地下水三氯甲烷污染的微生物治理实验研究

在厌氧环境中,以三氯甲烷为靶污染物,分6种条件加入不同共代谢基质对厌氧生物污泥分别进行驯化培养。将得到的可降解三氯甲烷的微生物菌群富集培养,分别投入模拟净化装置进行处理实验。实验结果表明,在厌氧条件下,三氯甲烷能够被微生物降解,加入共代谢基质后可提高降解效率。不同基质环境中降解效率不同,以葡萄糖和甲醇为共代谢基质驯化出的微生物菌群对污染物去除率可达到75%。     

土壤固化剂新材料在衬砌渠道中的应用研究

在内蒙古河套灌区首次采用固化土衬砌渠道作为渠道防渗抗冻的新技术。简要说明土壤固化剂原理,通过室内试验得出固化土性能,通过施工实践总结出固化土施工工艺。应用已有和自行开发的土壤固化剂制作固化板,进行防渗、抗冻观测试验,对冻深、冻胀量、防渗效果和工程造价作出定量结论,已在大型灌区田间渠道衬砌中推广应用。     

Changes in spatial and temporal variability of SAR affected by shallow groundwater management of an irrigated field, California

In the irrigated western U.S. disposal of drainage water has become a significant economic and environmental liability. Development of irrigation water management practices that reduce drainage water volumes is essential. One strategy combines restricted drainage outflow (by plugging the drains) with deficit irrigation to maximize shallow groundwater consumption by crops, thus reducing drainage that needs disposal. This approach is not without potential pitfalls; upward movement of groundwater in response to crop water uptake may increase salt and sodium concentrations in the root zone. The purposes for this study were: to observe changes in the spatial and temporal distributions of SAR (sodium adsorption ratio) and salt in a field managed to minimize drainage discharge; to determine if in situ drainage reduction strategy affects SAR distribution in the soil profile; and to identify soil or management factors that can help explain field wide variability. We measured SAR, soil salinity (EC_1:1) and soil texture over 3 years in a 60-ha irrigated field on the west side of the San Joaquin Valley, California. At the time we started our measurements, the field was beginning to be managed according to a shallow groundwater/drainage reduction strategy. Soil salinity and SAR were found to be highly correlated in the field. The observed spatial and temporal variability in SAR was largely a product of soil textural variations within the field and their associated variations in apparent leaching fraction. During the 3-year study period, the percentage of the field in which the lower profile (90-180 cm) depth averaged SAR was above 10, increased from 20 to 40%. Since salinity was increasing concomitantly with SAR, and because the soil contained gypsum, sodium hazard was not expected to become a limiting factor for long term shallow groundwater management by drain control. It is anticipated that the technology will be viable for future seasons.     

不同水分条件下冬小麦浅层地下水利用试验研究

使用蒸渗仪群开展了冬小麦对浅层地下水利用试验,讨论了在降雨、灌溉和不同地下水埋深等多种水分条件下冬小麦对浅层地下水的利用规律,并确定了适宜冬小麦生长的地下水埋深上限和相应的合理灌水量。结果表明,从返青至收获期,在40~150 cm埋深范围内,无灌溉无降雨条件下地下水对作物腾发的贡献率可达到90.0%以上,而降雨和灌溉处理的地下水贡献率减小到54.0%~78.9%。另外,无论是否有降雨影响,随着地下水埋深的增加,地下水贡献率都降低。试验结果还表明,150 cm是适宜冬小麦生长的地下水埋深上限,每公顷穗数较大是冬小麦产量高于其他埋深处理的主要原因。从返青至灌浆期,在150 cm埋深下,只需在拔节期灌水约60.0 mm,冬小麦产量就可达到8 846 kg/hm2,在无灌水和降雨时产量可达到拔节灌溉处理的80.0%左右。     

Soil Properties Degradation Assessment Using Infrared Scanning Technique of Soils （Case Study： Eastern of Congo）

Recently, near infrared reflectance （NIR） and mid-infrared （MIR） spectroscopy techniques are increasingly introduced as convenient and simple non-destructive techniques for quantifying several soil properties. This study uses MIR method to predict pH, soil organic C, total N, AI, Ca, Mg and K, CEC and soil texture for soil samples collected in Sud-Kivu, Congo. A total of 536 composite soil samples were taken from two locations （Burhale and Luhihi） at two depths （0-20 cm and 20-40 cm） using a spatially-stratified random sampling design within an area of 200 km2. Differences in characteristics were evaluated between the two locations, land use （cultivated vs. non-cultivated land） with soil depths. A random subset of the samples （10%） were analyzed using standard wet chemistry methods, and calibration models developed by MIR data to estimate soil properties for the full soil sample set. Partial least squares regression （PLS） method gave acceptable coefficients of determination between 0.71 and 0.93 for all parameters. Soil organic matter levels were higher in cultivated plots in Luhihi （3.9% C） than in Burhale （3.0% C）, suggesting lower levels of soil fertility in the later area. This indicates high levels of acidity, which are likely to limit crop production in the area. Phosphorus deficiency is acute in Burhale （2.4 mg P/kg） but less in Luhihi （5.4 mg P/kg）. In both locations, low levels of Ca and Mg indicate that soils may be susceptible to deficiencies in both elements.These findings provide new opportunities for monitoring soil quality in the region which can benefit multiple actors and scientists involved in the agricultural and environmental sectors.     

双掺大流动性混凝土性能研究

研究了不同粉煤灰掺量对双掺大流动性混凝土性能的影响,并结合高效减水剂及粉煤灰的水化机理及混凝土抗压强度、碳化深度对双掺大流动性混凝土作了一定的性能分析论述,总结出其抗压强度及碳化深度之间存在的关系。     

Light, temperature and burial depth effects on Rumex obtusifolius seed germination and emergence

Trials were carried out to investigate the effects of light and temperature on germination of Rumex obtusifolius L. After several months of storage, seeds gradually lost dormancy and became photosensitive. Thermal optima for germination were between 20 °C and 25 °C in light or in darkness. At lower temperatures there was a greater demand for light, so that the greatest differences in germination percentage (between low and high temperatures) were found within the 10–15 °C temperature range. The calculated thermal minima ( x -intercept method) in light and darkness were 8.3 °C and 6.1 °C respectively. Daily temperature fluctuation increased germination even after seed irradiation with far-red light, suggesting a lower demand for the far-red-absorbing form of phytochrome. Seed burial inhibited germination in proportion to depth; however, germination inhibition was independent of seed phytochrome photo-equilibrium, which had been diversified by seed pretreatment with light. Seedlings did not emerge when seeds were buried >8 cm deep. Recovery of ungerminated seeds showed that excessive burial did not impede seedling emergence but rather prevented seed germination. However, this induction of dormancy was lost once germination processes were activated (24–48 h at 20 °C) that made germination irreversible. Temperature was also involved in inhibition, and low temperature (<15 °C) induced the least inhibition. This is discussed in terms of processes of respiration and fermentation in buried seeds.     

阿拉善板滩井盆地地下水及水化学特征研究

本文依据作者在板滩井盆地从事的水文地质调查，钻探、水质分析和地下水动态资料，并利用卫片、航片解释，对该盆地及所属沙漠人工绿洲的地下水形成机制，水资源平衡，水质分布规律等进行了探讨。     

河西走廊水资源特征及其循环转化规律

河西走廊水资源主要以雪冰水资源、地表水资源与地下水资源的形式存在,分布于石羊河、黑河、疏勒河3大相对独立的流域水系.南部祁连山区发育大小河流共计57条,多年平均出山径流量71.29×108 m3,总体而言,近50 a出山径流变化比较稳定.走廊平原主要由8个大型的构造地貌盆地组成,盆地地下水主要接受出山河水及引灌河水的入渗补给,是地表水资源的重复表现形式,多年平均地下水补给量为42.42×108 m3.近50 a来,地下水补给量减少了17.19×108 m3,由此引起泉水资源23 a来衰减了24.6%.受构造地貌的制约,自南部山区至北部盆地,地下水与河水之间经过5个不同地带有规律的、大数量的、重复的转化过程,形成完整统一的"山区地下水-地表水-南盆地地下水-地表水(泉水)-北盆地地下水"水资源循环系统.