Spatiotemporal characteristics of cultivated land use eco-efficiency and its influencing factors in China from 2000 to 2020

Improving cultivated land use eco-efficiency(CLUE)can effectively promote agricultural sustainability,particularly in developing countries where CLUE is generally low.This study used provincial-level data from China to evaluate the spatiotemporal evolution of CLUE from 2000 to 2020 and identified the influencing factors of CLUE by using a panel Tobit model.In addition,given the undesirable outputs of agricultural production,we incorporated carbon emissions and nonpoint source pollution into the global benchmark-undesirable output-super efficiency-slacks-based measure(GB-US-SBM)model,which combines global benchmark technology,undesirable output,super efficiency,and slacks-based measure.The results indicated that there was an upward trend in CLUE in China from 2000 to 2020,with an increase rate of 2.62%.The temporal evolution of CLUE in China could be classified into three distinct stages:a period of fluctuating decrease(2000-2007),a phase of gradual increase(2008-2014),and a period of rapid growth(2015-2020).The major grain-producing areas(MPAs)had a lower CLUE than their counterparts,namely,non-major grain-production areas(non-MPAs).The spatial agglomeration effect followed a northeast-southwest strip distribution;and the movement path of barycentre revealed a"P"shape,with Luoyang City,Henan Province,as the centre.In terms of influencing factors of CLUE,investment in science and technology played the most vital role in improving CLUE,while irrigation index had the most negative effect.It should be noted that these two influencing factors had different impacts on MPAs and non-MPAs.Therefore,relevant departments should formulate policies to enhance the level of science and technology,improve irrigation condition,and promote sustainable utilization of cultivated land.

Sustainable Intensification and Large-scale Operation of Cultivated Land Use at the Farmers’ Scale:A Case Study of Shandong Province,China

Sustainable intensification of cultivated land use(SICLU) and large-scale operations(LSO) are widely acknowledged strategies for enhancing agricultural performance.However,the existing literature has faced challenges in precisely defining SICLU and constructing comprehensive indicators,which has hindered the exploration of factors influencing LSO within the SICLU framework.To address this gap,we integrated self-efficacy theory into the design of an index framework for evaluating SICLU.We subsequently employed econometric models to analyze the significant factors that impact LSO.Our findings reveal that SICLU can be divided into four key dimensions:intensive management,efficient output,resource conservation,and ecological environment optimization.Furthermore,it is crucial to incorporate belief-based cognitive factors into the index system,as farmers’ understanding of fertilizer and pesticide application significantly influences their willingness to engage in LSO.Moreover,we identify grain market turnover as the most influential factor in promoting LSO,with single-factor contribution rates reaching 70.9% for cultivated land transfer willingness and 62.5% for the total planting areas.Interestingly,unlike irrigation and agricultural machinery inputs,increased labor inputs correspond to larger planting areas for farmers.This trend may be attributed to reduced labor availability because of rural labor migration,whereas the reduction in irrigation and agricultural input is contingent on innovations in production practices and the transfer of cultivated land management rights.Importantly,SICLU dynamically influences LSO,with each index related to SICLU having an optimal range that fosters LSO.These insights offer valuable guidance for policymakers,emphasizing farmers as their central focus,with the adjustment of input and output factors as a means to achieve LSO as the ultimate goal.In conclusion,we propose research avenues for further enriching the SICLU framework to ensure that it aligns with the specific characteristics of regional agricultural development.

Comparative Study of Genetic Structure and Genetic Diversity betweenWild and Cultivated Populations of Taxus cuspidata,Northeast China

Taxus cuspidata is a rare plant with important medicinal and ornamental value.Aiming at the obvious differences between wild and cultivated populations of T.cuspidata from Northeast China,a total of 61 samples,that is,33 wild yews and 28 cultivated yews were used to analyze the differences and correlations of the kinship,genetic diversity,and genetic structure between them by specific length amplified fragment sequencing(SLAF-seq).Finally,470725 polymorphic SLAF tags and 58622 valid SNP markers were obtained.Phylogenetic analysis showed that 61 samples were classified into 2 clusters:wild populations and cultivated populations,and some wild yews were categorized into the cultivated populations;the genetic diversity analysis showed that the Nei diversity index of wild populations(0.4068)was smaller than that of cultivated populations(0.4414),and the polymorphic information content(PIC)of wild populations(0.2861)was smaller than that of cultivated populations(0.3309).The genetic differentiation analysis showed that the total populations of gene diversity(H_(t))of cultivated and wild populations were respectively 0.8159 and 0.5685,the coefficient of gene differentiation(G_(st))of cultivated and wild populations was respectively 0.3021 and 0.1068,and the gene flow(N_(m))(2.4967)of wild populations was larger than cultivated populations(0.8199).The molecular variance(AMOVA)revealed that inter-population variation accounted for 29.57%of the total genetic variation,while intra-population variation accounted for 70.42% of the total genetic variation(p<0.001),this suggested that the genetic variation in the T.cuspidata is mainly attributed to within-population factors.In conclusion,the genetic distance between geographical ecological groups of wild populations was generally smaller than that of cultivated populations,and the degree of genetic diversity and genetic differentiation was smaller than that of cultivated populations.As evident,the utilization of SLAF-seq technology enables efficient and accurate development of SNP markers suitable for genetic analysis of T.cuspidata species.These developed SNP markers can provide a molecular foundation for T.cuspidata breeding,construction of genetic maps,variety identification,and association analysis of agronomic traits.

Spatiotemporal patterns and drivers of cultivated land conversion in Inner Mongolia Autonomous Region,northern China

Protection and optimization of cultivated land resources are of great significance to national food security.Cultivated land conversion in northern China has increased in recent years due to the industrialization and urbanization of society.However,the assessment of cultivated land conversion in this area is insufficient,posing a potential risk to cultivated land resources.This study evaluated the evolution and spatiotemporal patterns of cultivated land conversion in Inner Mongolia Autonomous Region,China,and the driving factors to improve rational utilization and to protect cultivated land resources.The spatiotemporal patterns of cultivated land conversion in Inner Mongolia were analyzed using the cultivated land conversion index,kernel density analysis,a standard deviation ellipse model,and a geographic detector.Results showed that from 2000 to 2020,the trends in cultivated land conversion area and rate in Inner Mongolia exhibited fluctuating growth,with the total area of cultivated land conversion reaching 7307.59 km^(2) at a rate of 6.69%.Spatial distribution of cultivated land conversion was primarily concentrated in the Hetao Plain,Nengjiang Plain,Liaohe Plain,and the Hohhot-Baotou-Ordos urban agglomeration.Moreover,the standard deviational ellipse of cultivated land conversion in Inner Mongolia exhibited a directional southwest-northeast-southwest-northeast distribution,with the northeast-southwest direction identified as the main driving force of spatial change in cultivated land conversion.Meanwhile,cultivated land conversion exhibited an increase-decrease-increase change process,indicating that spatial distribution of cultivated land conversion in Inner Mongolia became gradually apparent within the study period.The geographic detector results further revealed that the main driving factors of cultivated land conversion in Inner Mongolia were the share of secondary and tertiary industries and per-unit area yield of grain,with explanatory rates of 57.00%,55.00%,and 51.00%,respectively.Additionally,improved agricultural production efficiency and the coordinated development of population urbanization and industry resulted in cultivated land conversion.Collectively,the findings of this study indicated that,from 2000 to 2020,the cultivated land conversion in Inner Mongolia was significant and fluctuated in time,and had strong spatial heterogeneity.The primary drivers of these events included the effects of agriculture,population,and social economy.

Spatio-temporal Evaluation of Multi-scale Cultivated Land System Resilience in Black Soil Region from 2000 to 2019:A Case Study of Liaoning Province,Northeast China

It is of great significance to systematically analyze the cultivated land system resilience(CLSR) for the black soil protection and national food security.The CLSR is impacted by planting structure adjustment and cultivated land quality decline,posing major hidden dangers to food security.It is urgent to evaluate the CLSR at multiple spatio-temporal scales.This study took Liaoning Province in the black soil region of Northeast China as an example.Based on the resilience theory,this study constructed the CLSR evaluation system from the input-feedback perspective at the provincial-scale and the city-scale,and used the rank-sum ratio comprehensive evaluation method(RSR) to analyze the key influencing factors of CLSR in Liaoning Province and its 14 cities from 2000 to 2019.The results showed that:1) the time series changes of CLSR at the provincial-scale and the city-scale in Liaoning Province were similar,both showing an increasing trend.2) The CLSR in Liaoning Province presented a spatial pattern of ‘high in the west and low in the east’ at the city-scale.3) There were seven and six main influencing factors of CLSR at the provincial-scale and the city-scale,respectively.In addition to the net income per capita of rural households,other influencing factors of CLSR were different at the provincial-scale and the city-scale.The feedback factors were dominant at the provincial-scale,and the input factors and feedback factors were dominant at the city-scale.The results could provide a reference for the utilization of black soil and draw on the experience of regional agricultural planning and adjustment.

Ways to Cultivate and Develop Human Resources in the New Situation

In the trend of globalization,digitization,and economic integration,human resources are the core competitiveness of enterprises,and cultivating and developing them is crucial for enhancing competitive advantages.This article delves into how human resource development drives enterprise innovation,promotes team collaboration,and optimizes performance management.Currently,although many enterprises are beginning to attach importance to human resource development,they still face problems such as insufficient investment,weak targeted training,and insufficient exploration of employee potential.Therefore,it is proposed that in the new situation,enterprises need to strengthen diversified training strategies,use digital tools to improve training efficiency,build a fair performance evaluation system,stimulate employee potential,and promote internal talent mobility.The implementation of these strategies will effectively enhance the efficiency of enterprise human resource management and consolidate market position.

碱激发垃圾焚烧底灰地聚物的制备及其水化特性研究

本文采用城市垃圾焚烧底灰(BA)、偏高岭土和矿粉作为原料,NaOH和水玻璃作为碱激发剂来制备底灰地聚物,重点研究了不同碱含量、BA掺量对聚合物抗压强度及水化特性的影响。研究表明:当碱含量达7%(质量分数,下同)时,过量的钠与活性钙、活性硅和铝反应,从而形成大量低强度N-A-S-H,使底灰地聚物强度下降;当碱含量固定、BA掺量达到80%时,底灰地聚物的强度大幅度降低。对于底灰而言,其聚合物体系对重金属离子具有显著的固化效果。因此,采用BA制备底灰地聚物对城市固废绿色再生利用和环境保护具有重要意义。

数字经济对区域旅游消费市场发展的影响——基于市场活力激发的中介效应检验

数字经济已经成为我国旅游消费市场高质量发展的重要驱动力。本文实证检验了数字经济对区域旅游消费市场发展的影响效应及其作用机制。研究发现:数字经济对我国区域旅游消费市场发展具有显著促进作用,但存在区域异质性影响,数字经济对我国东部和西部地区旅游消费市场发展的驱动效果较强,对中部地区的驱动效果相对较弱;数字经济通过供给结构优化、旅游产业集聚和提升市场吸引力有效激发了旅游消费市场活力,进而促进了区域旅游消费市场规模增长。

中国式现代化的动力机理与激发机制

中国式现代化的成功离不开中国式现代化动力的有效激发。中国式现代化体现了合规律性和主动建构性的统一,既符合现代社会发展的一般规律,也具有中国发展现代化的独特性,这种特点也体现在中国式现代化的动力方面。本文从中国式现代化主体的视角探究中国式现代化的动力机理与机制。从机理上看,中国式现代化的动力来自中国式现代化主体强烈的实现现代化的意愿,来自中国式现代化主体对中国式现代化实践必将取得成功的信心。从机制上看,中国式现代化的动力激发由中国式现代化领导主体的动力产生与增强机制、中国式现代化建设主体的动力激活与凝聚机制和中国式现代化外部力量的辅助性动力调动与协调机制共同完成。三个子系统机制既各自独立又相互统一,在共同作用下形成中国式现代化的强劲动力。

普通硅酸盐水泥对负温碱激发矿渣砂浆力学性能的影响

碱激发矿渣(AAS)在0℃下能持续水化,具有应用于冬季施工的潜力。为了进一步提升AAS砂浆作为寒冷修补材料的力学性能,掺入了5%、10%、15%和20%的普通硅酸盐水泥(OPC)作为AAS中粒化高炉矿渣(GGBS)的部分替代物。结果表明:在-10℃条件下,OPC含量为15%时,1 d龄期的抗压强度和抗折强度分别提高了31.3%和25.18%,28 d龄期的抗压强度和抗折强度分别提高了4.5%和7.2%。此外,对样品的水化热、生成产物和微观结构进行了对比分析。结果显示,在AAS中加入OPC可以提高水化热,增加C(-A)-S-H的生成率,优化微观结构。

复合激发剂调控碱激发材料收缩性能研究

为改善碱激发矿渣-粉煤灰(AASF)胶凝材料的高收缩特性,通过硅酸钠(NS)分别与碳酸钠(SC)、硫酸钠(SS)和磷酸钠(SP)复掺制备复合激发剂,研究复合激发剂对AASF干燥收缩行为的影响。结果表明:复合激发剂对AASF体系的干燥收缩具有显著的抑制作用,其中SC15、SS15和SP5(Na2O质量取代率分别为15%、15%和5%)的90 d干燥收缩相较于NS分别降低39.0%、33.3%、42.4%,SP的综合减缩效果最好。SC使水化产物中生成了碳酸钙,而SS和SP的掺入并未引入新的晶体类水化产物,但SC、SS、SP可以有效减少体系中的自由水含量并提高化学结合水含量。SC、SS和SP的掺入均可以显著降低中孔体积比例和孔隙率,其中SC15、SS15、SP15的中孔体积率相较于NS分别降低30.8%、36.3%、25.0%。复合激发剂的减缩作用主要表现在两方面:一是显著提高化学结合水含量并抑制蒸发失水;二是有效减小中孔体积率以缓解毛细管应力,同时降低整体孔隙率以提高基质微观结构的致密程度。此外,掺入复合激发剂的各组试样也具有良好的工作性能和力学性能,其流动度和28 d抗压强度分别维持在181 mm和60 MPa以上。

硼砂-硅酸钠碱激发矿渣砂浆干缩和微观特性试验研究

碱激发材料(AAMs)具有高强、低碳等优点,但是其相较于水泥基材料较大的干燥收缩率限制了其应用和推广。该文设计了一种复合激发剂,开展了硼砂-硅酸钠碱激发矿渣(AAS)砂浆的干缩和微观特性试验研究。采用压汞法(MIP)、X射线衍射(XRD)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FTIR)对样品进行测试和表征,分析了复合激发剂减缩机理。试验结果表明,硼砂-硅酸钠复合激发剂有效降低了AAS砂浆的干缩;XRD结果显示AAS砂浆中存在钠硼解石相(NaCaB_(5)O_(6)(OH)_(6)(H_(2)O)_(5));FTIR分析表明,最优硼砂比例下(20%),AAS砂浆的Si—O—T(T代表Si、Al或B)谱带明显增强,通过MIP分析得到AAS砂浆的中孔(<50nm)数量减少,这有助于缓解收缩应力,降低砂浆的干缩率。该研究结果可以为AAMs的减缩和应用提供参考依据,激发学生在建筑领域的碳减排思维,提升解决关键问题的能力。

激发剂对钢渣水泥的活化及作用机理

为考察不同碱性激发剂对钢渣水泥性能的影响,开展碱性激发剂(水玻璃、Na 2CO 3/NaOH、NaOH)对钢渣水泥宏观力学性能影响的试验研究,并采用水化热测试、X射线衍射(XRD)、热重分析(DSC-TG)、扫描电子显微镜(SEM)和压汞试验(MIP)对其微观结构进行研究。结果表明:碱性激发剂提高钢渣水泥早期水化时孔隙液的碱度,加速钢渣玻璃体解聚并生成H_(3)SiO_(4)^(-)和H_(3)AlO_(4)^(2-),增大体系反应速率,加速C-S-H凝胶和沸石类产物的形成,从而宏观上表现为凝结时间降低,诱导期缩短,反应热峰值和累计放热量增加,早期强度提高;激发剂对钢渣水泥性能的影响与其分子结构有关,影响顺序由大到小依次为水玻璃、Na_(2)CO_(3)/NaOH和NaOH;水玻璃不仅可增大钢渣水泥早期水化时液相的碱度,同时激发剂中的SiO_(3)^(2-)可与Ca(OH)_(2)反应,生成水化产物C-S-H凝胶。掺入碱性激发剂可促进钢渣水泥水化反应的进行,有助于钢渣水泥力学性能与微观结构致密性的提升。

碱激发矿渣液相环境中钢筋钝化膜形成及破坏规律

为探寻碱激发矿渣(AAS)液相环境中钢筋钝化膜的形成和破坏机制,本文制备了不同配合比的AAS胶凝材料体系,研究了AAS真实孔溶液pH值在不同激发剂种类、碱当量、水玻璃模数、粉煤灰掺量、养护时间等因素下的经时演变规律,并对模拟孔溶液中钢筋钝化膜的生成时间、组成成分、厚度和钝化膜破坏时的临界氯离子浓度进行了经时追踪检测及分析。结果表明,AAS真实孔溶液的pH值随养护时间的增加而下降,各样品28 d时的pH值均保持在12.8以上。模拟孔溶液中pH值的增加缩短了钢筋钝化膜的形成时间,增加了钝化膜厚度,并提高了其抗氯离子侵蚀能力。AAS真实孔溶液较高的pH值可为钢筋钝化膜的稳定存在提供更有利的液相环境,从而提高钢筋混凝土结构的长期服役性能。

水稻秸秆碳组分对土壤有机碳激发效应的影响机理

秸秆还田显著影响土壤有机碳激发效应,秸秆不同碳组分对土壤有机碳激发效应影响的方向和强度尚不明确,作用机理仍不清楚。本研究以淮北平原的黄潮土为研究对象,以13C标记的水稻秸秆的水溶性碳、脂溶性碳、残余碳组分和全秸秆碳作为外源碳,利用微宇宙培养方法,研究秸秆不同碳组分添加对土壤有机碳激发效应的影响及作用机理。结果表明,添加秸秆不同碳组分土壤CO_(2)-C排放累积量中,添加水溶性碳处理土壤CO_(2)-C排放速率最高,为29.60 mg·kg^(-1)·d^(-1),而添加脂溶碳、残余碳和秸秆碳之间差异不显著。添加水溶性碳和全秸秆两种外源碳为正激发效应,分别为11.16%和13.39%,而添加脂溶碳和残余碳则表现为负激发效应,分别为-17.04%和-3.06%。相关分析表明,土壤酶活性与秸秆碳组分的TN呈显著正相关(r=0.768**),与C/N呈显著负相关关系(r=-0.776**)。正激发效应与秸秆碳组分的TN和土壤酶活性呈显著正相关关系,负激发效应与秸秆碳组分的TC和TN呈正相关关系,与C/N呈显著负相关。综上,秸秆碳组分与土壤自身有机碳分解的“共代谢理论”是产生正激发效应的主要作用机理,秸秆碳组分C/N的“化学计量比理论”是产生负激发效应的主要作用机理。

激发材料对碱性钢渣替代水泥早期强度规律研究

以碱性钢渣为研究对象,在机械粉磨基础上,采用化学激发方式探究碱性钢渣替代水泥早期强度变化规律;研究不同种类、掺量化学激发剂对钢渣活性的作用,利用XRD、SEM对钢渣替代水泥的水化产物进行分析。结果表明:机械粉磨能够有效改善钢渣粒径中的粗颗粒和细颗粒含量,优化颗粒级配,最佳粉磨时间为20 min;化学激发能够在机械粉磨上进一步提高钢渣胶凝活性,当早强剂掺量为2.0%、芒硝掺量为3.0%、氢氧化钠掺量为1.0%、钢渣掺量为25%时效果最佳;钢渣替代水泥主要水化产物是方解石(CaCO_(3))、氢氧钙石(Ca(OH)_(2))、硅酸二钙(Ca_(2)SiO_(4))和C-S-H凝胶,微观组织呈现纤维网状结构,为力学性能的提高奠定了基础。

原位激发微生物矿化处理铅污染土的工程特性与环境安全性研究

随着城市化进程的加速,重金属污染场地的修复、开发和再利用日益受到社会关注。以典型重金属污染物铅为研究对象,利用原位激发微生物矿化方法探究了铅浓度对土壤酸碱度、活菌数以及尿素和铵根浓度等细菌活性指标的影响,通过测试固化土的无侧限抗压强度、渗透系数和毒性浸出浓度,评估了铅污染土的固化效果。结果表明,原位激发方法可以实现低铅浓度污染土中脲酶菌的富集,激发7d后土中活菌数最高可达到10^(9)CFU/g数量级,但高浓度的铅污染物将显著抑制微生物的生长与活性。原位激发MICP处理铅污染土的强度和防渗性均随固化时间呈增长趋势,其中40mM铅污染土固化14d的强度大幅提高,渗透系数可降低至6.5×10^(-6)m/s。铅的浸出浓度随固化时间均不断降低,低铅浓度污染土固化14 d后在中性或弱酸性环境下的浸出浓度可低于0.1 mg/L。根据固化铅污染土的工程特性与环境安全性试验结果,结合环境扫描电镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)和微生物16 s全基因组重测序等手段,揭示了原位激发微生物矿化处理铅污染土的固化机理。

基于快中子激发γ射线活化分析的柱状金属元素分布检测研究

利用氘-氚中子发生器结合高纯锗探测器搭建了平台,选取不锈钢柱状作为样品进行测量,对Fe和Cr元素的含量以及分布进行分析.通过蒙特卡罗模拟计算分析了样品处的有效快中子通量,并对标准样品进行了测量.结果显示,Fe和Cr的含量与特征峰净面积成线性变化关系,检测限分别为24.98%和11.54%,平台对Fe和Cr的空间分辨率分别为1.65和1.83 cm.该平台对未知样品中的Fe和Cr的分析结果与X荧光分析结果的偏差在7%之内.研究结果为该技术在后续实际应用提供了研究基础.

硅酸钠改善碱激发材料力学性能与凝结机理分析

为了进一步增强碱激发材料的力学性能,掌握碱激发材料的凝结规律,通过掺入不同种类与掺量硅酸钠进行增硅改性,增强矿渣碱激发材料反应活性,定期观测试件的力学性能并分析凝结规律,同时结合微观分析手段深入剖析硅酸钠的增硅增强机理。结果表明,固态与液态硅酸钠均能够显著提高试件的抗压强度,明显缩短初凝与终凝时间。随固态硅酸钠掺量的提升,试件抗压强度呈先上升后下降趋势,固态硅酸钠在试件内大量结晶是导致抗压强度下降的主要原因。随液态硅酸钠掺量的提升,试件抗压强度呈先显著上升后趋于平稳的趋势,这说明其增强作用具有最大限值,液态硅酸钠的激发效果明显优于固态。

碱激发地聚物固化海相淤泥质软土抗压强度及固化机制研究

海相淤泥质软土富含各类可溶性盐和有机质,使用水泥进行固化时易出现劣化效应。为了解决传统硅酸盐水泥固化常出现加固失效的工程问题,以NaOH为碱激发剂,使用地聚物-水泥联合固化海相淤泥质软土,研究水泥与地聚物掺量比、碱激发剂含量和养护龄期对固化土无侧限抗压强度的影响,并采用扫描电镜和X射线衍射试验分析碱激发地聚物固化海相淤泥质软土的微观形态和水化产物,进一步揭示其固化机制。研究结果表明:单独加入NaOH对水泥土强度的提升并不明显,水泥土强度并不会随着碱激发剂含量的增加而显著提高。同时不同钙系地聚物的固化效果差异显著:矿渣地聚物固化土早期强度增长迅速,后期强度增长缓慢,其无侧限抗压强度随NaOH含量的增加先增加后降低,随矿渣的掺量增加而提高。粉煤灰地聚物固化土强度增长较慢,NaOH含量越高其无侧限抗压强度越大,且强度随粉煤灰的掺量增加而降低。将1/2的水泥以矿渣替代,固化土28 d强度最高可达6.19 MPa,相较于水泥土提升了107.5%。而使用同样比例的粉煤灰替代,其28 d强度最高仅为3.012 MPa。微观试验分析表明碱激发剂和地聚物的加入,可促进可溶盐水化结晶和有机质碱性环境降解,有效增加有效水化产物,增强颗粒间的凝聚力使得土体结构更加紧密,宏观上表现为固化土强度的提升。研究结果可为解决水泥加固海相淤泥软土所引起的实际技术问题提供理论指导。