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Summary: N-enriched biochar can increase the accumulation of carbon (C), nitrogen (N), phosphorus (P), and biomass in rice plants. On the other hand, the biomass and C, N, and P contents of plant organs are important indicators to reflect plant C, N, and P storages. We established control, 4 t ha−1, and 8 t ha−1 N-enriched biochar treatment plots in a subtropical paddy field in China to investigate the effect of these treatments on C, N, and P storages, ecological stoichiometry in various rice plant organs, and their relationships with edaphic factors. The application of N-enriched biochar increased the biomass and storages of C, N, and P in rice roots, stems, leaves, and grains, mainly at 4 t ha−1. The application of N-enriched biochar decreased the C/N and C/P ratios of rice organs, but increased their N/P ratio. Changes in C/N were mainly due to the changes in storage, while N/P was positively correlated with N storage of stems, leaves, and grains and negatively correlated with P storage in roots. Pearson's correlation analysis revealed that pH was negatively correlated, and soil N content was positively correlated with P storage in various organs of rice. In addition, soil P content and chlorophyll were positively correlated with N storage. In conclusion, we found that the application of N-enriched biochar improved plant N and P storage and stoichiometrical relations among rice organs. [ABSTRACT FROM AUTHOR]

More efficient use of soil resources, such as nitrogen (N) and phosphorus (P), can improve plant community resistance and resilience against drought in arid and semi-arid lands. Intercropping of legume and non-legumes can be an effective practice for enhancing P mineralization uptake, and plant nutrient status. However, it remains unclear how intercropping systems using desert plant species impact soil-plant P fractions and how they affect N and water uptake capacity. Alhagi sparsifolia (a legume) and Karelinia caspia (a non-legume) are dominant plant species in the Taklamakan Desert in Xinjiang Province, China. However, there is a lack of knowledge of whether these species, when intercropped, can trigger synergistic processes and mechanisms that drive more efficient use of soil resources. Thus, in a field experiment over two years, we investigated the impact of monoculture and intercropping of these plant species on soil-plant P fractions and soil-plant nutrients. Both plant species' foliar nutrient (N, P, and K) concentrations were higher under monoculture than intercropping (except K in K. caspia). Nucleic acid P was higher in the monoculture plots of A. sparsifolia, consistent with higher soil labile P, while metabolic P was higher in monoculture K. caspia, associated with higher soil moderately labile Pi. However, both species had a higher residual P percentage in the intercropping system. Soils from monoculture and intercropped plots contained similar microbial biomass carbon (MBC), but lower microbial biomass N:microbial biomass phosphorus (MBN:MBP) ratio associated with reduced N-acetylglucosaminidase (NAG) activity in the intercropped soils. This, together with the high MBC:MBN ratio in intercropping and the lack of apparent general effects of intercropping on MBC:MBP, strongly suggest that intercropping improved microbe N- but not P-use efficiency. Interestingly, while EC and SWC were higher in the soil of the K. caspia monoculture plots, EC was significantly lower in the intercropped plots. Plants obtained better foliar nutrition and soil P mineralization in monocultures than in intercropping systems. The possible positive implications of intercropping for reducing soil salinization and improving soil water uptake and microbial N-use efficiency could have advantages in the long term and its utilization should be explored further in future studies. [ABSTRACT FROM AUTHOR]

Studying the pattern of species richness is crucial in understanding the diversity and distribution of organisms in the earth. Climate and human influences are the major driving factors that directly influence the large‐scale distributions of plant species, including gymnosperms. Understanding how gymnosperms respond to climate, topography, and human‐induced changes is useful in predicting the impacts of global change. Here, we attempt to evaluate how climatic and human‐induced processes could affect the spatial richness patterns of gymnosperms in China. Initially, we divided a map of the country into grid cells of 50 × 50 km2 spatial resolution and plotted the geographical coordinate distribution occurrence of 236 native gymnosperm taxa. The gymnosperm taxa were separated into three response variables: (a) all species, (b) endemic species, and (c) nonendemic species, based on their distribution. The species richness patterns of these response variables to four predictor sets were also evaluated: (a) energy–water, (b) climatic seasonality, (c) habitat heterogeneity, and (d) human influences. We performed generalized linear models (GLMs) and variation partitioning analyses to determine the effect of predictors on spatial richness patterns. The results showed that the distribution pattern of species richness was highest in the southwestern mountainous area and Taiwan in China. We found a significant relationship between the predictor variable set and species richness pattern. Further, our findings provide evidence that climatic seasonality is the most important factor in explaining distinct fractions of variations in the species richness patterns of all studied response variables. Moreover, it was found that energy–water was the best predictor set to determine the richness pattern of all species and endemic species, while habitat heterogeneity has a better influence on nonendemic species. Therefore, we conclude that with the current climate fluctuations as a result of climate change and increasing human activities, gymnosperms might face a high risk of extinction. [ABSTRACT FROM AUTHOR]

Drought is one of the major environmental stresses altering forest productivity. However, nutrient availability can modulate drought resistance. Phoebe zhennan (gold Phoebe) is a high‐quality timber‐producing but threatened tree species in China, facing serious anthropogenic disturbances and abiotic constraints that restrict its growth and development. However, little attention has been given to designing adaptive strategies for its management by evaluating the possible role of major nutrients, particularly nitrogen (N), on its morphological and physio‐biochemical responses under water stress. To evaluate these responses, a complete randomized design was followed to investigate the effects of two irrigation levels (well‐watered and drought‐stressed conditions) and N fertilization treatments (with and without N). Drought stress significantly affected the growth of seedlings, as indicated by impaired photosynthesis, pigment degradation, disrupted N metabolism, over‐production of reactive oxygen species and enhanced lipid peroxidation. Nitrogen supplementation under drought stress had remarkable positive effects on the growth through physio‐biochemical adjustments as shown by higher level of nitrogenous compounds and up‐regulation of N‐associated metabolic enzymes activities which might be due to N‐mediated improved leaf relative water contents and photosynthetic efficiency. In addition, N application reduced oxidative stress and membrane damage, and maintained a high accumulation of osmolytes. However, in well‐watered seedlings N fertilization significantly improved root biomass and net CO2 assimilation rate suggesting high N‐use efficiency of the seedlings. These findings reveal that drought significantly affects the growth of P. zhennan, while N fertilization plays a crucial role in alleviating water stress damage by improving its drought tolerance potential at low metabolic costs. Therefore, N fertilization could be considered as an effective strategy for the conservation and management of P. zhennan in the face of future climate change. [ABSTRACT FROM AUTHOR]

Three Gorges Reservoir in China was running since June 2003, and its impacts on soil erosion (SE) and soil conservation (SC) have attracted major public attentions. We quantified the soil conservation service of ecosystems in the Three Gorges Reservoir Area (TGRA) based on a GIS platform using the universal soil loss equation. We revealed the changes of spatial and temporal patterns of soil conservation (SC) and soil erosion (SE) after project construction as well as impact factors on local SE and SC. Results showed that the total amounts and mean capacity of soil conservation services in the TGRA were 15.38-billion t a and 2134.73 t ha a, respectively. Northeast reservoir area owned better services than the southwest, and the regions with a capacity of >5000 t ha a were primary located in mountain areas. An increasing trend in SC appeared in the TRGA and 'with increasing SC' totaled 22690.5 km (38.9%), while the areas 'with decreasing SC' amounted to 3460.4 km (5.9%) between 2000 and 2010. Moreover, the pattern of changing SC was continuous in this area. The spatial characteristics of soil conservation service in the TGRA were primarily affected by slope, climate and terrain features. In addition, the reforestation and/or forest protection would contribute to soil erosion control in the TGRA. The results revealed a great spatial heterogeneity of soil conservation service in this region, which may provide useful suggestions for land management, soil erosion control and ecosystem protection in the TGRA in China. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alhagi sparsifolia offers a variety of socio-ecological services in arid lands. • Unsustainable activities for agricultural purposes may threaten nutrient cycling. • Long-term burning and cutting affect the foliar nutrition of A. sparsifolia. • Long-term overexploitation can impact the nutritional quality of A. sparsifolia. • Sustainable management of A. sparsifolia is crucial for ecological restoration. Arid ecosystems are characterized by low availability and mobility of soil nutrients and slow geochemical cycles. Management of native vegetation in such ecosystems for fuel, livestock grazing, and other agricultural activities (burning and cutting) may threaten semi-natural communities due to the changes in nutrient cycles and soil fertility. Alhagi sparsifolia is a dominant perennial legume in the Taklamakan Desert of northwestern China and has been used as fodder for livestock and plays a crucial ecological role in stabilizing dunes in the oasis-desert ecotone. We evaluated the effects of long-term (12 years) burning and cutting of plant biomass on the mineral nutrition of A. sparsifolia and associated soils at two depths (0–50 and 50–100 cm) in the field conditions following the block design experiment. We found that burning effects tended to be restricted to the topsoil (0–50 cm), and the concentration of many micro-and macronutrients was increased. Burning was associated with a decrease in plant nitrogen (N) and phosphorus (P) concentration, whereas concentrations of other micro-and macronutrients increased; overall, burning reduced foliar stocks of N, P, and potassium (K). Annual cutting elicited smaller increases in soil mineral (total sulfur, total P, calcium, magnesium, and available P and K) concentrations than burning, and soil enzymatic activities increased. There were contrasting response patterns of leaf N and P concentration and macro-and micronutrients between the two management approaches. Burning and cutting reduced leaf N and P concentrations, while changes in root and shoot N and P concentrations depended on treatments. Thus, burning and cutting of A. sparsifolia impact organ nutrient stoichiometry (increased losses of macronutrients from arid plant-soil ecosystems) and nutritional quality (for feeding livestock), particularly due to predicted rises in extreme climatic events under climate change that are expected to increase risks of soil erosion, however, impacts on native trophic webs remain unclear. [ABSTRACT FROM AUTHOR]

• Crop planting distance and density to improve yield of intercropping systems. • Field experiments were conducted in a split-plot arrangement. • Increasing plant distance, yield of planting sweet potatoes decreased. Sweet potato is a high-yield food crop with strong adaptation and is widely cultivated in southwestern China. Adjusting crop planting distance and planting density to improve the yield and productivity of intercropping systems has become an important management practice around the globe. However, little is known about the response of the sweet potato yield and photosynthetic characteristics to intercropping with walnut saplings. Field experiments were conducted in a split-plot arrangement, e.g., three plant densities (Dl, low, 4 plants/m2; Dm, moderate, 8 plants/m2; and Dh, high, 12 plants/m2) were randomly assigned (subplot) to three planting distances (P1, 0.25 n; P2, 0.5 n; and P3, n) (main plot). The results showed that with increasing plant distance, the yield of high-density sweet potatoes decreased significantly (P < 0.05). However, the highest sweet potato fresh root tuber yield (FRTY) appeared in the combination of P1Dh (plant distance: 0.25 n; plant density: 12 plants m2). Our data further suggested that under the planting distance of P1 (0.25 n) or P2 (0.5 n), soil moisture content increased significantly (approximately 3%) with planting density (P < 0.05). The net photosynthetic rate (P n) of sweet potatoes was significantly improved in cases of high sweet potato density and a short distance between sweet potatoes and walnut saplings, which ultimately increased yield. For the walnut saplings and sweet potatoes, a more compact planting distance was associated with higher values of P n , T r and G s. Based on yield performance, photosynthetic traits and walnut sapling growth, the combination of 12 plants/m2 and P1 is the optimal scheme for walnut/sweet potato intercropping systems. [ABSTRACT FROM AUTHOR]

• The relative abundance of K-solubilizing Proteobacteria decreased as a result of warming. • The relative abundance of K-solubilizing Talaromyces increased as a result of warming. • The abundance of soil fungi and fungivores increased as a result of warming. • The interaction between fungi and fungivores enhanced soil K mineralization. Potassium (K) cycling in forest systems has received less attention than nitrogen (N) and phosphorus (P) cycles, despite its critical role in maintaining primary production and regulating water economy and use under climate warming. This study conducted a 10-year study in which we translocated dominant tropical forest tree seedlings and underlying soil (i.e., in situ soil) from high-altitude sites (600 m a.s.l.) to lower altitude sites at 300 m a.s.l. (+1.0 °C) and 30 m a.s.l. (+2.1 °C) to simulate climate warming in southern China. We investigated soil microbial and nematode communities, soil and foliar K concentrations at the aggregate level, and tree growth under different altitude sites. Microbial community was characterized by high-throughput sequencing, nematodes were identified to the genus level using microscope. The findings revealed that warming treatments significantly (p < 0.01) increased soil fungal gene abundance (+78 % at 300 m and +62 % at 30 m), fungal/bacterial abundance ratio (+121 % at 300 m and +101 % at 30 m), and soil fungivore abundance (+274 % at 300 m and +233 % at 30 m). These results indicate a shift in the soil decomposition pathway from bacterial to fungal-based channels. In addition, warming amplifies the interactions between fungi and fungivores. Aggregates had few effects on microbial biomass, but had significant effect on nematode abundance. Soil microcosm experiments consistently demonstrated that addition of the dominant fungivore Aphelenchoides significantly (p < 0.05) enhanced soil-exchangeable K by stimulating fungal gene abundance and activity. Furthermore, warming-induced changes in forest communities were observed. At the species-specific tree level, Syzygium rehderianum demonstrated the ability to take advantage of this scenario, exhibiting increased K uptake (−4% at 300 m and +32 % at 30 m). This may be attributed to the species being ectomycorrhizal-forming, where colonizing root surfaces can mobilize interlayer and structural K from the minerals. In contrast, Machilus breviflora exhibited lower foliar K concentrations (−42 % at 300 m and −41 % at 30 m) and reduced growth. However, warming had little effect on Schima superba , Myrsine seguinii , Itea chinensis , and Ardisia lindleyana growth. Warming-induced changes in the plant–soil system K cycle highlight the emergence of a new ecosystem structure with different soil web structures and distinct plant community species composition. Our results prompt further research to understand the microbiome-mediated complexities of understudied nutrient cycles, which are likely to be further altered in the future owing to climate change. [ABSTRACT FROM AUTHOR]

• The spatial variation in N 2 fixation of naturally grown A. sparsifolia is a plastic response to the salinity gradient of groundwater. • Symbiotic nitrogen fixation of A. sparsifolia is more salt-tolerant than the nitrate assimilation process. • N acquisition strategies of A. sparsifolia in the Taklimakan Desert are under the control of rhizosphere salinity levels. Salinity has adverse effects on the nitrogen (N) metabolism of legumes in dryland ecosystems. Although the response of biological N fixation (BNF) to salt stress has received much research attention, less is known about how N fixing plants may adjust their N acquisition strategies in response to variation in salt stress. Alhagi sparsifolia , a perennial deep-rooted legume located in both riparian and desert environments of the hyperarid Taklimakan Desert, China, is a regionally important species due to its capacity for fixing atmospheric N and increasing soil stability. We investigated how groundwater biogeochemistry was related to seasonal differences in BNF of Alhagi sparsifolia located at terminal ends of a soil salinity gradient (high salinity riparian; inland low salinity sand dunes) in the Taklimakan Desert. Additionally, to elucidate the plasticity of A. sparsifolia nitrogen fixation to variation in soil salinity, we experimentally treated Alhagi seedlings from the same parental lineage with NaCl, Na 2 SO 4 , NH 4 NO 3 , and groundwater, and evaluated N fixation potential via root nodule development. We did not find evidence that mineral nitrogen concentrations influenced the varied N 2 fixation rates (indicated by foliar δ 15N value) in A. sparsifolia that we observed in the field. Instead, BNF of Alhagi plants was higher in high salinity riparian areas, whereas these plants utilized groundwater N when located in low salinity inland sand dunes. In our experimental treatments, salt addition did not significantly influence the nodulation of Alhagi seedlings, suggesting that nitrate assimilation instead of BNF is suppressed by salt stress. Thus, BNF in A. sparsifolia is tolerant to salt stress, and can be adjusted in response to variation in N availability and soil salinity. Relationships between salt tolerance and biological nitrogen fixation in A. sparsifolia explains how these species can increase soil nutrient availability across differing dryland environments, and illustrates a possible strategy whereby dryland legumes enhance their adaptability to saline environments by both building symbiotic associations with Rhizobium and utilizing readily available N when salt stress is less prohibitive. [ABSTRACT FROM AUTHOR]

• Past and future climate variables were used as indicators for climatic stable areas. • Climate stable areas could be assumed as refugia for conifer conservation planning. • Mid-Holocene was the most suitable historical time for presence of conifer forests. • Climatic stability of warmest quarter explains the range stability of cold conifers. • Variability of driest quarter temperature explains the range shift of warm conifers. The distribution of forests can be hindcast or forecast when robust data and validation proofs are available. Distribution consequences for temperate coniferous forests during the Quaternary and future climatic fluctuations are little understood in China. Temperate coniferous forests are subdivided into two types where Pinus, Keteleeria, Tsuga and Cupressus species characterize the warm forests while Abies , Picea, Larix and Juniperus species characterize the cold forests. Both forest types were investigated using 12,675 unique records in the MaxEnt model to infer distribution patterns during six time periods: the present time, mid-Holocene, Last Glacial Maximum, Last Interglacial and the near- and far-future (2050, 2070). The results showed that the mean temperature of the driest quarter, followed by the temperature annual range and the precipitation of the warmest quarter were the most important variables controlling forests distribution. Suitable areas capable of supporting the presence of warm coniferous forests were highly contracted during the Quaternary; meanwhile, the cold coniferous forests expanded westwards from the last glacial maximum through the mid-Holocene to the present. The predicted future distributions showed a significant range-shift of warm forests northeastwards in response to climate change while cold coniferous forests are expected to migrate towards the Tibetan Plateau. Under increased global warming, the bioclimatic variables of the past and future periods were used as ecological indicators for the identification of areas showing "climatic stability", and predicted to be refugia for coniferous forests and as good tools for conservation planning in Sichuan and the Hengduan-Tibetan migration corridor. [ABSTRACT FROM AUTHOR]

Mangrove wetlands are highly productive ecosystems in tropical and subtropical coastal zones, play crucial roles in water purification, biodiversity maintenance, and carbon sequestration. Recent years have seen the implementation of pond return initiatives, which have facilitated the gradual recovery of mangrove areas in China. However, the implications of these initiatives for soil aggregate stability, microbial community structure, and network interactions remain unclear. This study assesses the impacts of converting ponds to mangroves-both in natural and artificially restored settings-on soil aggregate stability and microbial networks at typical mangrove restoration sites along China's southeastern coast. Our observations confirmed our hypothesis that pond-to-mangrove conversions resulted in an increase in the proportion of large aggregates (>0.25 mm), improved soil aggregate structural stability, and increased carbon sequestration. However, mangrove recovery led to a decrease in the abundance and diversity of soil fungi communities. In terms of co-occurrence networks, naturally restored mangrove wetlands exhibited more nodes and edges. The naturally recovered mangrove wetlands demonstrated a higher level of community symbiosis compared to those that were manually restored. Conversely, bacterial networks showed a different pattern, with significant shifts in key taxa related to carbon sequestration functions. For instance, the proportion of bacterial Desulfobacterota and fungi Basidiomycota in natural recovery mangrove increased by 15.03 % and 7.82 %, respectively, compared with that in aquaculture ponds. Soil fungi and bacteria communities, as well as carbon sequestration by aggregates, were all positively correlated with soil total carbon content (P < 0.05). Both bacterial and fungal communities contributed to soil aggregate stability. Our study highlights the complex relationships between soil microbial communities, aggregate stability, and the carbon cycle before and after land-use changes. These findings underscore the potential benefits of restoring mangrove wetlands, as such efforts can enhance carbon storage capacity and significantly contribute to climate change mitigation., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024. Published by Elsevier B.V.)

Soil salinization adversely affects soil fertility and plant growth in arid region worldwide. However, as the drivers of nutrient cycling, the response of microbial communities to soil salinization is poorly understood. This study characterized bacterial communities in different soil layers along a natural salinity gradient in the Karayulgun River Basin, located northwest of the Taklimakan desert in China, using the 16S rRNA Miseq-sequencing technique. The results revealed a significant filtering effect of salinity on the bacterial community in the topsoil. Only the α-diversity (Shannon index) in the topsoil (0-10 cm) significantly decreased with increasing salinity levels, and community dissimilarity in the topsoil was enhanced with increasing salinity, while there was no significant relationship in the subsoil. BugBase predictions revealed that aerobic, facultatively anaerobic, gram-positive, and stress-tolerant bacterial phenotypes in the topsoil was negatively related to salinity. The average degree and number of modules of the bacterial co-occurrence network in the topsoil were lower under higher salinity levels, which contrasted with the trends in the subsoil, suggesting an unstable bacterial network in the topsoil caused by higher salinity. The average path length among bacterial species increased in both soil layers under high salinity conditions. Plant diversity and available nitrogen were the main drivers affecting community composition in the topsoil, while available potassium largely shaped community composition in the subsoil. This study provides solid evidence that bacterial communities adapt to salinity through the adjustment of microbial composition based on soil depth. This information will contribute to the sustainable management of drylands and improved predictions and responses to changes in ecosystems caused by climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Coastal-wetlands play a crucial role as carbon (C) reservoirs on Earth due to their C pool composition and functional sink, making them significant for mitigating global climate change. However, due to the development and utilization of wetland resources, many wetlands have been transformed into other land-use types. The current study focuses on the alterations in soil organic-C (SOC) in coastal-wetlands following reclamation into aquaculture ponds. We conducted sampling at 11 different coastal-wetlands along the tropical to temperate regions of the China coast. Each site included two community types, one with solely native species (Suaeda salsa, Phragmites australis and Mangroves) and the other with an adjacent reclaimed aquaculture pond. Across these 11 locations we compared SOC stock, active OC fractions, and soil physicochemical properties between coastal wetlands and aquaculture ponds. We observed that different soil uses, sampling sites, and their interaction had significant effects on SOC and its stock (p < .05). Reclamation significantly declined SOC concentration at depths of 0-15 cm and 15-30 cm by 35.5% and 30.3%, respectively, and also decreased SOC stock at 0-15 cm and 15-30 cm depths by 29.1% and 37.9%, respectively. Similar trends were evident for SOC stock, labile organic-C, dissolved organic-C and microbial biomass organic-C concentrations (p < .05), indicating soil C-destabilization and losses from soil following conversion. Soils in aquaculture ponds exhibited higher bulk density (BD; 11.3%) and lower levels of salinity (61.0%), soil water content (SWC; 11.7%), total nitrogen (TN) concentration (23.8%) and available-nitrogen concentration (37.7%; p < .05) than coastal-wetlands. Redundancy-analysis revealed that pH, BD and TN concentration were the key variables most linked with temporal variations in SOC fractions and stock between two land use types. This study provides a theoretical basis for the rational utilization and management of wetland resources, the achievement of an environment-friendly society, and the preservation of multiple service functions within wetland ecosystems., (© 2024 John Wiley & Sons Ltd.)

Wetlands, which are ecosystems with the highest soil surface carbon density, have been severely degraded and replaced by artificial reclamation for fish and shrimp ponds in recent years. This transformation is causing intricate shifts in soil carbon pools and microbial stability. In this study, we examined natural wetlands and reclaimed aquaculture ponds in Southeast China to analyze the structure and network stability of soil microbial communities following the reclamation of estuarine wetlands and to elucidate the microbial-mediated mechanisms for regulating soil organic carbon (SOC). The aquaculture ponds presented significantly less average SOC content than the natural wetlands (p < 0.05). ACE, Chao1, and Shannon's indices of bacteria and fungi were decreased in aquaculture ponds. Less numbers of nodes and edge links in the co-occurrence network of soil fungi and bacteria in aquaculture ponds. This suggests reduced correlation and stability within the microbial network of aquaculture ponds. Decomposers in soil fungi (e.g. Dung Saprotroph) reduced. Reduced proportions of key phyla Ascomycota, Basidiomycota and Rozellomycota in the soil fungal network. Reduced proportions of key phyla Proteobacteria, Chloroflexi and Desulfobacterota in the soil bacterial network. In conclusion, our results suggest that converting wetland paddocks to intensive aquaculture ponds results in carbon pool loss and reduces soil microbial network stability. The results highlight the importance of protecting or moderately restoring mangrove wetlands along the coast of southeastern China. It is also predicted that such measures may enhance the storage capacity of soil carbon pools and improve the stability of carbon sequestration by soil microorganisms, thus offering a potential solution for mitigating global climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Vegetation restoration in deserts is challenging due to these ecosystems' inherent fragility and harsh environmental conditions. One approach for active restoration involves planting native species, which can accelerate the recovery of ecosystem functions. To ensure the effectiveness of this process, carefully selecting species for planting is crucial. Generally, it is expected that a more diverse mix of species in the plantation will lead to the recovery of a greater number of ecosystem functions, especially when the selected species have complementary niche traits that facilitate maximum cooperation and minimize competition among them. In this study, we evaluated the planting of two native species from the hyper-desert of Taklamakan, China, which exhibit marked morpho-physiological differences: a phreatophytic legume (Alhagi sparsifolia) and a halophytic non-legume (Karelinia caspia). These species were grown in both monoculture and intercrop communities. Monoculture of the legume resulted in the highest biomass accumulation. Intercropping improved several ecosystem functions in the 50 cm-upper soil, particularly those related to phosphorus (P), carbon (C), and sulfur (S) concentrations, as well as soil enzyme activities. However, it also increased soil sodium (Na + ) concentration and pH. Halophyte monocultures enhanced ecological functions associated with nitrogen concentrations in the upper soil and with P, S, C, and cation concentrations (K + , Ca 2+ , Mg 2+ , Cu 2+ , Fe 2+ , Zn 2+ , Co 2+ , Ni 2+ ), along with enzyme activities in the deep soil. It also maximized Na + accumulation in plant biomass. In summary, we recommend legume monoculture when the primary goal is to optimize biomass accumulation. Conversely, halophyte monoculture is advisable when the objective is to extract sodium from the soil or enhance ecosystem functions in the deep soil. Intercropping the two species is recommended to maximize the ecosystem functions of the upper soil, provided there is no salinization risk. When planning restoration efforts in desert regions, it is essential to understand the impact of each species on ecosystem function and how complementary species behave when intercropped. However, these interactions are likely species- and system-specific, highlighting the need for more work to optimize solutions for different arid ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Biochar has been proved to be an important soil amendment to alleviate soil phosphorus (P) in the paddy crops. However, the role of specially prepared biochar (N-enriched biochar) on the distribution and transformation of P soil in and rice leaves needs to be revealed. In this study, we studied in a field experiment the effects of two different levels of application of N-enriched biochar on the P fractions of soil and leaves. The results showed that: (1) in early rice, both rates of N-enriched biochar increased soil concentrations of labile inorganic P (Pi) (+51.5 % and +66.2 %, respectively) and labile organic P (Po) (+167 % and + 76.9 %, respectively) and moderately labile Pi (+37.8 % and +27.8 %, respectively) and decreased soil concentration of moderately labile Po (-17.0 % and -52.7 %, respectively) in the 0-15 cm layer. Soil total P concentration was positively correlated with soil labile P fractions and moderately labile Pi concentrations (p < 0.05); (2) in early and late rice, application of the biochar at 4 t ha -1 increased rice leaf concentration of inorganic (+13.3 % and +34.8 %, respectively), nucleic acid (+24.2 % and +13.0 %, respectively) (p < 0.05). The foliar inorganic and nucleic acid P concentrations were positively correlated with foliar total P concentrations; (3) redundancy analysis showed that with the application of N-enriched biochar, soil total carbon (C), nitrogen (N) and P concentration were important factors affecting the chemical forms of soil P, while soil organic matter, soil total P and leaf total P content were important factors affecting the chemical forms of leaf P; (4) allometric growth models showed that under the application of N-enriched biochar, 0-30 cm soil labile Po concentration was positively related to leaf concentration of nucleic acid P, 0-15 cm soil moderately labile Pi concentration was positively related to leaf concentration of inorganic P and nucleic acid P. Thus, this study provides evidence that N-enriched biochar increase the soil P-availability of labile and moderately labile P that in turn improved rice plants P use efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The incorporation of post-harvest crop straw and application of industrial and agricultural wastes to paddy soils increase rice crop yields and soil fertility. However, the impacts of combined applications of straw and waste products on greenhouse gas (GHG) emissions and global warming potential (GWP) of paddy soils are unclear. Therefore, we conducted a field experiment in subtropical rice in China to test the effects of applications of straw, straw+biochar, straw+shell slag, straw+gypsum slag, straw+silicon, and straw+steel slag on rice yields, GWP, and greenhouse gas emission intensity (GHGI). The results showed that, compared to the control, cumulative emissions of carbon dioxide (CO 2 ) from paddy soils were 15.2, 16.9, and 36.6 % lower following application of straw+steel slag, straw+silicon, and straw+gypsum, respectively, and cumulative emissions of methane (CH 4 ) were 5.0 and 62.1 % lower following application of straw+steel slag and straw+gypsum, respectively. Meanwhile, relative to the addition of straw alone, application of straw+steel slag and straw+gypsum reduced GHG emissions largely due to reductions in CO 2 emissions, further declining the GWP of CO 2 and GHGI. In addition, temperature sensitivity (Q 10 ) of CO 2 emissions was highest following application of straw+silicon and lowest following application of straw+gypsum. There were no treatment effects on mean dissolved porewater concentrations of CO 2 , CH 4 , or nitrous oxide (N 2 O) and soil emissions of CO 2 were negatively correlated with mean dissolved concentrations of CO 2 , CH 4 , and N 2 O. Rice yields were reduced following application of straw+gypsum and unaffected by the other treatments. Thus, relative to the addition of straw alone or control, we suggest the combined application of straw+steel slag may improve the sustainability of paddy rice production, because it reduces GWP, while maintaining yields., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Incorporating amendments of industrial waste such as biochar and steel slag in cropland has been used to enhance the storage of soil organic carbon (SOC) while sustaining crop production. Short-term laboratory and field studies have identified important influences of biochar on active SOC fractions associated with soil microbial activity in paddy soils, but the long-term effects remain poorly understood. To address these knowledge gaps, we examined the effects of slag, biochar, and slag+biochar treatments on total SOC concentration, active SOC fractions and soil microbial communities in a paddy field two years after incorporation. Across both two seasons, the addition of slag, biochar, slag+biochar increased soil salinity by 26-80%, 1.3-37% and 42-79%, and also increased soil pH by 0.8-5.7%, 2.1-2.4% and 4.0-6.3%, respectively, relative to the control. SOC concentration was higher in the slag, biochar, and slag+biochar treatments across both rice seasons by 4.3-5%, 0.5-17% and 4.3-7%, respectively. Soil C-pool activity and C-pool management indices in the late paddy season were significantly lower in the slag+biochar treatment than the control by 26.3 and 21.3%, respectively, indicating that the amendments contributed to the stability of SOC. The C concentrations of the biochar and slag amendments affected bacterial abundance more than fungal abundance and affected C cycling. Our study suggests that combined slag and biochar amendments may increase bacterial abundance that may maintain SOC storage and reduce the abundances of potential SOC decomposers in key functional genera, indicating strong coupling relationships with changes of soil properties such as salinity, pH, and SOC concentration. These outcomes due to the amendments (e.g. slag+biochar) may increase microbial C-use efficiency and support the stability of active SOC fractions, with opportunities for long-term C sequestration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Nematodes generally occupy multiple trophic levels in detrital food webs, which play a vital role in energy flow, material conversion and nematodes community structure stability in the underground ecosystem. Sulfur (S) is one of the important soil nutrients, and it plays an important role in the nutrient cycle of grassland ecosystem. However, the impacts of S on soil fauna and subsurface detrital food webs in grassland ecosystems were rarely studied. Accordingly, to investigate the effects of sulfur deposition on soil nematodes and detrital food webs, we conducted a S addition experiment with distinct intensities from 0 to 50 g S m -2  yr -1 (S 0, S 1, S 2, S 5, S 10, S 15, S 20, and S 50) to simulated sulfur deposition in a meadow steppe of northern China. We documented a significant effect of S addition on the diversity and richness of nematodes, and the species richness of soil nematodes was high in the study site. But S addition had no significant effect on the total abundance and dominant species of nematodes (Cervidellus and Aphelenchus). Results of correlation analysis and structural equation modeling consistently indicated that omnivores-predators were significantly affected by sulfur addition. A significant increase in the Structural Index (which indicates food web structure) suggested increased top-down forces and changed community structure, although bacterivores, fungivores, plant parasites did not significantly. The present results suggest that sulfur deposition would change the composition of nematode community, affect the stability of nematode community structure, and increase the disturbance to the underground ecosystem. The study provides that the detailed information of the response of nematode to S deposition can be used to analyze the process of global change affecting the underground ecosystem., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Agricultural management techniques such as mulching with crop straw can impact soil properties and may in turn change the structure and function of the soil food web. We investigated different straw mulching types and straw mulching coverage levels on soil nematodes community structure in walnut orchards. We set up a randomized experimental design with three straw mulch types, and three straw mulch distance treatments in a walnut plantation. The results indicated that the number of soil nematodes after straw mulching was lower than that found in the control (CK). However, the metabolic and structure footprints of the omnivore-predator nematodes showed higher values as compared to CK. The abundances of plant parasite and omnivore-predator nematodes were negatively correlated with ammonium nitrogen (NH 4+ -N) and dissolved organic nitrogen (DON), whereas soil moisture content (SM) had a negative correlation with the abundance of total nematodes. High structure index (SI), maturity index (MI) and low enrichment index (EI) values revealed a structured soil food web, medium soil enrichment, and fungal decomposition channel under the mix straw mulching treatments. Soil nematodes should be used as an indicator of soil functional changes resulting from straw mulching.

Straw mulching is an effective conservation tillage tool that utilizes waste resources and reduces environmental pollution. To determine the optimal levels of quality, placement and quantity of straw mulching, we performed a field experiment that used the Box-Behnken design combined with response surface methodology. The treatments designed for walnut saplings (Juglans regia) considered three independent variables: quality, placement, and quantity of straw mulching. Tree height of walnut saplings (THW) and net photosynthesis rate (NPR) were used as the response variables in a full, quadratic polynomial model. Analysis of variance (ANOVA) results showed that the selected models were significant (P < 0.05), expressing ideal relationships between the independent and dependent variables (R 2  ≥ 0.9225). The optimum conditions for the THW and NPR responses were determined to be a straw mulching quality which mixed rice and rapeseed straws, a straw mulching placement which covered the entire soil surface of experimental plots, and a straw mulching quantity applied as 3 kg/m 2 (i.e., the low level). This optimized scheme of straw mulching combinations offers an alternate choice for optimizing the growth and potential yield of walnut saplings, but practical field experiments should also be carried out to obtain more site-specific results.