Rice Biomass Research Articles

BIOMASS SUPPLY CHAIN OPTIMIZATION FOR RICE INDUSTRY IN PERLIS REGION

The efficient utilization of agricultural biomass holds significant promise in addressing energy and sustainability challenges. This study focuses on the optimization of the rice biomass supply chain in the Perlis region, aiming to enhance the resource utilization and minimize environmental impact. The abundance of rice residues generated after harvesting presents an opportunity to create a sustainable energy source while managing agricultural waste. This research encompasses a comprehensive analysis of the entire rice biomass supply chain, from residue collection at farms to the final biomass conversion process. Geographic information systems are employed to assess rice cultivation patterns and estimate potential biomass yield. Mathematical models are utilized to design an integrated supply chain network that considers collection, transportation, storage, and biomass conversion. Key factors influencing the supply chain are identified, including transportation costs, storage infrastructure, seasonal variations in biomass availability, and technological feasibility of conversion processes. Environmental implications are also evaluated, considering emissions reduction through the displacement of fossil fuels. The outcomes of this study contribute to the establishment of an efficient and sustainable rice biomass supply chain in the Perlis region. The developed optimization framework can serve as a blueprint for similar agricultural biomass utilization initiatives in other regions. The research not only addresses the technical aspects of biomass supply chain management but also considers the broader economic, social, and environmental implications, paving the way for a more resilient and resource-efficient agricultural sector.

MWCNTs Alleviated saline-alkali stress by optimizing photosynthesis and sucrose metabolism in rice seedling

ABSTRACTSaline and alkali stress affects the growth and development, survival rate, and final yield of rice, while new nano materials can have a positive effect on rice growth. In order to investing the effects of carboxymethyl multi walled carbon nanotubes (MWCNTs) on the growth and development of rice seedlings under salt alkali stress, rice seedlings were cultured using rice variety “Songjing 3” using nutrient solution water culture method. The effects of MWCNTs on water absorption capacity, leaf photosynthesis, and sucrose metabolism of rice seedlings under 50 mmol/L saline-alkali stress (1NaCl: 9Na2SO4: 9NaHCO3: 1Na2CO3) conditions were investigated. The results showed that MWCNTs can improve the water use ability of roots and leaves, especially the water absorption ability of roots, which provides a guarantee for the improvement of rice biomass and the enhancement of leaf photosynthetic capacity under adverse conditions. After treatment with MWCNTs, the photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr) of leaves increased significantly, and the photochemical quenching value (qP), photochemical quantum efficiency value (Fv/Fm), and electron transfer rate value (ETR) of chlorophyll fluorescence parameters increased significantly, which is beneficial to the improvement of the PSII photosynthetic system. MWCNTs treatment promoted the increase of photosynthetic pigment content in leaves under salt and alkali stress, improved the ratio of Chla and Chlb parameters, increased the activities of key photosynthetic enzymes (RUBPCase and PEPCase) in leaves, increased the value of total lutein cycle pool (VAZ), and significantly enhanced the deepoxidation effect of lutein cycle (DEPS), which can effectively alleviate the stomatal and non stomatal constraints on leaf photosynthesis caused by salt and alkali stress. MWCNTs treatment significantly enhanced the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SS) under salt and alkali stress, and decreased the activities of soluble acid invertase (SAInv) and alkaline/neutral invertase (A/N-Inv), indicating that MWCNTs promoted sucrose synthesis while inhibiting sucrose decomposition, thereby promoting sucrose accumulation in rice leaves. This study can provide theoretical and experimental basis for the application of MWCNTs to the production of rice under salt and alkali stress, and can find a new way for rice production in saline and alkaline lands.

Hyperaccumulator Solanum nigrum L. Intercropping Reduced Rice Cadmium Uptake under a High-Bed and Low-Ditch Planting System

Anthropogenic activities have raised cadmium (Cd) concentrations in agricultural soil, emerging as a primary catalyst for the decline in crop yield. Intercropping of two or several plants is one technique among many Cd phytoremediation techniques that has gained enormous attention recently. However, the impact of cultivation modes on Cd movement in rice plants when intercropped with heavy metal (HM) hyperaccumulator plants remains unclear. Thus, this study was designed to explore the effects of cultivation modes and the intercropping of rice with Solanum nigrum L. on rice growth and Cd uptake in Cd-contaminated soil. The experimental design encompassed five treatments: dry cultivation of monocultured rice, monocultured Solanum nigrum L., and intercropped rice–Solanum nigrum L.; flood cultivation of monocultured rice; and intercropped rice–Solanum nigrum L. in a high-bed and low-ditch planting system. The results revealed a significant increase in rice growth when intercropped with Solanum nigrum L., with a notable increase of 18.32 g∙plant−1 observed in rice biomass in dry cultivation under the intercropping system. In contrast, a more modest increase of 3.67 g∙plant−1 was observed in the high-bed and low-ditch intercropped rice–Solanum nigrum L. mode. The soil total Cd was higher in dry cultivation of monocultured rice and Solanum nigrum L. compared to intercropped rice/Solanum nigrum L.-cultivated soil, with lower values recorded for intercropped rice/Solanum nigrum L. under the high-bed and low-ditch planting system. In contrast, no significant effect was noted on soil exchangeable Cd content based on the planting pattern and cultivation mode. Intercropping with Solanum nigrum L. demonstrated a significant reduction of Cd content in various rice tissues, particularly in roots at the maturity stage, while Cd content was reduced across all rice tissues under the high-bed and low-ditch planting system. The Cd content in the stem, leaves, and bran of monocropped rice was higher compared to intercropped rice. This study suggests that the rice–Solanum nigrum L. intercropping system effectively reduces rice Cd uptake, particularly under the high-bed and low-ditch planting system.

Effects of Two Sowing Methods on the Growth, Yield, and Quality of Hybrid Rice under Mechanical Transplantation

Poor adaptability of hybrid-rice (Oryza sativa L.) mechanical transplanting is one of the main factors limiting hybrid-rice production. Mixed sowing ensured stronger seedlings and better mechanical transplanting quality than conventional sowing in mechanical transplanting hybrid rice. Field experiments were conducted to identify the effects of mixed and conventional sowing of hybrid rice on rice growth, yield, and quality under mechanical transplantation in Yangzhou City, Jiangsu Province, China in 2021 and 2022. Two hybrid-rice varieties, japonica rice Changyou 4 and indica rice Yuanliangyou, and two conventional rice varieties, japonica rice Nanjing 5055 and indica rice Yangdao 6 were included in this study. Both japonica and indica rice showed the following results. There were no significant differences in biomass and leaf-area index of rice under different sowing methods at the heading and maturity stages. The basic seedling and spike rate was 38.27% and 16.24% higher, respectively, in mixed sowing than those averages in conventional sowing. In addition, the spikelets per panicle of hybrid rice in mixed sowing was 10.88% greater than the average in conventional sowing, indicating better heterosis. Compared to conventional sowing, mixed sowing increased the average gel consistency and taste value by 15.86% and 28.21%, respectively, while chalkiness degree, amylose content, and protein content decreased by an average of 60.47%, 44.89%, and 36.63%, respectively. Our study showed that similar biomass and leaf-area index, large basal seedling and spike rate, and large spikelets per panicle of hybrid rice are the keys to ensuring high yield in mixed sowing. At the same time, mixed sowing improved the appearance, nutrition, and cooking/eating qualities of the rice.

Dark septate endophytic fungi associated with pioneer grass inhabiting volcanic deposits and their functions in promoting plant growth

Abstract. Growth of the pioneer grass Miscanthus condensatus, one of the first vegetation types to be established on volcanic deposits, is promoted by root-associated fungi, particularly dark septate endophytes (DSEs). Fungal taxa within DSEs colonize the root of Miscanthus condensatus in oligotrophic Andosol, and their function in plant growth promotion remains largely unknown. We, therefore, comprehensively assessed the composition of the DSE community associated with Miscanthus condensatus root in volcanic ecosystems using the approaches of both metabarcoding (next-generation sequencing) and isolation (culturing). Also, the promotion effects of DSEs on plant growth (rice as a proxy) were evaluated by inoculation of core isolates to rice roots. Here, we found the following: (i) 70 % of culturable fungi that colonized Miscanthus condensatus phylogenetically belonged to DSEs; (ii) seven orders were identified by both sequencing and culturing methods; and (iii) inoculation of DSE isolates (Phialocephala fortinii, P. helvetica, and Phialocephala sp.) validated their effects on rice growth, particularly under an extremely low pH condition (compared to the control without inoculation, rice biomass was enhanced 7.6-fold after inoculation of P. fortinii). This study helps improve our understanding of the community of Miscanthus condensatus-associated DSE fungi and their functions in promoting plant growth.

Copper oxide nanoparticles: an effective suppression tool against bacterial leaf blight of rice and its impacts on plants.

To address the challenges of food security for the ever-increasing population, the emergence of nanotechnology provides an alternate technology of choice for the production of safer pesticides which serves as a substitute for conventional fertilizer. The antidrug resistance of Xanthomonas oryzae pv. oryzae (Xoo) and build-up of chemicals in the environment has made it necessary to find alternative safe techniques for effective disease management. Hence, in this study, copper oxide nanoparticles (CuONPs) were produced by green synthesis using a Hibiscus rosa-sinensis L. flower extract. The characterization of CuONPs using ultraviolet-visible spectrophotometry, scanning electron microscopy with an energy-dispersive spectrum profile, Fourier transform infrared spectroscopy, and X-ray diffraction ascertained the presence of CuONPs, which were nanorods of 28.1 nm. CuONPs significantly obstructed the growth and biofilm development of Xoo by 79.65% and 79.17% respectively. The antibacterial mechanism of CuONPs was found to result from wounding the cell membrane, giving rise to an exodus of intracellular content and generation of oxidative reactive oxygen species that invariably inhibited Xoo respiration and growth. A toxicity study under greenhouse conditions revealed that CuONPs significantly increased growth variables and the biomass of rice, and reduced bacterial leaf blight. Application of CuONPs on Arabidopsis improved the chlorophyll fluorescence parameters; the ΦPSII was significantly increased by 152.05% in comparison to the control. Altogether, these results suggest that CuONPs in low concentration (200.0 μg mL-1 ) are not toxic to plants and can serve as nano-fertilizers and nano-pesticides. © 2023 Society of Chemical Industry.

Mitigation of arsenic accumulation in rice (Oryza sativa L.) seedlings by oxygen nanobubbles in hydroponic cultures

Arsenic (As) is a toxic non-essential metal. Its accumulation in rice has not only seriously affected the growth of rice, but also poses a significant threat to human health. Many reports have been published to decrease the arsenic accumulation in the rice plant by various additives such as chemicals, fertilizers, adsorbents, microorganisms and analyzing the mechanism. Nanobubble is a new technology widely used in agriculture because of its long existence time and high mass transfer efficiency. However, a few studies have investigated the effect of nanobubbles on arsenic uptake in rice. This study investigated the effect of oxygen nanobubbles on the growth and uptake of As in rice. The oxygen nanobubbles could rupture the salinity of nutrients and produce the hydroxyl radical. The hydroxyl radical caused the oxidation of arsenic As(III) to As (V) and the oxidation of ferrous ions. At the same time, the oxidized iron adsorbing As (V) created the iron plaque on the rice roots to stop arsenic introduction into the rice plant. The results indicated that the treatment of oxygen nanobubbles increased rice biomass under As stress, while they increased the chlorophyll content and promoted plant photosynthesis. Oxygen nanobubbles reduced the As content in rice roots to 12.5% and shoots to 46.4%. In other words, it significantly decreased As accumulation in rice. Overall, oxygen nanobubbles mitigated the toxic effects of arsenic on rice and had the potential to reduce the accumulation of arsenic in rice.

Causal Analysis Between Rice Growth and Cadmium Accumulation and Transfer under Arbuscular Mycorrhizal Inoculation

Cadmium (Cd) contamination in rice has been a serious threat to human health. To investigate the effects of arbuscular mycorrhizal fungi (AMF) on the Cd translocation in rice, a controlled pot experiment was conducted. The results indicated that AMF significantly increased rice biomass, with an increase of up to 40.0%, particularly in root biomass by up to 68.4%. Notably, the number of prominent rice individuals also increased, and their plasticity was enhanced following AMF inoculation. AMF led to an increase in the net photosynthetic rate and antioxidant enzyme activity of rice. In the AMF treatment group, the Cd concentration in the rice roots was significantly higher (19.1%‒68.0%) compared with that in the control group. Conversely, the Cd concentration in the rice seeds was lower in the AMF treatment group, indicating that AMF facilitated the sequestration of Cd in rice roots and reduced Cd accumulation in the seeds. Path coefficients varied across different treatments, suggesting that AMF inoculation reduced the direct impact of soil Cd concentration on the total Cd accumulation in seeds. The translocation of Cd was consistently associated with simultaneous growth dilution and compensatory accumulation as a result of mycorrhizal effects. Our study quantitatively analyzed this process through path analysis and clarified the causal relationship between rice growth and Cd transfer under the influence of AMF.

Molecular heterosis for biomass and biofuel related traits in rice

Molecular heterosis for biomass and biofuel related traits in rice

ANALYSIS OF THE AVAILABILITY OF URBAN SOLID WASTE AND BIOMASS IN SOUTHERN SANTA CATARINA AIMING AT ENERGY RECOVERY

Alternative treatments to urban solid waste (USW) landfill and its integration with biomass can generate social, economic, and environmental benefits beyond contributing to the just energy transition in the Carboniferous Region of Santa Catarina State (Brazil). In this paper, were collected and analyzed data on generation, quantity processed, and current USW treatment practices, as well as rice and forest biomass, aiming to identify the potential for application in the development of USW-derived fuel and biomass that can be used in the energy and industrial markets. In 2020, 236,272.2 t of USW were produced by the forty municipalities considered, with 50% concentrated in just five of these. With only three landfill sites in this region, many municipalities dispose of their USW at a distant location, which increases the overall cost of waste management for the municipalities. The total forest biomass handled in 2019 was 2,135,704.31 tons, and rice husk and straw (2020/2021 harvest) were 999,750.00 tons. Based on this amount and the analysis of the points of concentration of these materials, alternative treatments are being studied with a focus on adding value to the waste chain and advances in the development of the waste management sector in Santa Catarina and in Brazil.

The effects of multifactorial stress combination on rice and maize.

The complexity of environmental factors affecting crops in the field is gradually increasing due to climate change-associated weather events, such as droughts or floods combined with heat waves, coupled with the accumulation of different environmental and agricultural pollutants. The impact of multiple stress conditions on plants was recently termed "multifactorial stress combination" (MFSC) and defined as the occurrence of 3 or more stressors that impact plants simultaneously or sequentially. We recently reported that with the increased number and complexity of different MFSC stressors, the growth and survival of Arabidopsis (Arabidopsis thaliana) seedlings declines, even if the level of each individual stress is low enough to have no significant effect on plants. However, whether MFSC would impact commercial crop cultivars is largely unknown. Here, we reveal that a MFSC of 5 different low-level abiotic stresses (salinity, heat, the herbicide paraquat, phosphorus deficiency, and the heavy metal cadmium), applied in an increasing level of complexity, has a significant negative impact on the growth and biomass of a commercial rice (Oryza sativa) cultivar and a maize (Zea mays) hybrid. Proteomics, element content, and mixOmics analyses of MFSC in rice identified proteins that correlate with the impact of MFSC on rice seedlings, and analysis of 42 different rice genotypes subjected to MFSC revealed substantial genetic variability in responses to this unique state of stress combination. Taken together, our findings reveal that the impacts of MFSC on 2 different crop species are severe and that MFSC may substantially affect agricultural productivity.

Time-series Sentinel-1A SAR remote sensing of rice planting methods in Ebonyi State, Nigeria

Timely and reliable agricultural data are essential to monitoring the implementation of rice intervention programs and policies aimed at sustainably reducing hunger and poverty. The difficulties associated with traditional data-gathering methods have made using satellite imagery for data acquisition imperative due to its coverage of large agricultural areas, high repetitive coverage, and cost-effectiveness. However, the use of satellite images for rice research in Nigeria is hampered by the peculiarities associated with methods of rice crop establishment, where manual transplanting and direct seeding methods are practiced in single rice plots due to financial constraints. To examine the effect of different planting methods on sensor signals, we analysed the temporal variation of Sentinel-1 synthetic aperture radar (SAR) data. Also, the relationship between SAR backscatter coefficients and field-measured rice plant parameters (wet biomass and plant height) as a function of planting methods was determined in contrast to similar studies where only the temporal variations in the planting methods were investigated. Multi-temporal, dual-polarised C-band Sentinel-1A backscatter data at 20 m spatial resolution and field measurements were simultaneously acquired every 12 days over the study area during the rainy season, from August to December 2019, in Ebonyi state, Nigeria. Average backscatter values were derived per sampling rice plot, with the temporal profiles of rice SAR backscatter plotted to show variability due to planting methods. Simple regression analysis determined the relationships between measured rice parameters and VH (Vertical transmit, Horizontal receive) and VV (Vertical transmit, Vertical receive) polarisation backscatter coefficients. Results revealed variations in the temporal profile and responses of transplanted and direct-seeded rice fields at different crop growth stages. Regression analysis showed that VH and VV backscatter values for transplanted rice were significantly related to wet rice biomass (R2 = 0.6; 0.51) and rice plant height (R2 = 0.5; 0.59). Conversely, wet biomass (R2 = 0.24; 0.19) and plant height (R2 = 0.18; 0.2) were reported for broadcasted rice for VH and VV polarisations, respectively. These findings show that significant differences exist in the SAR backscatter responses of these crop establishment methods, affecting the retrieved data's accuracy and reliability. Therefore, a cautious approach is advocated in using SAR data from small rice plots with multiple planting methods.

An atypical heterotrimeric Gα and its interactome suggest an extra-large role in overcoming abiotic and biotic stress.

Canonical heterotrimeric G-proteins (G-proteins) are comprised of Gα, Gβ, and Gγ subunits. G-proteins regulate multiple crucial plant growth and development processes, incorporating environmental responses. Besides Gα, Gβ and Gγ, the discovery of atypical Gα subunits termed as extra-large G-proteins or extra-large GTP-binding proteins (XLGs) makes G-protein signaling unique in plants. The C-terminus of XLG shares similarities with the canonical Gα subunits; the N-terminus harbors a nuclear localization signal (NLS) and is rich in cysteine. The earlier explorations suggest XLG's role in flowering, the development of embryos and seedlings, root morphogenesis, stamen development, cytokinin-induced development, stomatal opening and regulation of rice grain filling. The XLGs are also known to initiate signaling cascades that prime plants against a variety of abiotic and biotic stresses. They are also engaged in controlling several agronomic parameters such as rice panicle length, grain filling, grain size, and biomass, highlighting their potential contribution to crop improvement. The present review explores the remarkable properties of non-canonical Gα subunits (XLGs) and reflects on the various developmental, abiotic and biotic stress signaling pathways controlled by them. Moreover, the bottleneck dilemma of how a tiny handful of XLGs control a multiplicity of stress-responsive activities is partially resolved in this review by addressing the interaction of XLGs with different interacting proteins. XLG proteins presented in this review can be exploited to gain access to highly productive and stress-tolerant plants.

Recovery of antioxidative phenolic compounds by the valorization of rice biomass under the influence of lignocellulolytic enzymes

The present work aimed to optimize the recovery of antioxidative phenolic compounds from steam treated and untreated rice biomass (rice bran and rice straw) by the influence of lignocellulolytic enzymes of Burkholderia sp SMB1. The optimization of extraction was carried out by response surface methodology targeting to maximize phenolic release. These compounds were separated from the extracts using charcoal and un-utilized hydrolysed rice bran wastes and analysed for antioxidant properties. 10% (w/v) rice biomass with 60 mg of enzyme loadings (mg of protein in crude enzyme extract) at 40 °C, pH 7 for 30 min. Ferulic acid, gallic acid, coumaric acid, syringic acid, caffeic acid, epicatechin and kaemferol were identified by HPLC in both rice biomass extracts. Maximum total phenolics (83.35 mg GAE/100 g), total flavonoid content (16.89 mg/100 g QE), total tannin content (78.69 mg/100 g TAE) and antioxidant properties viz., 87.68% for ABTS, 77.11% for DPPH and 0.82 absorbance for FRAP was obtained for steam treated rice bran followed by rice straw. This work signifies the biomass transformation into phenolics possessing antioxidant nature under simple extraction process. It not only favours waste management process but also increases the income to agriculture sector.

Effects of blast furnace slag on the immobilization, plant uptake and translocation of Cd in a contaminated paddy soil

The potential toxicity of Cd to soil and rice plant severely threaten human health. This study was conducted to investigate the remediation effects of blast furnace slag (BFS) on the bioavailability of Cd in a contaminated paddy soil from a perspective of soil solution chemistry. Batch experiments, pot culture experiments, and principal analysis (PCA) were used to study the effects and mechanisms of BFS addition changing Cd chemical behavior and Cd toxicity. Results indicated that BFS facilitated Cd adsorption in soils, increased pH, Eh, and EC values in soil solution, whereas reduced dissolved Cd content. BFS amendment was efficient in decreasing root Cd intake and Cd upward transport in rice plant, with the Cd translocation factor in brown rice decreased by ∼ 75% (BFS treatment, 6‰ wt) relative to Cd treatment, which in turn increased rice biomass and grain yield. PCA indicated that the dissolved Cd concentration had a close relationship with soil pH and metal concentration in soil solution. Results from this study indicated that BFS had potential ability for either immobilization or remobilization of Cd in soils, and the findings have important implications for Cd-polluted soil remediation or other resource utilization with slag-based materials.

Particle Size Determines the Phytotoxicity of ZnO Nanoparticles in Rice (Oryza sativa L.) Revealed by Spatial Imaging Techniques.

To understand the nanotoxicity effects on plants, it is necessary to systematically study the distribution of NPs in vivo. Herein, elemental and particle-imaging techniques were used to unravel the size effects of ZnO NPs on phytotoxicity. Small-sized ZnO NPs (5, 20, and 50 nm) showed an inhibitory effect on the length and biomass of rice (Oryza sativa L.) used as a model plant. ZnO NP nanotoxicity caused rice root cell membrane damage, increased the malondialdehyde content, and activated antioxidant enzymes. As a control, the same dose of Zn2+ salt did not affect the physiological and biochemical indices of rice, suggesting that the toxicity is caused by the entry of the ZnO NPs and not the dissolved Zn2+. Laser ablation inductively coupled plasma optical emission spectroscopy analysis revealed that ZnO NPs accumulated in the rice root vascular tissues of the rhizodermis and procambium. Furthermore, transmission electron microscopy confirmed that the NPs were internalized to the root tissues. These results suggest that ZnO NPs may exist in the rice root system and that their particle size could be a crucial factor in determining toxicity. This study provides evidence of the size-dependent phytotoxicity of ZnO NPs.

As(III)-Oxidizing Bacteria Alleviate Arsenite Toxicity via Reducing As Accumulation, Elevating Antioxidative Activities and Modulating Ionome in Rice (Oryza sativa L.).

Paddy rice trends to accumulate more arsenic (As) from soils than other terrestrial crops. The toxicity and mobility of As mainly depend on its chemical species. Transformation of arsenite [As(III)] into arsenate [As(V)] would be a promising method to mitigate As toxicity. In the current study, As(III)-oxidizing strain SMS11 isolated from As-contaminated soils was employed for As remediation. Co-cultured with SMS11 alleviated As(III) stress to the rice plants by increasing the length and biomass of rice shoots up to 10% and 15%, respectively. Evaluation of oxidative stress indices showed that the activity of catalase in the rice shoots was weakened when exposed to As(III), increasing the risk of hydroxyl radical (·OH) formation. When co-cultivated with the bacteria, ·OH formation was significantly inhibited in the rice shoots. The ionomes of the rice plants were impacted by the external conditions. As(III) stress significantly disturbed ionome homeostasis in the rice plants. Uptake of As simultaneously elevated the levels of macro and nutrient elements such as Mg, P, K, Ca, and Zn in the rice shoots. The ionomic variation in the rice plants under As(III) stress was mitigated by inoculated with SMS11. The results represented that the As(III)-oxidizing bacteria alleviated external As(III) stress to the rice plants through elevating antioxidative activities and modulating ionome homeostasis.

Application of Fe3[KG-*2/5]O4/Mulberry Stem Biochar Effects on Soil Arsenic Species and Rice Arsenic Content

The passivation effect of Fe3O4/mulberry pole biochar (Fe-MBC) prepared at different carbonization temperatures on soil available arsenic content was studied through soil culture experiments, and Fe-MBC-800 (prepared by carbonization at 800℃) with good passivation effect was selected and characterized. The effects of 1%-7% (mass fraction of biochar to soil) Fe-MBC-800, MBC-800, and Fe3O4 on soil pH value, soil electrical conductivity, soil arsenic form, rice biomass, and total arsenic (As) content in rice were studied using a pot experiment. The results showed that:①Fe-MBC-800 successfully loaded Fe3O4, and its main functional groups were C=O double bond, O-H bond, C-O bond, and Fe-O bond. The specific surface areas of Fe-MBC-800, MBC-800, and Fe3O4 were 209.659 m2·g-1, 517.714 m2·g-1, and 68.025 m2·g-1, respectively. ②The addition of Fe-MBC-800 could increase the soil pH value, decrease the soil EC value, increase the content of residual arsenic in soil, and reduce the content of water-soluble arsenic and available arsenic in the soil. Under the treatment using 7% Fe-MBC-800 (ω) amendments, the content of water-soluble arsenic and available arsenic in the soil decreased by 81.6% and 56.33%, respectively. ③When the addition ratio of Fe-MBC-800 in the soil was 5%-7%, it could promote the growth of rice plants, increase rice biomass, and reduce the bioaccumulation of arsenic by between 62.5% and 68.75%.

Metalloporphyrin doped rice husk-based biomass porous carbon materials as high performance electrocatalyst for oxygen reduction reaction in Zn-Air battery

Rice husk (RH) is one of the most abundant biomass having a unique natural structure. Herein, the highly porous rice husk carbon material (RHC) has been prepared. After loading metal (Fe, Co, Mn, Cu) complex of tetra-phenylporphyrin (TPP) and the followed calcination, a new kind of metal-nitrogen-carbon (M-N-C) electrocatalyst (MTPP/RHC) for the oxygen reduction reaction (ORR) was obtained. It was found that all prepared catalysts showed good ORR performance and the activity follows an order of Fe > Co > Mn > Cu catalyst. The best FeTPP/RHC catalyst exhibited an ORR activity with a half-wave potential of 0.88 V (Eonset = 0.96 V) and excellent long-term stability (97% retention after 30000s). In the constructed zinc-air battery, it even showed a higher specific capacity (766 mAh/g) and superior reversibility than commercial Pt/C catalysts. This work provides a new practical protocol for ORR electrocatalysts.

Linear relationship between CH4 fluxes and atmospheric CO2 concentration levels controlled by rice biomass and soil methanogenic communities

Linear relationship between CH4 fluxes and atmospheric CO2 concentration levels controlled by rice biomass and soil methanogenic communities