Morphological and physiological response of different root orders to biochar addition in continuous cropping cotton in Xinjiang,China北大核心CSCD

为缓解新疆棉花连作障碍,充分挖掘棉花根系生物学潜力,以新疆棉花根系为研究对象,采用模块根分级的方法探究不同根序根系的形态和生理特征以及它们对添加生物炭(BC)的响应.结果表明:根序对两个时期的生理指标、形态指标和根系生物量有显著影响.随着根序级的增加,吐絮期根系的可溶性蛋白含量、可溶性糖含量、全非结构性碳水化合物含量、第二和第三模块根的平均直径和根系生物量不断增加,两个时期比根长、比表面积和吐絮期组织密度不断减小.与对照相比,添加BC增加蕾期第一、第二模块根的可溶性蛋白含量分别为30.7%和21.8%,增加第一模块根的全非结构性碳水化合物含量79.8%、可溶性糖含量151%、比根长182%和比表面积193%,增加第二模块根的组织密度124%、吐絮期第一模块根的比根长6.3%和第一、第二模块根的组织密度分别为51.2%和23.8%.综上所述,棉花不同根序根系在生理和形态上存在异质性;第一模块根对BC添加最敏感,且BC使其在形态上更细更长,生理上活性更强,这有利于棉花对养分的吸收.(图4表3参57)     

Research progress on occurrence forms and microbial transformation of mercury北大核心CSCD

汞是一种高毒性且具有持久性的重金属污染物,汞污染的治理与修复在近几十年一直是国内外研究热点.了解微生物对汞赋存形态的转化作用,对汞污染的治理与修复具有重要意义.总结汞的不同赋存形态、毒性及对应的常用分析方法,其中甲基汞(methyl mercury,MeHg)是毒性最强的汞形态之一.环境中汞的化学形态能发生转化,尤其以微生物驱动的汞的甲基化、MeHg的去甲基化和汞的氧化还原最为常见.依据汞转化类型将汞转化相关微生物分为汞甲基化、MeHg去甲基化、汞还原、汞氧化等类群,将对应的汞转化作用机制分为基于hgcAB基因的汞甲基化、基于mer操纵子基因的MeHg去甲基化和Hg2+还原、胞内过氧化氢酶介导的Hg0氧化.微生物汞转化过程不仅受到pH和温度的显著影响,而且还受到汞的赋存形态和游离汞的浓度、微生物种/群结构与功能、矿物种类、中间体和次生产物及其交互作用的影响,基于此,提出正确客观表征汞的微生物转化过程需要综合分析微生物组和矿物组的变化规律及其交互作用的综合效应.针对酸性矿山废水(AMD)极端环境微生物汞转化研究的不足,未来的工作将聚焦结合多组学手段、同步辐射谱学和密度泛函理论(DFT)计算等分析技术研究汞赋存形态的微生物转化过程,分析和阐明汞转化中间体的键合作用方式和转化机制,从而为AMD汞污染的预防、治理和修复提供依据.(图2表2参107)     

Elucidation of adsorption mechanisms and mass transfer controlling resistances during single and binary adsorption of caffeic and chlorogenic acids

Environmental Science and Pollution Research - In this work, the potential of activated carbon to remove caffeic and chlorogenic acids in aqueous solution was investigated. The study focused on...     

Impacts of ozone on the biomass and yield of rice in open-top chambers

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Diversity and structural characteristics of nitrogen-fixing bacterial community in tobacco-growing soils at different elevations in Panzhihua北大核心CSCD

固氮细菌在土壤氮素转换过程中发挥重要作用.为深入认识攀枝花地区农田土壤固氮细菌群落特征及其与土壤理化性质的关联性,以攀枝花米易县不同海拔高度(1 600 m、1 800 m、2 000 m)植烟土壤为研究对象,采用高通量测序技术(high-throughput sequencing)对nifH基因进行测序,分析固氮细菌群落结构特征和多样性.结果显示,固氮酶活性随海拔升高而逐渐降低,并与土壤有机碳及全氮呈极显著正相关(P <0.01);固氮细菌群落多样性指数在海拔1 800 m处达到最大值.3个海拔土壤共获得高质量序列1 159 980条,所检测到的固氮细菌分属于4个门、11个纲、19个目、29个科、40个属.基于门分类水平分析结果,变形菌门(Proteobacteria)在所有海拔土壤中均为优势固氮菌群,相对丰度达64.69%-78.36%;而蓝细菌门(Cyanobacteria)仅在海拔高度2 000 m时为优势类群.在属水平上,伯克霍尔德菌属(Burkholderia)、克雷伯氏菌属(Klebsiella)相对丰度分别为海拔高度1 800 m与2 000 m土壤优势菌属,而类伯克霍尔德氏菌属(Paraburkholderia)是所有海拔土壤中的主要菌属.采用随机森林分析评估和筛选标志物种,确认Azohydromonas对固氮细菌群落结构差异存在重要影响.结合Pearson相关性分析与冗余分析结果,土壤含水量、硝态氮、碱解氮与有效磷是造成不同海拔土壤固氮细菌群落特征差异的主要环境因子.本研究表明海拔梯度及响应其变化的土壤理化因子,对调控固氮细菌群落结构与多样性有较大影响.(图8表3参41)     

Response of winter wheat yield and soil microbial biomass to fertilization with ridge mulching-furrow planting in the dry highlands of the Loess Plateau北大核心CSCD

As the typical planting pattern of winter wheat in the dry highlands of the Loess Plateau, ridge mulching-furrow planting (RMFP) has played an important role in fertilizer efficiency of different fertilizers, and the differences in fertilizer efficiency further influence the diversity of the structure of soil microbial communities. The effects of different fertilization practices on winter wheat yield formation, soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), and soil microbial biomass phosphorus (SMBP) were investigated by field experiments during 2014-2016 in the winter wheat growing region of the dry highlands in southern Shanxi. The treatments included four groups, farmer fertilization (FF), monitoring fertilization (MF), monitoring fertilization combined application of manure (MFM), and monitoring fertilization combined application of bio-organic fertilizer (MFB). Results showed a significant increase in winter wheat yield by optimized and balanced fertilization, and the grain yield of MFB was highest among all treatments, with a value of 4 107-5 400 kg/hm2, which was 14.5%-23.2% (P < 0.05) higher than that of FF. The effects of different fertilization treatments on the winter wheat yield formulation mainly depended on spike number; however, no effect was found on kernel number per spike and 1 000-grain weight. Soil microbial biomass was affected by both growth period and fertilization patterns, i.e., the content of SMBC from jointing to flowering stage was highest during the winter wheat growth period, whereas the maximum values of SMBN and SMCP were found during the jointing stage. Changes in the rates of SMBC, SMBN, and SMBP during the entire growth period were less than 50%; however, the average contribution rate of optimized fertilization on SMBC, SMBN, and SMBP reached 90%. Compared to single chemical fertilizer applications, the combined application chemical fertilizer and manure or bio-organic fertilizer significantly improved the contents of SMBC, SMBN, and SMBP; however, the contents of SMBC and SMBN between MFM and MFB had no significant difference, whereas the SMBP of MFB was 19.8%-47.1% (P < 0.05) higher than that of MFM owing to the effect of mixed phosphorus bacteria. The soil microbial biomass C/N and C/P of the different treatments were 6.9-9.8 and 14.4-41.0, respectively, and maximum values occurred during the flowering stage. Given the above, the combined application of reasonable chemical fertilizer and bio-organic fertilizer can effectively improve the winter wheat yield and soil microbial biomass under RMFP cultivation in the dry highlands of the Loess Plateau. © 2018 Science Press. All rights reserved.     

The effects of compost prepared from waste material of banana on the growth, yield and quality properties of banana plants

Three doses (15-30-45 kg plant(-1)) of the compost prepared from the clone of Dwarf cavendish banana were compared with farmyard manure (50 kg plant(-1)), mineral fertilizers (180 g N+ 150 g P +335 g K plant(-1)) and farmyard manure+ mineral fertilizers (25 kg FM+ 180 g N+ 150 g P +335 g K plant(-1)) which determined positive effects on the growth, yield and fruit quality characteristics of banana plants. The banana plants were grown under a heated glasshouse and in a soil with physical and chemical properties are suitable for banana growing. The contents of N, P, K and Mg in compost and in farmyard manure were found to be similar. Farmyard manure, farmyard manure + mineral fertilizers and 45 kg plant(-1) of compost increased growth, yield and fruit quality characteristics. According to obtained results, 45 kg plant(-1) of compost was determined more suitable in terms of economical production and organic farming than the other fertilizer types.     

Solid waste forecasting using modified ANFIS modeling

Solid waste prediction is crucial for sustainable solid waste management. Usually, accurate waste generation record is challenge in developing countries which complicates the modelling process. Solid waste generation is related to demographic, economic, and social factors. However, these factors are highly varied due to population and economy growths. The objective of this research is to determine the most influencing demographic and economic factors that affect solid waste generation using systematic approach, and then develop a model to forecast solid waste generation using a modified Adaptive Neural Inference System (MANFIS). The model evaluation was performed using Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and the coefficient of determination (R2). The results show that the best input variables are people age groups 0-14, 15-64, and people above 65 years, and the best model structure is 3 triangular fuzzy membership functions and 27 fuzzy rules. The model has been validated using testing data and the resulted training RMSE, MAE and R2 were 0.2678, 0.045 and 0.99, respectively, while for testing phase RMSE =3.986, MAE = 0.673 and R2 = 0.98.

Implications: To date, a few attempts have been made to predict the annual solid waste generation in developing countries. This paper presents modeling of annual solid waste generation using Modified ANFIS, it is a systematic approach to search for the most influencing factors and then modify the ANFIS structure to simplify the model. The proposed method can be used to forecast the waste generation in such developing countries where accurate reliable data is not always available. Moreover, annual solid waste prediction is essential for sustainable planning.     

Effect of Hybrid Tackifiers on Adhesion Properties of Epoxidized Natural Rubber-Based Pressure-Sensitive Adhesives

Viscosity, peel and shear strength of epoxidized natural rubber (ENR)-based pressure-sensitive adhesive was studied by using hybrid tackifiers consisting of a mixture of coumarone-indene resin and petro resin. The coumarone-indene resin concentration was fixed at 40 parts per hundred parts of rubber (phr). The concentration of petro resin, however, was varied from 20 to 80 phr. Toluene and polyethylene terephthalate (PET) film were used as the solvent and coating substrate respectively throughout the experiment. Viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas peel and shear strength was measured by a Lloyd Adhesion Tester. Results show that viscosity and shear strength decreases with increasing petro resin concentration. However, peel strength exhibits a maximum value at 40 phr petro resin, an observation which is attributed to maximum wettability and compatibility of adhesive on the substrate. ENR 25-based adhesive exhibits higher viscosity and peel strength but lower shear strength compared to the ENR 50 adhesive system.     

Integrating livelihoods and conservation in protected areas: understanding the role and stakeholder views on prospects for non-timber forest products,a Bangladesh case study

Protected areas (PAs) represent a key global strategy in biodiversity conservation. In tropical developing countries, the management of PAs is a great challenge as many contain resources on which local communities rely. Collection and trading of non-timber forest products (NTFPs) is a well-established forest-based livelihood strategy, which has been promoted as a potential means for enhanced conservation and improved rural livelihoods in recent years, even though the sustainability or ecological implications have rarely been tested. We conducted an exploratory survey to understand the role and stakeholder views on conservation prospects and perceived ecological feasibility of NTFPs and harvesting schemes in a northeastern PA of Bangladesh, namely the Satchari National Park. Households (n?=?101) were interviewed from three different forest dependency categories, adopting a stratified random sampling approach and using a semi-structured questionnaire. The study identified 13 locally important NTFPs, with five being critically important to supporting local livelihoods. Our study suggests that collection, processing and trading in NTFPs constitutes the primary occupation for about 18% of local inhabitants and account for an estimated 19% of their cash annual income. The household consensus on issues relating to NTFPs and their prospective role in conservation was surprisingly high, with 48% of respondents believing that promotion of NTFPs in the PA could have positive conservation value. The majority (71%) of households also had some understanding of the ecological implications of NTFP harvesting, sustainability (53%) and possible management and monitoring regimes (100%). With little known about their real application in the field, our study suggests further investigations are required to understand the ecological compatibility of traditional NTFP harvesting patterns and management.