西藏尼洋河流域土地利用变化对生态敏感性的影响

[目的]以西藏尼洋河流域作为高原生态脆弱区的典型代表,对流域1995—2020年土地利用变化影响下的生态敏感性进行探索分析,为该流域土地利用规划和生态环境保护提供理论依据。[方法]通过计算流域土地利用强度指数和生态系统服务价值,构建土地利用变化下的生态敏感性指数,基于土地利用强度指数和生态系统服务价值在各子流域内的时空变化,利用GIS空间分析技术获得尼洋河流域生态敏感性空间分布状况。[结果] 1995—2020年尼洋河流域林地和建筑用地面积呈增加的趋势,而未利用地和水域面积呈下降趋势;土地利用强度指数由1.725 5上升到1.725 9,土地利用生态系统服务价值减少了约3 000万元。土地利用强度指数上升的区域分布在下游流域;流域生态敏感性指数由0.3增加到9.4,流域中、高敏感区主要分布在中下游流域,且高敏感区面积呈扩增趋势。[结论]流域内区域生态敏感性变化由土地利用类型间的转移流动的方向所决定。总体而言,近25 a来流域生态敏感性对生态系统中土地利用变化的响应较为明显,中下游区域生态敏感性呈恶化的趋势。     

喀什市生态系统服务价值对土地利用变化的响应及预测

[目的]通过研究喀什市土地利用变化对生态系统服务价值的影响,为土地科学利用管理决策提供参考。[方法]参考Costanza(1997)和谢高地(2008)等人的研究成果,结合喀什市的实际情况,采用生态系统服务价值计算公式和敏感度分析,通过研究喀什市1997—2010年生态系统服务价值对土地利用变化的响应,并针对喀什市土地利用总体规划(2010—2020年)中土地利用类型的变化,对生态系统服务价值进行预测分析。[结果]按规划发展,1997—2020年,喀什市土地利用结构变化较大。土地利用程度呈加大趋势,生态系统服务总价值则逐年减少,其中耕地、水域的生态服务价值持续下降。敏感性指数分析表明,喀什市生态系统服务价值对生态服务价值系数是缺乏弹性的,研究结果可信。[结论]在喀什市土地利用总体规划实施过程中,应注重提升土地节约和集约利用水平,优化土地利用结构,保持生态系统的平衡和稳定。     

黑河中游土地生态价值及生态风险动态研究——以甘肃省民乐县为例

生态系统服务的价值评估是可持续发展评估研究的关键内容和焦点。甘肃省民乐县位于黑河中游,水资源贫乏,土地利用/覆被变化剧烈且具有独特的区域特征。为此基于GIS软件,参考Costanza生态系统服务价值计算方法和中国陆地生态系统单位面积服务价值表,研究了民乐县1996—2009年土地利用、生态服务价值及土地生态风险指数变化。研究结果表明：①耕地、林地、草地是研究区土地利用变化的重点。总趋势为耕地、草地和未利用地的面积减少,林地和建筑用地的面积显著增加。这一变化直接影响到生态服务价值的变化。②近13年来,生态系统服务价值减少了12.01%。2009年民乐县提供的生态服务仍然以土壤形成与保护为主,其次是生物多样性保护、废物处理、气体调节、水源涵养和气侯调节,而原材料、食物生产和娱乐文化功能比较弱。③各项生态系统服务价值对生态价值系数的敏感性指数均小于1,说明研究区内的生态系统服务价值缺乏弹性,研究结果可信。④生态服务价值与生态风险的研究结果相互印证。     

环京津地区土地生态服务价值时空分异特征

为促进京津冀一体化协同发展及生态环境建设,利用遥感解译获得的环京津地区73个县(市)的土地利用变化数据,计算1996~2011年该区域的土地生态服务价值,并运用敏感性指数验证了所计算的土地生态服务价值可信度。引入生态系统服务价值动态度及相对变化率指数模型,分别对环京津地区土地生态服务价值的时间、空间变化进行了分析。结果显示:在空间分布上,环京津地区土地生态服务价值表现出由西北向东南逐渐减少的特征;在时间变化上,环京津地区不同的土地利用类型生态系统服务价值量变化规律略有不同,其中园地、水域的生态服务价值量变化最为剧烈;耕地、草地的生态系统服务价值量变化最为缓和,但环京津地区土地生态服务总价值随时间的推移呈缓慢减少的趋势;在空间变化上,西部高山丘陵区的土地生态服务价值变化较剧烈,东南部平原区变化较缓,1996~2011年间,生态服务价值变化最剧烈的地区集中在保定西部山区及张家口局部地区。     

基于土地利用变化的高阳县生态系统服务价值和碳排放风险研究

研究土地利用变化下区域生态系统服务价值和土地碳排放风险的变化,对于了解土地利用变化的生态环境响应,促进区域经济与环境的协调发展,实现低碳土地利用具有重要意义。以高阳县为研究区,基于2009年和2016年土地利用数据,利用网格法划分评价单元,运用模型法定量评价了生态系统服务价值和土地碳排放风险,并分析了时空演变特征,最后对二者进行了相关性分析。结果表明:2009—2016年高阳县土地利用变化特点为建设用地迅速扩张、水域等生态类用地大量减少;生态系统服务价值总体偏低且研究期间呈下降趋势,县域东中部地区整体高于西部地区;土地碳排放风险总体偏低但在研究期间呈上升趋势,县域中西部地区整体高于北部和东南部地区;土地碳排放风险与生态系统服务价值存在显著负相关关系,表明生态系统服务分析在土地利用碳排放研究中应用的可能。     

基于土地利用的甘州区生态系统服务价值研究

以张掖市甘州区为研究对象,采用1987年、2000年、2009年3期土地利用数据,分析了甘州区1987—2009年在土地利用/覆盖变化驱动下的生态系统服务价值变化。研究表明:（1）甘州区农田和居民工矿用地一直处于增加趋势,林地和草地先减少后增加,水域处于减少状态;（2）甘州区生态系统服务价值呈现先降后升的“V”字形变化,1987年、2000年和2009年3个年份分别是25.2,19.53,20.21亿元;在不同生态系统类型中,农田、草地、水域提供的生态功能服务价值达到总价值的80%以上,在生态系统服务价值构成中占有重要地位;（3）生态系统单项服务功能价值中,水源涵养和废物处理的生态功能服务价值较高,二者之和占总价值的近40%;（4）各土地利用类型生态系统服务价值敏感性指数都小于1,表明甘州区生态系统服务价值缺乏弹性,研究结果可信;（5）从表面看,生态系统服务价值的变化直接源于土地利用的变化。实质上,在土地利用变化的背后隐含着不同时期人类活动强度和政府政策导向的间接驱动。     

尉犁县土地利用/覆被变化的区域生态系统服务价值变化

基于尉犁县1993年、2001年、2009年和2017年的遥感影像数据,采用中国陆地生态系统服务价值测算方法,结合研究区实际情况,对生态系统服务价值系数进行了修正,分析了尉犁县土地利用/覆被变化导致的生态系统服务价值变化。结果表明:1993—2017年,尉犁县不同土地利用类型面积总体呈“六增三减”态势;即耕地、建设用地、水域、湿地、盐渍化地与沙漠面积有所增加,林地、草地与未利用地面积有所减少;尉犁县土地利用生态系统服务总价值总体呈增加趋势,从1993年的173.61亿元增加到2017年的206.30亿元,增加了32.69亿元。在整个研究时段内,研究区各土地利用类型对生态系统服务总价值的贡献大小从高到低依次为湿地 > 草地 > 未利用地 > 沙漠 > 水域 > 林地 > 耕地 > 盐渍化地 > 建设用地;敏感性分析结果表明各土地利用类型敏感性指数均<1,表明各土地利用类型生态系统服务价值对生态系统服务总价值的影响较小,缺乏弹性,研究结果可信。     

沧州渤海新区土地利用总体规划实施的生态效应评估

[目的]定量分析土地利用总体规划实施过程对生态环境的影响,预防或减轻规划实施过程中产生的不良环境影响.[方法]以河北省沧州市渤海新区为研究区,以土地利用规划数据和2009—2013年土地利用现状数据为基础,采用生态系统服务价值评估方法、敏感性指数、灰色预测模型,分析研究区2009—2013年土地利用及其生态系统服务价值的变化,预测2015和2020年生态系统服务价值,并与规划目标进行比较。[结果](1)2009—2013年,研究区建设用地增加量已经超过规划期建设用地的增加总量,生态系统服务价值减少了1.11×107元,说明规划实施过程中过于重视经济效益,而忽视了生态效益;(2)预测结果显示,到2020年生态系统服务价值减少7.08×10~7元,规划实施过程中,研究区生态系统服务功能在逐渐减弱。[结论]当地政府应高度重视规划实施过程中生态环境退化的问题,并采取积极有效的措施,促进经济建设与生态环境保护协调发展。     

资源型城市土地利用变化对生态系统服务价值的影响——以安徽省淮南市为例

[目的]以安徽省淮南市为例,探讨资源型城市土地利用变化对生态系统服务价值的影响,为该市生态、经济、生态环境保护以及今后进行城市开发建设和农业发展提供科学参考。[方法]基于土地利用变化和生态系统服务价值评估的相关理论和方法,运用GIS软件,分析淮南市2000和2010年土地利用变化,并计算淮南市生态系统服务价值,研究土地利用变化对生态系统服务价值的影响。[结果]2000—2010年淮南市土地利用变化较大,主要土地类型以耕地、居民地及工矿用地和水域为主。土地利用结构发生变化,出现耕地、林地减少,水域、居民地及工矿用地、草地增加的现象。研究区生态系统服务价值总量呈减少的趋势,从2000年的11.72亿元减少到2010年的11.33亿元,减幅达3.33%。单位面积生态系统服务价值的分布变化也与研究区土地利用变化紧密相关,居民地及工矿用地的增加是造成生态系统服务价值减少的最主要原因。生态系统服务价值对生态价值系数的敏感性指数均小于1,说明研究区内的生态系统服务价值缺乏弹性,研究结果是可信的。[结论]淮南市应高度重视土地利用变化对生态系统服务价值的影响,优化调整土地利用结构,注重增加生态用地,稳步提升区域生态系统服务价值。     

延河流域土地利用变化对其生态服务价值的影响

土地利用变化明显影响流域生态系统服务价值.本文在谢高地等制定的中国陆地生态系统服务价值当量表的基础上,结合延河流域土地利用变化情况和生态系统服务特征,完善了延河流域生态系统服务价值估算表,并以延河流域1990年、2000年和2006年土地利用数据为基础,估算了各年度的生态服务价值.分析表明:在16a间,延河流域生态服务价值总体有所提高,2006年比1990年生态服务价值增加了5.72亿元.敏感性分析表明流域内生态服务价值对生态服务价值指数是缺乏弹性的,研究结果是可信的.     

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.