黄土高原山丘区土地生态安全动态评价及预测

以2001—2010年晋城市土地生态安全相关数据为基础,运用PSR框架模型构建了土地生态安全动态评价指标体系,运用主成分分析法确定指标权重,对晋城市土地生态安全状况进行了动态评价,并采用GM（1,1）模型对未来土地生态安全状况进行了预测。研究结果表明:晋城市土地生态安全综合值总体上呈上升的趋势,土地生态安全等级从2001年的Ⅲ级变成2010年的Ⅱ级,土地生态安全状态从2001年的“敏感”状态变成2010年的“较安全”状态。晋城市土地生态安全状况空间分异显著,不同区县（市）由于社会经济发展水平、自然条件状况、环保投入水平、土地利用结构和产业布局的不同,导致全市土地生态安全格局分布的差异性和空间演化的异质性。该研究为黄土高原山丘区土地生态安全动态评价提供一种思路,为制定科学有效的生态环境相关政策和土地整治提供依据。     

土地生态安全预警系统设计与实现

土地生态安全问题是区域生态安全的核心问题之一。定量化、可视化、自动化的评价和预测土地生态安全状况并进行实时预警,对土地资源的可持续利用具有重要意义。本文以河北省为研究实例,基于PSR(压力、状态、响应)模型构建了土地生态安全评价指标体系,采用投影寻踪模型对土地生态安全状况进行评价,采用主成分相关分析法诊断土地生态安全的主要影响因子,采用空间差异系数模型分析了土地生态安全的时空格局,采用马尔科夫预测模型对土地生态安全水平进行预测,通过划分土地生态安全预警等级建立了预警机制,并利用MATLAB的图形用户界面(GUI)开发了土地生态安全预警系统。结果表明:1)2010—2018年,河北省土地生态安全指数呈不断增长态势,由0.300上升到0.611,年均增长率为12.92%,土地生态安全状态由"恶化级"转变为"敏感级",预警等级由"巨警"转变为"中警",土地生态安全总体水平仍然较低。2)土地生态安全主要限制因子是人口密度、工业化率、单位播种面积农药负荷、单位土地工业三废负荷、城市建设用地比重、工业用地比重和GDP能耗等。3)河北省各地级市土地生态安全区域差异性不断缩小,近年趋于平稳,至2018年,空间差异系数为32.54%,各市之间的差异性仍然不容忽视,大部分地级市土地生态安全状态处于"敏感级",预警等级为"中警",土地生态安全水平有待进一步提高。4)2019—2025年,河北省土地生态安全指数呈稳步上升趋势,到2025年为0.834,达到"较安全级",预警等级为"轻警",土地生态朝着良性方向发展的潜力较大。     

基于正态云模型的湖北省土地资源生态安全评价

针对综合指数法与模糊综合法无法同时兼顾评价指标模糊性与随机性的问题,该研究将正态云模型引入区域土地资源生态安全评价。基于正态云模型,以湖北省为例,对区域土地资源生态安全状况进行了定量测度。研究结果表明：2000-2010年间,湖北省土地资源生态安全状态从敏感级上升到良好级,土地资源生态安全综合值从2.9397上升为3.6033,区域土地资源生态安全整体水平有变好的趋势,但目前仍有部分指标处于恶劣、危险或敏感级,其单因子指标值<2.5,有待于进一步提高与改善;正态云模型使土地资源生态安全的定量评价兼顾随机性和模糊性,该研究可以为区域土地资源可持续发展提供一定借鉴与参考。     

基于土地生态安全的黔江区土地利用结构优化

通过构建黔江区土地生态安全评价指标体系,对黔江区2005—2012年土地生态安全状况进行了动态分析,在此基础上,采用灰色多目标规划模型,以综合效益最大化为目标,对黔江区土地利用结构进行优化。结果表明:(1)黔江区土地生态安全水平由2005年的0.426 9上升到2012年的0.586 2,土地生态安全级由"较不安全"上升到"临界安全",土地生态安全水平还有待改善,需要对土地利用结构进行优化;(2)黔江区土地利用结构优化后,土地生态安全等级由"临界安全"级上升到"较安全"级,土地生态安全水平达到0.748 9;(3)从优化结果看,农用地中耕地面积有所减少,园地、林地、其他农用地都有所增加,建设用地中交通水利用地和其他建设用地增幅较大,其他土地中自然保留地面积有所减少。研究结果对黔江区提高土地利用综合效益,维持土地生态系统的相对平衡和持续利用以及经济社会的可持续发展具有重要的现实意义。     

基于DPSIR-EES-TOPSIS模型的重庆市土地生态安全评价及其时空分异

土地生态安全是生态环境保护以及区域生态文明建设的基础。以长江经济带的重要节点重庆市为研究对象,基于DPSIR—EES模型构建区域土地生态安全评价体系,在运用TOPSIS法揭示了重庆市土地生态安全整体变化状况的基础上,通过ESDA—GIS法开展了区域土地生态安全时空分异研究。结果表明:(1) 2009—2016年,重庆市土地生态安全呈现波动上升的趋势,土地生态安全由"敏感级"向"良好级"转变;土地生态安全各子系统整体趋于好转;(2) 2009—2016年,主城区土地生态安全有所退化,而渝西片区、渝东北片区、渝东南片区得以改善;总的来说,土地生态安全"敏感级"和"危险级"集中于主城区和渝西片区,而"临界级"和"良好级"主要分布在渝东北及渝东南片区;(3)重庆市土地生态安全存在较强的空间正相关和聚集性,其"高—高"和"低—低"值区呈现增加趋势,"高—高"和"低—低"值区的分布与自然生态状况、人类活动密切相关。研究结果能为区域的土地生态系统保护与社会经济可持续发展提供参考依据。     

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P-S-R模型的生态涵养发展型区域土地生态安全评价——以重庆市丰都县为例

针对生态涵养发展型区域的生态环境状况和土地资源特点,基于PSR（压力—状态—响应）概念框架模型,构建土地生态安全综合评价指标体系,采用熵权法确定权重,运用综合指数法对重庆市丰都县2006—2011年的土地生态安全状况进行评价。结果表明,丰都县土地生态安全状态2006年处于敏感级安全状态（综合指数29.72）,到2011年处于临界级安全状态（综合指数31.65）。土地生态安全状况的好转,得益于国家和地方对现有生态环境问题的治理以及对生态建设和环境保护的大力投入。2006—2011年丰都县生态涵养能力与经济社会发展水平不同步,经济的快速发展带来巨大环境压力,生态涵养和发展尚未实现良性互动。     

山地城镇化进程中土地生态安全动态评价研究——以贵阳市为例

为促进其土地资源可持续利用及其未来生态环境质量改善和生态安全规划管理提供依据,对贵阳市近20 a来的土地资源生态安全状况进行动态评价研究。基于P-S-R模型构建城市化驱动力下土地生态安全评价指标体系,采用多指标综合评价法计算土地资源生态安全水平,利用SPSS软件和GM（1,1）模型进行相关性分析与短时间序列预测。结果表明:近20 a贵阳市土地生态安全指数1992—2000年处于恶化级、2001—2009年处于风险级、2010—2011年处于敏感级,总体呈波动上升趋势,但基本处于不安全状态;人类社会经济活动的响应对土地资源生态安全的影响较大;预测在2011年后5 a内该区域压力值、状态值、响应值和综合值均呈上升趋势,土地生态环境良性循环发展潜力具大,但生态系统脆弱且敏感性显著等问题一直存在。控制人口增长,优化人口结构,加快转型发展,构建绿色经济生态体系,统筹城乡协调发展,优化合理利用土地,探索节约集约用地的新型城镇化模式,加大环境保护力度,建立生态补偿机制是保护贵阳市土地资源生态安全的合理性对策。     

重庆市黔江区土地生态安全评价及时空变化分析

[目的]揭示重庆市黔江区土地生态安全的时空变化特征,为黔江区土地资源的可持续利用提供科学依据。[方法]从生态负荷、生态保护、生态功能及生态经济4个方面构建黔江区土地生态安全评价指标体系,采用主客观组合赋权和综合指数法对该区土地生态安全状况进行分析。[结果](1)研究区土地生态安全水平呈上升趋势,但总体水平不高,有待进一步改善;(2)黔江区土地生态安全空间差异显著,呈现"区中心土地生态安全水平低,四周土地生态安全水平较高"的土地生态安全格局。[结论]主客观组合赋权有助于克服单一的主观赋权及单一客观赋权的不足;将"压力—状态—响应(PSR)"模型和"自然—经济—社会"模型有机结合构建的基于生态负荷、生态保护、生态功能及生态经济的评价指标体系较好地反映了黔江区土地生态安全的时间变化及空间差异状况。     

基于云模型与熵权法的安徽省土地生态安全评价研究

土地生态环境条件是区域社会经济可持续发展的基础。本研究以安徽省为例,根据"自然-社会-经济"复合系统理论构建土地生态安全评价指标体系,应用云理论,将正态云模型与熵权法引入安徽省土地生态安全评价研究中,揭示近10年来安徽省土地生态安全状况、演变规律及障碍因子。研究结果表明:12005年、2010年和2013年,安徽省土地生态安全水平分别处于一般、良好和健康水平,土地生态安全状况趋于良性发展;2基于综合指数评价方法,2005年、2010年和2013年的土地生态安全水平评价结果分别为0.184 8、0.342 4和0.473 0,表明安徽省土地生态安全处于稳步上升趋势,与云模型评价结论一致;3指标隶属度分析显示,2005年、2010年和2013年,安徽省土地生态安全处于良好及以上水平的指标分别为7个、13个和17个,处于上升趋势;而一般及以下水平的指标分别为16个、10个和6个,处于下降趋势。因此,近10年来,安徽省土地生态系统整体状况趋于良性发展,在一定程度上体现了生态文明建设对土地生态系统的优化效应。     

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.