基于芯样的沥青路面抗剪性能评价指标

以沥青路面的取芯芯样为研究对象,采用动载单轴贯入试验方法,通过有限元理论分析和对比试验确定了试验条件和参数,确定以一定作用次数下的贯入深度作为指标,能够较好地评价沥青路面的抗剪切性能.     

全区造林核查数据处理软件的研制

文章从全区人工造林更新实绩核查的实际出发 ,论述了全区造林核查数据处理软件的研制方法和过程 ,并详细介绍了软件的功能及使用效果。该软件的研制和使用对全区造林核查管理工作具有十分重要的价值。     

Soil Salinization in Some Irrigated Areas of the Kingdom of Bahrain

Monitoring and assessment of agricultural land degradation is of vital importance for better land and water management planning and reclamation. It requires setting baseline information and basic analysis at specific time and space. About 33 geo-referenced soil sampling spots were selected in two agricultural production locations in the Kingdom of Bahrain to assess the status and preliminary causes of land degradation. Soil samples were taken from 13 sites in Diraz location while 19 samples were taken from Budayyi location. The samples were taken to 90 cm depth at 30 cm intervals. Standard procedures were followed to determine soil physiochemical properties. In addition, field observations on farm condition, distance from the sea, method of irrigation and irrigation water source were taken. Some of the soil samples were deliberately taken from outside the irrigated basins among trees compared with samples taken from inside the actively growing area for comparison. The results indicated that the salinity level was significantly （P 〈 0.001） higher at the 0-30 cm soil depth compared with 30-60 cm or 60-90 cm depths in both locations. The distance from the sea did not show clear correlation with surface soil salinity in Budayyi area compared with Diraz. Both locations showed significantly higher salinity levels on samples taken outside the actively growing areas compared with those taken from within. The effect is more prominent at the 0-30 cm depth. The observed variability on salinity levels may be attributed to farm management practices and deteriorating quality of ground water. Thus, agricultural land degradation in Bahrain cannot be attributed to ground water deterioration alone. The use of tertiary treated sewage water （TSE） may ease the pressure on ground water, but the pH of the TSE should be carefully monitored and managed with proper studies on leaching requirements to avoid further salinity complications.     

Multi-element analysis of soils and sediments by wavelength-dispersive X-ray fluorescence spectrometry

Soil and sediment reference materials were used to calibrate and evaluate an analytical method for the determination of major (Si, Al, Fe, Mg, Ca, Na, K, Mn, P, Ti) and trace elements (As, Ba, Cd, Co, Cr, Cu, Ga, Mo, Mb, Ni, Pb, Rb, S, Sb, Sn, Sr, Th, U, V, Y, Zn, Zr) by sequential wavelength X-ray fluorescence spectrometry. Samples were prepared as pressed pellets and analysis was done with a total measuring time of thirty minutes per sample. Special attention was given to the selection of the thirty reference materials used for calibration of the spectrometer. Another set of eleven RM (reference materials) was analyzed for the evaluation of accuracy. Detection limits for trace elements (1-2 mg kg^-1) are adequate both for geochemical and environmental purposes, except for Cd and Sb. Accuracy for trace elements falls within the expected interval of certified or recommended values in most cases, but for some major elements, like SiO₂, some results showed discrepancies, evidencing difficulties associated with the determination of light elements in complex matrices. But when quality criteria proposed by mapping programs are applied to the results, their requirements are fulfilled. Both instrumental precision, obtained by twelve sample replicate analyses, and analytical precision, considering also sub-sampling and pellet preparation, lie between the limits of the Horwitz expression, except at concentrations close to the detection limits.     

杉木生长过程特征和生长期划分

本文用典型分析方法研究了浙江湖州不同立地条件下杉木胸径、树高和材积的生长过程特征。在目前的栽植密度范围内,立地条件愈好,该边缘产区的杉木生长冲劲愈大,各生长指标的连年生长量高峰出现愈早,持续时间相应愈长,具有典型的“冲劲大,后劲小”的特点。而立地较差的林分,连年生长量高峰不明显,其平均生长量基本处于低水平的缓慢增长状态。用有序样本聚类法进行了杉木胸径、树高和材积的生长阶段划分。结果表明该3个生长指标均可分为4个生长阶段,即幼树阶段、速生阶段、干材阶段和滞长阶段。     

Tracing sources of soil nitrate using the dual isotopic composition of nitrate in 2 M KCl-extracts

Soils comprise a critical interface between the atmosphere, lithosphere, hydrosphere and biosphere, and play a major role in the cycling of nitrogen (N), an element crucial to plant growth. Isotope techniques constitute a powerful tool to study the origin and fate of N compounds (e.g. NO₃⁻) within the environment including soils. The objective of our study was to test the usefulness of the isotope composition of soil NO₃⁻ extracted with 2 M KCl (soil NO₃) as a tool to investigate the origin and fate of NO₃⁻ in the environment. Specifically issues related to repeat extractions, crop type, length of fertilization, and soil depth were addressed. Soils from four contrasting agricultural management regimes were sampled. Within the relatively confined study area (4 ha), the isotopic compositions of soil NO₃ differed markedly due to management treatments (up to 6 and 17‰ for δ¹⁵N and δ¹⁸O, respectively), but were repeatable among replicate plots (±1‰). Differences in both δ¹⁵N and δ¹⁸O values were observed between legume and non-legume treatments, as well as fertilized versus non-fertilized treatments, which were larger than the variability observed between replicate plots. Differences in the isotopic composition of extractable soil nitrate were not limited to the surface layer, but also occurred within deeper soil layers. This study indicates that the analysis of the natural abundance stable isotope composition of soil NO₃ may provide a promising additional tool for tracing the origin and fate of NO₃⁻ in the soil zone.     

我国磷酸一铵、磷酸二铵产品质量状况浅析

通过总结1999~2006年磷酸一铵、磷酸二铵产品质量国家监督抽查结果,分析了我国磷酸一铵、磷酸二铵产品质量状况,指出我国该类产品质量较好,但限于磷矿资源不足,矿源复杂,质量控制越来越困难。同时,该类产品农田使用量降低,多数用做复混肥料原料,应加大施肥技术推广。     

昆虫标本微机管理信息系统

本系统是在ＩＢＭＰＣ／ＸＴ微机上研究开发的．具信息贮存、修改、联合检索查询、报表输出打印等功能，操作简单，使用方便，不仅能提供分类系统，而且还能提供生物学特性、生境、防治措施等多种信息．适用于昆虫标本室（馆）及基层森防单位，对实现昆虫标本信息管理现代化、科学化有着重要意义．     

杨树溃疡病病原的多重PCR检测技术

利用真菌通用引物ITS1/ITS4,EF1-728F/EF1-986R对4种杨树溃疡病病原菌株和环境样本的核糖体DNA内部转录间隔区ITS序列和转录延伸因子EF-1α基因序列分别进行普通和多重PCR检测,再进行测序比对分析。结果表明:退火温度为55.6℃,各引物终浓度为0.2μmol·L-1,可以成功地扩增出菌株和环境样本的目的条带,并通过测序比对鉴定出多种来自培养和环境病害组织中的溃疡病病菌,多重PCR能够检测到1ng的基因组DNA。研究结果将为建立溃疡病病原多重PCR鉴定技术和以环境溃疡病病害样本为直接检测鉴定对象的高通量的基因芯片检测方法奠定基础。