A review of soil nematodes as biological indicators for the assessment of soil health

Healthy soils are essential for sustainable agricultural development and soil health requires careful assessment with increasing societal concern over environmentally friendly agricultural development. Soil health is the capacity of soil to function within ecological boundaries to sustain productivity, maintain environmental quality, and promote plant and animal health. Physical, chemical and biological indicators are used to evaluate soil health; the biological indicators include microbes, protozoa and metazoa. Nematodes are the most abundant metazoa and they vary in their sensitivity to pollutants and environmental disturbance. Soil nematode communities are useful biological indicators of soil health, with community characteristics such as abundance, diversity, community structure and metabolic footprint all closely correlated with the soil environment. The community size, complexity and structure reflect the condition of the soil. Both free-living and plant-parasitic nematodes are effective ecological indicators, contributing to nutrient cycling and having important roles as primary, secondary and tertiary consumers in food webs. Tillage inversion, cropping patterns and nutrient management may have strong effects on soil nematodes, with changes in soil nematode communities reflecting soil disturbance. Some free-living nematodes serve as biological models to test soil condition in the laboratory and because of these advantages soil nematodes are increasingly being used as biological indicators of soil health.     

栽培措施对土壤健康影响的研究

土壤健康衰退已经波及整个农业生态领域,针对其衰退现象,采用不同的栽培措施从土壤理化性质、土壤养分指标、土壤生物性状、植物病害和植株生理等指标综合分析其对土壤质量的影响。结果表明,采用免耕、合理的间作和轮作能够较好地维持土壤理化性质,减少土壤的盐分积累,维持了微生物的数量和多样性,维持微生物碳氮源的供应,减少了植物病害发病率,促进了植株的生长。     

青藏高原北部戈壁区植物多样性及其环境解释

为了揭示青藏高原北部戈壁区植物多样性与环境因子的关系,用38个青藏高原北部戈壁区的群落样方调查数据和环境数据,通过单因素方差分析、CCA分析和方差分解等方法研究了青藏高原北部戈壁区植物多样性及其与环境因子的关系。结果表明:1)共记录植物12科29属36种,以藜科、柽柳科、禾本科和菊科植物为主,红砂分布频率最大,该地区植物生活型主要为灌木和草本;2)该区域不同优势群落外貌特征不同,在植株密度上存在极显著差异(P < 0.01),在植被盖度上存在显著差异(P < 0.05),但各群落的物种丰富度和香农指数无明显差异;3)经过CCA分析,年平均降水量显著影响该区域植物物种分布;4)该地区群落结构主要受土壤因子、气候因子、生物因子共同影响,三者的解释率达到51.68%,其中土壤因子的单独解释率最高,达到25.36%,剩余48.91%未解释部分说明还有其他因素影响着该区域植物群落结构。总而言之,青藏高原北部戈壁区植物多样性水平低,群落结构简单,其植物多样性主要受土壤条件的影响。      

Summary and Improvement Measures for Soil Compaction Caused by Machinery

近年来,农业机械化作业越来越普遍,随着农业机械的不断发展,农田机械土壤压实已逐渐成为一个不容忽视的问题。农业机械多次或大载荷作业造成的土壤压实都会对土壤的各种性能产生不同程度的影响。土壤压实会使土壤容重增加,机械阻力增大,持水和蓄水能力以及土壤通气性下降,同时影响农作物对化学元素的吸收。因此,土壤压实对土壤的物理、化学、生物特性及农作物的生长都会产生很大的不良影响。本文分析了近年来产生土壤压实的原因和土壤压实的危害,并在此基础上提出了改善土壤压实的有效措施和技术方法,以期减轻农业机具对农田土壤的压实程度。     

植物对土壤微生物多样性的影响研究进展

土壤微生物是植物-土壤系统中比较活跃的组成成分,土壤微生物多样性代表着微生物群落的稳定性,对植物的生长发育和群落结构的演替具有重要作用.通过植物类型、植物多样性、植物不同生长发育阶段、同一植物不同基因型、植物根系分泌物和外来植物入侵对土壤微生物多样性的影响分析,探讨植物和土壤微生物多样性之间的内在联系,为植物保护和农业可持续发展研究提供参考.     

水土流失对农村贫困的影响

概述了我国农村贫困的总体状况及地区差异,指出水土流失较为严重的中西部地区农村的贫困状况表现尤甚。结合前人研究,以农业GDP为因变量,以耕地面积、农业劳动力、农业资本存量、灌溉面积、化肥用量等为自变量,建立了反映水土流失对农村贫困影响的C-D生产函数进行回归分析。结果表明,耕地、劳动力、资本、灌溉、化肥等生产要素对农业GDP有正效应,水土流失对农业生产有显著的负效应;我国西部的全要素生产力最低,水土流失也最为严重。为走出水土流失与农村贫困的双重困境,必须改变粗放的农业发展方式,保护生态环境,走农业生态集约发展之路。     

Rainfall variability,carbon cycling,and plant species diversity in a mesic grassland

Ecosystem responses to increased variability in rainfall, a prediction of general circulation models, were assessed in native grassland by reducing storm frequency and increasing rainfall quantity per storm during a 4-year experiment. More extreme rainfall patterns, without concurrent changes in total rainfall quantity, increased temporal variability in soil moisture and plant species diversity. However, carbon cycling processes such as soil CO2 flux, CO2 uptake by the dominant grasses, and aboveground net primary productivity (ANPP) were reduced, and ANPP was more responsive to soil moisture variability than to mean soil water content. Our results show that projected increases in rainfall variability can rapidly alter key carbon cycling processes and plant community composition, independent of changes in total precipitation.     

Effects of seven different companion plants on cucumber productivity,soil chemical characteristics and Pseudomonas community

Companion cropping can influence cucumber productivity by altering soil chemical characteristics and microbial communities.However,how these alterations affect the growth of cucumber is still unknown.In this study,seven different plant species were selected as companion plants for testing their effects on cucumber productivity.The effects of different companion plants on changes in soil chemical properties such as electrical conductivity(EC)and contents of essential nutrients as well as the structure and abundance of the soil Pseudomonas community were evaluated.The results showed a higher cucumber yield in the wheat/cucumber companion system than that in the cucumber monocultured and other companion cropping systems.The lowest phosphorus(P)and potassium(K)contents in the soil were found in the cucumber monocultured system,and the highest NO_3~+-N and NH_4~+-N contents were observed in the rye/cucumber companion system.PCR-denaturing gradient gel electrophoresis(DGGE)and real-time PCR analysis showed that the trifolium/cucumber companion system increased the diversity of the soil Pseudomonas community,while the chrysanthemum/cucumber companion system increased its abundance.Interestingly,plant-soil feedback trials revealed that inoculating the soil of the wheat/cucumber companion system increased the growth of cucumber seedlings.In conclusion,the effects of different companion plants on cucumber productivity,soil chemical characteristics and the soil Pseudomonas community were different,and wheat was a more suitable companion plant for increasing cucumber productivity.In addition,the altered microbial community caused by companion cropping with wheat contributed to increased cucumber productivity.     

厚垣轮枝孢菌(Verticillium chlamydosporium)防治植物线虫研究进展

厚垣轮枝孢菌(Verticilliumchlamydosporium)是一种重要的噬植物线虫真菌。文章对该菌的分类地位、生物学习性、噬线虫机制及其在防治植物线虫中的应用情况进行了综述,探讨了影响该菌防治植物线虫的一些因素,并指明了今后的研究方向。     

广州南沙区河涌沿岸植物景观特征及其与人类活动的关系

为了解河涌沿岸植被特征及其与人类活动的关系,选取广州市南沙区4条河涌作为研究对象,对河涌沿岸的农业景观、工业景观和村落景观3种类型河段的植物景观特征进行了分析。结果表明:①河涌沿岸植物共计有70科126属144种,其中农业景观河段有45科51属58种,工业景观河段有25科33属40种,村落景观河段有64科119属130种。②河涌沿岸各景观类型河段植物区系分布均以广义热带成分为主,占比均达80%以上,符合所在区域气候特点。③植物功能需求差异和人为利用方式差异,导致不同景观类型河段的优势植物组成产生差异。农业景观河段,食用型果树表现出显著优势;工业景观河段,防护植物和城市绿化植物占有优势;村落景观河段,食用型果树和观赏型植物表现出显著优势。④3种景观类型河段植物多样性特征存在差异,植物丰富度、多样性和均匀度从高到低均为村落景观河段、农业景观河段、工业景观河段。⑤道路建设活动与农业景观河段乔木丰富度呈负相关。建筑物构造活动对各景观类型河段的植物多样性特征具有积极影响,其中对农业景观河段的影响体现在乔木的多样性上,对工业景观河段的影响体现在灌木的丰富度、多样性和均匀度上,对村落景观河段的影响体现在乔木和灌木的丰富度、多样性上。     

持续农业浅述

综述自60年代“绿色革命”以来,欧美农业生产采取了一系列新技术措施,首先是大量消耗不可再生的能源,其次是大量使用化肥和农药,在农业产量上固然有大幅度的提高,但在此同时,也带来了一系列其它问题,从长远的、持久的利益出发,国内外农业界知名人士考虑能不能从加深对农业生态系统本身内在复杂关系的认识,并加强对农业生产的管理,寻求一种既经济而又符合环境要求的稳定、经久不衰的农业生态体系,以取代现代农业中那种高投入、高成本的农业生产体系。     

Resource availability through rainwater harvesting influenced vegetation diversity and herbage yield in hillslope of Aravalli in India

Recent decline in biological diversity has stimulated the research on the effects of resource conservation on biodiversity and vice versa. We examined soil water and nutrients influenced by rainwater harvesting (RWH) in hillslope and its effects on herbage diversity and productivity at up (USP), middle (MSP) and lower position (LSP) in 75 plots, each of 700-m² area laid in < 10%, 10%–20% and > 20% slopes, respectively. The five RWH treatments were Contour trench (CT), Gradonie (G), Box trench (BT), V-ditch (VD) and control. Soil water content (SWC), species number, population, diversity and herbage yield increased (P < 0.05) downward suggesting positive relations between soil resource and diversity/productivity. The highest species number, population, richness and diversity in 10%–20% slope were associated with soil water usage and NO₃-N and NH4-N concentrations. SWC was 5.0%–19.0% greater in RWH areas than in control influencing herbage species, population, growth and yields. The increase in diversity and yields was the highest (P < 0.05) in V-ditch reinforced by soil fertility. The positive effect of diversity on yield increased with resources, and the effect was compositional rather than that of species richness. Conclusively, slope gradient and soil texture influenced herbage regeneration, diversity and productivity, which were positively affected by existing soil fertility and applied RWH and mobilizing soil water and nutrients. The effect of V-ditch was the highest on composition and yield. Thus, RWH enhanced herbaceous vegetation and restoration of degraded forest/rangelands. But long-term effects of diversity in restoring ecosystem productivity could be established through long-term data collections on optimum water/nutrient usage, diversity and productivity.     

森林凋落物生态功能研究进展

凋落物的生态功能包括凋落物对土壤理化性质、土壤生物学特性、植被更新、植物种子萌发、植物生长、演替、生产力及凋落物的水文生态效益等的影响。该文着重对凋落物对土壤理化性质、土壤生物学特性、土壤水文生态功能以及森林植被更新4个方面的影响进行综述。     

藏东南林芝地区典型农业土地利用方式对土壤微生物群落特征的影响

为研究藏东南林芝地区土壤微生物群落对农业土地利用方式的响应特征及其关键影响因素,可深入认识农业土地利用对该区域生态系统稳定性的影响,并为该地区农业土地资源合理利用提供科学依据。采集藏东南林芝地区2种典型农业土地利用方式(农田及放牧草地)土壤样品,以自然森林土壤样品为对照,利用磷脂脂肪酸法(PLFA)和MiSeq高通量测序分析不同土地利用方式下土壤微生物数量、多样性和群落组成的差异性,并结合土壤理化指标探讨影响土壤微生物群落组成和结构的关键因素。结果表明:与自然森林相比,农田和放牧草地土壤中微生物PLFA总量降低了38.7%~51.8%,其中革兰氏阳性细菌、革兰氏阴性细菌、放线菌和真菌的生物量分别降低了26.1%~47.6%、40.0%~61.1%、44.1%~60.6%和5.2%~31.3%。农田种植显著降低土壤真菌的多样性,其丰富度、香农多样性相比于森林土壤分别降低了53.0%和71.4%,而细菌群落的丰富度、香农多样性则显著降低了15.7%和5.1%。农田种植显著增加土壤细菌中放线菌门(A ctinobacteria)的相对丰度,但是显著降低了浮霉菌门(Planctomycetes)、绿弯菌门(Chloroflexi)和厚壁菌门(Firmicutes)的相对丰度,放牧草地则显著促进拟杆菌门(Bacteroidetes)和蓝藻门(Cyanobacteria)的生长。农业土地利用显著提高土壤真菌群落中担子菌门伞菌纲(A garicomycetes)的优势度,其在农田和放牧草地土壤中的相对丰度分别是自然森林土壤的23倍和19倍,而子囊菌门(A scomycota)和接合菌门(Zygomycota)的相对丰度则分别降低了67.7%~89.6%和58.7%~67.4%。基于距离矩阵的冗余分析表明,土壤细菌和真菌的群落结构在3种土地利用方式下有显著差异。土壤微生物的数量、多样性和群落组成受到土壤pH值、土壤有机碳、土壤C/N等理化性质的显著影响,并且土壤真菌对环境因子改变的响应比细菌敏感。研究表明,典型农业土地利用方式导致藏东南林芝地区土壤微生物群落的数量和多样性相比于自然植被显著降低,并改变细菌和真菌的群落组成和结构,而且真菌对农业土地利用方式的响应比细菌敏感。     

土壤微生物介导植物抗盐性机理的研究进展

土壤盐渍化是农业可持续生产面临的严重威胁之一.利用高效、低成本和适应性强的方法对盐渍区进行修复是一个具有挑战性的目标.土壤微生物在调节植物根际环境、调控生长发育和提高系统生产力等方面具有重要作用.近年来,由微生物驱动的植物胁迫耐受性受到了广泛关注.通过识别和利用能与植物相互作用的土壤微生物来减轻盐胁迫,为盐渍区改良提供...     

基于结构方程模型的高安市耕地产能影响因素研究

以高安市为研究区域,基于147个产能监测点,以耕地产能、土壤养分、农田水利、地学特征与土壤性质为潜变量,运用结构方程构建耕地产能影响因素模型,探讨影响高安市耕地产能的主要因素。结果显示,土壤养分、农田水利与土壤性质是影响耕地产能的主要因素,对耕地产能存在直接或间接的正向影响,直接影响程度从高到低依次为土壤养分(0.55)>土壤性质(0.26)>农田水利(0.23)。地学特征对耕地产能无直接影响,而是通过影响土壤养分(路径系数为0.51)间接影响耕地产能。坡度对耕地产能有负向作用。高安市耕地产能受多方面因素的影响,综合各影响因素间的相互作用与影响效应,建议通过完善水利设施、加强农田质量建设、提高农产品品质、建设耕地健康产能,实现区域粮食生产的协调可持续。     

艾比湖湿地植物群落特征与土壤环境关系研究

结合野外调查和室内实验的数据,对艾比湖湿地植物群落多样性指数与土壤环境的关系进行研究。结果表明：研究区的42种植物,分属16科36属,多数为典型荒漠植被,归属于16个植物群落类型。各群落的组成简单,多样性指数值都较低,且不存在较大差异。土壤中的有机质含量都很贫乏,土壤偏碱性,多为盐渍土。除物种丰富度与pH值呈显著相关外,多样性指数与土壤因子之间无相关性。     

Gliocladium and Trichoderma in agricultural soil

Gliocladium and Trichoderma are common fungi in agricultural soil. Several species of them were isolated and identified, great diversity was displayed in different agricultural soils of different crops, agricultural climate zones, different seasons, depths, different treated soybean cyst nematode soil, healthy and diseased crop soil. Among five crops soil samples, wheat and corn soil were found to possess the largest number of Gliocladium and Trichoderma separately. Gliocladium and …     

腐殖酸对土霉素和土壤酶活性交互响应研究

腐殖酸是一种具有多种官能团，能够与土壤中微量元素络合，增强土壤团粒结构，促进植物根系生长发育，提高作物对营养元素的吸收，改良土壤好氧细菌活性的有机化合物质。课题通过试验研究，探索腐殖酸在改良受土霉素污染的土壤方面的生物学作用，模拟自然环境下土霉素对土壤环境的污染，土壤中各类活性酶的状况，如脲酶、磷酸酶、过氧化氢酶等的生物活性，深入挖掘腐殖酸在土壤修复及农业生产中的重要作用，为农业生产及区域经济发展提供理论支撑。     

植物入侵对土壤微生物的影响

入侵植物通过影响入侵地土壤微生物生物量、微生物群落多样性及功能菌群等造成环境威胁,危害生态、经济和社会安全。植物入侵已成为全球性问题,也是当前的研究热点之一。综述了国内外植物入侵影响土壤微生物的研究进展,总结了毛竹Phyllostachys edulis入侵天然阔叶林影响土壤微生物特征的生物学机制。研究发现:入侵植物会提高入侵地土壤微生物生物量,增加土壤微生物多样性,为入侵创造有利土壤环境;入侵植物通过改变土壤微生物功能类群进而改变养分循环和其他环境条件,最终实现入侵。加强植物入侵对土壤微生物影响及其驱动的养分循环研究,阐明"植物-土壤"反馈机制,有助于预防和控制植物入侵。