Soil inorganic carbon (SIC), especially pedogenic carbonates (PIC), plays a role in carbon sequestration in arid and semi-arid regions, yet its coupling with soil organic carbon (SOC) fractions and microbial processes remains poorly resolved. To address this, we collected soil samples in maize- and cotton-based systems at Bole and Wuwei in Northwest China. We explicitly distinguished stable SOC (mineral-associated OC, MAOC; heavy-fraction OC, HFOC) from labile SOC (particulate OC, POC; light-fraction OC, LFOC; dissolved OC, DOC) to evaluate their separate relationships with inorganic carbon pools. We found that Bole maize soils were enriched in SIC, PIC and dissolved inorganic carbon (DIC) and dominated by stable SOC, cotton soils by POC and lithogenic carbonates (LIC), whereas Wuwei soils by labile SOC with weaker inorganic carbon association. Across sites, MAOC and HFOC were positively related to SIC, PIC and DIC, while DOC and LFOC were negatively associated with SIC. Microbial diversity and biomass were also associated with carbon fractions, with fungal diversity being particularly responsive to SOC-SIC co-variation and bacterial communities more strongly related to inorganic carbon forms and pH. Meanwhile, microbial biomass C and N correlated positively with SOC, SIC and PIC but not LIC. Furthermore, random forest and partial least-squares path modeling identified C:N ratio, cation exchange capacity (CEC), microbial status and MAOC as key predictors of PIC formation and organic-inorganic carbon associations. Collectively, these results suggest coordinated variation among organic and inorganic carbon fractions and highlight that coupling between microbial status, nutrient stoichiometry and stable SOC fractions is an important component of SIC and PIC accumulation in arid croplands of northwest China.

Suaeda salsa L. is a leaf succulent euhalophyte. Its leaves are rich in secondary metabolites, such as polyphenols and flavonoids, which enhance its salt tolerance and have industrial value in pharmaceuticals, antioxidants, and food additives. Its growth is promoted under moderate salinity conditions. However, the mechanisms by which euhalophytes maintain a balance between growth and salt stress tolerance have not been elucidated, especially under K+ deficiency. Here, we used multi-omics and physiology analyses to investigate the role of Na⁺ in the growth and metabolic processes of S. salsa. Exogenous NaCl application significantly enhanced the photosynthetic efficiency of S. salsa under K⁺ deficiency, including the net photosynthetic rate, PSII photochemistry (Fv/Fm), photochemical quenching (qP), non-photochemical quenching (NPQ), and the activities of enzymes such as ferredoxin-NADP+ reductase (FNR) and Rubisco. Meanwhile, transcriptomic analysis revealed that NaCl treatment upregulated genes related to photosynthetic subunits, light-harvesting complexes (LHCs), and key Calvin cycle enzymes, including phosphoglycerate kinase (PGK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and Rubisco. These findings provide strong molecular evidence for the observed recovery of photosynthetic efficiency in NaCl-treated S. salsa under K⁺ deficiency. Furthermore, the relative contents of flavonoids and isoflavonoids, including isorhamnetin, isolupalbigenin, osajin, corylin, and wedelolactone, as well as unsaturated fatty acids (9-Hexadecenoic acid), were significantly upregulated treating with NaCl and KCl. These results suggest that S. salsa can utilize Na⁺ to enhance photosynthesis under high salinity and low K⁺ conditions, thereby enabling it to balance salt tolerance and growth. Our findings elucidate the key mechanisms underlying the critical role of Na+ in the physiological and metabolic processes of halophytes, providing a theoretical basis for the development of saline agriculture.

Halophyte-based phytoremediation is widely used to ameliorate saline soils in arid regions, yet biological assessments rarely incorporate soil microfauna. Using a seven-year field chronosequence of the euhalophyte Suaeda salsa in northern China, we quantified responses of protists and nematodes and tested whether cross-kingdom community organization, represented by co-occurrence networks linking bacteria, fungi, protists, and nematodes, improved the assessment of restoration maturity and soil multifunctionality recovery. Community composition clearly separated the irrigated bare-soil control from cultivated soils and shifted directionally with cultivation duration. Bacterial and fungal Shannon diversity increased mainly during short-term cultivation (1-3 yr), whereas protist and nematode diversity increased more strongly during long-term cultivation (5-7 yr). Crosskingdom networks under long-term cultivation were more integrated and robust, with greater nematode representation, higher connectivity, 82.8% more edges, 21.6% higher modularity, and greater resistance to targeted node-removal. Soil multifunctionality increased along the chronosequence. Its biotic associations shifted with cultivation duration, from microbial diversity and composition during short-term cultivation to soil fauna diversity and network structural attributes during long-term cultivation. Partial least squares path modeling further showed stronger links among network complexity, soil microfauna diversity, and multifunctionality under longterm cultivation. Overall, microfauna profiles and cross-kingdom network metrics provide complementary indicators of functional recovery in phytoremediated saline soils.

Mulched drip irrigation (MDI) improves water use efficiency in arid regions, but also leads to heterogeneous soil water and salt distribution. Based on a meta-analysis of 385 soil profiles from 87 publications, we investigated this distribution and its influencing factors. Results showed that soil water heterogeneity in the 0–40 cm layer is negatively correlated with field capacity, positively correlated with sand content, emitter flow and days after irrigation, and affected by climate and crop type. MDI led to salt redistribution rather than leaching, resulting in desalination in the root zone and salt accumulation in bare areas and deeper layers. Specifically, salt accumulation in bare areas was 1.9 times that in root zones, and accumulation in the 40–60 cm layer under the mulch was 1.38 times. This accumulation correlates positively with initial soil salinity and irrigation amount, and negatively with emitter flow. The depth of salt accumulation under the root zone is not strongly influenced by irrigation (saline water irrigation, irrigation amount) or environmental factors (crop type, groundwater level, initial salinity), but is jointly regulated by emitter flow and soil sand content. When sand content is < 50 %, accumulation becomes shallower with higher flow, concentrating at 20–40 cm; at > 50 % sand content, accumulation depth increases with flow. Saline water irrigation resulted in a more uniform salt profile than freshwater but increased overall salinity in the 0–80 cm layer. These findings provide critical insights for optimizing MDI strategies to achieve sustainable agriculture in arid regions.

Soil salinization is a major environmental constraint on plant growth. Although halophytes can grow well in saline soils, their nitrogen-use strategies under saline conditions remain poorly understood. In this study, the typical euhalophyte Suaeda salsa was used as the study species to investigate how different salinity levels and nitrogen forms (nitrate-N, ammonium-N, and a nitrogen-free control) regulate its growth, physiological traits, nitrogen metabolism, osmotic adjustment, oxidative stress, and metabolomic responses. The results showed that S. salsa adopted distinct strategies for utilizing nitrate and ammonium under salt stress. Nitrate nutrition more strongly promoted biomass accumulation, shoot height, and root elongation, while also supporting nitrate accumulation as an inorganic osmoticum. Under high salinity, NO3--N accounted for 62.11% of total nitrogen, and the osmotic contribution of nitrate reached -0.16 MPa. This nitrate-retention strategy was associated with enhanced antioxidant capacity, reduced oxidative damage, and the accumulation of metabolites related to jasmonate signaling, glutathione turnover, and phenylpropanoid metabolism. In contrast, ammonium nutrition favored tissue hydration, canopy width, and root thickening. More than 84% of total nitrogen was maintained in organic forms under NH4+-N supply, indicating efficient ammonium assimilation and detoxification. Metabolomic profiling further showed that ammonium treatment promoted the accumulation of nitrogen-rich osmotic and buffering metabolites, including arginine, histidine, and ornithine, particularly under high salinity. Overall, S. salsa exhibits dual nitrogen-use strategies, and this physiological and metabolic plasticity may contribute to its ecological success in saline environments.

Plant spring phenology advancements have been broadly observed, but the change in autumn phenology has varied greatly among different regions and species under global warming. Moreover, how plant phenology responds to climate change in grasslands and deserts is not well understood compared with that in forests. Here, we used long-term (2005 2020) phenological and climatic in situ observation data from six grassland and desert sites in China to analyze temporal trends in the start (SOS) and end (EOS) of the growing season for 27 herbaceous and shrub species and their responses to climatic factors. The results demonstrated that 70

Halophyte-based intercropping alleviates salt stress in glycophytes by desalinization. However, the role of root interactions, which are key to system sustainability, is often overlooked. This study evaluated soybean (Glycine max) salt tolerance when intercropped with Suaeda salsa, a halophyte with high salt tolerance, under different root interaction modes: plastic sheet separation (PL), nylon mesh separation (NL), and no separation (NS). Soil electrical conductivity did not differ significantly between NL and PL, indicating that soybean salt tolerance differences arose from root interactions, while the differences between NS and PL resulted from both root interactions and desalinization. Results showed that desalinization significantly reduced Na+ and Cl- content in both soil and soybean shoots in saline soils. However, it exacerbated reactive oxygen species (ROS) levels and introduced competition for soluble nutrients, partially counteracting its positive effects on biomass. Root interactions significantly increased soybean biomass by 80% without a significant effect on Na+ and Cl- content, but effectively scavenged salt stress-induced ROS through the upregulation of antioxidant enzymes (glutathione peroxidase and glutathione reductase) and non-enzymatic antioxidants (glutathione, melatonin, flavonoids), and alleviated desalinization-induced oxidative damage by further enhancing guaiacol peroxidase and ascorbate peroxidase activities. These results highlight the positive role of root interactions in alleviating soybean salt stress through enhanced antioxidant capacity. Additionally, root interactions demonstrate the capacity to enhance nutrient uptake in soybean such as Ca and Mg. Our findings suggest that, with water and fertilizer management, Suaeda salsa-soybean intercropping can be sustainably cultivated in saline soils.

Cadmium (Cd) contamination poses a significant hazard to the environment and human health, making it important to explore more effective amendments for Cd-contaminated soils. To verify the effects of biochar derived from a typical halophyte, Salicornia europaea, on immobilizing Cd in acidic soil, incubation experiment, column leaching experiment, and pot trials were conducted. The results showed that the addition of biochar enhances the soil’s adsorption capacity for Cd. Biochar reduced the content of acid-extractable Cd while increasing the levels of reducible and residual Cd. Compared with the control, 1

Suaeda salsa (S. salsa), a typical euhalophyte, serves as a model halophyte for studying salt tolerance, with leaf succulence playing a key role in its response to salt stress. However, the molecular mechanisms underlying cell enlargement contributing to organ succulence remain poorly understood. This study integrates transcriptome and physiological analyses to investigate the effects of sodium chloride (NaCl), calcium chloride (CaCl2), and their interaction treatment on leaf succulence in S. salsa. Results indicate that NaCl, CaCl2, and their combination significantly increase leaf succulence and epidermal cell size. These treatments also enhance the content of cellulose, hemicellulose, and pectin, along with the upregulation of cell wall remodeling genes (XTHs, EXPs, and LRXs), thereby improving cell wall extensibility. Protein-protein interaction network analysis further identified a strong association between SAUR19 (in the auxin signaling pathway) and EXPA10, a gene related to cell wall loosening (Combined score = 0.638). SAUR gene expression was markedly upregulated under all treatments, suggesting a critical role for auxin in promoting succulence. Additionally, increased sodium, chloride, and calcium concentrations enhanced leaf water content, driving cell expansion and contributing to the succulence of organs. These findings demonstrate that ion homeostasis, auxin signaling, and cell wall remodeling collectively mediate succulence in S. salsa under salt stress. This study offers new insights into the molecular basis of organ succulence in halophytes. It offers theoretical insights for improving salt tolerance in crops, with potential applications in sustainable agriculture for regions with saline soils.

Halophytes are vital tools for saline-alkali land reclamation, in part due to their ability to establish stable rhizosphere microbial communities in saline environments. However, the mechanisms by which rhizodeposition mediates microbiome enrichment under salt stress remain poorly understood. Our objectives were to assess the impact of salinity on halophyte-rhizosphere microbe interactions and identify potential "keystone metabolites"—compounds with functional links to specific microbial lineages that significantly influence the structure of rhizosphere microbiomes. Suaeda salsa was grown in marginal soil under varying salinity levels of control, 0.5

Soil salinity, primarily caused by NaCl, disrupts plant Na+/K+ homeostasis, hindering growth. While euhalophytes like Suaeda salsa thrive in saline conditions, the mechanisms by which Na+ promotes their growth, especially under K+ deficiency, remain poorly understood. Here, we used transcriptomic, metabolomic, and physiological analyses to investigate how Na+ alleviates K+ deficiency in S. salsa. Exogenous NaCl application promoted the growth of S. salsa under K+ deficiency, which was associated with upregulated expression of genes for photosynthetic subunits, light-harvesting complexes (LHCs), and key Calvin cycle enzymes, including phosphoribulokinase (PRK), phosphoglycerate kinase (PGK), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and Rubisco. Consequently, Na+ application enhanced the net photosynthetic rate, PSII photochemistry (Fv/Fm), photochemical quenching (qP), non-photochemical quenching (NPQ), and the activities of enzymes like ferredoxin-NADP+ reductase (FNR) and Rubisco. Transmission electron microscopy revealed that NaCl treatment increased the number and size of chloroplasts, maintaining their ultrastructural integrity under K+ deficiency. Furthermore, the relative contents of L-glutamate, serine, and threonine were elevated, with concurrent upregulation of their biosynthetic genes. These findings demonstrate that Na+ enhances photosynthesis and related metabolic pathways to promote biomass accumulation under K+ deficiency in S. salsa. Our findings elucidate the key mechanisms underpinning the survival of euhalophytes in environments characterized by high salinity and potassium deficiency.

Halophytes reduce soil salinity through significant shoot salt accumulation and facilitation of salt leaching. However, quantitative evidence on how Suaeda salsa L. (S. salsa) roots interact with saline soil to facilitate salt leaching remains limited. This study investigated the effects of S. salsa planting on salt removal, soil salinity, and soil quality under four soil salinity levels (0.1 % none-saline, 0.6 % lightly saline, 1.1 % moderately saline, and 2.6 % severely saline soils) using soil column experiments. Results showed that S. salsa planting significantly reduced soil salinity in the 0-20 cm layer. In lightly to moderately saline soils (0.6 %-1.1 % salt content), aboveground Na removal accounted for 12.1 %-19.3 % of soil total Na; in severely saline soils (2.6 % salt content), this dropped to 4.3 %. Compared with bare saline soil, S. salsa planting improved soil quality through increasing total soil porosity (TSP) by 51.6 %-109.6 %, pore connectivity (PC) by 144.5 %-550.7 % in the 0-20 cm layer; enhancing saturated hydraulic conductivity (Ks) by 100.7 %-373.8 %, and reducing bulk density (BD) by over 4.0 % in 0-100 cm soil profile. Correlation analysis revealed that root length (RL) and root average diameter (RAD) were positively correlated with TSP, PC, connected pore numbers (CPN), and Ks but negatively correlated with BD and soil moisture (SM). Root-induced soil quality improvements promoted salt leaching in the 0-20 cm layer, achieving desalination rates of 45.5 %-54.8 % in lightly to moderately saline soils and 24.6 % in severely saline soils. Furthermore, S. salsa planting reduced topsoil salt accumulation, decreasing salinity by over 55.0 % in the 0-20 cm layer compared to uncultivated soils. Therefore, continuous cultivation of S. salsa is an effective biological strategy for remediating saline-alkali land by improving soil quality and promoting salt removal.

Halophytes have evolved various mechanisms to adapt to saline conditions. However, their morpho-anatomical changes, along with the root metabolic responses to increased salt stress in saline-alkali soils, remain poorly understood. This study aimed to elucidate the adaptive mechanisms of Suaeda salsa under four saline-alkali soil levels (non-saline; NS, lightly saline; LS, moderately saline; MS, and severely saline; SS) by analyzing their anatomical morphological traits, nutritional components, and root differential metabolites through a combination of imaging and metabolomics technologies. Results showed that increased salt stress markedly enhanced leaf succulence, root vessel diameter, and epidermal thickness. Compared to NS treatment, leaf perimeter increased by 11.48, 28.29 and 47.94 %, respectively; root vessel diameter increased by 11.07, 24.39 and 14.31 % (p < 0.05). Root epidermal thickness increased by 24.34 and 109.37 % in MS and SS treatments, compared to NS treatment (p < 0.05). High salt stress disrupted leaf chloroplast and mitochondrial membranes, as indicated by malondialdehyde (MDA) increases of 32.45, 73.36 and 112.96 % in LS, MS and SS treatments (p < 0.05). Antioxidant enzyme activities (catalase; CAT, peroxidase; POD, superoxide dismutase; SOD) significantly increased in LS, MS, and SS treatments by 49.25-71.89 %, 90.64-278.86 %, and 12.94-116.37 %, respectively (p < 0.05). Elevated soil salinity increased sodium/potassium (Na/K) ratios by 223-518 % in roots, 215-330 % in stems, and 303-524 % in leaves; sodium/calcium (Na/Ca) ratios increased by 99-180 % in roots, 842-1810 % in stems, and 1111-2901 % in leaves. Additionally, root metabolic pathways associated with galactose/alanine, aspartate, and glutamate were markedly enhanced, leading to the upregulation of L-aspartate, β-alanine, glycine, galactinol, glycerol, and galactonic acid. Consequently, halophytes highlight their robust adaptive mechanisms by substantial morphological, physiological, and metabolic adjustments in response to salinity stress.

Halophyte-based remediation emerges as a novel strategy for ameliorating saline soils, offering a sustainable alternative to conventional leaching methods. While bioremediation is recognized for its ability to energize soil fertility and structure, the complex interplays among plant traits, soil functions, and soil microbial diversity remain greatly unknown. Here, we conducted a 5-year field experiment involving the continuous cultivation of the annual halophyte Suaeda salsa in saline soils to explore soil microbial diversity and their relationships with plant traits and soil functions. Our findings demonstrate that a decline in soil salinity corresponded with increases in the biomass and seed yield of S. salsa, which sustained a consistent seed oil content of approximately 22% across various salinity levels. Significantly, prolonged cultivation of halophytes substantially augmented soil microbial diversity, particularly from the third year of cultivation. Moreover, we identified positive associations between soil multifunctionality, seed yield, and taxonomic richness within a pivotal microbial network module. Soils enriched with taxa from this module showed enhanced multifunctionality and greater seed yields, correlating with the presence of functional genes implicated in nitrogen fixation and nitrification. Genomic analysis suggests that these taxa have elevated gene copy numbers of crucial functional genes related to nutrient cycling. Overall, our study emphasizes that the continuous cultivation of S. salsa enhances soil microbial diversity and recovers soil multifunctionality, expanding the understanding of plant-soil-microbe feedback in bioremediation. IMPORTANCE The restoration of saline soils utilizing euhalophytes offers a viable alternative to conventional irrigation techniques for salt abatement and soil quality enhancement. The ongoing cultivation of the annual Suaeda salsa and its associated plant traits, soil microbial diversity, and functionalities are, however, largely underexplored. Our investigation sheds light on these dynamics, revealing that cultivation of S. salsa sustains robust plant productivity while fostering soil microbial diversity and multifunctionality. Notably, the links between enhanced soil multifunctionality, increased seed yield, and network-dependent taxa were found, emphasizing the importance of key microbial taxa linked with functional genes vital to nitrogen fixation and nitrification. These findings introduce a novel understanding of the role of soil microbes in bioremediation and advance our knowledge of the ecological processes that are vital for the rehabilitation of saline environments.

Under the sufficient nitrogen supply, it is of great significance to investigate the law of biomass allocation, root morphological traits, and the salt absorption capacity of euhalophytes to evaluate their biological desalination in saline soil. Although the curvilinear responses of biomass accumulation and root morphology in response to soil salinity have been recognized, these perceptions are still confined to the descriptions of inter-treatment population changes and lack details on biomass allocation in organs at an individual level. In this study, Suaeda salsa was grown in root boxes across a range of soil salt levels. The study showed that their growth and development were significantly affected by soil soluble salts. The law of biomass allocation was described as follows: increased soil soluble salts significantly increased the leaf mass ratio and decreased the stem mass ratio, and slightly increased the root mass ratio among treatments. For individuals at each treatment, leaf mass ratio > stem mass ratio > root mass ratio, except in the control treatment at the flower bud and fruit stages. Biomass responses of the control treatment indicated that salt was not rigorously required for Suaeda salsa in the presence of an adequate nitrogen supply, as verified by the correlation between biomass, nitrogen, and soil soluble salt. Salt could significantly inhibit the growth of Suaeda salsa (P<0.01), whereas nitrogen could significantly promote its growth (P<0.01). Root morphology in response to soil soluble salts showed that salt acquisition by the root was highest at a salt level of 0.70%, which corresponds to light saline soil. Consequently, we conclude that phytodesalination by Suaeda salsa was optimal in the light saline soil, followed by moderate saline soil.

Actual evapotranspiration (ETa) is an important component of the surface water cycle. The geeSEBAL model is increasingly being used to estimate ETa using high-resolution remote-sensing data (Landsat 4/5/7/8). However, due to surface heterogeneity, there is significant uncertainty. By optimizing the quantile values of the reverse-modelling automatic calibration algorithm (CIMEC) endpoint-component selection algorithm under extreme conditions through 212 global flux sites, we obtained the optimized quantile values of 11 vegetation types of cold- and hot-pixel endpoint components (Ts and NDVI). Based on the observation data of the global FLUXNET tower, the sensitivity of 20 parameters in the improved geeSEBAL model was determined through Sobol’s sensitivity analysis. Among them, the parameters dT and SAVI,hot were confirmed as the most sensitive parameters of the algorithm. Subsequently, we used the differential evolution Markov chain (DE-MC) method to analyse the uncertainty of the parameters in the geeSEBAL model used the posterior distribution of the parameters to modify the sensitive parameter values or ranges in the improved geeSEBAL model and to simulate the daily ETa. The results indicate that by analysing the end element components of the geeSEBAL model (Ts and NDVI), quantile numerical optimization and parameter optimization can be performed. Compared with the original algorithm, the improved geeSEBAL model has significantly improved simulation performance, as shown by higher R2 values, higher NSE values, smaller bias values, and lower RMSE values. The most suitable values of the predefined parameter Zoh were determined, and the reanalysis of meteorological data inputs (relative humidity (RH), temperature (T), wind speed (WS), and net radiation (Rn)) was also found to be an important source of uncertainty for the accurate estimation of ETa. This study indicates that optimizing the quantiles and key parameters of the model end component has certain potential for further improving the accuracy of the geeSEBAL model based on high-resolution remote-sensing data in estimating the ETa for various vegetation types.

Study region: Global and 28 large river basins Study focus: Actual evapotranspiration (ETa) plays a key role in the redistribution of water, carbon and energy. The emergence of many ETa products has made uncertainty assessment increasingly important. The FLUXNET2015 dataset and 28 large watershed water balance datasets were used in this study. The monthly scale products of the ERA5-Land reanalysis data (ERA5), Global Land Data Assimilation System (GLDAS), Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA) and Penman-Monteith-Leuning Model Version 2 (PML) terrestrial evapotranspiration models were evaluated from 2001 to 2017. The differences in composition (vegetation transpiration (T), soil evaporation (Es), canopy interception loss (Ei) and other components (open water and ice and snow sublimation) (Eo)) and vegetation among the four ETa products were compared.New Hydrological Insights for the Region: At the site scale, the ERA5 and MERRA products significantly outperformed the GLDAS and PML products, with the latter exhibiting poorer reliability in site validation. The PML product's basin-scale water balance KGE metric overall outperformed those of the ERA5, GLDAS, and MERRA products, with KGE > 0 in 23 basins. The use of basin-scale data mitigates the impact of local outliers on the simulation results, leading to KGE validation metrics at the basin scale that are overall superior to those obtained from site-scale validation. There were large errors in the estimates of T and Es in the ERA5 product, related to the overestimation of Es and underestimation of T. The boundary between sea and land (used to divide marine evapotranspiration and land evapotranspiration) was unclear in the PML products. Eo/ETa was overestimated, and there were clearly high values at the land margin (Eo peaks as high as 3803 mm/yr). The difference in evapotranspiration components had a considerable influence on the uncertainty of ETa. The vegetation types in the 4 ETa products for DBF***, EBF***, ENF***, MF***, GRA***, and CRO*** all exhibited significant differences at the P<0.001 level. This study contributes to product uncertainty analysis and the determination of ways to improve ETa products.

The morphological adjustments of euhalophytes are well-known to be influenced by the soil-soluble salt variation; however, whether and how these changes in morphological traits alter the biomass allocation pattern remains unclear, especially under different NaCl levels. Therefore, an allometric analysis was applied to investigate the biomass allocation pattern and morphological plasticity, and the carbon (C), nitrogen (N), and phosphorus (P) stoichiometric characteristics of the euhalophyte Suaeda Salsa (S. salsa) at the four soil-soluble salt levels of no salt (NS), light salt (LS), moderate salt (MS), and heavy salt (HS). The results showed that soil-soluble salts significantly change the biomass allocation to the stems and leaves (p < 0.05). With the growth of S. salsa, the NS treatment produced a downward leaf mass ratio (LMR) and upward stem mass ratio (SMR); this finding was completely different from that for the salt treatments. When S. salsa was harvested on the 100th day, the HS treatment had the highest LMR (61%) and the lowest SMR (31%), while the NS treatment was the opposite, with an LMR of 44% and an SMR of 50%. Meanwhile, the soil-soluble salt reshaped the morphological characteristics of S. salsa (e.g., root length, plant height, basal stem diameter, and leaf succulence). Combined with the stoichiometric characteristics, N uptake restriction under salt stress is a vital reason for inhibited stem growth. Although the NS treatment had the highest biomass (48.65 g root box−1), the LS treatment had the highest salt absorption (3.73 g root box−1). In conclusion, S. salsa can change its biomass allocation pattern through morphological adjustments to adapt to different saline–alkali habitats. Moreover, it has an optimal biological desalting effect in lightly saline soil dominated by NaCl.

The objective of this study is to produce multi-criteria model for the dry weight prediction of Wedelia trilobata under flooding and nitrogen conditions.Plants of W. trilobata were grown in a greenhouse, and treatments were given for two months.Growth parameters of 60 plants were used to build a numerical model.The neural network model was built using Quasi-Newton approaches that containing Broydenfletcher-goldfarb-shanno gradient (BFGS) learning algorithm, multilayer perceptron (MLP) training algorithm and sigmoid axon transfer function along with 10 neurons at the input network, 9 neurons in the hidden layer, and 1 neuron in the output layer (10-9-1).The selection and validation of the best predictor model were based on lower values of errors and higher value of R 2 .The selected model had a higher values of R 2 = 0.90 and lower values of errors i.e (relative approximate error, RAE = 0.004, root mean square error, RMS = 0.027, mean absolute error, MAE = 0.004, mean absolute percentage error, MAPE = 0.013).Moreover, the highest rank 1 was obtained for leaf area during sensitivity analysis followed by water potential and photosynthesis ranked 2 rd and 3 th , respectively.The constructed model of W. trilobata under flooding and nitrogen conditions is the new feature in the management of invasive plant species and gives direction to control its spread.

Halophyte-based desalinization is emerging as a promising technology for saline agriculture. However, few studies have integrated halophytes into intercropping systems. This study investigated Suaeda salsa and soybean intercropping and the associated mechanisms, including changes in salt, nutrients, and bacterial communities at three salt treatments (control, 3‰, and 5‰). The results showed that regardless of salt treatment, soybean biomass and P content significantly increased in intercropping compared with monocropping, by an average of 32% and 51%, respectively (p < 0.05), indicating interspecific facilitation. Under 5‰ salt, soybean mortality decreased from 37% in monocropping to 10% in intercropping, and shoot Na decreased by over 60% in intercropping; the rhizosphere Na+, Cl−, and NO3−–N decreased in intercropping by over 75% compared with monocropping, and the response ratios correlated negatively with S. salsa biomass (p < 0.01). The soybean rhizosphere bacterial community in intercropping was enriched with the genera Sphingomonas, Salinimicrobium, Lysobacter, Allorhizobium–Neorhizobium–Pararhizobium–Rhizobium, and Ramlibacter, and the bacterial co-occurrence network exhibited increases in the number of nodes and edges, average degree, and average clustering coefficient. Considering the combined effects, the soybean biomass of intercropping correlated positively with bacterial co-occurrence network parameters, including average degree and number of edges, independent of tissue salt and nutrient content, and that of monocropping correlated negatively with tissue salt content. These results demonstrate that S. salsa intercropping could alleviate salt stress in soybean by creating a low-salt environment and improving its nutrient accumulation and rhizosphere bacterial community, and emphasize the importance of microbial communities in influencing soybean growth.