Sustainability assessment on paddy-upland crop rotations by carbon, nitrogen and water footprint integrated analysis: A field scale investigation.

Nutrients of carbon, nitrogen and water of farmland ecosystem are essential foundation to guarantee crop production, but also environmental flows associated greenhouse gas (GHG), reactive nitrogen (Nr) releases, and water consumption. Their flow characteristics serve as a crucial starting point for creating efficient management practices and mitigation measures. Therefore, the objectives of this study are to quantify the carbon footprint (CF), nitrogen footprint (NF), water footprint (WF), and comprehensive environmental footprint (ComF) of six paddy-upland rotation systems, including fallow-paddy rice (FA-PR), Chinese milk vetch-paddy rice (CMV-PR), wheat-paddy rice (WH-PR), rapeseed-paddy rice (RA-PR), green forage wheat-paddy rice (WF-PR), and vicia faba bean-paddy rice (FB-PR), as well as to analysis their relationships and define driving factors. Results showed that the lowest area-scaled CF of 3.74 t CO2-eq ha-1 were observed in the CMV-PR rotation, which were 41% lower than that for WH-PR (the highest CF, 9.13 t CO2-eq ha-1) when soil carbon change was taken into account. It is of importance that soil carbon sequestration in CMV-PR rotation could offset up to around 57% of its CF, while the WH-PR rotation only offset 25%. The RA-PR rotation had the highest area-scaled NF and WF, which was 1.8 and 1.9 times greater than those of the lowest rotation in FA-PR. In terms of comprehensive environmental effects, the six rotation systems showed the order of FA-PR < CMV-PR < FB-PR < RA-PR < WF-PR < WH-PR, with NH3 volatilization accounting 60.7%-66.7% and blue-green WF for 17.5%-26.6% of the total. Therefore, priority should be given to optimizing N fertilizer application and water consumption for paddy-upland rotation systems. The study also suggested that appropriate inter-annual adjustment of rotation system could contribute to achieving GHG mitigations and Nr losses.

Dam Construction as an Important Anthropogenic Activity Disturbing Soil Organic Carbon in Affected Watersheds.

To explore whether and how anthropogenic activities related to surface water regulation (i.e., dam construction) disturb soil ecosystems in the surrounding uplands, a long-term monitoring program was conducted from 1998 to 2017 in the Three Gorges Reservoir Region, China. The Three Gorges Dam (TGD) is the largest hydraulic engineering project in the world. We present a direct, ecosystem-scale demonstration of changes in the soil organic carbon (SOC) content in the TGD watershed before and after the surface water was reshaped. The average SOC content decreased from 12.9 to 9.5 g/kg between 2004 and 2012 and then recovered to 13.8 g/kg in 2017. Dynamics of SOC were partly attributed to shifts in the composition of soil microbial communities responsible for carbon biogeochemistry. The shifts in microbial taxa were associated with the changed microclimate affected by the TGD as well as global and regional climate variability. The microclimate, soil microorganisms, and plant organic carbon input explained 40.2% of the variation in the SOC content. This study revealed that dam construction was an important and indirect driver for the SOC turnover, and the subsequent effects on the upland soil ecosystem must be considered when large-scale disturbance activities (such as dam construction) are conducted in the future.

Protection Mechanisms of Periphytic Biofilm to Photocatalytic Nanoparticle Exposure.

Researchers are devoting great effort to combine photocatalytic nanoparticles (PNPs) with biological processes to create efficient environmental purification technologies (i.e., intimately coupled photobiocatalysis). However, little information is available to illuminate the responses of multispecies microbial aggregates against PNP exposure. Periphytic biofilm, as a model multispecies microbial aggregate, was exposed to three different PNPs (CdS, TiO2, and Fe2O3) under xenon lamp irradiation. There were no obvious toxic effects of PNP exposure on periphytic biofilm as biomass, chlorophyll content, and ATPase activity were not negatively impacted. Enhanced production of extracellular polymetric substances (EPS) is the most important protection mechanism of periphytic biofilm against PNPs exposure. Although PNP exposure produced extracellular superoxide radicals and caused intracellular reactive oxygen species (ROS) accumulation in periphytic biofilm, the interaction between EPS and PNPs could mitigate production of ROS while superoxide dismutase could alleviate biotic ROS accumulation in periphytic biofilm. The periphytic biofilms changed their community composition in the presence of PNPs by increasing the relative abundance of phototrophic and high nutrient metabolic microorganisms (families Chlamydomonadaceae, Cyanobacteriacea, Sphingobacteriales, and Xanthomonadaceae). This study provides insight into the protection mechanisms of microbial aggregates against simultaneous photogenerated and nanoparticle toxicity from PNPs.

Single-cell and Bulk RNA-Seq reveal angiogenic heterogeneity and microenvironmental features to evaluate prognosis and therapeutic response in lung adenocarcinoma.

Background: Angiogenesis stands as a pivotal hallmark in lung adenocarcinoma (LUAD), intricately shaping the tumor microenvironment (TME) and influencing LUAD progression. It emerges as a promising therapeutic target for LUAD, affecting patients' prognosis. However, its role in TME, LUAD prognosis, and its clinical applicability remain shrouded in mystery. Methods: We employed integrated single-cell and bulk transcriptome sequencing to unravel the heterogeneity of angiogenesis within LUAD cells. Through "consensus clustering", we delineated distinct angiogenic clusters and deciphered their TME features. "Monocle2" was used to unravel divergent trajectories within malignant cell subpopulations of LUAD. Additionally, regulon submodules and specific cellular communication patterns of cells in different angiogenic states were analyzed by "pyscenic" and "Cellchat" algorithms. The "univariate Cox" and "LASSO" algorithms were applied to build angiogenic prognostic models. Immunohistochemistry (IHC) on clinical samples validated the role of model factors in LUAD angiogenesis. We utilized CTRP 2.0 and PRISM databases for pinpointing sensitive drugs against lung adenocarcinoma. Results: Two clusters for the activation of angiogenesis were identified, with Cluster 1 showing a poor prognosis and a pro-cancerous TME. Three differentiated states of malignant epithelial LUAD cells were identified, which had different degrees of angiogenic activation, were regulated by three different regulon submodules, and had completely different crosstalk from other cells in TME. The experiments validate that SLC2A1 promotes angiogenesis in LUAD. ARS (Angiogenesis related score) had a high prognostic value; low ARSs showed immunotherapy benefits, whereas high ARSs were sensitive to 15 chemotherapeutic agents. Conclusion: The assessment of angiogenic clusters helps to determine the prognostic and TME characteristics of LUAD. Angiogenic prognostic models can be used to assess the prognosis, immunotherapeutic response, and chemotherapeutic drug sensitivity of LUAD.

Distribution of methanogenic and methanotrophic consortia at soil-water interfaces in rice paddies across climate zones.

Periphytic biofilms (PB) at the soil-water interface contributes 7-38% of the methane emission from rice paddies, yet the biogeographical mechanism underlying and affecting the process remain elusive. In this study, rice fields along an edapho-vclimatic gradient were sampled, and the environmental drivers affecting distribution of methanogenic and methanotrophic communities were evaluated. The methanogenic and methanotrophic communities at soil-water interface showed less complex inter/intra-generic interactions than those in soil, and their relative abundances were weakly driven by spatial distance, soil organic carbon, soil total nitrogen and pH. The nutrient supply and buffering capacity of extracellular polymeric substance released by PB reduced their interaction and enhanced the resilience on edaphic environment changes. Climate affected soil metal content, extracellular polymeric substance content, and thus the methane-related communities, and caused geographical variation in the impacts of PB on methane emissions from rice paddies. This study facilitates our understanding of geographical differences in the contribution of PB to methane emission.

Combined ARHGEF6 and Tumor Mutational Burden may serve as a potential biomarker for immunotherapy of lung adenocarcinoma.

ARHGEF6, a member of the Dbl-related guanylate exchanger (GEF) family, is highly expressed in gastric cancer and glioma. However, scientists still do not know whether it plays a pivotal role in the pathogenesis of lung adenocarcinoma（LUAD）. The prognostic significance of ARHGEF6 expression was assessed by TCGA data. This paper focuses on the level of immune infiltration associated with ARHGEF6 and explored the relationship of this gene with the tumor mutational burden (TMB), immune checkpoints, and drug sensitivity. The results showed that the high expression of ARHGEF6 was associated with a good prognosis in LUAD patients, and positively correlated with a variety of immune cells and drugs. Meanwhile, ARHGEF6 was found to be negatively correlated with TMB. In conclusion, the results of this study suggest that ARHGEF6 is a protective gene in LUAD patients. A combination of ARHGEF6 and TMB could be used as a potential biomarker in the screening of immunotherapy regimens, which are provided to patients with LUAD.

Soil organic carbon stocks and dynamics in a mollisol region: A 1980s-2010s study.

Mollisols are globally distributed in grain-producing regions, and soil organic carbon (SOC) dynamics in mollisol regions are closely related to food security. Regional climate, land use and cover, and field management practice have massively changed since the 1980s in mollisol region in Northeast China, however, the dynamics of topsoil and profile SOC stocks and their distribution have not updated. To explore the dynamics of SOC stocks and their horizontal and vertical distributions in the 1980s-2010s, we took the mollisol region in Northeast China as an example location to conduct profile-scale soil surveys. The in situ surveys indicated that the topsoil SOC stock (0-20 cm) remained relatively stable throughout the 1980s, 2000s, and 2010s, and was 57.3 ± 5.5, 58.2 ± 3.3, and 57.4 ± 4.4 t C ha-1, respectively. The average profile SOC stock (1 m) increased from 148.9 ± 18.5 t C ha-1 in the 1980s to 162.0 ± 14.0 t C ha-1 in the 2010s. A slowdown in land reclamation and implementation of conservation tillage helped maintain and restore SOC stocks. Although the overall SOC stock tended to accumulate, the study area suffered an increasingly unbalanced redistribution of SOC related to severe soil erosion. Soil particles and SOC at erosional positions such as backslope were stripped from the soil surface, leading to attenuated soil thickness and SOC stock; SOC-rich sediment accumulated and was buried at depositional positions, especially at the foot-slope, increasing the soil thickness and SOC stock. These results confirmed that not only the total SOC stock, but also changes in SOC spatial distribution deserve great attention. This study provides a platform to examine and modify the simulation effectiveness of carbon-cycling models, as well as solid foundations for optimal global mollisols management.

Contribution of periphytic biofilm of paddy soils to carbon dioxide fixation and methane emissions.

Rice paddies are major contributors to anthropogenic greenhouse gas emissions via methane (CH4) flux. The accurate quantification of CH4 emissions from rice paddies remains problematic, in part due to uncertainties and omissions in the contribution of microbial aggregates on the soil surface to carbon fluxes. Herein, we comprehensively evaluated the contribution of one form of microbial aggregates, periphytic biofilm (PB), to carbon dioxide (CO2) and CH4 emissions from paddies distributed across three climatic zones, and quantified the pathways that drive net CH4 production as well as CO2 fixation. We found that PB accounted for 7.1%-38.5% of CH4 emissions and 7.2%-12.7% of CO2 fixation in the rice paddies. During their growth phase, PB fixed CO2 and increased the redox potential, which promoted aerobic CH4 oxidation. During the decay phase, PB degradation reduced redox potential and increased soil organic carbon availability, which promoted methanogenic microbial community growth and metabolism and increased CH4 emissions. Overall, PB acted as a biotic converter of atmospheric CO2 to CH4, and aggravated carbon emissions by up to 2,318 kg CO2 equiv ha-1 season-1. Our results provide proof-of-concept evidence for the discrimination of the contributions of surface microbial aggregates (i.e., PB) from soil microbes, and a profound foundation for the estimation and simulation of carbon fluxes in a potential novel approach to the mitigation of CH4 emissions by manipulating PB growth.

Dual benefits of long-term ecological agricultural engineering: Mitigation of nutrient losses and improvement of soil quality.

Soil erosion of sloped farmland in the Three Gorges Reservoir area (TGRA) has led to the serious loss of nutrients, soil quality degradation and the downstream water quality being threatened. Thus, a series of ecological agricultural engineering measures was established in 2011, as a field experiment using citrus (navel orange) plants to reduce soil erosion, which was monitored from 2011 to 2018. These ecological agricultural engineering measures included three treatments: 1) citrus intercropped with white clover (WC), 2) citrus orchard land mulched with straw (SM) and 3) citrus intercropped with hemerocallis (Hemerocallis flava) contour hedgerows (CH). The conventional citrus orchard management was regarded as control (CK). The results show, that compared with CK, nutrient loss from the experiments were reduced by the following amounts: for nitrogen - WC (35.5%), SM (44.0%) and CH (52.0%); for phosphorus - WC (40.0%), SM (51.7%) and CH (58.3%). Therefore, the ecological agricultural engineering measures effectively mitigate the nutrient loss loads of the navel orange citrus gardens. The citrus intercropped with the hemerocallis hedgerows is the most effective measure for the control of nutrient loss. After 8 years of experiment, the soil quality represented by average soil quality index (SQI) in these three treatments, are significantly higher than that of the CK (and the beginning of the experiment). This is because the application of these measures prevented the loss of: soil organic matter, bulk density and total phosphorus. It is predicted that the soil qualities of these three treatments will remain in the range of soil grade II and I for the next 5 years but the soil quality of CK will decrease to soil quality grade II and III. These results show that ecological agricultural engineering measures are a long-term promising and feasible method to reduce soil erosion and enhance soil quality.

Bismuth impregnated biochar for efficient estrone degradation: The synergistic effect between biochar and Bi/Bi2O3 for a high photocatalytic performance.

An innovative advanced oxidation process was successfully developed to photocatalytic-degradation of estrone through the synergistic effect of biochar and Bi/Bi2O3 in bismuth-containing photocatalytic biochar (BiPB). The highest reaction rate constant (kobs) of estrone degradation by BiPB was 0.045 min-1 under the conditions of initial concentration of estrone =10.4 µmol L-1, [BiPB] =1 g L-1, pH = 7.0. The kobs was almost tenfold and more than 20 times than that of biochar without bismuth impregnation and pristine Bi/Bi2O3, respectively. The best photocatalytic performance of BiPB composites for the degradation of estrone was primarily attributed to generation of OH radicals. Impregnation of bismuth helped control the concentration of persistent free radicals (PFRs) and develop a hierarchical porous structure of biochar. The presence of biochar facilitated pre-concentration estrone on BiPB and improved the separation and transfer efficiency of charge carriers. The synergistic effect between biochar and Bi/Bi2O3 contributed to the generation of OH radicals for estrone degradation under neutral pH conditions. The transformation pathway of estrone was also proposed based on the measured transformation products in the presence of BiPB. The high efficiency of BiPB composites indicated that this easily-obtained material was promising for estrone-wastewater treatment applications as a low-cost composite photocatalyst.

The unexpected concentration-dependent response of periphytic biofilm during indole acetic acid removal.

Due to its extensive application in agriculture as a germinating agent and growth promoter, indole acetic acid (IAA) is present in a variety of aquatic ecosystems. To explore the response of microbial aggregates to exogenous IAA in aquatic ecosystems, periphytic biofilm, a typical microbial aggregate, was exposed to IAA at different concentrations. Results reveal an unexpected concentration-dependent effect of IAA on periphytic biofilm. Concentrations of IAA less than 10 mg/L inhibit periphytic growth, but stimulate growth when the IAA concentration exceeds 50 mg/L. Periphytic biofilm adapts to different IAA concentrations by antioxidant enzyme activation, community structure optimization and carbon-metabolism pattern change, and promotes bioremediation of IAA contaminated water in the process. The removal rates of IAA reached up to 95%-100%. This study reveals the capacity of periphytic biofilm for IAA removal in practice.

Carbon-nutrient stoichiometry drives phosphorus immobilization in phototrophic biofilms at the soil-water interface in paddy fields.

Phototrophic biofilms are distributed widely at the sediment/soil-water interfaces (SWI) in paddy fields, where they immobilize phosphorus, thereby reducing its runoff loss. However, how soil carbon, nutrient availability and nutrient ratios drive the phototrophic biofilm community and its contribution to phosphorus cycling is largely unknown. A large scale field investigation in Chinese paddy fields reported here shows that soil organic carbon (SOC) and soil total nitrogen (STN) contents rather than soil total phosphorus (STP) triggered phosphorus immobilization of paddy biofilms, as they changed algal diversity and EPS production. High C: P and N: P ratios favored phosphorus immobilization in biofilm biomass via increasing the abundance of green algae. The C: N ratio on the other hand had only a weak effect on phosphorus immobilization, being counteracted by SOC or STN. Results from this study reveal how the in-situ interception of phosphorus in paddy fields is driven by soil carbon, nutrient availability and nutrient ratios and provide practical information on how to reduce runoff losses of phosphorus by regulating SOC and STN contents.

Quantitative assessment of soil productivity and predicted impacts of water erosion in the black soil region of northeastern China.

As Northeastern China is the country's most significant grain production base, soil productivity in this region has consistently attracted attention. National food security is threatened by an ongoing drain of soil nutrients and decline in soil productivity. Black soil is the key natural resource in this region of China, which is thus known as the "black soil region". It is necessary to study the impact of soil erosion on black soil and its productivity to protect this important resource and ensure its sustainable productivity. Through a field investigation and laboratory analysis, the physicochemical properties in 112 soil profiles from a typical black soil sub-region were measured to assess soil productivity using a soil productivity index (PI) model. The soil PI in the study area was relatively high and showed an increasing trend from southwest to northeast. PI values and their spatial distribution were affected by soil organic matter, soil clay content, soil thickness, slope and geomorphological position. Soil productivity and cluster analysis revealed that the southern and northwestern areas of the typical black soil sub-region under study were subject to the greatest risk. To maintain the region's soil productivity, it is vital to prevent the black soil layer, especially the topsoil, from being destroyed.