西藏高寒地区不同边坡生态修复类型土壤的肥力变化

[目的] 对西藏DG水电站6种不同边坡生态修复类型土壤的肥力变化进行对比研究,为西藏水电工程扰动区生态环境的修复提供理论依据和技术支撑。[方法] 采用实地测量和室内试验等方法,分析不同边坡生态修复类型的肥力变化特征及植被生长情况,并用相关性分析确定边坡土壤肥力时空变化与植被生长情况之间的相关性,探讨影响边坡植被生长土壤的肥力主控因素。[结果] 在6种边坡生态修复类型土壤中有机质和氮元素波动变化均较大,随季节变化呈现先降低后增加再降低的趋势,而pH值、速效磷、速效钾变化相对较小。从不同边坡对比结果来看,边坡的土壤养分含量从高到低依次均为：弃土弃渣地 > 土质边坡 > 一般施工场地 > 土石混合边坡 > 岩质边坡 > 施工硬化地表,不同边坡的植被恢复生长状况方面,与土壤养分含量呈现相同的排序。各肥力指标中氨氮、硝氮、速效磷与植被生长情况的相关性最高,其次为速效钾、有机质,而与pH值相关性最低,说明氨氮、硝氮、速效磷对边坡植被生长效果的影响较大。[结论] 在不同边坡的土壤肥力状况中,弃土弃渣地表现最佳,而岩质边坡和施工硬化地表均表现较差,且土壤肥力中氨氮、硝氮、速效磷含量与植被生长情况紧密相关。     

雅砻江官地水电站生态护坡工程初期土壤肥力状况

以雅砻江官地水电站生态修复工程为例,对种植槽客土回填植草技术(ESS)和植被混凝土基材生态防护技术(CBS)在工程扰动区应用初期的土壤肥力状况进行了研究。通过选取4块具有一定代表性的生态恢复边坡样地及一块对照样地,对各样地的土壤肥力相关指标进行了测定,同时应用土壤标准综合级别法分析了土壤肥力的变化。结果表明,4块修复边坡样地土壤中有机质、全氮、全磷、速效氮、速效磷和速效钾含量均高于对照样地,同时土壤肥力水平亦显著高于对照边坡,其中右岸植被混凝土边坡肥力最高。说明生态护坡技术可有效改善官地水电站工程扰动区的土壤环境,其中以植被混凝土护坡技术效益最为显著。     

基于恢复生态学理论的裸露山体生态修复模式研究

裸露山体的生态修复是一个系统、综合、复杂的过程。结合裸露山体的生态修复特点,深入分析目前山体生态修复中的不足,并以恢复生态学理论为基础,提出了裸露山体生态恢复的规划设计方法以及要遵循的原则,以岩质边坡和废渣堆积体的生态修复为主要设计对象,提出了综合应用植被混凝土生态防护技术和防冲刷基材(PEB)生态护坡技术的裸露山体生态修复模式。     

晋西黄土残塬区坡面的日蒸散模型

 基于蒸发的物理机制,分析晋西黄土残塬区影响坡面蒸发的主导因子,提出了可以在不饱和土壤水分情况下应用的坡面土壤蒸发模型。认为坡度、坡向、土壤含水量、最高气温及植被盖度是影响坡面蒸发的主导因子。该模型对精确定量黄土残塬区小流域的生态需水及指导小流域水土保持生态环境建设具有重要意义。     

岩石边坡植被建植初期植被特征与土壤养分动态

为了解边坡生态防护工程植被建植初期植物特征与基质养分变化规律,依托实际工程,采用定位研究法,对3个不同坡向、坡度的边坡在人工植被建植后第1周年主要群落特征(物种、盖度和高度等)和土壤养分因子(如有机质和速效态养分元素)等每月进行跟踪测试。结果表明:1)边坡人工植被建植1周年内,植物植被的数量特征总体上存在明显的季节性变化,物种数在建植初期较多,在冬、春季物种数最低,第2年返青后逐渐增加。3个边坡存活部分盖度在冬春季平均盖度最低,到5月份随气温回升而突增,经建植周年后,平均盖度基本相同,在60%左右,群落存活部分平均高度的时间变异特征符合3次幂函数。2)3个边坡土壤速效态养分与有机质总体上在周年内有较为一致的变化趋势,但相互之间存在明显的差异,周年期末碱解氮和有效磷含量与建植初期相比有所下降,速效钾与有机质含量均高于建植初期。3)通过多元逐步回归分析,除有机质与植被群落数量特征无线性回归关系外,其余速效态的土壤元素均有一定的多元线性关系,然而边坡之间的同一土壤养分因子与植被群落特征相关指标之间的相关性差别较大,无法形成统一的解释方程,还需后续研究中综合考虑多种影响因子及其之间的交互关系。     

微立地因子植被恢复法在汶川地震植被重建中的应用

“5·12”汶川大地震造成的滑坡、泥石流、崩塌等地质次生灾害使当地的植被毁坏严重,微立地因子植被恢复法适用于地震灾区复杂的立地条件植被重建。在研究灾区植被破坏类型的基础上,将损毁植被的坡面划分为岩质边坡、土质边坡、土石边坡3种类型,并对不同坡面进行微立地因子类型划分,针对不同立地条件选择适宜植被恢复技术,促使灾区尽快植被重建,并为微立地因子植被恢复法的完善提供重要依据。     

高寒高海拔地区水电站施工扰动区生态修复技术及植物物种选择

以西藏雅鲁藏布江中游某在建水电站为例,通过对水电站各施工扰动区的施工特点、扰动情况及其立地条件的分析,进行扰动破坏面及其问题的归类梳理,结合项目区环境特点和国内外水电站工程施工扰动区生态修复技术,对岩质边坡、土(石)质边坡、弃土弃渣堆垫面、施工硬化地表和一般扰动面,分类提出了相应的生态修复措施和植物配置方式,并通过对项目区植被类型、物种的调查、研究,筛选出了可能适宜各施工扰动区的植物物种。最后结合项目特点探讨了高寒高海拔地区水电站施工扰动区植被生态修复的研究思路。     

庆丰采石场岩质边坡植被恢复状况和土壤特性研究

通过对庆丰采石场人工修复边坡的植被恢复状况和土壤特性进行调查,探讨了土壤理化性质及土壤酶活性与边坡植被恢复状况间的关系,以及影响土壤质量的主要因子,以期为岩石边坡的防护及生态恢复提供可以借鉴的理论依据。结果表明,在人工修复边坡上,无论是物种多样性、群落的结构及稳定性,还是土壤质量等,在短期内都难达到周边自然边坡的状态。土壤性质与修复边坡草本层及木本层植物的Margalef指数、Shannon—Wiener指数、Pielou指数间存在不同程度的相关性,其中草本层植物的物种多样性对土壤含水量、酸性磷酸酶活性、蛋白酶活性影响较大;木本层植物的物种多样性对土壤全磷质量分数、蛋白酶活性影响较大。土壤速效养分、土壤酶活性和土壤有机质等因子是影响土壤质量的主导因子。     

坡度和坡位对岩质边坡早期生态恢复土壤养分变异性的影响

通过对浙江省经过1a生态恢复的16个岩质边坡,在坡面没有植被和坡面环境形成交互发展的植被早期恢复进行研究,结果表明:(1)除45°～52°类型的边坡土壤有效磷含量为坡下>坡中>坡上外,其它3个坡度类型中全氮、全磷、全钾都呈现出较明显的坡中>坡下>坡上的分布规律。(2)在相似坡度及不同坡位条件下,全氮、全钾、有机质都没有表现出显著性差异。土壤养分多重比较出现较多差异的是有效态养分。(3)在相同坡位不同坡度条件下,对岩质边坡早期生态恢复的土壤养分进行多重比较,结果发现坡度在30°～52°的情况下,岩质边坡早期生态恢复演替中的土壤养分不会受到坡度的影响。     

裸露山体生态修复技术研究

裸露山体一般都是在工程建设过程中对自然山体开挖破坏而形成的,以边坡裸露、水土流失严重、土壤贫乏等为特征。裸露山体的生态修复是一个系统、综合、复杂的过程。在分析裸露山体生态修复特点的基础上,以北京至四平高速公路辽宁省朝阳段的岩质边坡生态修复实践为例,提出了综合应用植被混凝土生态防护技术的裸露山体生态修复模式。     

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.     

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.     

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.     

细菌、真菌及植物氮营养信号研究进展

氮素吸收代谢是所有生物生命活动的核心部分,因此,各种生物对氮的吸收与同化过程都有精细的调节。这种调节依赖于生物对体内氮素状况信号及体外（生长介质中）氮素信号的感受。过去几十年中,在细菌、真菌中已经对氮素营养信号有了较好的研究,而植物中则相对缓慢,但也有了一定的认识。本文重点比较细菌、真菌及植物中氮信号系统的组成,以期为进一步认识植物中的氮信号接受与转导系统提供启示。     

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.     

“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。