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1.
用国外优良玉米杂种交种作,通过多代自交分离选择,育成了自交系南21-3,对该系主要经济性状的一般和特殊配合力进行测定,并与国内外优良自交系进行了比较,表明南21-3主要经济性状的配合力都接近或超过国内外优良自交系。我所应用该系作亲本组配的优良玉米要交种有4个,累计推广面积已达80万ha,获得了显著的经济效益。  相似文献   

2.
本技术利用具有苗期叶片黄化症状的R24-12作母本,以任意苗期叶片正常的辣椒自交系作父本,配制出杂种一代,然后取一定量的杂种一代种子,播于培养皿或培养盒或菜地中,苗期叶片绿色的是杂交种,黄色的是自交种(假杂交种)。实施本技术具有如下效果:根据黄化标记性状在苗期鉴定,结果准确可靠,使鉴定期缩短了3个月左右,降低纯检成本费用70%;生产上可利用该技术及早在苗期剔除黄化苗假杂交种杂交辣椒苗期的纯度鉴定技术  相似文献   

3.
本方法用美国引进种质 1 6与美国引进种质 1 8杂交 ,选株自交 3代后 ,经抗病鉴定和配合力测定 ,再经 4代自交纯合 ,育成了高产多抗、株型紧凑的优异自交系 698 3;然后以自交系 698 3为母本 ,自交系 2 0 0B为父本 ,组配成强优势杂交种成单 2 3。本玉米杂交种具有产量高、适应性  相似文献   

4.
本选育方法包括:选育自交系,调节播期,播种密度和人工辅助授粉措施,利用自交系丹598为母本,自交系9046为父本配制而成玉米杂交种丹2100。本方法的优点是高产、稳产、适应性强,而且突出表现抗病、抗倒,活秆成熟,适宜辽宁省无霜期较长的地区、吉林省南部以及河北春玉米区种植玉米杂交种的选育方法  相似文献   

5.
离子选择电极法测定水和废水中总氰化物   总被引:2,自引:0,他引:2  
商文新 《四川环境》1995,14(4):23-26
本文在查阅国内外文献的基础上,对氰化物测定中的前处理方法和干扰消除进行了简要综述。同时对氰离子选择电极法测定氰化物进行了研究,测定的pH应控制为12-13,检测下限为0.03mg/l。并用离子交换的方法分离阳离子,以PbCO3为沉淀剂分离S^2-后,对废水样进行分析,效果良好。  相似文献   

6.
广元市道路贯穿辐射剂量水平研究   总被引:1,自引:0,他引:1  
本文在广元市环境天然放射性水平调查的基础 上,通过对全市范围道路贯穿辐射剂量水平进行分析和研究,得出:(1)道路陆地γ辐射剂 量率为(6.43±1.21)×10-8Gyh-1;(2)道路贯穿辐射剂量率为(9.66±1.3 5)×10-8Gyh-1;(3)道路γ辐射剂量水平与道路贯穿辐射剂量水平的地理分布 相似。即:北部中山区最高,东南低山区和东部次之,中部河谷平坝区和西南低山区最低。 (4)依不同路面材料,其道路陆地γ辐射剂量率的排列顺序为:泥土路>碎石路>砖路>柏 油路>水泥路。  相似文献   

7.
硅酸盐工业灰渣的基本化学成人是CaO、SiO2,Al2O3等,目前主要用于生产水泥等建筑材料, 西方对工业灰渣CaO-SiO2-Al2O3三元系高钙相平衡过程进行了分析讨论和数学处理。  相似文献   

8.
文摘     
文摘《铝合金在不同温度的海水中的疲劳性状》──《EngFractMech》V45,N3,Jun1993,P297-307(英):使用一个特殊设计的环境试验箱对铝合金在不同温度的海水中进行了疲劳试验,试验箱安装在一台标准回转弯曲疲劳试验机上。在20~2...  相似文献   

9.
内江市磷肥厂磷矿石,磷肥样品中天然铀,镭—226含量分析   总被引:1,自引:0,他引:1  
本文报道了内江市8个磷肥的磷肥及其原料矿石中天然铀,^226Ra含量水平,其结果为,磷肥样品中^226Ra含量245.8±112.9Bq.kg^-1,天然铀含量27.2±16.4ppm;磷矿石样品中^226Ra含量407.6±94.3Bq.kg^-1,天然铀含量31.4±21.0ppm。  相似文献   

10.
国内外市场展望国际货币基金组织预测,随着美国经济复苏的扩展和发展中国家经济的强劲增长,1995年世界经济将取得比1988年以来的最好成绩。国际货币基金组织对半年的世界经济展望预测,1994年全球经济增长率将达3%,1995年可达3.7%,而1993年...  相似文献   

11.
Phosphorus flux from bottom sediments in Lake Eucha, Oklahoma   总被引:1,自引:0,他引:1  
Phosphorus inputs into reservoirs include external sources from the watershed and internal sources from the reservoir bottom sediments. This study quantified sediment P flux in Lake Eucha, northeastern Oklahoma, USA, and evaluated the effectiveness of chemical treatment to reduce sediment P flux. Six intact sediment-water columns were collected from three sites in Lake Eucha near the reservoir channel at depths of 10 to 15 m. Three intact sediment and water columns from each site were incubated for 21 d at approximately 22 degrees C under aerobic conditions, and three were incubated under anaerobic conditions (N2 with 300 ppm CO2); sediment P flux was estimated over the 21 d for each core. The overlying water in the cores was bubbled with air for approximately 1 wk and then treated with aluminum sulfate (alum). The cores were incubated at approximately 22 degrees C for an additional 14 d under aerobic or anaerobic conditions, and sediment P flux after alum treatment was estimated for each core. Sediment P flux was approximately four times greater under anaerobic conditions compared with aerobic conditions. Alum treatment of the intact sediment-water columns reduced (8x) sediment P flux under anaerobic conditions. Internal P flux (1.03 and 4.40 mg m(-2) d(-1) under aerobic and anaerobic conditions, respectively) was greater than external P flux (0.13 mg m(-2) d(-1)). The internal P load (12 Mg yr(-1)) from reservoir bottom sediments was almost 25% of the external P load (approximately 48 Mg yr(-1)) estimated using a calibrated watershed model.  相似文献   

12.
浅谈广元市南河水质污染状况及治理措施   总被引:1,自引:0,他引:1  
本文通过对1996-2000年广元市南河水质监测数据的分析讨论,显示南河水质污染日益严重,并对此提出一些治理措施。  相似文献   

13.
汪昉 《资源开发与市场》2005,21(6):569-570,573
西南地区旅游资源丰富多样,但经济发展水平相对落后.要实现西南地区经济社会的腾飞,必须实施生态文化旅游科技发展战略.在分析西南地区旅游资源特点的基础上,指出了旅游发展的战略目标及主要任务,并提出了相关建议.  相似文献   

14.
我国自改革开放以来在构建环境与资源保护法律体系方面取得了可喜的成绩,但也存在一些问题。主要表现为:可持续发展战略尚未成为我国环境与资源保护立法的指导思想,我国的环境与资源立法不能完全适应社会主义市场经济的要求和社会发展的需要,我国关于环境与资源的法律法规之间不相统一。造成上述问题的原因有外部因素和内部因素,同时我国的具体国情又使它们更具特殊性。为了有效地解决这些问题,我国须在加强环境立法、健全现有制度、协调内部功能等方面进行不懈的努力。  相似文献   

15.
Beneficial effects of leaving residue at the soil surface are well documented for steep lands, but not for flat lands that are drained with surface inlets and tile lines. This study quantified the effects of tillage and nutrient source on tile line and surface inlet water quality under continuous corn (Zea mays L.) from relatively flat lands (<3%). Tillage treatments were either fall chisel or moldboard plow. Nutrient sources were either fall injected liquid hog manure or spring incorporated urea. The experiment was on a Webster-Canisteo clay loam (Typic Endoaquolls) at Lamberton, MN. Surface inlet runoff was analyzed for flow, total solids, NO(3)-N, NH(4)-N, dissolved P, and total P. Tile line effluent was analyzed for flow, NO(3)-N, and NH(4)-N. In four years of rainstorm and snowmelt events there were few significant differences (p < 0.10) in water quality of surface inlet or tile drainage between treatments. Residue cover minimally reduced soil erosion during both snowmelt and rainfall runoff events. There was a slight reduction in mineral N losses via surface inlets from manure treatments. There was also a slight decrease (p = 0.025) in corn grain yield from chisel-plow plots (9.7 Mg ha(-1)) compared with moldboard-plow plots (10.1 Mg ha(-1)). Chisel plowing (approximately 30% residue cover) alone is not sufficient to reduce nonpoint source sediment pollution from these poorly drained flat lands to the extent (40% reduction) desired by regulatory agencies.  相似文献   

16.
It is generally recognized that soil N(2)O emissions can exhibit pronounced day-to-day variations; however, measurements of soil N(2)O flux with soil chambers typically are done only at discrete points in time. This study evaluated the impact of sampling frequency on the precision of cumulative N(2)O flux estimates calculated from field measurements. Automated chambers were deployed in a corn/soybean field and used to measure soil N(2)O fluxes every 6 h from 25 Feb. 2006 through 11 Oct. 2006. The chambers were located in two positions relative to the fertilizer bands-directly over a band or between fertilizer bands. Sampling frequency effects on cumulative N(2)O-N flux estimation were assessed using a jackknife technique where populations of N(2)O fluxes were constructed from the average daily fluxes measured in each chamber. These test populations were generated by selecting measured flux values at regular time intervals ranging from 1 to 21 d. It was observed that as sampling interval increased from 7 to 21 d, variances associated with cumulative flux estimates increased. At relatively frequent sampling intensities (i.e., once every 3 d) N(2)O-N flux estimates were within +/-10% of the expected value at both sampling positions. As the time interval between sampling was increased, the deviation in estimated cumulative N(2)O flux increased, such that sampling once every 21 d yielded estimates within +60% and -40% of the actual cumulative N(2)O flux. The variance of potential fluxes associated with the between-band positions was less than the over-band position, indicating that the underlying temporal variability impacts the efficacy of a given sampling protocol.  相似文献   

17.
Internal cycling of nutrients from the sediment and water column can be an important contribution to the total nutrient load of an aquatic ecosystem. Our objective was to estimate the internal nutrient loading of the Lower St. Johns River (LSJR). Dissolved reactive phosphorus (DRP) and ammonium (NH(4)-N) flux from sediments were measured under aerobic and anaerobic water column conditions using intact cores, to estimate the overall contribution of the sediments to P and N loading to the LSJR. The DRP flux under aerobic water column conditions averaged 0.13 mg m(-2) d(-1), approximately 37 times lower than that under anaerobic conditions (4.77 mg m(-2) d(-1)). The average NH(4)-N released from the anaerobic cores (18.03 mg m(-2) d(-1)) was also significantly greater than in the aerobic cores for all sites and seasons, indicating the strong relationship between nutrient fluxes and oxygen availability in the water column. The mean annual internal DRP load was estimated to be 330 metric tons (Mg) yr(-1), 21% of the total P load to the river, while the mean annual internal load of NH(4)-N was determined to be 2066 Mg yr(-1), 28% of the total N load to the LSJR estuary. As water resource managers reduce external loading to the LSJR the frequency of anaerobic events should decline, thereby reducing nutrient fluxes from the sediment to the water column, reducing the internal loading of DRP and NH(4)-N. Results from this study demonstrate that the internal flux of nutrients from sediments may be a significant portion of the total load and should be accounted for in the total nutrient budget of the river for successful restoration.  相似文献   

18.
There is continuing concern over potential impacts of widespread application of nutrients and pesticides on ground- and surface-water quality. Transport and fate of nitrate and pesticides were investigated in a shallow aquifer and adjacent stream, Cow Castle Creek, in Orangeburg County, South Carolina. Pesticide and pesticide degradate concentrations were detected in ground water with greatest frequency and largest concentrations directly beneath and downgradient from the corn (Zea mays L.) field where they were applied. In almost all samples in which they were detected, concentrations of pesticide degradates greatly exceeded those of parent compounds, and were still present in ground waters that were recharged during the previous 18 yr. The absence of both parent and degradate compounds in samples collected from deeper in the aquifer suggests that this persistence is limited or that the ground water had recharged before use of the pesticide. Concentrations of NO(-)(3) in ground water decreased with increasing depth and age, but denitrification was not a dominant controlling factor. Hydrologic and chemical data indicated that ground water discharges to the creek and chemical exchange takes place within the upper 0.7 m of the streambed. Ground water had its greatest influence on surface-water chemistry during low-flow periods, causing a decrease in concentrations of Cl(-), NO(-)(3), pesticides, and pesticide degradates. Conversely, shallow subsurface drainage dominates stream chemistry during high-flow periods, increasing stream concentrations of Cl(-), NO(-)(3), pesticides, and pesticide degradates. These results point out the importance of understanding the hydrogeologic setting when investigating transport and fate of contaminants in ground water and surface water.  相似文献   

19.
高职环保类专业职业技能培养课程体系开发   总被引:1,自引:0,他引:1  
课程体系是高职专业办出特色、持续发展的载体。针对高职环保类专业人才培养存在课程体系不合理、实践教学薄弱、职业技能培养方法陈旧等问题,以职业岗位需求为基础,以职业技能培养为主线,构建了以实际污染治理项目为载体的高职环保类专业职业课程体系和职业核心课程。通过职业核心课程建设、双师型师资队伍建设、校内外实训基地建设等措施实现职业技能的培养。  相似文献   

20.
田间试验和示范表明,在玉米作物生产中施用兼具多元素复合和氮肥加价作用的保氮增效剂,可显著地改善植株性状,促果穗增长增粗,使秃尖率下降、穗粒数和百粒重增加。保氮增效剂用量为玉米施氮肥量的2.92%~4.99%,玉米增产51.5~68.4kg/亩。肥料报酬提高2.2~2.6倍,增收经济效益达34.1~44.7元/亩。  相似文献   

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