Water deficit severely constrains sugar beet productivity by impairing photosynthetic capacity. However, the underlying structure-function mechanisms conferring photosynthetic resilience remain poorly characterised. This study investigates the temporal dynamics of photosynthetic limitations and structural adaptations in sugar beet during water deficit and subsequent rehydration. We found that water deficit significantly reduced the maximum net CO2 assimilation rate (ANmax) and the Rubisco carboxylation rate (Vcmax) by impairing CO2 diffusion and biochemical processes. The reduction in photosynthetic capacity is primarily and stably attributed to mesophyll limitation, while contributions from stomatal and biochemical limitations flexibly change with deficit degree and rehydration. Severe water deficit caused irreversible structural damage that hinders recovery even after rehydration, while moderate water deficit allows partial restoration of leaf and chloroplast function. Partial least squares structural equation modelling (PLS-SEM) demonstrated that CO2 diffusion was governed by the volume fraction of intercellular air space (fias, beta = 0.28) and surface areas of the chloroplasts exposed to leaf intercellular air spaces (Sc/S, beta = 0.35), with Sc/S indirectly influencing mesophyll conductance (gm) through fias mediation (beta = 0.53). Severe water deficit caused irreversible fias reduction and chloroplast interface damage (59% cell volume loss). These findings establish that resilience to water deficit in sugar beet depends on mesophyll structural integrity, with fias and Sc/S as key modulators of gm recovery. The study advances understanding of stress recovery mechanisms in sugar beet and provides a framework for multiscale crop improvement in the context of climate change.

Straw return is a conventional practice in mitigating soil salt damage. However, the effect of changed straw structure on the adsorption and migration of salt ions in saline soil is still unknown. This study investigated the adsorption process of straw residues at different decomposition levels. The adsorption process of straw residues towards salt ion displayed a biphasic trend with its decomposition, first increasing and then decreasing. The maximum adsorption value was 25 mg/g, representative of about 60 % decomposition rate of straw residues. This altered adsorption capacity was attributed to the balance between disruption of the dense crystalline structure and the exposure of C-O functional groups within cellulose and lignin components. The increased crystallinity index and weakened hydrogen bonding strength on the salt-adsorbing straw material surface directly confirmed the adsorption mechanisms involving pore filling and hydrogen bonding. Elevated environmental temperature (>30 °C) inhibited salt ion adsorption by straw residues. On the contrary, the adsorption of straw residues towards salt ions in the soils were independent of soluble organic and inorganic substances. Furthermore, incorporating decomposed straw residues significantly impacted soil bacterial and fungal communities. The abundance of the top 10 soil microbial taxa increased and showed a significant positive correlation with the improvements in soil structure and properties. These effects collectively alleviated salt damage symptoms during cotton seed germination and also promoted seedling growth. It demonstrated that straw return further alleviated salt damage through its structural turnover with its decomposition.

To clarify the effects of different microbial fertilizers on the photosynthetic characteristics, enzyme activities, and yield of oil sunflower under combined saline-alkali stress, and to screen suitable microbial fertilizer types and application concentrations for oil sunflower cultivation in saline-alkali soils, this study used the salt-tolerant oil sunflower cultivar NX53177 and the salt-sensitive cultivar NKY1502 as experimental materials. A randomized block design was adopted, with three microbial fertilizers (Qiaosengen, polylactic acid, and Aikesha) each applied at three concentrations (low, medium, and high) along with a control treatment. Photosynthetic parameters, stress-resistance-related enzyme activities, osmotic adjustment substances, and grain yield were systematically determined at different growth stages of oil sunflower. The results showed that under combined saline-alkali stress, the application of microbial fertilizers significantly increased leaf SPAD values, net photosynthetic rate (Pn), and stomatal conductance (Gs), thereby enhancing photosynthetic efficiency. Meanwhile, proline (Pro) content, superoxide dismutase (SOD) activity, and peroxidase (POD) activity were increased, whereas malondialdehyde (MDA) content was decreased, effectively alleviating oxidative damage caused by saline-alkali stress and enhancing plant stress resistance. Among all treatments, the medium concentration of Aikesha microbial fertilizer (T8 and T17) exhibited the optimal effect. At the flowering stage, Pn of the two cultivars increased by 22.82% and 19.49%, respectively, compared with the control. At the grain-filling stage, MDA content decreased by approximately 21% compared with the control. Grain yield reached 4879.65 kg/hm² and 4709.59 kg/hm², representing yield increases of 26.20% and 22.17%, respectively, relative to the control. The overall performance of the three microbial fertilizers followed the order: Aikesha > polylactic acid > Qiaosengen, and the medium concentration treatments were generally superior to both the low and high concentrations. The results of this study provide a scientific basis and technical support for the rational application of microbial fertilizers in oil sunflower cultivation on saline-alkali soils.

Owing to their environmental benignity, Zinc (Zn)-based single-atom catalysts (SACs) are attractive candidates for sustainable oxidation catalysis. Their unsatisfactory Fenton-like activity, due to the 3d10 configuration of Zn2+, significantly limits their catalytic performance. Herein, a Zn-ferrum dual-atom catalyst (ZnFe-NC) with ZnFeN6 moieties anchored uniformly onto nitrogen-doped carbon was developed for activating peroxymonosulfate (PMS). The optimized ZnFe-NC/PMS system achieved over 96% phenol removal (20 mg L- 1) in 10 min and maintained exceptional degradation efficiency over a wide range of pH (3-11). The degradation process proceeds primarily via a non-radical pathway as determined by reactive oxygen species (ROS) quenching and trapping assays and is largely driven by singlet oxygen (1O2), with only minor contributions from high-valent metal-oxo species (HVMO), hydroxyl radicals (center dot OH), and superoxide radicals (O2 center dot-). Density functional theory (DFT) calculations confirmed that the placement of Fe adjacent to Zn modulates the d-band center of Zn, optimizing its electronic structure for catalysis. Compared to ZnN4 and FeN4, ZnFeN6 outperforms with respect to excellent PMS adsorption energy, charge transfer, and stretches and weakens the peroxide bond of PMS. The synergistic ZnFeN6 configuration effectively transforms the intrinsically underperforming Zn centers into highly reactive sites, overcoming the performance limitations of conventional Zn-based catalysts, offering a new paradigm for designing eco-friendly and high-performance catalysts in Fenton-like water decontamination.

This study reports the incorporation of nitrogen-doped biochar(N-BC) as a support into the LaCoO3 perovskite structure, demonstrating high catalytic activity for the neonicotinoid insecticide imidacloprid (IMI) in solution through peroxymonosulfate(PMS) activation. The prepared LaCoO3/N-BC catalyst achieved near-complete IMI degradation (99.52%) within 40 min. Through Combined quenching experiments and EPR analysis, SO4•- and •OH were unambiguously identified as the dominant reactive oxygen species mediating IMI oxidation. Density functional theory (DFT) calculations demonstrated that anchoring LaCoO3 onto N-BC significantly enhances peroxymonosulfate adsorption, while the while the La-induced coordination environment facilitates the Co3+/Co2+ redox cycling. Notably, the LaCoO3/N-BC catalyst exhibited exceptional stability, maintaining high efficiency across a broad pH range (5–11) and showing strong resistance to common aqueous matrix interferents (e.g. SO42-, H2PO4-, and humic acid). After four consecutive catalytic cycles, the material retained 79.52% IMI degradation efficiency, confirming its structural stability and reusability. By liquid chromatography-mass spectrometry (LC-MS) analysis, critical degradation intermediates were characterized, allowing for the elucidation of potential IMI degradation pathways. These findings collectively establish LaCoO3/N-BC as a highly efficient and stable catalyst for PMS-activated remediation of IMI-contaminated water.

Nitrogen-doped cotton straws biochar-loaded cobalt tetraoxide (Co3O4/N-BC) catalysts were prepared by a twostep calcination method, and the calcination temperature of nitrogen-doped biochar (N-BC) was systematically optimized with the loading temperature of Co3O4 nanoparticles, which was then used to activate peroxynitrite (PMS) for the removal of imidacloprid (IMI). Under a catalyst dosage of 0.3 g/L, PMS concentration of 5 mM, and pH of 7, 98.2 % of a 30 mg/L solution of IMI was degraded in 20 min, 40 min later, the removal rate reached 100 %. The leaching rate of cobalt ions after removal is only 0.74 mg/L, which meets the national emission standard (GB 24567-2010). Nitrogen doping was mainly in the form of pyridine nitrogen, pyrrole nitrogen and graphite nitrogen, where pyridine nitrogen was the main reactive nitrogen species that enhanced the activation of PMS. Quenching experiments and electron paramagnetic resonance spectroscopy (EPR) showed that the free radical pathway represented by SO4-center dot and (OH)-O-center dot was the main pathway for IMI removal with a contribution of 93.05 %. The intermediates formed during the removal of IMI were analyzed by LC-MS, and three possible degradation pathways of IMI were proposed based on nine possible intermediates. Most of the degradation intermediates were eventually converted to low or non-toxic substances as analyzed by ECOSAR software. This study introduces a sustainable approach for reusing waste cotton straw and efficiently treating pesticide production wastewater.

Regulating the allocation of assimilates is a vital path to increase crop yield. Paclobutrazol is a plant growth retardant that can promote the yield formation of grain crops. It works by regulating the allocation of assimilates to the reproductive organs that are harvested. Still, its effect on the allocation of assimilates to sugar beet taproot, a vegetative organ vital for yield formation, is not yet clear. In a field trial carried out in 2022-2023 in northwest China, paclobutrazol was sprayed on sugar beet varieties Strube 13092 (ST) and Beta 796 (BT) 45 days after emergence (the canopy rapid growth stage). The concentrations used were 0 (M0), 150 (M1), 300 (M2), and 600 (M3) g ha-1. The goal was to clarify how the treatment affected sugar beet leaf physiology, dry matter accumulation, and distribution. The results showed that the physiological stress (O2 center dot-) brought by paclobutrazol caused a stress response in sugar beet leaves. Paclobutrazol treatment at the right concentration (M1) greatly enhanced the function of sugar beet leaves. It increased antioxidant enzyme activity (superoxide dismutase 3.1), osmolyte content (soluble sugars and free proline), chlorophyll content, and photosynthetic rate (Pn) compared to the control (M0). Paclobutrazol treatments significantly reduced the LAI (leaf area index) and slowed down the leaf senescence in the middle - late growing season. They postponed the time for sugar beets to reach the maximum dry matter accumulation, and also made the dry matter partitioning index (PI) for taproots reach 50 % 24 days earlier than the M0 treatment. At harvest, the sugar yield, taproot yield, sugar content, and net revenue of the paclobutrazol treatments were 18.1 %, 11.8 %, 31.6 %, and 34.5 % higher than those of the M0 treatment, respectively. Therefore, spraying with paclobutrazol at the right concentration during the canopy rapid growth stage could simultaneously increase the sugar content & yield of taproots. This technique has great potential in enhancing yield as well as economic benefits of sugar beet.

Soil salinization poses a significant threat to agricultural sustainability. This study investigated the effects of different microbial fertilizers on the rhizosphere fungal community and physicochemical properties of saline–alkali soil cultivated with sunflower. Three microbial fertilizers were applied at three concentration gradients to two sunflower varieties with contrasting salt–alkali tolerance (salt-tolerant NX53177 and salt-sensitive NKY1502) to elucidate the mechanisms underlying microbial fertilizer-mediated amelioration of saline–alkali soils. Among all treatments, the application of Aikesa microbial fertilizer at 50 g per pot (treatments T8 and T17) demonstrated the most pronounced ameliorative effects. In the salt-tolerant variety NX53177, the 50 g/L Aikesa fertilizer treatment increased the relative abundance of the beneficial genus Mortierella by 46.2%. It decreased the potentially pathogenic genus Lophotrichus by 82.2% compared to the no-fertilizer control. Soil fungal diversity was significantly improved, with the Shannon index increasing by 9.86% and the Simpson index decreasing by 25.83%. Concurrently, critical soil properties were enhanced: soil pH decreased by 7.79%, salinity decreased by 3.13%, and the contents of organic matter, available nitrogen, available phosphorus, and available potassium increased by 42.13%, 49.96%, 12.34%, and 53.22%, respectively. In the salt-sensitive variety NKY1502, the 50 g/L Aikesa fertilizer treatment increased Mortierella abundance by 15.96% and decreased Lophotrichus by 73.6% compared to the no-fertilizer control. The ACE and Shannon diversity indices increased by 10.00% and 9.92%, respectively, while the Simpson index decreased by 12.17%. Soil health was also markedly improved, with pH decreasing by 7.47%, salinity by 2.95%, and substantial increases in organic matter (57.94%), available nitrogen (75.78%), available phosphorus (13.20%), and available potassium (52.97%). In conclusion, the 50 g/L Aikesa fertilizer treatment effectively improved the rhizosphere fungal community structure and significantly enhanced soil physicochemical properties under saline–alkali stress. These findings provide a theoretical foundation and practical guidance for utilizing microbial fertilizers in ecological restoration and sustainable agricultural development of saline–alkali lands.

Currently, advanced oxidation processes (AOPs) are an efficient method for the degradation of recalcitrant organic pollutants. In this work, copper oxide (CuO) catalysts were synthesized using mesoporous silica (SiO2) as a template for the activation of peroxomonosulfate (PMS) for the removal of the target pollutant bisphenol A (BPA). The results showed that the CuO catalysts not only increased the specific surface area and active sites, but also enhanced the efficient activation of PMS to produce a large amount of reactive oxygen species. In this paper, the degradation process and mechanism of BPA by CuO in PMS activation system were comparatively investigated by characterization data and experimental data. Under the optimum conditions, the degradation rate of BPA (30 mg/L) was as high as 97.8

Potassium is vital for sugar crop growth, yet excessive application often limits yield and quality improvements in sugar beets. To determine the optimal type and application rate of potassium fertilizer for drip-irrigated sugar beets in lime soils, a field experiment was conducted in 2024. Two cultivars (KWS9899 and KWS7748) were treated with two potassium sources (KCl and K2S04) at four application rates (K2O) [0 (CK), 105, 210, and 315 kg/ha]. We evaluated their effects on taproot yield, sugar content (total soluble sugar, sucrose, fructose, glucose), and K+ content in the shoots and taproots. Results revealed that taproot yield and sugar production increased initially but declined with further potassium application, maximum at 210 kg/ha. Compared with the non-fertilized control, potassium application increased taproot yield by 17.42–72.08

The organic-inorganic composite polymer amendment (SAP) can be an effective way to enhance the stress resistance of sand crops in arid areas and increase productivity. The sandy soil in arid areas lacks water and fertilizer retention, and suffers from compound salt damage, which restricts crop growth and leads to insufficient nutrient absorption and weak stress resistance. In addition, the existing amendments have high costs and poor net benefits, which cannot meet the needs of local agricultural development. Therefore, there is an urgent need for low-cost and efficient soil improvement solutions. This study proposes a new improvement plan for organic-inorganic composite soil conditioner (SAP) to address the compound salt damage problem faced by rapeseed feed in sandy soils in arid areas. The study investigated the six treatment methods were compared through field experiments(CK:Organic fertilizer+chemical fertilizer; T1:Organic fertilizer+ chemical fertilizer+SAP;T2: Organic fertilizer+chemical fertilizer+PI humic acid type; T3: Organic fertilizer+chemical fertilizer+PII concave convex rod type; T4: Organic fertilizer+chemical fertilizer+PI+PII; HF: The effect of single application of chemical fertilizer)on nutrient absorption, physiological characteristics, yield and quality of rapeseed for feed.The results showed that the combination of organic-inorganic composite SAP, PⅠ, PⅡ, and PⅠ+PⅡ alleviated salt damage in sandy soil and increased nutrient content in various organs of crops. Analysis shows that composite SAP treatment performs the best. At the same time, (1)Salt damage alleviation: Compound conditioners increased root K+ content by 57.14-63.09%, decreased Na+ content by 60.16%, and significantly improved K+/Na+ratio (p<0.05); (2)Physiological improvement: The total chlorophyll content (TCC) increased by 86.85%, the highest SOD/POD enzyme activity increased by 161.58%, and the dry matter accumulation increased by 376.8%; (3)Yield and quality: T1 treatment increased yield by 148.32%, increased stem and leaf crude protein content by 86.05%, and reduced crude fiber by 43.59%; (4)Economic benefits: The net profit (NR) of SAP treatment reached 197.62 dollars per hectare, significantly better than other treatments (p<0.05).The comprehensive evaluation found that organic-inorganic composite SAP conditioners can synergistically improve the yield and quality of rapeseed feed in sandy areas by improving soil aggregation structure, enhancing antioxidant enzyme activity and photosynthetic efficiency, providing an economically effective solution for sustainable agricultural development in arid regions.

Soil amendments have been widely applied in the remediation of saline soil and the improvement of crops resistance to external stresses. However, the responses of soil microbial community composition, structure, function, and resource competition strategy to soil amendment in saline and alkaline soil remain unclear. In this study, we conducted a barrel experiment in which soil was mixed with NaCl and Na2CO3 to achieve a salinity level of 8 g·kg−1, and then placed in barrels with a diameter of 50 cm and a height of 60 cm, then the barrels were buried in cotton fields. And soil conditioner GS was applied to improve the salt-stressed and alkali-stressed soil. This study investigated the effect of soil conditioner GS on soil microbial life history strategies under simulated saline and alkaline stress during cotton flowering in saline soils. The study explore the effects of soil amendment GS on soil microbial life history strategies under simulated saline and alkali stresses during cotton flowering stage for saline soil. The results showed that saline and alkali stresses disrupted soil microbial succession and altered rhizosphere soil micro-environment. However, after the application of amendment in saline soil, the abundance of dominant bacteria (Subgroup_17) and fungi (Mortierella, Chaetomium), soil metabolic functions (biosynthesis of amino acids and fatty acid), soil K+ content and Si/N ratio significantly increased, while soil Na+ content and electrical conductivity (EC) significantly reduced. After the application of amendment in alkaline soil, the abundance of dominant soil bacteria (Aeromicronium, Rokubacteriales, RB41) and fungi (Mycosphaeralla, Aspergillus), phenylalanine metabolise and fatty acid biosynthesis pathways soil K+/Na+ ratio, organic carbon content, total nitrogen, and Si/N ratio significantly increased, while soil Na+ content, pH, and Si/C ratio significantly decreased. Application of soil amendment could significantly increased soil nutrient content,the formation of different life cycle strategies of soil microorganisms, so as to alleviate the saline stress and alkali stress. This study provides reference for alleviating the saline and alkaline stresses to cotton by influencing key soil microorganisms using soil amendment.

Soil conditioners have great potential in saline soil remediation. However, it is still unclear that how soil conditioners affect cotton photosynthesis to improve cotton resistance to saline and alkaline stresses. Therefore, we used the self-developed soil conditioner was used to clarify whether soil conditioner has a repair effect on cotton photosynthesis under saline and alkaline stresses. The photosynthetic performance and chlorophyll fluorescence characteristics of cotton leaves have increased in PY and PJ. Transcriptome and Proteome analysis results showed that Photosystem II protein, Chlorophyll A-B binding protein, Rubrerythrin and Cytochrome B6-F complex Fe-S subunit were up-regulated in the PY and PJ group. All above changes induced by conditioner application promoted chlorophyll biosynthesis, and regulation of the photosynthetic system. This study will deepen our understanding of the molecular mechanism of soil conditioner regulating cotton photosynthetic, and provide reference for saline and alkaline soil remediation in arid areas.

Polymer application combined with nitrogen (N) fertilization can increase soil N transformation efficiency. However, the mechanism of polymer influencing soil biocommunity characteristics and nitrogen transformation is still unclear. In this field experiment, a self-developed water-soluble polymer material (PPM, a mixture of anionic polyacrylamide, polyvinyl alcohol, and manganese sulfate) was combined with N fertilization N100 (300 kg/hm2 of N), PN100 (PPM + 300 kg/hm2 of N), and PN80 (PPM + 240 kg/hm2 of N) to investigate soil biodiversity, enzyme activities, and metabolomics. The results showed that under the application of PPM, the contents of soil total nitrogen (TN), alkali hydrolyzable nitrogen (ANS), nitrate nitrogen, organic carbon (SOC), and microbial biomass nitrogen (MBN) increased with a decrease in the N application rate, while soil bulk density, pH, and EC (electrical conductivity) decreased. The Chao 1 index of soil bacterial and nematode communities of the PN80 treatment was 30.6% and 10.7% higher than that of the N100 treatment, respectively, and the Shannon index was 2.72% and 2.64% higher than that of the N100 treatment, respectively. In the short term, the application of PPM affected the structure and composition of soil bacterial and nematode communities. In particular, the relative abundances of omnivorous (Aporcelaimellus) and bacterivorous (Prismatolaimus) nematodes were significantly higher than those of the N100 treatment. These changes further regulated the soil metabolites, promoting soil nitrogen transformation. This study will provide a scientific basis for nitrogen reduction in drip-irrigated wheat planting in arid regions.

Soil salinization and alkalization can cause great losses to agricultural production in arid regions. Cotton, a common crop in arid and semi-arid regions in China, often encounters saline stress and alkaline stress. In this study, NaCl (8 g·kg−1), Na2CO3 (8 g·kg−1), and a compound material (an organic polymer compound material) were mixed with field soil before cotton sowing, and the ion content, photosynthetic characteristics, and metabolite levels of the new cotton leaves were analyzed at the flowering and boll-forming stage, aiming to clarify the photosynthetic and metabolic mechanisms by which compound material regulates cotton’s tolerance to saline stress and alkaline stress. The results showed that the application of the compound material led to an increase in the K+/Na+ ratio, stomatal conductance (Gs), efficiency of PSII photochemistry (ψPSⅡ), potential activity (Fv/Fo), and chlorophyll content (Chla and Chlb), as well as the abundances of D-xylonic acid and DL-phenylalanine in the NaCl treatments. Additionally, there were increases in the K+ content, K+/Na+ ratio, Chla/b ratio, net photosynthetic rate (Pn), transpiration rate (Tr), ψPSⅡ, and D-saccharic acid abundance in the Na2CO3 treatments. A correlation analysis and a metabolic pathway analysis revealed that the compound material mainly regulated the photosynthetic characteristics of and the ion balance in the new leaves through regulating the abundance of key metabolites when the cotton was under NaCl stress or Na2CO3 stress. Furthermore, the positive impact of the compound material on the cotton’s NaCl stress tolerance was stronger than that on the cotton’s Na2CO3 stress tolerance.

To achieve sustainable agriculture development in arid regions, it is imperative to improve the soil quality of arid sandy soils. This study explored the effects of the combined application of organic–inorganic fertilizers with soil conditioners on the physiological characteristics, yield, and quality of rapeseed in arid sandy lands. The aim was to provide a technical reference for improving sandy soil and increasing rapeseed yield in arid regions. This field study designed six treatments (control group: organic fertilizer + chemical fertilizer (CK); T1: organic fertilizer + chemical fertilizer + super absorbent polymer (SAP); T2: organic fertilizer + chemical fertilizer + humic acid (PI); T3: organic fertilizer + chemical fertilizer + attapulgite (PII); T4: organic fertilizer + chemical fertilizer + PI + PII; HF: chemical fertilizer) to evaluate their effects on the nutrient absorption, physiological characteristics, yield, and quality of rapeseed. The results showed that the combination of organic–inorganic fertilizers with SAP, PI, PII, or PI + PII could significantly reduce the salinity of sandy soil while increasing the nutrient content in various parts of rapeseed. Among the combinations, the SAP treatment (T1) had the most significant effect, with the following specific impacts: (1) Alleviation of salt stress: The SAP treatment increased the root potassium ion content by 63.09% and reduced sodium ion content by 60.16% compared with CK, significantly increasing the potassium/sodium ratio. (2) Physiological improvement: The SAP treatment increased the total chlorophyll content (TCC), superoxide dismutase/catalase activity, and dry matter accumulation by 86.85%, 161.58%, and 376.8%, respectively, compared with CK. (3) Yield and quality enhancement: The SAP treatment increased rapeseed yield and the crude protein content in stems and leaves by 148.32% and 86.05%, respectively, but decreased crude fiber content by 43.59% compared with CK. (4) Economic benefits: The net revenue (NR) of the SAP treatment reached 197.62 USD per hectare, which was significantly higher than that of other treatments. A comprehensive evaluation showed that the combined application of organic–inorganic fertilizers with SAP enhanced plant antioxidant enzyme activity and photosynthetic efficiency, synergistically enhancing the yield and quality of rapeseed in sandy areas. This study provides an economically efficient solution for sustainable agricultural development in arid regions.

CuO@UiO-66-NH2 was constructed using a hydrothermal method and used for the enhanced peroxymonosulfate (PMS) activation and bisphenol A (BPA) degradation. The results showed that under the optimal conditions, the degradation rate of BPA (6 mg/L) was 95.08

Context: Limited irrigation is a measure to avoid sugar beet yield reduction and improve water use efficiency in arid areas. However, it is unclear whether the optimization of traditional nitrogen fertilizer management under the limited irrigation conditions can further improve sugar beet yield and economic benefits. Methods: In this three-year field experiment in the arid region of northwest China, N fertilizer (150 (N1, recommended N application rate) and 225 kg ha(-1) (N2, traditional N application rate) was applied in three methods, i.e., N fertilizer was applied at the ratios of 20: 80 (T1), 30: 70 (T2), and 40: 60 (T3, traditional N fertilization method) before sowing and at the rapid canopy growth stage. Then, the effects of the above N fertilizer managements on the growth parameters, canopy productivity, nutrient uptake, yield, and economic benefits of drip-irrigated sugar beets under limited irrigation was explored. To avoid the subjectivity of human evaluation, four comprehensive evaluation models were used for the evaluation of the N fertilization managements. Results: The results showed that under the two N application rates, T1 treatment promoted plant nutrient uptake by increasing the available N content in the soil compared with the T3 treatment. This then increased the shoot and taproot growth rates by an average of 18.8 % (p < 0.05) and 26.5 % (p < 0.05), respectively by increasing the leaf area duration (LAD) during 45-120 DAE (days after emergence). In addition, T1 treatment increased the leaf senescence rate (LSR) of sugar beet during 120-150 DAE, which promoted yield formation and increased the taproot yield (TY) by 17.3 % (p < 0.05) compared with T3 treatment. Although N2T1 treatment resulted in higher net return (NR) than N2T3 (traditional N management method) and N1T1 treatment, N2T1 treatment did not increase marginal benefit (MB) and N use efficiency compared with N1T1 treatment. The results of the four comprehensive evaluation models showed that the N1T1 treatment had the highest evaluation value and the highest ranking compared with the other treatments. Conclusions: When limited irrigation is carried out in sugar beet cropping in arid areas, it is suggested that the traditional N fertilizer application rate can be reduced to 150 kg ha(-1), and the proportion of topdressed N during limited irrigation can be increased.

Crop growth is highly susceptible to drought stress due to water scarcity in arid areas. Silicon (Si) fertilizer could improve the tolerance of crops to drought stress, but the effect of drip fertigation of Si fertilizer on the growth and yield of sugar beets under drought stress is still unclear. In this field experiment conducted in 2022 and 2023 in the arid northwest China, the effects of different Si fertilizer application rates (0 kg ha -1 (Si0), 15 kg ha -1 (Si1), 38 kg ha -1 (Si2), 75 kg ha -1 (Si3)) on the growth, yield, and resource use efficiency of sugar beets (cultivars Beta356 (BT) and Strube13092 (ST)) under deficit irrigation (60 % of crop evapotranspiration (ETc), W2) were explored. The results showed that deficit irrigation (W2Si0) reduced the taproot and fibrous root growth, leaf net photosynthetic rate (Pn), leaf relative water content (LRWC), and leaf area index (LAI) of cultivar BT compared with full irrigation (100 % of ETc, W1). Under deficit irrigation, Si application (W2Si1, W2Si2, and W2Si3) alleviated the drought stress by increasing the number of fibrous roots in 17.5 -70.0 cm soil layer and promoted the growth of taproots. Besides, it also increased the leaf moisture and photoassimilate production by increasing plant Si uptake, LRWC, LAI, and Pn. This finally increased the taproot yield (TY), irrigation water use efficiency (IWUE), and partial factor productivity of nitrogen (PFPN) by 11.2 %22.9 %, 6.5 %19.3 %, and 6.3 %19.3 %, respectively in cultivar BT and by 8.8 %27.1 %, 13.4 %30.8 %, and 13.4 %30.8 %, respectively in cultivar ST, compared with W2Si0. Regression analysis showed that the Si fertilizer application rate 64 kg ha -1 could maximize the TY of cultivar BT, but the net revenue (NR) was significantly lower than that of the W1 treatment. The Si fertilizer application rate 71 kg ha -1 could increase the TY of cultivar ST and achieve a NR similar to that of the W1 treatment. Therefore, in arid regions, Si application could alleviate the adverse effects of drought stress on drip-irrigated sugar beet root and shoot growth and improve yield, but the Si application rate varied with sugar beet cultivars.

Drip irrigation with brackish water increases the risk of soil salinization while alleviating water shortage in arid areas. In order to alleviate soil salinity stress on crops, polymer soil amendments are increasingly used. But the regulation mechanism of a polymer soil amendment composed of polyacrylamide polyvinyl alcohol, and manganese sulfate (PPM) on rapeseed photosynthesis under drip irrigation with different types of brackish water is still unclear. In this field study, PPM was applied to study the responses of the rapeseed (Brassica napus L.) phenotype, photosynthetic physiology, transcriptomics, and metabolomics at the peak flowering stage under drip irrigation with water containing 6 g·L−1 NaCl (S) and Na2CO3 (A). The results showed that the inhibitory effect of the A treatment on rapeseed photosynthesis was greater than that of the S treatment, which was reflected in the higher Na+ content (73.30%) and lower photosynthetic-fluorescence parameters (6.30–61.54%) and antioxidant enzyme activity (53.13–77.10%) of the A-treated plants. The application of PPM increased the biomass (63.03–75.91%), photosynthetic parameters (10.55–34.06%), chlorophyll fluorescence parameters (33.83–62.52%), leaf pigment content (10.30–187.73%), and antioxidant enzyme activity (28.37–198.57%) under S and A treatments. However, the difference is that under the S treatment, PPM regulated the sulfur metabolism, carbon fixation and carbon metabolism pathways in rapeseed leaves. And it also regulated the photosynthesis-, oxidative phosphorylation-, and TCA cycle-related metabolic pathways in rapeseed leaves under A treatment. This study will provide new insights for the application of polymer materials to tackle the salinity stress on crops caused by drip irrigation with brackish water, and solve the difficulty in brackish water utilization.