基于生态健康的贵阳市云岩区土地集约利用研究

城市土地集约利用是城市发展的必然要求.目前的土地集约利用评价指标重点考虑经济、社会因素,较少考虑环境因素以及土地集约利用对环境的效应.本文从生态健康的角度入手,建立城市土地集约利用的评价指标体系,包括3大评价因子、20个评价指标,并确定各评价指标的权重.以贵阳市云岩区为例,运用GIS方法对云岩区城市土地集约利用水平进行了研究.结果表明:云岩区城市土地集约利用属较集约水平,还有一定的土地集约利用潜力;在空间上,云岩区城市土地集约利用水平呈现出从中南部向北部、西部、东部递减的特征.土地集约区域面临生态环境恶化的障碍,粗放区域面临社会经济投入产出不足的障碍;针对不同集约水平的区域应采取不同的发展策略,实现生态、社会、经济的协调发展.     

基于PSR模型的江苏省城市土地集约利用评价

根据城市土地集约利用的内涵,从压力—状态—响应3个方面选取13个指标,构建了城市土地集约利用评价指标体系和综合评价模型,对江苏省13个地级城市进行了评价。结果表明:2013年较2005年江苏省城市土地集约利用水平有显著提升,增幅为71%,主要在于地均经济投入、产出指标的增长;集约利用水平总体呈现出由南向北递减的空间分异特征,主要影响因素是地理区位条件和经济发展水平。评价结果基本上反映了研究时段内江苏城市土地集约利用的时空变化特征,说明构建的评价指标体系和建立的综合评价模型是可行的。     

基于PSR的天山北坡经济带土地集约利用水平的空间差异研究

[目的]对天山北坡经济带12个主要城市的土地集约利用水平进行评价。[方法]从土地利用的经济性、社会性及生态性3个内涵出发,构建基于过程的"压力—状态—响应"(PSR)评价指标体系,采用主成分分析法对评价指标进行赋权,按百分制分别测算土地集约利用水平和PSR系统协调度。[结果]天山北坡经济带城市土地集约利用水平差异的主要影响因素一方面在于各城市的经济发展水平,另一方面在于人口密度、土地利用结构、经济增长等对土地集约利用产生压力的因素。将PSR协调度与土地集约利用水平进行相关分析,其Pearson相关系数达到0.886,二者显著相关,说明在总体上PSR系统协调度越高,城市土地集约利用的水平也越高。[结论]为提高城市土地集约利用水平,在规划开发中一方面要结合城市土地集约利用的内涵,另一方面也要从各城市所处的发展阶段及发展目标出发,通过合理的产业转型,优化土地利用结构等方式,制定有效的引导措施来提高土地利用的综合效率。     

城市土地集约利用效益障碍因子研究——以咸宁市为例

提高城市土地集约利用效益是建设"两型社会"的必然要求。从社会发展、经济水平、生态响应、环境质量四个方面构建城市土地集约利用效益评价指标体系,采用熵权TOPSIS法和障碍度模型,对咸宁市城市土地集约利用效益及障碍因子进行分析。研究表明:(1)1999—2010年咸宁市城市土地集约利用效益在波动中呈稳步上升态势,年均增长速度为10.38%,研究后期增幅更快。城市土地集约利用效益经历了低级(1999—2001年)、中度(2002—2007年)和良好(2008—2010年)三个阶段,中度效益阶段占主导地位;(2)经济水平和生态响应对城市土地集约利用效益的影响较大。2010年以前,人均国内生产总值是最大障碍因子。2010年,单位面积废气排放量是最大障碍因子。     

合肥市城市土地集约利用评价及对策研究

以安徽省合肥市为例,采用地租理论、土地报酬规律理论、可持续发展理论和经济理论,分析了合肥市的社会经济概况、土地集约利用水平进行评价。主要研究内容及结论如下:(1)构建了合肥市城市土地集约利用指标体系。(2)对合肥市2005-2012年的城市土地集约利用水平进行评价,结果表明土地集约利用水平总体上较低,总体上是呈现出上升的趋势。(3)提出了保障社会经济可持续发展的土地集约利用对策。     

基于生态文明的西安市经济技术开发区土地集约利用合理度研究

为了全面掌握土地集约利用状况,更准确地对土地集约利用合理程度进行评价,从经济、空间、生态3个方面建立土地集约利用合理度评价指标体系,应用FAHP法确定指标权重,采用模糊综合评价法和综合指数法建立土地集约利用合理度的复合评价模型,对西安经济技术开发区土地集约利用合理度进行定量计算、分析和评价。结果表明,西安经济技术开发区土地集约利用合理度综合分值为78.67,土地集约利用总体上较为合理,经济效益和空间效益集约合理度水平一般,生态效益集约合理度很好。最后根据评价结论提出了有针对性的对策建议。该研究结果可为定量评价土地集约利用合理程度提供参考,为区域土地利用、发展定位、规划决策提供借鉴。     

生态文明建设目标下的广东省城市土地集约利用时空演变分析

[目的] 探究生态文明建设目标下广东省城市土地集约利用水平的时空格局特点,促进土地可持续及集约利用。[方法] 利用熵值法确定权重测度土地集约利用水平指数,然后利用核密度估计和空间自相关分析方法分析其时空格局分布特点。[结果] ①时序方面,根据最佳自然断裂点方法将广东省土地集约利用水平值划分为Ⅰ,Ⅱ,Ⅲ,Ⅳ 4个级别。在2012—2019年期间,该区土地集约利用水平值呈现上升趋势。广东省各地级市城市之间土地集约利用水平具有一定差距,但差距在缩小。②空间方面,土地集约利用水平具有集聚的特点,在空间上的集聚态势分别为低—低、低—高、高—高3种类型的区域。高值区域主要分布于珠三角部分区域,低值区分布在粤北等区域,存在明显的空间正自相关性。同时区域间的相关性表现出整体减弱的特点。③广东省各城市土地集约利用水平在时序上存在差距,但城市土地集约利用水平得到提升。部分城市土地集约利用水平在空间上具有集聚的特点且存在关联性。[结论] 广东省各城市应朝着因地制宜的方向发展。珠三角区域应继续优化产业结构,而粤西、粤北等地区则要在政府政策的帮扶下加强区域间的联系,进而缩小区域差距。     

喀斯特地区县域土地集约利用评价——贵州省绥阳县为例

随着城镇化进程的加快,社会经济发展对土地的需求不断增加,土地供需矛盾、土地生态环境恶化等问题日益突出。以绥阳县15个乡镇土地利用、社会经济数据为依据,建立土地集约利用评价指标体系,运用定量的评价方法,对绥阳县各乡镇土地集约利用水平进行评价。结果表明:(1)绥阳县各乡镇土地集约利用水平大都处于适度利用水平;其中,土地利用效益和土地投入水平是制约各乡镇集约利用水平的重要因子;(2)绥阳县土地集约利用水平呈阶梯差异,从东向西逐步降低的特征;(3)土地集约利用水平高低主要受地形地貌和经济发展水平的影响,集约度的高低与地形地貌、经济发展水平的高低具有一致性。     

黑龙江省煤炭型城市土地集约利用评价研究

在我国人地矛盾日益突出的背景下,节约集约利用土地已成为社会发展的必然选择,同时也成为促进我国城市健康和可持续发展的关键。以黑龙江省煤炭型城市——鸡西市、双鸭山市、七台河市、鹤岗市为研究区,从经济潜力、社会潜力、生态潜力3方面构建研究区土地集约利用评价指标体系,采用层次分析法与熵值法确定权重,运用多因素综合评价法对研究区2004—2013年的土地集约利用进行综合评价,并分析其驱动力因素。研究结果表明:2004—2006年,黑龙江省煤炭型城市处于不集约状态,属于土地集约利用等级层次中的Ⅳ级,2007—2013年,黑龙江省煤炭型城市处于集约状态,属于土地集约利用等级层次中的Ⅲ级;地均固定资产投资、地均GDP、煤炭开采机械化率、煤炭产值、城市人口与用地增长弹性系数、煤炭挖掘面平均月进度指标是影响煤炭城市土地集约利用的驱动因子。     

广州市建设用地集约利用评价研究

城市土地的集约利用直接关系到区域土地的可持续利用,如何衡量土地的集约利用程度是一个复杂而重要的过程。以广州市1990—2007年建设用地数据、各类社会经济数据为基础,构建适合广州市建设用地集约利用评价的指标体系,综合运用主成分分析和BP神经网络建立建设用地集约利用评价模型,计算其集约利用程度,并与前人通过模糊综合评价法得出的结论进行比较。结果表明:1990—2007年广州市整体集约利用水平呈上升趋势,1990—1994年、1996—1997年处于粗放利用,1995年、1998—2003年处于中度集约,2004—2007年处于高度集约。主成分分析和BP神经网络的评价方法与模糊综合评价法的结果平均误差为4.37%。     

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.