首都圈典型区土地退化的原因分析

 根据野外工作,在地理信息系统和遥感技术的支持下,探讨以防止风蚀为目的的首都圈的范围及主要特征,着重分析首都圈典型地区土地退化的机制、分布状况和防治的季节。结果表明,土地退化的主要原因是近年持续干旱少雨,土地利用的强度过大,以及在干旱季节里没有适当的防护措施等。建议采用适宜于首都圈的封育和垄耕等防治措施。     

Transformation of the Bryansk Paleosol in Microdepressions in the Center of the East European Forest-Steppe during the Maximum of Valdai Glaciation and in the Holocene

Eurasian Soil Science - Recent and Late Pleistocene soils of the central forest-steppe in the East European Plain have been studied. The main objective of the work is to reveal changes in the...     

Tomato glycoalkaloids: role in the plant and in the diet

Tomatoes, a major food source for humans, accumulate a variety of secondary metabolites including phenolic compounds, phytoalexins, protease inhibitors, and glycoalkaloids. These metabolites protect against adverse effects of hosts of predators including fungi, bacteria, viruses, and insects. Because glycoalkaloids are reported to be involved in host-plant resistance, on the one hand, and to have a variety of pharmacological and nutritional properties in animals and humans, on the other, a need exists to develop a better understanding of the role of these compounds both in the plant and in the diet. To contribute to this effort, this integrated review presents data on the history, composition, and nutrition of tomatoes, with special focus on the assessment of the chemistry, analysis, composition, nutrition, microbiology, and pharmacology of the tomato glycoalkaloids comprising alpha-tomatine and dehydrotomatine; their content in different parts of the tomato plant, in processed tomato products, and in wild and transgenic tomatoes; their biosynthesis, inheritance, metabolism, and catabolism; plant-microbe relationships with fungi, bacteria, viruses, insects, and worms; interactions with ergosterol and cholesterol; disruption of cell membranes; tomatine-induced tomatinases, pantothenate synthetase, steroid hydroxylases, and cytokines; and inhibition of acetylcholinesterase. Also covered are tomato-human pathogen relationships and tomatine-induced lowering of plasma cholesterol and triglycerides and enhancement of the immune system. Further research needs in each of these areas are suggested. The overlapping aspects are discussed in terms of general concepts for a better understanding of the impact of tomato glycoalkaloids in the plant in general and in food in particular. Such an understanding can lead to the creation of improved tomatoes and to improved practices on the farm and in the consumption of tomatoes.     

Coregionalization of trace metals in the soil in the Swiss Jura

The provenance of trace metals in soil, whether from the parent material or from pollution, is rarely known with certainty, and the metals' history must usually be pieced together from fragmentary statistical information. This is particularly true in the Swiss Jura where the concentrations of several heavy metals around La Chaux de Fonds exceed the statutory recommended thresholds for safety. The topsoil of the 14.5-km² region was sampled on a square grid at 250-m intervals with additional nesting with distances of 100 m, 40 m, 16 m and 6 m. The concentrations of seven potentially toxic metals, namely Cd, Co, Cr, Cu, Ni, Pb and Zn, were measured. Their coregionalization could be represented by a linear model consisting of a nugget component plus two spherical structures with ranges of 0.2 km and 1.3 km. The short-range component dominated the variograms of Cd, Cr, Cu and Pb; the long-range component dominated those of Co and Ni; the variogram of Zn combined the two in approximately equal proportions. The coregionalization matrices contain moderate correlation among the nugget and the short-range components, notably between Cu and Pb, between Cd and Zn, and between Cr, Ni and Zn. The strongest correlations are at the long range between Co, Cr and Ni, and to a somewhat smaller degree between Zn and Co. Analysis of variance showed Co and Ni to be related to geology, and to the Argovian formation in particular. The indicator variogram of this formation has also a short-range component. The analysis also showed Cr and Cu to be related to land use (in different ways). Copper and Pb are strongly correlated to one another and distinct from the five other metals. The long-range structure is almost certainly a geological effect, whereas the one of short range probably results from both the geology and human activities.     

Minerals in the three-component combination of agrochernozems in the Kamennaya Steppe

Properties and mineralogy of fine fractions separated from agrochernozems forming a three-component noncontrasting soil combination in the Kamennaya Steppe have been characterized. The soil cover consists of zooturbated (Haplic Chernozems (Clayic, Aric, Pachic, Calcaric)), migrational-mycelial (Haplic Chernozems (Clayic, Aric, Pachic)), and clay-illuvial (Luvic Chernozems (Clayic, Aric, Pachic)) agrochernozems. All the soils are deeply quasi-gleyed because of periodical groundwater rise. The mineralogy of the fraction <1μm includes irregular mica–smectite interstratifications, di- and trioctahedral hydromicas, imperfect kaolinite, and magnesium–iron chlorite. The profile distribution of these minerals slightly varies depending on the subtype of spot-forming soils. A uniform distribution of clay minerals is observed in zooturbated agrochernozem; a poorly manifested eluvial–illuvial distribution of the smectite phase is observed in the clay-illuvial agrochernozem. The fractions of fine (1–5 μm) and medium (5–10 μm) silt consist of quartz, micas, potassium feldspars, plagioclases, kaolinite, and chlorite. There is no dominant mineral, because the share of each mineral is lower than 35–45%. The silt fractions differ in the quartz-to-mica ratio. The medium silt fraction contains more quartz, and the fine silt fraction contains more micas.     

Accumulation of chemical elements in the raised peatbogs of the subtaiga Trans-Urals in the Holocene

The results of studying the variability of the geochemical parameters of the layers of the Sartamskii upland peatbog in the south of Tyumen oblast based on the radiocarbon time scale are given. Four basic types of peat and stages of peat deposits formation in the Holocene are distinguished: the organomineral layer of the sediments in a paleolake (up to 5065 ± 60 years ago), the low moor layer (4300–4900 years ago), the transitional layer (3100–4300 years ago), and the high moor peat (250–3100 years ago). The upper peat layer (last 200–300 years) significantly differs from its main portion; in particular, it is characterized by an increased ash content and the accumulation of a number of elements. The relationship between the various characteristics of the deposit is analyzed using principal component analysis, and the conditions of the formation of the peat deposit in different time periods are estimated, including the climatic conditions (in relative units). The anthropogenic signal of the accumulation of some elements in wetland systems is identified.     

20世纪陇南洪涝灾害特征分析

历史上发生的自然灾害可以作为今后防灾减灾的重要参考资料。通过整理统计历史文献资料,对陇南20世纪洪涝灾害的时空分布特征、区域差异性进行分析、灾害序列趋势持续性计算。结果表明:20世纪陇南共发生洪涝灾害33次,平均3.3年1次;中度灾害最多,为11次,特大灾害共发生3次;灾害多发生在1949年到1990年,月份主要集中在6、7月,连年洪涝灾害也有发生;本区内的西和为高发区,礼县、两当、武都次之;徽县、成县最少。R/S分析法计算结果表明陇南市洪涝灾害时间序列具有长期相关的特征,未来有增加的趋势。     

库区周边湿地开发利用途径探讨

对三峡库区的湿地生增进行了分析研究,由水库的调度方式形成的库区周边湿地,可分为四个区域段,不同的区域段可采用相适宜的开发利用方式,这种因地制宜的湿地生境开发利用途径对缓解库区人地矛盾,改善库区生态环境和景观将发挥积极作用 。     

Inferences from fluctuations in the local variogram about the assumption of stationarity in the variance

Geostatistics is commonly used to describe and predict the variation of soil properties over the landscape. However, many geostatistical methods require the assumption that our observed data are a realization of a random function which is intrinsically stationarity. Under stationarity, observations of a single realization of the random function at different positions can be treated as a form of replication. There are various ways in which a random function may breach the assumption of intrinsic stationarity and numerous geostatistical techniques have been developed that are able to cope with some forms of non-stationarity. What is currently needed is a set of diagnostic tools capable of detecting and identifying when data cannot plausibly be treated as a realization of a process which is stationary in the variance.In this paper, we propose an inferential method that can identify when stationarity in the variance cannot plausibly be assumed. The basis of our approach is to obtain a model for the random function under the assumption of intrinsic stationarity. If the global dataset can be regarded as a realization of a Gaussian process (perhaps after transformation), then the global variogram is sufficient for this purpose. By using a window-based method to locally estimate variograms, we can define some statistic of homogeneity of the sample variation of the data. This allows us to obtain a sample distribution for this statistic, under the null hypothesis of intrinsic stationarity, by generating multiple realizations of the postulation random function at the original sample points using Monte Carlo methods and recomputing the statistic for each realization. We selected as statistics the interquartile ranges of: i) the spatial dependence ratio (s), the proportion c₁ / (c₀ + c₁), ii) a distance parameter (a), which is the maximum lag over which the random function is autocorrelated for variograms like the spherical, and iii) the local variances (v; c₀ + c₁), where (c₀) is the nugget component and (c₁) the spatially structured component. We demonstrated this method using data from the large scale sampling (n = 1341 over 8248 km²) of the Florida Everglades, United States.     

Changes in soil respiration in the course of the postagrogenic succession on sandy soils in the southern taiga zone

The dynamics of the CO₂ emission from sandy soils in the course of the postagrogenic succession in the southern taiga zone were studied. We measured total emission from the soil surface and, separately, respiration from the litter and mineral soil horizons during the warm (snowless) seasons of 2010 and 2011 on differently aged fallow plots: 0 years (cropland) and 7, 23, 55, 100, and 170 years. It was demonstrated that changes in the CO₂ emission in the course of the succession have a nonlinear pattern: the emission sharply increases in the first decade, then somewhat decreases, and then gradually increases again up to the maximum values. This is explained by the dependence of the rate of the emission on the soil carbon pools (humus + litter + underground phytomass) that are also subjected to nonlinear changes. Initially, the emission is mainly due to mineralization of labile organic substances added to the plowed soils in the form of organic fertilizers. Then, in parallel with a gradual increase in the pools of litter and underground phytomass, the total pool of soil organic carbon increases, and its role in the emission becomes more pronounced. The seasonal dynamics of the soil respiration are mainly controlled by the soil temperature; the soil moistening plays an important role only during the initial meadow stage of the succession.     

下层土壤反硝化作用的研究

在夏玉米生长期间 ,采用乙炔抑制 -原状土柱培养方法研究了北京褐土下层 (15～ 6 0cm)土壤的反硝化作用 ,并探讨影响该层土壤反硝化作用的主要因素。试验结果表明 ,施氮量越高 ,反硝化量越大。随着土壤层次的加深 ,反硝化量呈直线下降 ,但在亚表层土壤 (15～ 30cm)反硝化值仍保持了较高的量 ,约相当于表层的 10 .7%～ 33.5 % ;下层土壤 (15～ 6 0cm)的总反硝化量约相当于表层土壤的 14%～ 51%。加入碳源无论对表层土壤还是下层土壤 ,其反硝化损失氮量大大增加 ,尤其是对下层土壤增加的趋势更为明显。在计算夏玉米季土壤反硝化损失氮量时 ,如果忽略下层土壤的反硝化作用 ,肯定会低估其数值     

21世纪我市可持续农业发展的耕地资源问题探讨

本阐明了耕地资源是可持续农业发展的基础，并提出利用耕地资源的对策，为农业可持续发展提供参考依据。     

Seasonal changes in the communities of microorganisms and algae in the litters of tree plantations in the steppe zone

Specific structural and dynamic parameters of communities from various ecological and trophic groups of microorganisms and algae in the litter of artificial tree stands were studied using the example of the Staro-Berdyansky Forest in the steppe zone of Ukraine. The composition of the communities was shown to vary by seasons and depend on the forest-forming woody species. In spring, in all the litters, the maximal number of actinomycetes and aminotrophs was recorded; in the leaf litter, the number of phosphate-mobilizing organisms was also the largest. In summer, the development of cellulolytic organisms, ammonifiers, and nitrogen-fixers was intensified; in autumn, the number of micromycetes and oligotrophic organisms decreased. The composition of dominants, the species richness of algae and their abundance also varied by seasons. Representatives of the Chlorophyta division predominated. The highest species richness of algae was characteristic of the spring litter samples, and their number, for the spring and autumn ones. The positive correlation was established between the numbers of micromycetes and oligotrophs, micromycetes and algae. The negative correlation was found between the numbers of micromycetes and actinomycetes, cellulose-decompose bacteria and algae in the litters.     

Evolution of forest pedogenesis in the south of the forest-steppe of the Central Russian Upland in the Late Holocene

The Late Holocene stage of forest pedogenesis has been studied on the interfluves along river valleys in the forest-steppe zone of the Central Russian Upland. The development of gray forest soils from the former chernozems as a result of the Late Holocene advance of forest vegetation over steppes is discussed. It is argued that the climatic conditions of the Subatlantic period were unstable, so that multiple alternation of forest and steppe vegetation communities took place. This specified a complex character of soil evolution upon contrasting substitution of forest pedogenesis for steppe pedogenesis. On the interfluves near the natural drainage network (balkas, ravines, and steep slopes of river valleys), the climate-driven dynamics of forest and steppe vegetation with corresponding changes in the character of pedogenesis could take place during the entire Holocene, which is reflected in a lower thickness of humus profiles and deeper leaching of carbonates from chernozems of the Early Iron Age in comparison with their analogues formed under steppe cenoses in central parts of the interfluves. Two variants of the evolution of gray forest soils can be suggested: the pulsating evolution typical of balkas and interfluves near river valleys and the continuous progressive evolution typical of automorphic (plakor) positions in central parts of the interfluves.     

豫中黄土地区全新世土壤剖面成壤环境变化研究

通过对河南新郑黄土-土壤剖面的野外考察及室内的磁化率、烧失量、碳酸钙及粒度分析研究,认为:豫西山地山前丘陵台地的完整黄土-土壤剖面,是在气候波动变化的条件下形成的。全新世气候的变化,导致了以风尘堆积为主的成黄土期与以风化成壤作用为主的成壤期互相更迭。在全新世早期,风尘堆积旺盛,形成了过渡性黄土层(Lt),在8500aB.P.～3100aB.P.的全新世大暖期,发育了浊红棕色古土壤(S0)。这一时期降水丰沛,土壤水分充足,导致了古土壤层(S0)及其以下的过渡层(Lt)、马兰黄土层(L1)顶部都受到了明显的淋溶作用影响,而完全脱钙。3100a B.P.之后,气候恶化,沙尘暴活动显著增强,加之黄河下游人类活动影响不断加剧,黄泛平原风沙活动十分强烈,风尘堆积形成了沙质黄土(L0)。1500aB.P.以来,近代黄土持续堆积,由于气候的转暖与人类农业耕作影响在持续堆积的近代黄土L0表层形成了现代土壤(TS)。     

Changes in the physical properties of soils in the Kamennaya Steppe under the impact of shelterbelts

The physical properties of ordinary chernozems and meadow-chernozemic soils under different land management practices (maple, larch, birch, and pine sections of the shelterbelts; continuous (since 1959) fallow; and arable field (since 1952)) were studied in the Kamennaya Steppe. The soils had favorable physicochemical properties, light clayey texture, and high microaggregation independently from the type of land management. The long-term impact of the shelterbelts improved the soil structure in the upper part of the humus horizon: the content of agronomically valuable aggregates increased, the content of coarse aggregates (>10 mm) decreased, the aggregation coefficient increased by 3.7–4.3 times, and the water stability of the aggregates became by 8–12% higher. The soils under the shelterbelts were characterized by minimum values of the bulk density and solid phase density and by maximum values of the total, active, and air porosities. At the same time, no considerable differences between water reserves in the studied range of soils were detected. The ratio of the optimum productive water range to the active (productive) water range (OPWR/AWR) within the upper soil meter varied from 0.42–0.44 to 0.45–0.54. This points to changes in the character of perched water: the content of intra-aggregate capillary-perched water decreases, and content of film perched water increases down the soil profile.     

近50年博斯腾湖水位变化特征分析

以干旱区博斯腾湖为研究对象,依据博斯腾湖1956—2012年期间的水位监测数据,采用小波分析及MannKendall(M-K)趋势检验等统计学方法,揭示了近50a博斯腾湖水位变化趋势及规律。结果显示:博斯腾湖1956—2012年水位变化分为3个阶段下降(1956—1987年)—上升(1988—2002年)—下降(2003—2012年),其中1956—1987年水位下降了3.39m;1988—2002年上升了3.7m;2003—2012年再次下降了3.21m。水位总体上呈现出显著的下降趋势,且通过了α=0.05时的显著性检验。就其周期性变化规律而言,博斯腾湖水位存在18a的主周期,而38a的周期由于水位资料序列有限难以确定,需要更长的资料序列进行分析验证。     

Changes in the humus status and the structure of the microbial biomass in hydrogen exhalation places

The exhalation of hydrogen out of the earth’s deep sediments in the areas usually confined to tectonic fractures has been investigated. In places of hydrogen exhalation, ring-shaped structures of subsidence are formed. They are well identified on satellite images. The concentrations of molecular hydrogen measured in the field exceed to a great extent its probable production in soils. The soils influenced by two factors—a flux of molecular hydrogen and temporary waterlogging—are shown to degrade rapidly. The humus content decreases by 2–3 times; the optical density of the humic acids drops significantly; and the humus distribution, according to the morphological features, points to its high mobility. On the whole, hydrogen emissions inhibit the microbial activity resulting in a drastic decrease of the total microbial biomass and a greater contribution of bacteria to its structure. In a model experiment with hydrogen passing through a soil column, the bleaching of the soil by 2% and some reduction in the optical density of the humic acids were recorded.     

Composition of the benthos in relation to pH in the LaCloche lakes

In the LaCloche Mountains of Ontario, 11 lakes spanning the pH range 4.8 to 6.7 were sampled for benthic organisms. Sixty sediment cores were collected from each lake, organisms >0.5 mm were separated and 25 taxa were identified. The number of taxa present was correlated negatively with [H⁺]: Y=23.2?4.27 × 10⁵ ×, r²=0.61, p<0.005. The density of all organisms was not correlated with lake pH. Six taxa: gastropods, pelecypods, daphnids, ephemeropterans, amphipods and ceratopogonids, either were reduced in abundance or absent from the more acid lakes. Bosminids and acari were more abundant in lakes of pH 5.0 to 5.5. The densities of the remaining taxa, notably chironomids and oligochaetes, appeared to be independent of pH over the range 4.4 to 6.7. These results are discussed in relation to the hypotheses which have been advanced to explain the differences observed in benthos distribution between lakes in Europe and in North America.