水氮耦合对苹果光合特性和果实品质的影响

通过不同灌水量和施氮处理,研究水氮耦合对红富士苹果光合特性及品质的影响。结果表明:红富士苹果的光合特性在不同水肥组合下的变化不同,其光合作用存在明显的“午休”现象。中水高肥和高水高肥的肥水组合对光合速率的保持有一定的作用。低水中肥的肥水组合的蒸腾速率最低,保水效果最好。中度水分供应条件下,施用较多的氮肥可以提高气孔导度利于光合的进行。肥水管理以灌溉量5250m³/hm²、氮肥施用量600kg/hm²方案能获得较高的品质效益。     

圆叶决明的栽培技术及其防蚀培肥的功效

经多年种植结果表明，圆叶决明具有覆盖率高、固氮率高、适应性和抗逆性强等特点，是山地茶果园水土流失地套种的先锋作物，本文阐述了圆叶决明的特征特性、栽培技术以及防治水土流失、培肥地力的作用。     

Soil organic matter and the adsorption and decomposition of the herbicides atrazine and linuron

Soil was subjected to a variety of treatments so as to provide a series of materials with different organic residues. These preparations were inoculated with an aqueous extract of untreated soil, then incubated at 20°C with atrazine or linuron and rates of herbicide degradation were followed. The rates were lowest when virtually all the organic matter had been removed by peroxidation. The most rapid break-down occurred in samples which had been successively extracted with ethanol + toluene, hot water, dilute acid and dilute alkali. It is suggested that the organic residue left after this sequence contained hydrolysed materials that were easily metabolized and hence could support the most active microbial population. There was no relationship between extent of adsorption and decomposition rate.     

Mobility and breakdown of asulam in the soil and the possible impact on the environment

Asulam reaching the soil either directly as spray drift or as rain washings from bracken fronds would, due to its rapid mobility in soil, be expected to leach down the soil profile into the drainage water and thereby contaminate streams and water catchments. The mobility of asulam in soil is influenced by pH, where undissociated asulam will leach less rapidly than the associated form (asulam pK_a 4·82). This is particularly relevant in the case of bracken as it can grow satisfactorily over a wide range of pH values (3·6 – 7·6). Adsorption coefficients expressed as Kd values [(μg asulam/g soil)/(μg asulam/ml solution)] were 2·54, 1·94 and 0·96 at pH readings of 4·0, 4·3 and 4·9 respectively. Another factor involved, the breakdown of asulam, was shown to be temperature dependent, 30·95, 7·65 and 2·50% remaining after 28 days at 5, 18 and 25°C respectively, thus underlining the influence of geographical regions and climatic conditions on asulam behaviour.     

甘蔗节间蛋白质含量与生长发育关系的研究

选用8个不同基因型的甘蔗，即粤糖86-368、新台糖16号、农林8号、拔地拉、割手密和从甘蔗杂交后代F1中选出的3株种茎的无性系(单株)。在甘蔗伸长初期，测定其 2节间至 8节间的长度、茎径，同时取 3、 5、 8节间，测定其可溶性蛋白质、细胞壁离子型结合蛋白质、细胞壁共价型结合蛋白质及可溶性总糖的含量。结果表明：从 2节间到 8节间，不同基因型的节间长度的变化极为相似，除割手密外，其它基因型甘蔗的节间长度都在 6节达到最长；但其茎径在 6节间以后仍保持稍微的增粗。从 3节间到 5、 8节间，所有基因型的三类蛋白质含量都逐渐下降，而可溶性总糖含量都逐渐提高。其中，三个节间较粗的基因型即拔地拉、粤糖86—368和无性系3号，其三类蛋白质含量相对较高，而可溶性总糖含量相对较低。     

Solods of the Baraba Lowland and the Priobskoe Plateau: Their properties and genesis and the methods of their diagnostics

The properties, hydrological features, and genesis of the solods occurring in the Baraba Lowland and Priobskoe Plateau were studied. Methods for determining the hydromorphism degree are considered; the features of the similarity and differences between the solods and other soils with textural profile differentiation are shown. Depending on the reasons for the waterlogging, the solods should be divided into two groups: the solods of groundwater waterlogging and the solods of surface waterlogging. Criteria for their discrimination are suggested: the ratio between the contents of the clay fraction in the parent rock (or in the B2 horizon) and that in the A2 horizon, the changes in the pH values along the soil profiles, and the content of nonsilicate iron compounds. The solods studied are shown to be formed under the conditions of a stagnant-percolative regime and gleying. This circumstance is an obligatory and sufficient reason for the formation of the light-colored acid eluvial (A2) horizons. According to some basic properties of the soil solid phase (the acidity, the total chemical composition, and the clay pattern in the eluvial part), the gleyed solods are close or identical to the gleyed soddy-podzolic and gleyed chernozem-like podzolic soils. At the same time, the solods differ from the gleyed chernozem-like podzolic soils by their thicker A1 (or Ap) horizon and their higher humus content (5–7%).     

图书馆与大力发展文化创意产业之间的关系

党的十七届六中全会提出了要推动文化创意产业成为国民经济的支柱性产业。图书馆拥有丰富的文献资源和信息服务能力,在为文化创意产业项目提供信息服务的同时,应提升自身形象,谋求更大发展。     

Glyphosate and the response of the soil microbiota

Limited information on the effect of glyphosate (N-phosphonomethylglycine) on soil microorganisms justified an inquiry into the response of soil actinomycetes, bacteria and fungi in terms of their respiration, and sensitivity of isolates. Low concentrations of glyphosate had little effect on total populations of these organisms during the 214-day experiment, while high concentrations initially increased actinomycete and bacterial numbers by 2 and 1$\text{case1}\text{2}$ logs, respectively. The stimulation was followed by a decline and fluctuation showing a gradual increase in numbers. The respiration rates of the soil microbiota in soil suspensions, showed some irregular stimulation and retardation with up to 10 μg glyphosate ml^?1. In contrast high doses suppressed O₂ uptake by the microbiota. Fungi were the least affected. Pronounced inhibition of actinomycete and bacterial respiration was in agreement with the results from isolate replication. The results indicated both stimulation and inhibition of O₂ uptake by some organisms within these groups. In contrast to some reports of limited, short-term inquiries these results showed considerable effects of glyphosate on soil microorganisms.     

突出重点 抓好落实 加快黄河上中游地区水土流失防治步伐

对1999年以来黄河上中游地区生态建设的成绩给予了充分肯定。结合当前水土保持工作面临的各种内外部条件,认为落实科学发展观,推进水土保持工作,最根本的目标就是实现水土资源的可持续利用和生态环境的可持续维护,以此支撑经济社会的可持续发展。围绕“两个可持续”,指出当前和今后一段时间内黄河上中游地区水土保持应进一步抓好以下几项重点工作:加强水土流失区的坡改梯建设;实施好黄土高原淤地坝工程;重视制定生态修复的配套政策,确保其顺利推进;强化水土保持监督执法;注重水土保持社会参与和激励机制、项目管理的监督制约机制以及水土保持生态补偿机制的创新和完善;做好“十一五”规划、水土流失监测评价等水土保持基础工作。     

Mineralogical composition of the clay fraction and micromorphology of the Middle and Late Pleistocene loesses and paleosols in the center of the East European Plain

The mineralogical composition of the clay fraction and microfabrics of the cryogenic soil-loess sequences of the Middle and Late Pleistocene ages have been studied near the northern boundary of loess sediments on the East European Plain. Poorly ordered mixed-layered mica-smectitic minerals with different portions of smectitic layers predominate in the clay fraction; di-and trioctahedral hydromicas occupy the second place. The clay fraction also contains chlorite, clay-size quartz grains, and feldspars. Individual smectite is present in some of the samples. Interstadial chernozem-like paleosols are specified by the higher content of clay, the maximum concentration of smectitic layers in the mixed-layered minerals, and the presence of individual smectite. The clay fraction in the profiles of interglacial paleosols is sharply differentiated: in the eluvial part, it is depleted of smectite and enriched in kaolinite, hydromica, and clay-size quartz. These features allow us to suppose that interglacial paleosols were subjected to podzolization processes. According to the mineralogical indices, Middle Pleistocene paleosols can be differentiated into those subjected to lessivage (the Kamenskii interglacial paleosol) and podzolization (the Inzhavin interglacial paleosol).     

略论西北地区水资源开发利用与水土保持相互作用

水资源的配置既要满足经济用水的需要，也要充分考虑生态用水和环境用水。水土保持生态建设也必须充分考虑水资源的承载能力，以水定治理开发。对于西北地区来讲。箱好水土保持生态建设的关键是科学调控雨水径流，从而提高有限降水资源的利用率。     

Geoarchaeology and the search for the first Americans

Research into the origins and subsequent development of the first American cultures (“Paleoindians”), in particular the timing and place of their arrival, has provoked heated, contentious debates in North American archaeology since the 19th century. Many of the questions in this archaeological puzzle are fundamentally geological and thus many of the answers have come from the geosciences, including geology, geography, and soil science, and at a wide range of spatial scales. Stratigraphy, perhaps the most basic principle in both archaeology and geology, first established the antiquity and chronology of the earliest artifact assemblages at sites such as Folsom and Clovis in New Mexico by demonstrating clear association of artifacts and Pleistocene fauna. Geologists and paleontologists further provided age estimates of sites in the absence of other forms of numerical age control. Geologists also were prominently involved in developing the radiocarbon method and applying it to Paleoindian sites. Many Paleoindian sites also yielded not only extinct fauna, but stratigraphic records with evidence of markedly different depositional environments in the past. These sites were inviting to geologists because many investigators had backgrounds in Pleistocene paleontology. The ancient fauna and the striking contrasts between past and present depositional environments drew the attention of archaeologists and earth scientists alike who recognized the paleoenvironmental implications. At regional, subcontinental scales the peopling of the New World has been a question revolving around lowered seas levels and fluctuating glacier margins. Modeling sea-level changes and the paleogeography of the “Bering Land Bridge” and the high-precision dating of ice retreat over Canada is helping to understand the environmental conditions faced by Native American forbears in Beringia and the environment, route(s), and timing of their entry into North America.     

Micromycetes in the rhizosphere, the rhizoplane and the roots of wheat under conventional and zero tillage

The effects of different soil cultivation on the occurrence of micromycetes in the rhizosphere, at the root surface (rhizoplane) and in the root interior were investigated in a long-term field experiment on a chernozem soil at Hru?ovany u Brna, in an area of the corn production type. Cereals were grown as a monoculture with conventional and zero tillage.Soil cultivation had no significant effect on the total number of species of micromycetes. Zero tillage resulted in an increased number of colonies isolated from the rhizosphere and the rhizoplane. On the contrary, conventional tillage resulted in an increased number of isolates from the roots interior. The abundance of individual species of micromycetes varied somewhat in individual years, larger differences being observed with the saprophytic rather than with the parasitic (Gaeumannomyces graminis, Fusarium) species. In wheat roots, Gaeumannomyces graminis was more common under conventional tillage that under zero tillage, while the reverse was true of Fusarium.     

陶寺古城形成与选址的环境与文化背景研究

临汾地区的陶寺遗址是黄河中游地区发现的夏代之前的都邑性古城。通过对临汾地区和陶寺遗址区域自然环境条件的研究和分析,结合区域考古学文化的发展,探讨了陶寺古城的形成原因以及选址影响因素。研究表明:全新世中期至陶寺文化时期,临汾盆地由于较为暖湿的气候条件、良好的土地资源和水资源条件,区域内的新石器文化获得了持续发展。仰韶文化中晚期,我国中原地区及北方地区的新石器文化均获得了快速发展。临汾地区不仅处于这一文化发达区域的中心位置,而且地处我国中原核心地区同北方和东北地区文化交流的重要通道上,同时也是我国东西向文化交流的通道之一,由于这种优越的地理位置,临汾地区的区域文化优势地位逐渐显露出来。相当于龙山文化晚期的陶寺文化时期,相较其他中原核心地区,临汾地区受水患影响较小,区域文化的强势地位进一步凸显,因而成为都邑性古城兴起之地。陶寺文化时期,古城所在的黄土台地冲沟尚未下切,南河和宋村沟均为宽浅的沟谷型河流,高于平原地面的黄土台地既有利于设防又能有效规避水患,在塔儿山上游地区拥有较大汇水面积的南河和宋村沟又可以提供丰富稳定的水源,因而是营建古城的理想场所。     

Simulating the carbon flux between the terrestrial environment and the atmosphere

A Terrestrial C Cycle model that is incorporated in the Integrated Model to Assess the Greenhouse Effect (IMAGE 2.0) is described. The model is a geographically explicit implementation of a model that simulates the major C fluxes in different compartments of the terrestrial biosphere and between the biosphere and the atmosphere. Climatic parameters, land cover and atmospheric C concentrations determine the result of the dynamic C simulations. The impact of changing land cover patterns, caused by anthropogenic activities (shifting agriculture, de- and afforestation) and climatic change are modeled implicitly. Feedback processes such as CO₂ fertilization and temperature effects on photosynthesis, respiration and decomposition are modeled explicitly. The major innovation of this approach is that the consequences of climate change are taken into account instantly and that their results can be quantified on a global medium-resolution grid. The objectives of this paper are to describe the C cycle model in detail, present the linkages with other parts of the IMAGE 2.0 framework, and give an array of different simulations to validate and test the robustness of this modeling approach. The computed global net primary production (NPP) for the terrestrial biosphere in 1990 was 60.6 Gt C a^?1, with a global net ecosystem production (NEP) of 2.4 Gt C a^?1. The simulated C flux as result from land cover changes was 1.1 Gt C a^?1, so that the terrestrial biosphere in 1990 acted as a C sink of 1.3 Gt C a^?1. Global phytomass amounted 567.5 Gt C and the dead biomass pool was 1517.7 Gt C. IMAGE 2.0 simulated for the period 1970–2050 a global average temperature increase of 1.6 °C and a global average precipitation increase of 0.1 mm/day. The CO₂ concentration in 2050 was 522.2 ppm. The computed NPP for the year 2050 is 82.5 Gt C a^?1, with a NEP of 8.1 Gt C a^?1. Projected land cover changes result in a C flux of 0.9 Gt C a^?1, so that the terrestrial biosphere will be a strong sink of 7.2 Gt C a^?1. The amount of phytomass hardly changed (600.7 Gt C) but the distribution over the different regions had. Dead biomass increased significantly to 1667.2 Gt C.     

Sulfur and iron influence the transformation and accumulation of mercury and methylmercury in the soil-rice system

Journal of Soils and Sediments - Much attention is directed to the accumulation of mercury and methylmercury (MeHg) in rice grown on Hg-contaminated paddy fields, since they pose a risk to the...     

水土的合理保持与颐和园周边环境的保护

颐和园是清代北京西郊皇家园林区的重要组成部分,它的兴建与当地独特的自然环境密不可分,而当地独特的自然环境又与水土的合理保持关系密切,克服水土失衡是颐和园周边环境保护的重要方面.