新疆罗布泊超大型卤水钾矿发现20年     

宣之强 《化工矿产地质》2016,(1):60-64

"罗布泊超大型卤水鉀矿"的发现,是中国众多地学科学家40年探寻预测的。王弭力研究员及其团队,于1995年秋首次踏进罗布泊"罗北凹地",当年找到4356万t优质卤水鉀矿;经五年科研和勘探,查明儲量达2.5亿t、为超大型卤水鉀矿。理论创新,成为完成科硏和勘探的关键,加速了百万吨级"罗钾公司"硫酸钾肥生产成功投产。古丝绸之路上生命回归、一颗新星"罗布泊"镇诞生,"百年罗钾"资源保障科研探钾即将启动,中国几代"钾盐人"的梦想成真。  相似文献   

Effects of heavy metal (Pb) concentration on some growth parameters of plants grown in lead polluted soil under organic fertilizer amendment     

Ojo M. Oseni  Adekunle A. Adelusi  Esther O. Da  Abdulfatai B. Rufai 《寒旱区科学》2016,8(1):36-45

This study investigated morphological variation and biomass accumulation that occurred in Sida acuta and Chromolaena odorata plants grown in lead polluted soil under organic fertilizer amendment. The study was carried out in the screen house at the Biological Gardens of the Obafemi Awolowo University, Ile-Ife, Osun State. The experiment was a factorial combination of one heavy metal (Pb) at five levels of concentration (0, 200, 400, 800 and 1,000 mg/kg) in a completely randomized design, and were replicated three times for each of the two plants and two levels (0 g/kg and 9.4 g/kg) of organic fertilizer (OBD-Plus). Each pot was filled with 5 kg of air-dried and sieved soil and placed on a plastic tray for the collection of excess water. Two weeks after planting, seedlings of uniform height were transplanted from the nursery to experimental pots at the rate of one seedling per pot and grown for 10 weeks. The growth parameters of the plants were biomonitored for 7 weeks. After 10 weeks of treatment, the plants were harvested and dried to calculate the biomass accumulation. The two plant species performed better under fertilizer application than without it. For each of the plant species the growth parameters decreased as the levels of Pb concentration increased. Furthermore, the plants' biomass decreased significantly (p<0.05) as the levels of Pb concentration increased. The organic fertilizer helped to improve the plants' performance in lead-polluted soil.  相似文献   

浙江省萧山北部地区农业地质环境调查成果     

顾金秋  汪庆华  董岩翔  任荣富  周建华  梁河 《浙江国土资源》2000,(2)

萧山北部地区农业地质环境调查从氮磷钾的合理配比和微量元素合理施用方面为农业生产科学施肥提供了科学的依据 ;从制定农田耕作层的保护措施 ,控制化肥施用 ,实行平衡施施肥 ,降低农田灌溉水的污染 ,充分发挥肥效等方面 ,提出了保护土地资源、实施“沃土计划” ;根据农业地质的基础资料进行了农业环境保护区划 ,将本区划分为沿江陆域岸线保护带、萧山南沙大堤保护带和农业环境保护区 ;并提出要加强钱塘江海堤建设 ,防治地质灾害的发生  相似文献   

Understanding the Past and Present and Predicting the Future: Farmers’ Use of Multiple Nutrient Best Management Practices in the Upper Midwest     

Riva C. H. Denny  Sandra T. Marquart-Pyatt  Matthew Houser 《社会与自然资源》2019,32(7):807-826

Understanding what drives farmers’ voluntary adoption of nutrient and soil best management practices has important consequences for many environmental outcomes including water quality. We build on research revealing the need for simultaneous use of multiple nitrogen best management practices to achieve water quality improvement goals. Using social, economic and attitudinal variables we predict the use of multiple nitrogen best management practices at three time points: current use (2013), past use (before 2013), and likelihood of use on their largest field in the next three years. Our empirical analysis uses structural equation modeling with latent variables and 2014 farmer survey data from three Midwestern US states. Most farmers in our sample used at least one of the six best management practices. Our results reveal that farmers’ attitudes, use of information sources, and conservation program participation affect the number of nitrogen best management practices concurrently in use at multiple time points.  相似文献   

Travel time controls the magnitude of nitrate discharge in groundwater bypassing the riparian zone to a stream on Virginia's coastal plain     

Samuel A. Flewelling  Janet S. Herman  George M. Hornberger  Aaron L. Mills 《水文研究》2012,26(8):1242-1253

Groundwater that bypasses the riparian zone by travelling along deep flow paths may deliver high concentrations of fertilizer‐derived NO₃^? to streams, or it may be impacted by the NO₃^? removal process of denitrification in streambed sediments. In a study of a small agricultural catchment on the Atlantic coastal plain of Virginia's eastern shore, we used seepage meters deployed in the streambed to measure specific discharge of groundwater and its solute concentrations for various locations and dates. We used values of Cl^? concentration to discriminate between bypass water recharged distal to the stream and that contained high NO₃^? but low Cl^? concentrations and riparian‐influenced water recharged proximal to the stream that contained low NO₃^? and high Cl^? concentrations. The travel time required for bypass water to transit the 30‐cm‐thick, microbially active denitrifying zone in the streambed determined the extent of NO₃^? removal, and hydraulic conductivity determined travel time through the streambed sediments. At all travel times greater than 2 days, NO₃^? removal was virtually complete. Comparison of the timescales for reaction and transport through the streambed sediments in this system confirmed that the predominant control on nitrate flux was travel time rather than denitrification rate coefficients. We conclude that extensive denitrification can occur in groundwater that bypasses the riparian zone, but a residence time in biologically active streambed sediments sufficient to remove a large fraction of the NO₃^? is only achieved in relatively low‐conductivity porous media. Instead of viewing them as separate, the streambed and riparian zone should be considered an integrated NO₃^? removal unit. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Field measurements of NO and NO2 emissions from fertilized and unfertilized soils   总被引：3，自引：0，他引：3  

F. Slemr  W. Seiler 《Journal of Atmospheric Chemistry》1984,2(1):1-24

Field measurements of NO and NO₂ emissions from soils have been performed in Finthen near Mainz (F.R.G.) and in Utrera near Seville (Spain). The applied method employed a flow box coupled with a chemiluminescent NO _x detector allowing the determination of minimum flux rates of 2 g N m^-2 h^-1 for NO and 3 g m^-2 h^-1 for NO₂.The NO and NO₂ flux rates were found to be strongly dependent on soil surface temperatures and showed strong daily variations with maximum values during the early afternoon and minimum values during the early morning. Between the daily variation patterns of NO and NO₂, there was a time lag of about 2 h which seem to be due to the different physico-chemical properties of NO and NO₂. The apparent activation energy of NO emission calculated from the Arrhenius equation ranged between 44 and 103 kJ per mole. The NO and NO₂ emission rates were positively correlated with soil moisture in the upper soil layer.The measurements carried out in August in Finthen clearly indicate the establishment of NO and NO₂ equilibrium mixing ratios which appeared to be on the order of 20 ppbv for NO and 10 ppbv for NO₂. The soil acted as a net sink for ambient air NO and NO₂ mixing ratios higher than the equilibrium values and a net source for NO and NO₂ mixing ratios lower than the equilibrium values. This behaviour as well as the observation of equilibrium mixing ratios clearly indicate that NO and NO₂ are formed and destroyed concurrently in the soil.Average flux rates measured on bare unfertilized soils were about 10 g N m^-2 h^-1 for NO₂ and 8 g N m^-2 h^-1 for NO. The NO and NO₂ flux rates were significantly reduced on plant covered soil plots. In some cases, the flux rates of both gases became negative indicating that the vegetation may act as a sink for atmospheric NO and NO₂.Application of mineral fertilizers increased the NO and NO₂ emission rates. Highest emission rates were observed for urea followed by NH₄Cl, NH₄NO₃ and NaNO₃. The fertilizer loss rates ranged from 0.1% for NaNO₃ to 5.4% for urea. Vegetation cover substantially reduced the fertilizer loss rate.The total NO _x emission from soil is estimated to be 11 Tg N yr^-1. This figure is an upper limit and includes the emission of 7 Tg N yr^-1 from natural unfertilized soils, 2 Tg N yr^-1 from fertilized soils as well as 2 Tg N yr^-1 from animal excreta. Despite its speculative character, this estimation indicates that NO _x emission by soil is important for tropospheric chemistry especially in remote areas where the NO _x production by other sources is comparatively small.  相似文献   

Analysis of ventilation shock losses by finite element method     

C. W. Liu  Y. J. Wang 《Geotechnical and Geological Engineering》1987,5(4):377-390

Summary This paper presents an analysis of ventilation shock losses using the two-dimensional finite element method. It outlines the finite element formulation, in which the ventilation air flow is assumed to be a steady-state, viscous, incompressible and fully developed turbulent flow. In addition, the modified version of Van Driest model is assumed for the effective kinematic viscosity.The shock losses were estimated for the case simulating the airway configuration for (a) split, (b) junction and (c) gradual contraction. The results are compared and discussed with the shock loss data available in the ventilation literature. To estimate the shock losses, the flow solution in terms of pressure was first obtained for each airway configuration using the finite element method. The solution was then compared with that of a straight airway for estimating the difference in the head losses.  相似文献   

城市污水处理厂污泥利用现状及潜在环境问题   总被引：9，自引：0，他引：9  

陈军 《矿产与地质》2005,19(6):732-734

根据国家环保总局要求,在2010年前全国主要城市的污水处理率要达到70%,这将使我国的水环境得到明显改善,另一方面也带来了污泥的处置和利用问题.污泥是一种优质的有机肥料,有选择地控制使用,既可满足作物生长对养分的需要,又可培育土壤.符合污泥固废“减量化”和“资源化”的处置要求.  相似文献   

Effect of chemical fertilizers on the fractionation of Cu,Cr and Ni in contaminated soil   总被引：1，自引：0，他引：1  

Jie Liu  Chang-Qun Duan  Yi-Nian Zhu  Xue-Hong Zhang  Cheng-Xian Wang 《Environmental Geology》2007,52(8):1601-1606

Effect of chemical fertilizers (urea, NH₄Cl, Ca(NO₃)₂, KCl and KH₂PO₄) on the fractionation of Cu, Cr and Ni was studied by a 4-month incubation experiment. Using sequential extraction procedure, it was found that the application of fertilizers could change the distribution of Cu, Cr and Ni in the fractions of soil. Applying urea (CO(NH₂)₂) significantly decreased the concentrations of Cu, Cr and Ni in water soluble plus exchangeable (WE) fraction, but increased those in Fe–Mn oxides bound (FM) fraction (p < 0.01). However, application of NH₄Cl caused an increase in the WE fraction by 27.7% for Cu, 111.5% for Cr and 20.4% for Ni. The CO(NH₂)₂ raised the soil pH from 4.51 to 4.96, whereas NH₄Cl lowered the pH of soil by 0.44 units. The WE fraction of the three heavy metals was significantly increased, while the FM fraction was significantly decreased by adding KCl (p < 0.01). Moreover, the supply of KH₂PO₄ reduced the WE and carbonate bound (CB) fractions of Cu, Cr and Ni in the soil, however, it raised Cu and Ni in the residual (RS) fraction and Cr in the FM fraction. In addition, the mobility index indicated that KCl and NH₄Cl increased the mobility of Cu, Cr and Ni in the soil, whereas urea and KH₂PO₄ decreased the mobility of the three metals in the soil. These results suggest that applying chemical fertilizers does not only provide plant nutrients, but may also change the speciation and mobility of heavy metals in the soil.  相似文献   

桉树腐殖酸(HA)专用肥区域试验与配方的优选     

钱国钦 《福建地理》2007,(4)

采用随机区组设计,以等价投入的常规化肥为对照,开展专用肥多点施肥试验研究.通过专用肥对林木生长量、林相特征的影响分析,结果表明:与等价投入(肥料成本)的常规化肥相比,施用系列专用肥的林分生长量均显著或极显著地高于常规化肥处理,且叶片浓绿、树势强壮,施后19个月内,树高、胸径、材积分别提高了7.8%~51.8%、9.8%~53.0%和30%以上,叶片叶绿素含量提高26.3%~94.2%,叶面积指数提高41.0%~172.8%.经对HA桉树专用肥的增产性、适应性和稳定性的综合分析与评定,选出基肥专用的优化配方为:有机质≥30.0%、N P2O5 K2O≥6.0%(2.5-2.0-1.5)、腐殖酸总量≥8.0%,并加上适量的"绿滴"复合微生物菌剂(于施用时和基肥按每50 kg∶1 kg的量掺入);追肥专用的优化配方为:有机质≥20.0%、N P2O5 K2O≥20.0%(9-8-3)、腐殖酸总量≥6.0%.  相似文献