in inferior grains. Balancing the N and P levels can harmonize the key enzyme activities of starch synthesis in superior and inferior grains during the filling period, affecting the comprehensive advantages of grain filling characteristics and yield components of rice, and achieving increased and stable rice yield.

Carbon-carbon double bonds in vegetable oils are the precursor to form hydroxyl group. This study investigated the effect of carbon-carbon double bonds in different vegetable oils on the physicochemical properties of polyols, and characterized the structures and properties of the polyurethane coatings derived from these polyols. The structure-property relationships among carbon-carbon double bonds, polyol characteristics, and the performances of the polyurethane coatings were elucidated, to reveal the regulatory mechanism of the carbon-carbon double bonds on the performance of the coatings.

Four vegetable oils (linseed oil, soybean oil, olive oil, and palm oil) were used as feedstock, and the epoxidation/ring-opening method was used to synthesize four vegetable oil polyols, denoted as LOP, SOP, OOP, and POP. Then the four polyols were reacted with isocyanate to prepare coated urea LPCU, SPCU, OPCU, and PPCU within coating machine through in-situ reaction technology, respectively. The hydroxyl value, acid value, and viscosity of vegetable oil-based polyols were analyzed, the microstructures of the vegetable oil polyols and the coatings were characterized by Fourier Transform Infrared Spectroscopy (FTIR), ¹H Nuclear Magnetic Resonance Hydrogen Spectroscopy (¹H NMR), and X-ray Photoelectron Spectroscopy (XPS). The cumulative N release periods of the coated urea samples were tested using water dissolving and soil incubation methods. Finally, LPCU was used by a pot experiment.

The C=C bond contents in LO, SO, OO, and PO were 5.71, 4.26, 4.29, and 1.97, respectively. After modification, FTIR spectra of all polyols showed O-H stretching vibration peak near 3500 cm⁻¹, and ¹H NMR methylene proton peak adjacent to hydroxyl group at 3.60 ppm, indicating the successful synthesis of four types of vegetable oil polyols. The hydroxyl values of LOP, SOP, OOP, and POP were 194, 137, 141, and 132 mg KOH/g, the functionalities were 4.4, 3.6, 3.8, and 2.6, and the viscosities were 1431, 2016, 2858, and 746 mPa·s, respectively. Polyurethane coatings derived from these polyols showed significant differences in the C-O stretching vibration (1250−1000 cm⁻¹), with the fitted peak area percentages in LPU, SPU, OPU, and PPU of 18.15%, 15.43%, 11.03%, and 10.70%, respectively, and the C=O fitting peak area percentages were 4.20%, 4.15%, 3.53%, and 3.46%, respectively. The initial nitrogen release rates (<2.5%) of LPCU, SPCU, OPCU, and PPCU were 1.7%, 1.9%, 1.0%, and 2.4%, demonstrating the integrity of the coatings. The N release periods were 56, 35, 35, and 14 days, with only PPCU failing to meet controlled-release criteria. The pot experiment showed that although LPCU was reduced by 30%, the crop yield did not decrease.

The content and position of carbon-carbon double bonds in vegetable oils critically affected the physicochemical properties of modified vegetable oil polyols and the structure and function of polyurethane coatings. Vegetable oils with high conjugated trienes and dienes exhibited higher hydroxyl values after modification, leading to higher crosslinking densities in the controlled-release coatings and improved controlled-release performances of the coated urea samples. However, the minimum number of carbon-carbon double bonds required in vegetable oils to form high-quality coatings, as well as the lower limit of double bonds at different positions, still need further research. Additionally, the process for increasing the hydroxyl values of modified vegetable oils also requires further exploration.

The efficiency of membrane separation technology in concentrating kitchen waste biogas slurry was evaluated, and the fertilization efficacy and economic performance of the compounded humic acid water-soluble fertilizer derived from the concentrated slurry was assessed.

Ultrafiltration (UF) membrane technology was employed to concentrate kitchen waste biogas slurry at 2×, 4×, 6×, and 8×folds, respectively. The concentrations of N, P, K, and humic acid (HA) in the concentrates were analyzed. Based on the analysis results, concentration at 6 folds was chosen in the following research. Potassium humate, monopotassium phosphate, and urea were added to the 6-fold concentrate of kitchen waste biogas slurry to formulate a humic acid water-soluble fertilizer. A 1 L sample of this fertilizer was stored at 4±2°C and 30±2°C for 63 days. Samples were collected at 7-day intervals to determine humic acid, total N, total P, total K, pH, and EC. The fertilizer was diluted at 100×, 200×, and 300× for pot experiments using cherry radish as test crop material, with distilled water as a control. The seedling height, stem diameter, fresh and dry biomass, and leaf SPAD values were measured, and the contents of soluble sugars and vitamin C were analyzed. At the same time, soil pH, organic matter, and available N, P, and K levels were analyzed. Subsequently, the 100× dilution of the biogas slurry humic acid fertilizer was selected for comparison with humic acid, chemical fertilizer, and commercial humic acid fertilizer in another pot trial to evaluate their effects on plant growth and soil improvement. Economic cost analysis and sensitivity analysis were conducted to further assess the economic viability and cost-sensitive factors of the fertilizer.

As the concentration factor increased, the contents of nitrogen and potassium in the concentrate remained relatively stable, while humic acid and TP concentrations significantly increased. At 6× concentration, the humic acid content rose from 2.33 g/L to 13.96 g/L. The cost of concentration decreased initially and reached its lowest at 6× concentration before increasing again. After 63 days of storage at both 4±2°C and 30±2°C, the humic acid fertilizer exhibited stable nutrient content, pH, and EC. Pot experiment results indicated that higher dilution led to reduced plant growth-promoting effects and lower soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium levels. Application of the biogas slurry humic acid fertilizer significantly enhanced cherry radish growth, biomass, and SPAD values compared to those treated with humic acid alone, chemical fertilizer, or commercial humic acid fertilizer. Economic sensitivity analysis revealed that, at a 6× concentration rate, a 20% increase in the prices of humic acid, NPK fertilizers, and concentration energy consumption resulted in cost increases of 2.57 CNY/L, 0.79 CNY/L, and 6.54 CNY/L, respectively.

UF membrane technology effectively concentrates humic acid and P in kitchen waste biogas slurry effectively, with 100% humic acid and 80% P retention rate at 6× concentration, while the N and K retention is low, ranged from 10% to 50%. The resulting concentrate, with a humic acid content of 13.96 g/L, is suitable for formulating humic acid-based fertilizers. The prepared humic acid water-soluble fertilizer meets national standards, and maintains excellent stability under storage conditions of 4-30°C. When applied to soil at a 100× dilution, it demonstrates superior plant growth promotion and soil improvement effects compared to chemical and commercial humic acid fertilizers. The costs of humic acid addition and energy consumption during concentration are the primary factors influencing the overall production cost of the fertilizer.

We conducted a field experiment to optimize the combination of tillage method and straw return amount, in order to support the sustainable and efficient maize production in Xiliao River Plain Irrigation Area, Northeast China.

A positioning experiment was carried out for three years at the Experimental Demonstration Base of Tongliao City Animal and Plant Science Research Institute, the test crop was maize. Nine treatments were included in the experiment: rotary tillage without straw return (RT), clearing stubble and straw in ridge and deep spin in strip cultivation (SCN), clearing stubble and return all straw followed with deep rotary tillage in strip (SCA), subsoil tillage without or with straw return (STN, STA), deep plow tillage without or with straw return (PTN, PTA), no-tillage without or with straw return (NTN, NTA). From 2018 to 2020, soil physical properties, moisture conditions, and water use efficiency were investigated each year. The key soil factors affecting water use efficiency (WUE) were also explored.

Among several tillage methods, totals straw return following subsoiling (STA) showed the best effect on decreasing soil bulk density and increasing porosity of 0−45 cm soil layer, and improving the water use efficiency of maize. Compared with the conventional shallow tillage (RT), STA reduced soil bulk density by an average of 8.18%, increased soil porosity by 11.69%, increased soil water content in 40−80 cm layer by 8.03% and the soil water storage by 8.23%, reduced the water consumption by 6.82%, and increased maize yield by 17.34%, the water use efficiency was thus increased by 31.36%. The soil water storage and water content contributed the highest to the WUE, accounting for 64.59%, 62.89% of the WUE increment, respectively.

Full straw returning following by subsoiling could reduce soil bulk density and increase porosity of 0−45 cm layer, thereby enhance soil water reservoir, and increase maize water use efficiency and yield. Full straw returning following by subsoiling is regarded as an ideal tillage method for high maize yield and efficient use of water resources in the Xiliao River Plain irrigation areas.

Chemical fertilizers are often over applied in citrus orchards for high fruit yield. Citrus is mycorrhiza - dependent plants, has relatively few root hairs, so requiring assistance from microorganism for sufficient nutrient absorption. Therefore, we studied the effects of fertilization practices on the community structure,diversity, and co-occurrence network patterns of arbuscular mycorrhizal fungi (AMF)in citrus soil.

The research choosed 24 citrus orchards in Quzhou City, Zhejiang Province, including 5 orchards without fertilizer application (NF), 10 orchards only applying chemical fertilizer (CF), and 9 orchards with co-application of chemical and organic fertilizers (COF). Soil samples were collected in the orchards, and the wet-screened decanting-sucrose centrifugation method was used to determine AM fungi spore density, the high-throughput sequencing technique was used for analysis of soil AM fungal community.

Compared to NF orchards, COF significantly increased the fruit Vc and solid acid contents by 22.1% and 65.5%, enhanced soil organic carbon, total N, and available NPK contents. Neither COF nor CF changed soil pH, easily extractable glomalin, and AM fungal spore density significantly. The dominant genera of soil AM fungi were Funneliformis, Glomus, and Rhizophagus. Compared to NF, CF and COF decreased the relative abundance (RA) of Funneliformis but increased that of Rhizophagus significantly. The RA of Rhizophagus was positively correlated with soil organic carbon, and available K contents, positively correlated with fruit Vc content and solid-acid ratio. The RA of Glomus and Funneliformis negatively correlated with soil organic carbon, and available Kcontents. However, Compared to NF, CF and COF did not affect on the Shannon and Simpson indices of AM fungal community, but decreased AM fungal richness (Chao1 index) and changed the community structure significantly. Fertilization changed the Co-occurrence network patterns of AM fungi, and the network under NF treatment being the most stable.

Fertilization significantly altered soil AM fungal community structures and changed their relative abundances at genus level through modifying soil organic carbon and available K content, consequently declined the complexity and stability of AM fungal community networks. The co-application of organic and chemical fertilizers significantly improved the fruit quality of citrus, and soil nutrient content and the relative RA of Rhizophagus due to high soil organic carbon and available K, and the high spore density.

This study explored the effects of organic materials on nutrient accumulation in maize, and provide nutrient management techniques for maintaining soil microbial ecosystems and sustainable agricultural development.

A positioning field experiment was carried out in Heilongjiang for two consecutive years. The experiment included one chemical fertilizer control ( CK ) and three chemical fertilizer combined with organic material treatments ( decomposed straw, humic acid, chicken manure ). During the maize harvest period, the study investigated the accumulation of nutrients in the upper part of the maize field, the activity of soil enzymes, and the microbial diversity of soil bacteria and fungi.

Compared with CK, all the three combined organic material application increased the yield and accumulation of nitrogen and phosphor and potassium in maize plant. The chicken manure treatment resulted significantly different bacteria and fungal community structures, relative to the other treatments. In all the treatment soils, the number of differential microbial species specific to bacteria was higher than that to fungi. The four bacterial phyla with a relative abundance greater than 5% are Proteobacteria, Acidobacteriota, Gemmatimonadota and Actinobacteriota. Three bacterial families are Sphingomonadaceae, Gemmatimonadaceae and Vicinamibacteraceae, and one bacterial genus is Sphingomonas. The three fungal phyla with a relative abundance of more than 5% are Ascomycota, Basidiomycota and Mortierellomycota, and one fungal family is Chaetomiaceae. One genus of fungi is Podospora. All the organic material treatments, except for humic acid on sucrase and straw on catalase, did not significantly change the activities of soil enzymes. The relative abundance of Basidiomycota was negatively correlated with maize N and K accumulation, and the relative abundance of Mortierellomycota was positively correlated with maize K accumulation.

At the base pf conventional chemical fertilizer, combined application of organic materials further inproved the nitrogen and phosphor and potassium accumulation and yield of maize. Chicken application resulted significantly different bacteria and fungal structures. Chicken and maize straw application increased the differential bacteria number, but decreased the differential fungal number, and humic acid did bit have impaction on them. Enzyme activities showed close relative relationship with soil microbial composition, especially Sphingomonas in bateria phylum and Podospora in fungal phylum. Maize nitrogen and phosphorous uptake are correlated with soil sucrase activity.

We explored the alleviation effect of exogenous 6-benzylaminoadenine (6-BA) on the decline of photosynthetic performance and yield of wheat after low temperature (LT) stress at booting stage, and the appropriate spray concentration.

A low temperature insensitive wheat variety ‘Yannong 19’ and a not sensitive wheat variety ‘Wanmai 52’ were selected as the test materials in a pot experiment. The wheat pots were filled with the 0−20 cm layer soil in a paddy, and burried into soil during the wheat growing periods. At the boosting stage, wheat pots were dig out and subjected to low temperature stress in a growing chamber for one day. The designed low temperature were −2°C, and 0°C during 18:00−06:00, and 5°C during 06:00−18:00. Then the wheat pots were moved back to the field and sprayed with 10, 20 and 30 mg/L 6-BA solution, and the same amount of distilled water as control, respectively. At the booting, grain filling and maturing stage of wheat, the flag leaf samples were collected for the measurements of SPAD, photosynthetic parameters and relative enzyme activities. Grain samples were collected since the 10th day of anthesis for the determination of grain filling rate, at maturing stage, yield and 1000-kernal weight were investigated.

Compared with the control group, spraying 6-BA increased the SPAD value, net photosynthetic rate (P_n), stomatal conductance (G_s), transpiration rate (T_r) and maximum photochemical efficiency (F_v/F_m) of flag leaves of wheat subjected to low temperature stress, and increased the RuBP carboxylase activity by 15.17%−43.61% and the PEP carboxylase activity by 6.40%−30.64%. Compared with the control, spraying 6-BA increased the average grain filling rate and grain weight of Yannong 19 by 5.56%−21.28% and 1.32%−20.84%, respectively, and increased the average grain filling rate and grain weight of Wanmai 52 by 3.26%−13.98% and 6.26%−27.67%, respectively.

Spraying 6-BA at booting stage can significantly improve the photosynthetic characteristics of wheat flag leaves after low temperature stress, speed up the grain filling rate and enhance the 1000-gain weight of wheat, thus reduce the yield loss caused by low temperature stress. In this experiment, 20 mg/L 6-BA solution shows the best mitigation effect on the effects of low temperature stress.

In north China, there are many problems such as low nitrogen utilization efficiency and unstable yield in the large area of medium and low yield fields. Therefore, this paper studies the influence of reducing 20% of nitrogen fertilizer and applying different amounts of organic fertilizer on winter wheat yield and fertilizer utilization rate on the basis of farmers' habit of applying nitrogen.

During 2022−2024, a field trial were conducted for two consecutive winter wheat seasons in central of north China plain. Seven treatments were setup, including no nitrogen fertilizer (N0), conventional nitrogen application rate (N1), reducing nitrogen rate by 20% (N2), and combined application of humic acid compound fertilizer (N3), functional bio-organic fertilizer (N4), microalgae (N5), and weathered coal bio-fertilizer (N6) at the same total N input with N2. The photosynthetic parameters of flag leaves of wheat were measured at anthesis stage. The plant samples were taken to investigate the dry matter accumulation, nitrogen uptake, and transport at the key growing stages. And grain yield and protein content were analyzed at harvest.

Compared to N2, the net photosynthetic rate increment of wheat flag leaves treated with four different organic fertilizers did not reach a significant level; the transpiration rate increased significantly by 4.3% to 33.5%, with N7's transpiration rate being significantly higher than N6's; N3 reduced the inter-row CO₂ concentration; N3 and N4 treatments increased dry matter accumulation at all stages, while N5 and N6 increased dry matter accumulation during the flag emergence, flowering, and maturity stages, with an increase in above-ground dry matter accumulation of 8.9% to 18.2% during maturity; N3, N4, N5, and N6 treatments increased nitrogen accumulation from green-up to flowering stages, with only N4 increasing nitrogen accumulation during maturity, by 15.8%. Compared to N1, N2 treatments either decreased or remained unchanged in pre-flowering nitrogen transport, whereas N3, N4, N5, and N6 treatments increased pre-flowering nitrogen transport. Compared to N1, N2 reduced grain weight (2022) and effective ear number (2023), while N3, N4, N5, and N6 treatments significantly increased effective ear number, grain weight, and nitrogen fertilizer agronomic efficiency, with N3 and N4 significantly increasing yield; N2, N5, and N6 treatments reduced protein content in grains, while N3 and N4 had no significant effect on protein content. Structural equation analysis results show that fertilization directly affects wheat nitrogen and dry matter accumulation (path coefficients 0.86**, 0.90**), which in turn affects leaf photosynthetic characteristics (0.52*), and dry matter accumulation directly affects grain yield (0. 7*), the comprehensive effect of each fertilizer treatment in two years was ranked as N4>N3>N6>N5>N1>N2>N0.

Farmers habitually reducing nitrogen by 20% has no significant impact on wheat photosynthetic efficiency, dry matter accumulation, and nitrogen utilization. Applying functional bio-organic fertilizers and humic acid compound fertilizers on top of a 20% nitrogen reduction can further increase the accumulation of dry matter and nitrogen during all growth stages, promoting the transfer of dry matter and nitrogen to grains. This ultimately significantly boosts wheat yield and protein content, enhancing nitrogen fertilizer efficiency. Applying weathered coal bio-fertilizer on top of a 20% nitrogen reduction can increase nitrogen accumulation before flowering, but the nitrogen accumulation during flag leaf emergence and flowering is notably lower compared to applying functional bio-organic fertilizers after a 20% nitrogen reduction. Considering the large area of medium-and low-yield wheat fields in the North China Plain, it is recommended that applying functional bio-organic fertilizers on top of a 20% nitrogen reduction can achieve cost savings and increased efficiency.

This study explored the effect of spraying KH₂PO₄ on alleviating the damage of heat stress on weight formation of superior and inferior grains.

A field experiment was conducted using a semi-winter wheat cultivar Annong0711 as experimental material. Four spraying treatments were setup, including: water (SW), water+heat stress (SW+HT), 0.3% KH₂PO₄ (KDP) and 0.3% KH₂PO₄+heat stress (KDP+HT). Spraying treatment was conducted on the 3rd and 11th day after anthesis, and heat stress treatments were made by shelting wheat with plastic film between 11:00 and 16:00 during post-anthesis 20−24 day. Flag leaf SPAD, soluble sugar and sucrose content were measured at the 19 d (before hot stress), 24 d (after hot stress), and maturing stage, and the starch accumulation and weight of superior and inferior grains were measured.

Hot stress significantly reduced flag leaf chlorophyll content, while KDP mitigated the decline and maintained higher chlorophyll levels until maturing stage. Compared to SW, KDP treatment was recorded significantly higher soluble sugar and sucrose content in flag leaves and stems + sheaths before and after hot stress (P<0.05), and the amylose, amylopectin and total starch content in both superior and inferior grains, regardless of hot stress. Hot stress significantly decreased amylopectin content, with a greater reduction in inferior grains, and KDP reduced the starch content decrease under hot stress. Heat stress significantly decreased the average grain-filling rate after the hot stress period, with a larger decline in inferior grains than in superior grains. KDP significantly improved grain-filling rates in the late grain-filling stage, resulting in a notable increase in grain weight, with a greater enhancement observed inferior grains compared to superior grains. Compared to SW+HT, SW, KDP and KDP+HT treatments increased grain yield at maturity by 9.46%, 11.06%, and 16.79%, respectively.

Hot stress weakens wheat's photosynthetic and material production capacity, inhibits grain filling rates, especially that inferior grains, and ultimately reduces grain weight and yield. Post-anthesis foliar application of 0.3% KH₂PO₄ helps delay the senescence of flag leaf under heat stress, maintain the supply of photosynthetic assimilates, and improve grain-filling capacities of both superior and inferior grains, narrows the lag between superior and inferior grains weight formation, thereby increasing overall grain yield.

Traditional maize production uses to apply full doses of phosphorus and potassium fertilizer in base, only apply nitrogen fertilizer in base and topdressing. We studied the effects of multiple topdressing of all the NPK fertilizers across maize growing season, by use of the shallow-buried drip irrigation.

Taking spring maize cultivar ‘Dika 159’ as test materials, three field experiments were conducted in 2022 and one in 2023 in four different cities in West Liaohe Plain Irrigation District of Inner Mongolia. Three fertilization treatments, with the same total amount of N, P and K fertilizer amounts (N 270 kg/hm², P 120 kg/hm², and K 70.5 kg/hm²), were set: conventional fertilization (CK), topdressing total fertilizer in three times (WF-3), and in six times (WF-6). In addition, no nitrogen (N0), phosphorus (P0), or potassium (K0) treatments were arranged for calculation of fertilizer use efficiency. Plant samples were collected at silking, milk maturity, and maturity stage for analysis of biomass, and NPK contents. At harvest, the yield and yield components were investigated.

Compared with CK, the average increments of four experiments in two years in WF-3 and WF-6 treatments were: population biomass by 3.60% and 8.61%, kernel number per ear by 2.78% and 6.37%, 1000-kernel weight by 2.03% and 4.96%, yield by 5.26% and 12.35% through increased of 1000-grain weight and kenal number per ear, and net profits by 7.77% and 12.32%, respectively; N agronomic efficiency by 16.17% and 41.63%, N accumulation in vegetative organs by 8.64% and 9.77%, N export from vegetative organs by 5.61% and 6.57%, post anthesis grain N accumulation by 13.62% and 15.07%; phosphorus agronomic efficiency by 16.24% and 41.76%, post-anthesis grain P accumulation by 13.38% and 24.56%; potassium agronomic efficiency by 16.37% and 41.83%, vegetative organ K accumulation by 10.87% and 13.35%, K export from vegetative organs by 15.07% and 17.96%. In addition, the effects of WF-6 treatment were all significantly higher than WF-3.

Split topdressing all the NPK fertilizers boosts dry matter accumulation pre- and post-anthesis stage, improves pre-anthesis nutrient uptake and accumulation and the distribution to grains resulting in notable increases in yield, nutrient efficiency, and economic returns. All the results of four experiments in two years proved the satisfactory effect of topdressing fertilizers in six times by means of drip irrigation for spring maize production in Inner Mongolia.

To investigate the effects of zinc fertilizer and its combination with organic fertilizer on soil zinc content and wheat zinc accumulation in dry-crop wheat fields under different biochar application rates in the long term.

A long-term field experiment investigating biochar application was established in 2012 with four treatment levels: 0 t/hm² (C0), 10 t/hm² (C10), 30 t/hm² (C30), and 50 t/hm² (C50). In 2020, three subplot treatments were implemented within each main plot: no zinc application (CK), zinc fertilizer alone (Zn), and zinc fertilizer combined with organic manure (Zn+M). Following the 2021 winter wheat harvest, we measured aboveground biomass and zinc concentrations in plant tissues. Soil samples were collected to analyze total zinc content, bioavailable zinc, and zinc fraction distribution.

After nine years of biochar application, no significant effects were observed on total zinc (Tol-Zn) or available zinc (DTPA-Zn) in the soil. Zinc application significantly increased soil Tol-Zn and DTPA-Zn levels. Compared to the control (CK), Zn and Zn+M treatments elevated Tol-Zn by 7.5% and 12.5%, respectively, and DTPA-Zn by 210.2% and 249.7%. Furthermore, Zn+M enhanced Tol-Zn and DTPA-Zn by 4.7% and 12.7% compare to Zn alone (P<0.05). Under CK (no zinc), biochar reduced exchangeable zinc (Ex-Zn) but increased loosely organic-bound (Lom-Zn) and manganese oxide-bound zinc (Mon-Zn). In Zn-treated soils, biochar raised Lom-Zn, tightly organic-bound zinc (Sbo-Zn), and carbonate-bound zinc (Carb-Zn), while reducing Mon-Zn. With Zn+M, Lom-Zn levels under C50 and C30 biochar treatments were significantly higher than C10 and C0 (P<0.05), though no differences were observed for other zinc fractions. Compared to CK, both Zn and Zn+M enhanced Lom-Zn, Carb-Zn, Sbo-Zn, and residual zinc (Res-Zn), with Zn+M demonstrating greater efficacy. The combined application of biochar and zinc significantly increased winter wheat grain biomass. Across plant tissues, biomass and zinc content followed the order: Zn+M > Zn > CK (P<0.05). Under no zinc application (CK), C30 and C50 treatments increased zinc content in wheat stems, with C50 also enhancing leaf zinc content. However, both treatments reduced zinc levels in grains. Compared to CK, Zn and Zn+M treatments increased average grain zinc content by 13.7% and 28.3%, respectively, with Zn+M demonstrating significantly greater enhancement than Zn alone. Compare to CK, stem+leaf accumulation rose by 203.0% and 257.2%, grain+shell by 40.0% and 64.8%, and total aboveground accumulation by 60.6% and 89.1%. Zn+M again outperformed Zn in enhancement effects. Correlation analysis revealed significant positive associations (P<0.01) between wheat zinc accumulation and all measured soil zinc fractions, with the strongest relationships observed for DTPA-Zn and Lom-Zn. Random forest analysis identified Sbo-Zn, Lom-Zn, and DTPA-Zn as the primary contributors to zinc accumulation in winter wheat.

Long-term biochar application did not increase total or available zinc in rainfed wheat field soils but elevated more bioavailable Lom-Zn fractions. Zinc fertilizer application, particularly when combined with organic manure, significantly enhanced total zinc, available zinc, and organic-bound zinc fractions (loosely- and tightly-bound), thereby enhancing its potential availability. Without zinc fertilization, high biochar rates increased winter wheat grain biomass but reduced grain zinc content. When zinc fertilizer was applied, biochar further boosted grain yield without compromising zinc content at application rates of 10-30 t/hm². The combined use of zinc fertilizer and organic manure proved significantly more effective than zinc fertilizer alone in improving soil zinc availability and grain zinc enrichment.

The application of beneficial microbial seed soaking prior to sowing represents a novel technology that has yet to be employed in Lanzhou lily cultivation. We conducted an experiment to investigate the impact of this soaking method on the fungal and bacterial community structures using next-generation sequencing technology (NGS).

Lily bulbs were soaked in a kind of seed treating agent containing beneficial microbial (SP treatment) for 4 hours, then planted in soil in July and sampled in September for investigation of the plant growth, and the rhizosphere soil physicochemical properties and the microorganism community structures. Furthermore, we utilized the software PICRUSt and FUNGuild to predict bacterial pathways and fungal functions.

Under SP treatment, there were significant alterations in fungi and bacteria community structures, companied by improved soil nutrient conditions. Nota, the relative abundance of dominant microorganism groups, such as the fungi Basidiomycota, Pseudeurotium, Cladophialophora, Microascus, and Dactylonectria; as well as the bacterial Proteobacteria, Chloroflexi and Ochrobactrium, Lysobacter and RB41, underwent notable changes. Microorganism function prediction results indicated a reduction in pathotrophic fungi (including the plant pathogens) and an increase in endophytic and saprotrophic fungi under SP treatment. Among the top 20 metabolism pathways, 80% were upregulated in SP treatments compared to the CK.

Seed soaking with beneficial microbial strain promoted growth of Lanzhou lily bulbs. The beneficial microorganisms played a crucial role in regulating soil microbial structures, enhancing the accumulation of endophytic fungi, reducing pathogens, and improving soil function. Furthermore, specific microbial groups were fund to be involved in maintaining soil health.

The microstructure and hydrophilicity of coating materials are important factors that affect the nutrient release characteristics of coated urea. We investigated the variations in water contact angle and water absorption rate of the coating material with prolonged immersion duration, establishing correlations between hydrophilicity characteristic parameters and nutrient release patterns. This study provides a theoretical basis for precise regulation of nutrient release in coated urea formulations.

Three kinds of polyurethane membranes (COPU1, COPU2 and ESOPU) with different hydrophilicity were selected as coating materials. Based on this, three coated urea samples were prepared with the coating materials with an addition amount of 3%. The functional group characteristics of different membrane materials were characterized by Fourier infrared spectroscopy (FTIR). The microstructure, water contact angle, water absorption rate of coating materials and the nitrogen accumulation and release rate of coated urea samples were observed after being immersed in non-ionized water, with Scanning Electron Microscopy (SEM), contact angle measuring instrument and conventional methods, respectively, and thus the relationships between microstructure and hydrophilic and hydrophobic characteristics and urea nutrient release of coated urea samples were analyzed.

The water contact angle of three coating materials decreased first and then increased with the soaking time. When the film was not soaked, the order of water contact angle was ESOPU>COPU1>COPU2, which was opposite to the initial release rate of coated urea. The water absorption rate of coating materials had the trend of ESOPU>COPU2>COPU1, in line with the controlled-release performance of coated urea. There was a significant negative correlation between the nitrogen cumulative release rate and the water contact angle of the coating materials before the latter reached the minimum. However, a significant positive correlation existed between the nitrogen cumulative release rate and the water absorption rate of coating materials before the latter reached the saturation. There was a significant linear correlation between the release periods of coated urea and the time when the water absorption of coating materials reached saturation (y=1.94x, R²=0.987). Compared with COPU1 and COPU2, the ESOPU had more types of polar groups, and the pore size and surface porosity of coating materials were coincided with the water absorption rate and nutrient release characteristics, but the surface porosity changed inversely with the water contact angle with the extension of soaking time.

The water absorption rate of coating materials could be used as an indicator to evaluate the controlled-release performance of coated urea, the time when it reached saturation could predict the release period of coated urea, and the chemical composition and porosity of coating materials were essential reasons for affecting the release of nutrients in coated urea.

Aiming at the current situation that farmers in Inner Mongolia blind fertilizer application, resulting in crop yield potential not being able to realized, low fertilizer use efficiency and soil nutrient imbalance, we curried out recommended fertilizer application field experiments for maize, sunflower and potato in Inner Mongolia using a nutrient expert system based on yield response and agronomic efficiency, and compared it with local farmers’ fertilization practices, to verify the feasibility of applying the system in Inner Mongolia in terms of for yields, economic benefits and nutrient use efficiency.

A total of 146 field experiments were conducted in the main maize, sunflower, and potato production areas of Inner Mongolia from 2017 to 2023. There were five fertilizer treatments for each treatment: 1) fertilizer recommendation based on the nutrient expert system (NE); 2) farmers’ practices (FP); and 3)-5) omission nitrogen (N), omission phosphorus (P) and omission potassium (K) treatments based on NE. The differences in the yield, net benefits, nutrient uptake and fertilizer use efficiency between NE and FP were compared.

Compared with FP treatment, the NE treatment significantly increased the yields and economic benefits of maize, sunflower and potato (P<0.001), and the yields increased by 1167, 235 and 2433 kg/hm², and the economic benefits increased by 1546, 1572 and 2582 yuan/hm², respectively. The NE system balanced the amount of N, P and K fertilizer, and in particular, it increased K fertilizer application rate. The NE treatment increased the fertilizer input costs for maize and sunflower, so all of their net benefits derived from increased yields. The balanced fertilizer application in the NE treatment increased nutrient accumulation at maturity, and compared with the FP treatment, N accumulation in maize, sunflower and potato increased by 8.4%, 9.1% and 9.9%, P accumulation increased by 8.4%, 6.6% and 10.9%, and K accumulation increased by 11.5%, 9.9% and 11.5%, respectively. The increase in yield and nutrient uptake significantly improved the nutrient use efficiency of NE. As compared to FP, the recovery use efficiency of N fertilizer (REN) increased by 4.6, 13.6 and 14.3 percentage points in maize, sunflower and potato, respectively, and the recovery use efficiency of P fertilizer (REP) by 7.6, 8.7 and 7.1 percentage points, respectively; the agronomic efficiency of N fertilizer (AEN) increased by 3.2, 2.1, 17.4 kg/kg, respectively, and P fertilizer agronomic efficiency (AEP) by 12.6, 4.0, and 27.9 kg/kg, respectively. The recovery use efficiency of K fertilizer (REK) increased by 13.8 percentage points in potato, and K fertilizer agronomic efficiency (AEK) by 8.7 kg/kg, respectively.

Fertilizer recommendation for maize, sunflower and potato using nutrient expert system which based on yield response and agronomic efficiency in Inner Mongolia, will play an important role in guaranteeing food security and improving the agricultural productivity by balancing the amount of N, P, and K fertilizers to increase crop yield and net benefits, while improving nutrient uptake and fertilizer use efficiency. Therefore, this recommended fertilization method is applicable to smallholder production systems in Inner Mongolia.

Wheat grain nitrogen (N) content is the basis for calculating N management indicators. Studying wheat grain N content and its influencing factors in different agro-ecological zones in China is an important basis for scientifically formulating management measures to increase wheat yield and quality.

We searched the Web of Science and CNKI databases for literature published between 1980 and 2023 using the keywords of “wheat”, “yield” and “grain N content”, we adhered to the following criteria to avoid bias in screening literature: (1) the trials were conducted in the field condition in China; (2) the number of replications of the experimental treatments was at least three; (3) the experiment included at least one complete wheat growing season; (4) the grain N content must be reported, or it can be calculated by the reported grain yield and N harvest. Finally, we got 333 papers, including sample size of 3086 of grain yield and 1789 of grain N content. We analyzed the differences of wheat grain yield and N content in the four major agrecological zones of Northwest China, North China Plain, Middle and Lower Yangtze River Plain, and Southwest China, wheat N harvest and N surpluses in different agro-ecological zones were also calculated, and Pearson's correlation coefficient analysis, Meta-analysis, and Analysis of Variance (ANOVA) were used to study the effects of climate, soil, N fertilizer management, and varietal differences on wheat grain N content. Thus to analyze the reasons for the spatial differences in wheat grain N content.

The average N content of wheat grain in China is 2.37%, with significant differences in different agro-ecological zones. The N content of wheat grain in the North China Plain and Northwest China is relatively high, at 2.43% and 2.37%, respectively, while that in Southwest China and the Middle and Lower Yangtze River Plains is relatively low, at 2.21% and 2.18%, respectively. Wheat N harvest (N surplus) calculated based on the national average N content differed from those calculated using the regionalized grain N content by 0, -4, 10 and 8 kg/hm² in the Northwest China, North China Plain, Middle and Lower reaches of Yangtze River and Southwest China, respectively. Wheat grain N content was negatively correlated with the average annual rainfall (P≤0.001) while positively correlated with the average annual air temperature and the amount of N applied (P≤0.01). There were significant differences in the yields of different functional kinds of wheat in China, which were characterized as medium gluten (6.25 t/hm²) > strong gluten (5.99 t/hm²) > weak gluten (5.76 t/hm²). There was no direct correlation between wheat grain yield and N content, and synergy between yield and quality can be achieved at medium levels of yield. There was also a significant difference in grain N contents among different wheat varieties. Variety selection and rational N application are effective measures to synergize the improvement of wheat yield and grain N content.

When calculate wheat N harvest, it is necessary to consider the differences in grain N content in different agro-ecological zones to accurately assess regional N surpluses and N use efficiency. The main factors affecting wheat grain N content include average annual rainfall, average annual temperature and N application. The wheat grain N content can be significantly enhanced by optimizing N application methods, such as split-application of N, reduction of the proportion of basal fertilizer and deep application of N fertilizer.

We studied the effect of Se fertilizer on the endophytic bacterial communities and its subsequent impact on the growth and quality of tea leaves.

A field experiment was conducted in Taoyuan, Hunan Province, using the tea cultivar 'Taoyuandaye'. The treatments included spraying water (CK), 90 mg/L Se fertilizer (Se1), and 180 mg/L Se fertilizer (Se2) before budding. When new twigs with one bud and two leaves covered 30% of the canopy, we assessed twig number and length, bud weight, and leaf chlorophyll content. Additionally, Illumina sequencing was used to analyze the endophytic bacterial community, and Se, total polyphenols, catechins, and total free amino acids in the twigs were measured.

Compared to CK, Se1 and Se2 significantly increased leaf Se content to 3.06 mg/kg and 4.78 mg/kg, respectively, but did not significantly affect one-hundred-bud weight, leaf length, bud length, or chlorophyll content. However, Se1 and Se2 increased free amino acid content by 7.04% and 16.15%, respectively, and reduced the TP/AA ratio, indicating improved tea flavor quality. The result of Illumina sequence analysis showed that Se1 did not significantly influence the α diversity of the endophytic bacterial community, whereas the Se2 significantly decreased it. Compared with CK, the Se1 reduced the relative abundance of endophytic bacteria affiliated with Herbaspirillum, Sphingomonas, and unclassified Rhodanobacteraceae. However, it became the dominant endophytic bacterial group in leaves and increased the proportion of some minority taxa, such as bacterial communities belonging to Corynebacterium, unclassified Acetobacteraceae, Cellvibrio, Reyranella, and Mesorhizobium. Moreover, Se2 restructured the endophytic bacterial communities more profoundly than Se1 in tea leaves. PICRUSt analysis showed that selenium fertilizer significantly increased endophytic bacteria with metabolic functions, such as amino acids, carbohydrates, coenzymes, vitamins, terpenoids, and ketones, and also enhanced the relative abundance of endophytic bacteria potentially involved in pathways related to environmental adaptation, replication and repair, energy metabolism, and the biodegradation and metabolism of xenobiotics. Correlation analysis showed that the relative abundance of Pseudomonas positively correlated with the content of total free amino acids and theanine. Several species, such as Corynebacterium, unclassified Acetobacteraceae, and Methylobacillus, negatively correlated with ester-catechins (EGCG, GCG, ECG).

Applied prior to budding, selenium fertilization significantly elevated the selenium content in tea leaves, thereby promoting the abundance of endophytic bacterial groups with metabolic functions associated with amino acids, carbohydrates, coenzymes, vitamins, terpenoids, and ketones. Furthermore, it enhanced the abundance of endophytic bacteria involved in processes related to environmental adaptation, DNA repair, energy metabolism, and the biodegradation and metabolism of xenobiotics.