城市森林土壤肥力质量指标筛选——以南京市为例

土壤质量指标的筛选是科学地进行土壤质量评价的前提.本文以城市森林土壤为研究对象,探讨了土壤肥力指标的筛选方法.采集南京市不同功能区森林土壤样品(0 ～ 20 cm),分析了24个土壤质量指标.根据指标间的相关性和聚类分析结果,筛选出体积质量(容重)、黏粒含量、分散系数、可蚀性因子K值、水稳性指数、pH值、有机质、速效钾和纤维素酶活性,共9个指标作为城市森林土壤肥力质量评价的因子.     

黄土丘陵区空心村土地复垦后不同年限土壤肥力评价

为提升空心村土地整治质量,科学指导复垦耕地培肥及管理,以陕西省渭南市澄城县空心村为研究对象,采集了不同复垦年限村庄复垦前后土壤及周边荒草地土壤样品,选取物理、化学等8个评价指标,采用层次分析法确定因子权重,构建评价模型并进行了土壤肥力评价。结果表明:(1)复垦前后及周边荒草地土壤肥力指标的权重分别为容重0.028,质地0.75,pH值0.016,电导率0.041,有机质0.303,全氮0.159,速效磷0.159,有效钾0.159,CR<0.1,符合一致性检验;(2)村庄复垦前平均肥力指数为57.67,复垦后最高肥力指数为72.91,平均值达到68.59,不同利用的土壤综合肥力指数表现为:空心村复垦后>荒草地>空心村复垦前;(3)空心村复垦后土壤综合肥力指数与复垦年限正相关,复垦后肥力改良指数平均值为20.08%;(4)有机质对土壤肥力影响最大,与土壤综合肥力的指数相关系数R 2为0.5246,因子间影响大小表现为:有机质>速效钾>有效磷>全氮>电导率>pH值。综上,复垦可提升空心村土壤肥力,在复垦过程中调控有机质含量可较快提升土壤肥力。     

城市绿地土壤肥力质量综合评价方法初探

土壤肥力是影响城市绿地植物生长的关键因素,是绿地生态系统调节生态环境功能和发挥生态服务价值的重要保障。但目前对于绿地土壤肥力质量的研究较薄弱,关于绿地土壤肥力质量的综合评价缺乏统一的衡量标准,基本是沿用农业或林业土壤的评价方法,而城市绿地土壤受人为因素干扰严重,有其自身的特殊性。本文介绍了国内外土壤肥力质量评价方法及其研究现状,在对绿地土壤肥力质量评价指标、标准进行分析的基础上,构建了绿地土壤肥力质量综合评价方法,并利用该方法对上海绿地土壤肥力质量进行综合评价。结果表明:上海绿地土壤肥力质量以"一般"为主,肥力质量为"一般"的土壤面积占总土壤面积的比例高达89.25%,而肥力质量为"优"和"差"的土壤面积所占比例较少,这与其地上植物长势相一致。因此,本研究提出的土壤肥力质量综合评价方法可为城市绿地土壤质量标准体系的完善提供参考。     

基于产量的稻田肥力质量评价及障碍因子区划——以进贤县为例

土壤肥力质量评价及土壤肥力障碍因子分析,对于区域土壤利用和改良、指导农业生产结构布局具有重要意义。以江西省进贤县为研究区,通过水稻遥感解译测产,结合主成分分析进行土壤质量评价;采用综合指数法表征土壤肥力质量水平,分析该区域低肥力质量区域主要障碍因素,并进行障碍因子区划。结果表明,该地区土壤肥力质量评价的最小数据集(MDS)指标包括:有机质、阳离子交换量(CEC)、全钾(TK)、交换性钙(Ex.Ca)、容重、粉黏比;土壤质量综合指数与水稻产量相关系数达到0.73(p0.01),以当地水稻平均产量7.215 t hm~(-2)确定土壤质量综合指数阈值为0.65。分析得出,该地区影响土壤肥力的主要障碍包括有机质含量低和容重较大反映的低熟化度障碍、中量元素缺乏反映的酸化障碍、全钾含量低和高粉黏比反映的结构障碍等。根据障碍因素将研究区域划分为三大障碍区:东南部丘陵区主要障碍因子为酸化和土壤结构障碍;中西部低岗平原主要为土壤酸化障碍;北部滨湖区主要障碍为水稻土熟化程度低。通过对不同区域施行针对性改良措施有益于提高土壤肥力。     

遵义市典型茶园土壤肥力质量评价

为对贵州省遵义市典型茶园土壤的养分状况及其肥力质量进行综合评价,选用遵义市湄潭县和余庆县两大优势产茶区的6个茶园进行土壤样品的采集,通过对土壤9个肥力指标进行分析,并运用Fuzzy综合评价法进行等级评价。结果表明,湄潭县永兴茶园和余庆县松烟茶园的土壤肥力质量等级为Ⅲ级,处于中下水平;湄潭县的兴隆茶园、湄江茶园和余庆县的花山茶园、关兴茶园的土壤肥力质量等级为Ⅱ级,处于中上水平。     

利用数字土壤制图技术评价桉树林土壤肥力

精细的土壤肥力空间信息有助于森林质量精准管理。本研究以广西高峰桉树林场为研究区,利用数字土壤制图技术对研究区主要肥力因子空间分布进行数字制图,在此基础上,应用灰色关联度模型对桉树人工林土壤肥力进行了综合评价。结果表明:研究林场的土壤肥力质量较好,土壤肥力水平2级和3级林地面积占总面积的68.6%,1级和4级林地面积占26%,5级林地面积占5.4%;土壤肥力综合指数（IFI）具有较强的空间自相关性。本文提出的土壤肥力评价方法可用于森林土壤肥力质量空间分布的精准评价,为森林质量精准经营提供基础支撑。     

改进属性识别模型在秦巴山区土壤肥力评价中的应用

针对秦巴山区特点,选取安康市汉阴县作为研究区。利用GPS定位共在研究区内取得2420个耕层(0~20 cm)土壤样品。通过对土壤样品的全氮、有机质、碱解氮、有效磷、速效钾以及pH值等6项土壤肥力指标进行室内化验分析得到的结果,运用基于墒权和层次分析相结合的改进属性识别模型,对研究区内土壤肥力进行综合评价,并借助ArcGIS9.3绘制了土壤肥力空间分布图。结果表明:研究区肥力属中等偏上水平,其中北部及东南部低中山处肥力水平较好,中部及西南部低山丘陵地区肥力水平相对较差;改进的属性识别模型在进行评价时较为准确,且简单稳定,为土壤肥力的的综合评价提供有力的技术支撑。     

连续化肥减量配施有机肥提升植烟土壤肥力质量的综合评价

为准确评价连续多年化肥减量配施有机肥料对烤烟产量及植烟土壤综合肥力质量的影响,探究植烟土壤质量提升与烤烟绿色优质协同的化肥减量有机替代技术。以长期定位试验的第7 年数据为基础,运用因子分析法、相关系数法、内梅罗指数法,对不施肥(CK)、当地推荐常规施肥(100% 化肥,CF)、化肥减量20% 配施有机肥(OF)和配施生物有机肥(BIO)4 个处理的土壤肥力质量进行综合评价,并采用随机森林回归分析,探讨各土壤单项肥力指标对烤烟产量的解释度。结果表明,在连续7 年化肥减量20% 条件下,配施有机肥和生物有机肥均能降低烤烟青枯病和黑胫病的发病率和病情指数,提高烤烟经济性状、产量可持续性与稳定性,提高植烟土壤养分含量和土壤肥力综合质量。随机森林分析表明,植烟土壤有效磷、碱解氮、全氮是影响烤烟产量的决定因素,其解释率分别为19.66%、15.38%、12.07%。在3 种评价方法下,植烟土壤综合肥力指数IFI 值均表现为BIO>OF>CF>CK,BIO 和OF 处理较CF 处理分别提高23.03% ～ 31.75% 和4.92% ～ 7.94%。3 种评价方法的IFI 值与烤烟相对产量均呈显著或极显著正相关关系,相关系数大小依次为内梅罗指数法(0.884)> 因子分析法(0.867)> 相关系数法(0.747)。因此,连续多年化肥减量配施不同有机肥具有提高植烟土壤综合肥力质量和烤烟产量及质量的持续效应,且以化肥减量20% 配施生物有机肥的效果最优。     

西藏麦地卡湿地国家级自然保护区土壤肥力评价

以麦地卡湿地国家级自然保护区内土壤环境为研究对象,在完成样品现场采集、指标分析测定的基础上,对土壤各肥力指标的统计学参数进行研究,再进一步通过改进的内梅罗综合指数法对麦地卡湿地各类型土壤的肥力进行综合评价。结果表明:研究区土壤综合肥力系数(F)大小顺序为高山草甸土(1.72)＞高山灌丛草甸土(1.66)＝寒漠土(1.66)＞沼泽土(1.56)＞粗骨土(1.43);除了高山草甸土肥力等级属于肥沃以外,其余4种土壤均属于一般等级。多独立样本的非参数检验结果表示,研究区土壤容重、有机质、阳离子交换量、TOC、土壤水分以及土壤盐度的含量分布与土壤类型具有一定的相关性,而pH、速效钾、有效磷以及氨氮与土壤类型没有相关性。整体而言,地处高寒高海拔藏北区域的麦地卡湿地土壤肥力与西藏其他区域的耕地以及人工造林作业区土壤肥力相当。     

基于县域耕地资源管理信息系统的土壤综合肥力评价

应用ArcGIS 9.3,MapGIS 6.7和县域耕地资源管理信息系统,综合运用层次分析法、模糊数学法,将临泽县土壤图、土地利用现状图、行政区划图叠加求交生成评价单元图,进一步采用层次分析法确定土壤肥力评价因子的权重,对评价指标建立相应的隶属函数,通过计算其隶属度,求得每个评价单元的土壤肥力综合指标值,并依据综合值确定了土壤肥力等级及其面积。结果表明:临泽县土壤综合肥力较高的区域占临泽县耕地总面积的46.51%;土壤综合肥力中等区域占18.54%;土壤综合肥力一般区域占14.17%;土壤综合肥力较差区域占20.68%。利用县域耕地资源管理信息系统与GIS可以快速科学地对土壤肥力进行科学评价,与传统的评价方法相比,可以节约大量的人力、财力和物力。     

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。     

Aircraft operations near concentrations of birds in Antarctica: The development of practical guidelines

Aircraft operations have the potential to disturb and to impact negatively on bird life. A gradient of increasing behavioural response is evident in birds when exposed to increasing aircraft stimulus. The most major disturbance is likely to lead to impacts on the health, breeding performance and survival of individual birds, and perhaps bird colonies. A process of revision to policies on aircraft operations contained in management plans for a number of specially protected areas in Antarctica by the United Kingdom, accompanied by consultations made within the scientific community through the Scientific Committee on Antarctic Research (SCAR) and with operational interests through the Council of Managers of National Antarctic Programmes (COMNAP) resulted in new guidelines being adopted by the Antarctic Treaty Consultative Parties in June 2004. The principal recommendations of the guidelines are that bird colonies should not be overflown below 2000 ft (∼610 m) above ground level and landings within 1/2 nautical mile (∼930 m) of bird colonies should be avoided wherever possible. These guidelines are less stringent and less specific than those that were recommended by the SCAR specialist group on birds, and represent a compromise to accommodate operational needs. While the adoption of clear and consistent guidelines for the operation of aircraft in Antarctica is welcome in that this provides practical advice that is likely to reduce incidences of close aircraft/bird encounters, there remains insufficient knowledge of the interactions between aircraft and birds in Antarctica, and the consequent impacts on individual birds and on bird populations. It is important, therefore, that the guidelines adopted are considered interim, and should be kept under scrutiny with revisions made as new and improved research results appear.     

The abundance of heterocystous blue-green algae in rice soils and inocula used for application in rice fields

Summary Algal populations were quantified (as colony-forming units [CFU] per square centimetre) in 102 samples of rice soils from the Philippines, India, Malaysia and Portugal, and in 22 samples of soil-based inocula from four countries. Heterocystous blue-green algae (BGA) were present in all samples. Nostoc was the dominant genus in most samples, followed by Anabaena and Calothrix. In soils, heterocystous BGA occurred at densities ranging from 1.0 × 10² to 8.0 × 10⁶ CFU/cm² (median 6.4 × 10⁴) and comprised, on average, 9% of the total CFU of algae. Their abundance was positively correlated with the pH and the available P content of the soils. In soil-based inocula, heterocystous BGA occurred at densities ranging from 4.6 × 10⁴ to 2.8 × 10⁷ CFU/g dw (dry weight), comprising only a moderate fraction (average 13%) of the total algae. In most soils, the density of indigenous N₂-fixing BGA was usually higher than that attained by applying recommended rates of soil-based inoculum. Whereas research on the practical utilization of BGA has been mostly directed towards inoculation with foreign strains, our results suggest that attention should also be given to agricultural practices that enhance the growth of indigenous strains already adapted to local environmental conditions.Maître de Recherches ORSTOM (France), Visiting Scientist at IRRI