福建省土地利用隐性形态与土地生态安全耦合协调分析

为了摸清土地利用形态转型的规律,促进绿色经济的发展,以福建省9个设区市为研究对象,采用综合指数模型、耦合协调度模型和地理探测器方法,探讨了福建省土地利用隐性形态时空特征、转型模式并分析其与土地生态安全的耦合协调性特征。结果表明:福建省土地利用隐性形态指数总体呈上升趋势,形态上逐渐往高级发展,沿海城市土地利用隐性形态指数比内陆城市高。研究期内土地利用转型存在阶段性特征,在一定周期内呈现出"S型"的演化态势。土地生态安全水平总体呈波动上升态势,并与地区所处的土地隐性转型模式密切相关,西北内陆地区土地生态水平总体比东南沿海地区高。近15年来福建土地利用隐性形态与土地生态安全耦合协调度均值由0.44上升至0.61,沿海城市协调性高于内陆城市;协调性差异的主要影响因素是土地利用强度、土地产出效益和生态资源禀赋。应当将土地利用隐性形态转型及其与生态安全的协调发展规律应用到土地利用中,因地制宜地施行管理政策,促进城市间协同绿色发展。     

升金湖国家自然保护区土地利用生态风险评价

[目的]为了有效保护升金湖国家自然保护区生态环境。[方法]根据安徽省升金湖国家自然保护区1986,2002和2011年3期TM遥感影像,运用ERDAS,ArcGIS等软件,结合升金湖自然保护区土地利用现状,将升金湖自然保护区试验区、核心区、缓冲区3个功能区的影像进行监督分类,划分成建设用地、草地、耕地、林地、水域、未利用地、交通用地和园地8个地类,并统计各土地利用类型面积。采用层次分析法和模糊数学法建立土地利用生态风险评价模型,计算土地利用生态风险指数。[结果]保护区整体的土地利用生态风险等级为中级,1986—2011年,土地利用生态风险逐渐增强。其中,核心区的土地利用生态风险指数相对较低,但也呈逐渐增强趋势;试验区的土地利用生态风险指数较大,缓冲区的土地利用生态风险指数变化明显,土地利用生态风险较严重。[结论]升金湖自然保护区生态风险呈上升趋势,需要采取措施,建立预警机制,有效控制升金湖的生态风险。     

基于GIS的石漠化山区县域土地利用空间变化的生态风险测度

为深入探寻石漠化山区土地利用动态变化的空间规律和土地生态环境的演变方向,利用晴隆县1988年、2000年、2016年3期遥感影像数据,在RS与GIS技术支持下运用土地利用动态变化空间分析模型、空间变化率指数、土地生态风险指数、土地利用变化综合生态风险度来测度土地利用变化对土地生态环境造成的风险。结果表明:(1)耕地、草地、未利用地三种用地类型间的剧烈转化,使研究区土地生态环境逐渐恶化;(2)人口上涨、城镇化进程加快、城乡工矿及居民用地极速扩张等对研究区的土地生态安全造成威胁;(3)近30年间土地生态风险程度呈先增大后减小趋势,但后16年间土地利用程度综合指数的增大、植被覆盖指数和多样性指数的减小,说明研究区存在石漠化程度加深、景观类型单一、生态稳定性差、土地生态风险概率加大等问题,晴隆县土地生态状况仍有恶化的趋势。土地利用变化的综合生态风险度与土地生态风险指数的测算结果相互印证,说明将上述方法用于评价石漠化山区县域土地利用变化的生态风险是可行的。     

生态脆弱区土地生态安全动态评价——以河北省张家口市为例

[目的]通过研究河北省张家口市土地生态安全的演变趋势及时空差异特征,旨在为张家口市土地资源管理及可持续利用提供科学依据。[方法]从土地自然基础状况、土地利用状况、土地污染、退化状况、土地景观格局状况、土地生态建设状况及土地社会经济状况6个方面构建张家口市土地生态安全评价指标体系,运用综合指数法对张家口市2000和2010年土地生态安全状况进行动态评价,分析其土地生态安全动态变化趋势及其空间异质性特征。[结果]2000—2010年张家口市多数区县的土地生态安全评价综合指数呈增长趋势,且土地生态安全状况多处于安全、较安全及敏感态,土地生态安全状况处于风险态和恶劣态的区县主要集中在中部市区及其周边地区。[结论]近10a来,张家口市土地生态安全状况总体变好,这与退耕还林还草工程及其他生态建设工程的实施具有密切关系。     

基于PSR模型的广西石漠化地区土地生态安全动态评价

[目的]对广西壮族自治区轻度及以上石漠化地区进行土地生态安全评价,为该区土地生态安全及其可持续发展提供科学参考。[方法]基于PSR模型构建了广西石漠化地区土地生态安全评价指标体系,采用熵权赋权法确定权重,运用生态安全综合模型,对研究区2005,2015年的土地生态安全综合指数进行计算。[结果]广西石漠化地区土地生态安全主导因素为人口密度、单位GDP综合耗能、土地垦殖率、耕地粮食单产、城市化水平、人口自然增长率等因素;压力指数、状态指数和响应指数共同决定广西石漠化地区土地生态安全评价的综合指数;从时间上看,2005—2015年广西石漠化地区土地生态安全经历了从临界安全等级向较安全等级的变化趋势,土地生态安全的状况主要因响应状态系统的提升,而使得综合土地生态安全指数有所上升。从空间上看,2005年贵港地区的土地生态安全等级处于不安全级,2015年南宁、贵港、来宾等地区的土地生态安全等级处于较不安全级。[结论]广西石漠化地区的土地生态安全略有上升,但受压力和状态子系统承载力水平的限制,研究区的土地生态安全仍处于中等水平,需要进一步加强土地生态安全建设。     

基于GIS的宁夏中部干旱带土地利用生态安全动态评价

土地利用生态安全评价是区域可持续发展关注的重要内容之一。以宁夏中部干旱带为例,针对研究区实际生态问题,基于RS和GIS技术,构建"隐患—状态—免疫"生态安全评价指标体系,采用熵权法与综合指数模型,实现了30m×30m栅格水平可视化的土地利用生态安全综合评价。结果表明:2004—2014年,研究区土地利用变化和区域政策的实施结果一致。草地、林地面积急剧扩大,旱地和未利用地面积持续下降,建设用地和水域面积变化不大,水浇地面积呈缓慢增加趋势。结合已有研究成果与研究区实际,采用聚类法,将研究区土地利用安全分为5个等级:生态安全区(Ⅰ)、生态较安全区(Ⅱ)、生态临界安全区(Ⅲ)、生态不安全区(Ⅳ)和生态极不安全区(Ⅴ)。研究区土地利用生态安全指数从2004年的-0.12上升为2014年的0.03,整体状态呈变好趋势,但ESI指数仍小于0.1,处于临界安全状态。具体表现为:Ⅰ级乡镇从4个增加为5个、Ⅱ级区从10个增至11个、Ⅲ级乡镇从13个减少为12个、Ⅳ级乡镇从5个减少为4个、Ⅴ级乡镇从8个减少为7个,针对评价结果分析其动态演变机制。通过对宁夏中部干旱带土地利用生态安全动态评价,以期为宁夏境内生态移民区选址和生态环境保护提供数据支撑。     

湘南红壤丘陵区土地生态安全动态评价——以衡阳市为例

选择衡阳市为研究区,并选取水土流失率、退化土地治理率、坡耕地＞25°百分比等19个能反映该区域土地利用特点的指标,构建区域土地生态安全评价指标体系;运用熵值法和指数加法模型,研究2006 2010年衡阳市土地生态安全.结果表明:2006 2010年衡阳市土地生态安全综合指数整体呈上升趋势,即土地生态安全状况逐步好转,但评价等级为临界安全与较不安全水平,区域土地资源生态安全仍不乐观.研究认为,加强全民生态安全意识,增大水土流失治理率,切实协调好城市化进程与生态环境建设的关系,建立资源节约型的社会生产和生活消费体系,发展生态农业,综合有效利用现有资源,是生态安全前提下衡阳市实现经济社会可持续发展的保证.     

2000—2020年福建省土地利用隐性转型的影响因素

[目的] 分析福建省县域土地利用转型主导驱动力与影响因素的时空特征,构建土地利用转型影响因素逻辑分析框架,为福建省土地利用高质量发展提供参考。[方法] 基于2000,2010和2020年福建省土地利用数据和社会经济数据,采用理论分析法、土地利用转移矩阵、综合指数法、地理加权回归（GWR）等方法,构建土地利用转型影响因素逻辑分析框架,并在此基础上对福建省土地利用转型主导驱动力、地类转移、土地利用隐性形态时空特征及影响因素进行系统分析。[结果] ①福建省各地区呈现出以发展型经济—生态安全驱动力为主要动力的发展趋势; ②2000—2020年福建省建设用地增加了2 897.45 km²,主要由耕地转换而来,其次为林地和草地;③福建省县域土地利用隐性形态呈现出“条带状”空间特征,形成福州—莆田—厦门高级形态区以及福鼎—闽侯—仙游—安溪—诏安和武夷山—南平—三明—龙岩中级形态区; ④交通密度和城市化是福建省土地利用转型的主要影响因素。[结论] 福建省应该加强内陆和沿海、偏远地区和市区之间的交通建设,实施新型城镇化战略,同时深入推进新时代山海协作,充分发挥福州、厦门等沿海城市的带动作用。     

干旱区河谷城市土地利用生态风险动态预测——以新疆伊宁市为例

土地利用规划和土地生态安全是土地资源可持续利用的基础和核心。基于伊宁市土地利用总体规划(2010—2020年),依照规划基期年及末期年土地利用结构特征,借助土地利用变化、土地利用类型动态度和生态风险空间分析方法,测算了土地利用生态风险指数。并通过运用ArcGIS 9.3对生态风险进行了系统采样、半变异函数分析及空间插值,研究伊宁市土地利用生态风险动态演变和空间分异特征。结果显示:伊宁市土地利用总体规划对全市土地利用空间结构进行了较大调整,土地生态风险具有明显的区域性,生态安全状况由北向南逐渐加重,且高、较高风险区在南部区域呈圆环式蔓延趋势。在未来土地利用变更中应加强生态环境保护意识,在伊宁市河谷构建良好的生态用地格局,提高土地利用的综合效益。     

甘肃省庆阳市土地集约利用与土地利用结构的耦合协调关系

[目的]探究甘肃省庆阳市土地集约利用与土地利用结构之间的协调关系,为该市土地利用结构优化和社会经济的可持续发展提供理论依据。[方法]以庆阳市为例,采用多因素综合评价法计算2007—2016年土地集约利用、土地利用结构的综合指数,应用耦合协调模型,分析二者变化特征及耦合协调关系。[结果]①庆阳市土地集约利用综合指数呈上升趋势,达到了高度集约利用水平。②庆阳市土地利用结构信息熵总体呈下降趋势,均衡度逐渐降低,优势度逐渐增强。③土地集约利用与土地利用结构耦合度呈先上升后下降的趋势,耦合协调度都呈上升趋势,二者耦合性越来越强,相对呈现出协调、稳定的发展趋势。[结论] 2007—2016年庆阳市土地集约水平总体变化呈逐年上升状态,但信息熵呈下降趋势,是由于大力开发未利用地,植树造林使得土地利用结构调整。土地集约利用和土地利用结构两系统协调度都呈上升趋势,二者耦合性越来越强。说明庆阳市在大力推动经济发展的同时,也注重提高土地利用的效率,调整土地利用结构,优化布局。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.