Evaluation of advanced rice germplasm under water stress environment     

Y. Ali  G. Sarwar  Z. Aslam  F. Hussain  T. Rafique 《International Journal of Environmental Science and Technology》2005,2(1):27-33

Thirteen genotypes of rice comprising of approved varieties and elite candidate lines were studied at three different water regimes by supplying 12, 8 and 4 numbers of irrigations at different intervals/ stages. The experiment was conducted at NIAB Farm Faisalabad, Pakistan on a clay loam soil applying normal doses of N and P fertilizers during 2002–2003 keeping varieties in the main plot while treatments in sub plot. The data for twelve morphological characters i.e. days to flower, days to mature, plant height, panicle length, number of productive tillers, number of primary and secondary branches, 1000 grain weight, sterile grains per spike, number of total grains per spike, fertility percentage, grain yield were recorded and subjected to analysis of variance and means were compared following DMR test. Effect of water stress on different morphological attributes in all treatments showed significant differences. Plant height, branches per plant, number of grains and grain yield reduced at less number of irrigations while sterility percentage was increased at less moisture conditions. Maximum grain yield (5349 Kg/ha) was achieved at T1 where 12 number of irrigations were applied at T2 (8 irrigations) and T3 (4 irrigations). The yield reduction was observed from 30.32% to 42.53%, respectively as compared to T1 (12 irrigations). Rice variety DM 64198 produced the highest seed yield (4766 Kg/ha) followed by DM-3-89 (4770 Kg/ha).This might be due to different genetic make up of the breeding lines and their behavior and interaction in water stress environment. Furthermore, high irrigation level made possible the appropriate water availability possible at proper time for performing different types of physiochemical processes of development that hindered at less number of irrigation or water stress environment. It may be concluded that for achieving maximum economic yield, at least 12 irrigations were essential otherwise the production will be reduced to a considerable extent.  相似文献   

Chemical study of limestone and clay for cement manufacturing in Darukhula,Nizampur District,Nowshera, North West Frontier Province （N.W.F.P.）, Pakistan     

Khurshid Ali  ;Noor-ul-Amin  ;M.Tahir Shah 《中国地球化学学报》2008,27(3):242-248

Limestone and clay samples were collected from Darukhula and adjoining areas of the Nizampur District Nowshera, N.W.EE, Pakistan, and analyzed for different parameters in order to search for new reserves of suitable material for the manufacture of different types of cements in N.W.F.P. It was found that the area under study contains three types of limestones, including high grade limestone, Darukhula limestone and siliceous limestone, which contain 53%, 49.03% and 45.19% CaO, respectively, and three types of clay, including maroon color, yellow to yel- lowish-green color and green color clay containing 57.76%, 65.47% and 61.24% SiO2, respectively. Chemical analysis of the limestone and clay samples collected from the deposits in the area under study showed that all the elements found in these samples are within the range of permissible limits for the production of high-strength Portland cement, sulphate resisting cement and white cement. This paper covers the detailed version of the potential raw material deposits at Darukhula and adjoining areas of the Nizampur District.  相似文献   

Complexation and reduction as factors in the link between metal ion concentrations and organic matter in the Indian River     

Tahir R. Khan  Cooper H. Langford  George B. Skippen 《Organic Geochemistry》1984,7(3-4)

Complexation of metal ions by organic matter is frequently considered to play a part in metal ion dissolution in natural waters. A field study of a relatively unperturbed stream, high in organics, associates this with the fraction related to soil organic acids (humic acids). The association might have two origins. The first is complexation. However, well known sequences of complexing tendency do not predict the behaviour. A better theory uses the additional factor of the reducing capacity of dissolved organic matter toward Fe(III) and Mn(IV).  相似文献   

Changes in soil properties following conversion of Acacia senegal plantation to other land management systems in North Kordofan State,Sudan     

B.A. El Tahir  D.M. Ahmed  J. Ardö  A.M. Gaafar  A.A. Salih 《Journal of Arid Environments》2009,73(4-5):499-505

Changes in soil texture, bulk density, pH, concentrations and stocks of OC, N, P and K before and after conversion of a 6-year-old Acacia senegal plantation to other land management systems (LMS) were investigated, after three cropping seasons, in the drylands of western Sudan. LMS included pure and intercropped sorghum (PS), roselle (PR) and grasses (PG) with A. senegal at high- and low-tree densities (HD 433 and LD 266 trees ha^?1). Significant changes included increase in coarse sand and a decrease in fine sand under pure and intercropped systems at LD; decrease in clay contents in PS and PR; an increase in clay ratio in all pure crops and HD + R; a decrease in aggregated mean concentrations of OC, N and P under all LMS by 42%, 68% and 45%, respectively; increase in soil pH under all LMS; a depletion of aggregated mean stocks of OC, N, P and K in all LMS by 38%, 30%, 52% 13%, respectively. The study established that wholesale tree clearance constitutes a major cause of soil degradation, and tree inputs and cycling of nutrients are of major importance to soil fertility in the study area.  相似文献   

A review of earthquake occurrences and observations in Nigeria   总被引：1，自引：0，他引：1  

Ofonime Umo  Akpan Tahir  Abubakar Yakubu 《地震学报(英文版)》2010,(3):289-294

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Gas and fluid venting at the Makran accretionary wedge off Pakistan   总被引：2，自引：1，他引：1  

U. von Rad  U. Berner  G. Delisle  H. Doose-Rolinski  N. Fechner  P. Linke  A. Lückge  H. A. Roeser  R. Schmaljohann  M. Wiedicke  SONNE / Scientific Parties  M. Block  V. Damm  J. Erbacher  J. Fritsch  B. Harazim  J. Poggenburg  G. Scheeder  B. Schreckenberger  N. von Mirbach  M. Drews  S. Walter  A. Ali Khan  A. Inam  M. Tahir  A. R. Tabrez  A. H. Cheema  M. Pervaz  M. Ashraf 《Geo-Marine Letters》2000,20(1):10-19

The Makran accretionary complex shows a distinct bottom-simulating reflector, indicating a thick gas-hydrate-bearing horizon between the deformational front and about 1350 m water depth which seals off the upward flow of gas-charged fluids. A field of presently inactive mud diapirs with elevations up to 65 m was discovered in the abyssal plain seawards of the deformation front, suggesting that in the past conditions were favorable for periodic but localized vigorous mud diapirism. Regional destabilization of the gas hydrate leading to focused flow was observed where deep-penetrating, active faults reach the base of the gas-hydrate layer, as in a deeply incised submarine canyon (2100–2500 m water depth). At this location we discovered seeps of methane and H₂S-rich fluids associated with chemoautotrophic vent faunas (e.g., Calyptogena sp.). Driven by the accretionary wedge dynamics, the landward part of the gas-hydrate layer below the Makran margin is being progressively uplifted. Due to reduced hydrostatic pressure and rising ocean bottom-water temperatures, gas hydrates are progressively destabilized and dissociated into hydrate water, methane and H₂S. Sediment temperatures lie outside the methane stability field wherever water depth is less than 800 m. Above this depth, upward migration of fluids to the seafloor is unimpeded, thus explaining the abundance of randomly distributed gas seeps observed at water depths of 350 to 800 m. Received: 14 June 1999 / Revision accepted: 6 February 2000  相似文献   

Pulse-like ground motion observed during the 6 February 2023 MW7.8 Pazarcık Earthquake (Kahramanmaraş, SE Türkiye)          下载免费PDF全文

Fan Wu  Junju Xie  Zhao An  Chenghao Lyu  Tuncay Taymaz  Tahir Serkan Irmak  Xiaojun Li  Zengping Wen  Baofeng Zhou 《地震科学（英文版）》2023,36(4):328-339

In this study, we analyzed 100 three-component strong ground motion records observed within 200 km of the causative fault of the 6 February 2023 M_W7.8 Pazarcık (Kahramanmaraş) Earthquake in SE Türkiye. The wavelet method was utilized to identify and analyze the characteristics of pulse-like ground motions in the near-fault region, while considering the uncertainty of the pulse orientation during the analysis. Our investigation focused on the effects of the focal mechanism and rupture process on the spatial distribution, pulse orientation, and maximum pulse direction of the observed pulse-like ground motion. We also analyzed the amplitude and period of the observed ground pulses and the effect of long-period amplification on the ground motion response spectra. Our results indicated the following: (1) A total of 21 typical ground velocity pulses were observed during this earthquake, exhibiting complex characteristics due to the influence of the strike-slip mechanism and rupture directivity. Most ground pulses (17 out of 21) were recorded within 20 km of the fault, in a wide range of orientations, including normal and parallel to the fault direction. The waveforms exhibited unidirectional features, indicating the effects of left-lateral fault slip. Distinct pulses observed more than 20 km from the fault were mainly oriented normal to the fault. The waveforms were bidirectional with double- or multi-round trips as a result of rupture directivity. (2) The amplitudes of the observed pulses ranged from 30.5 to 220.0 cm/s, with the largest peak velocity of 220.0 cm/s observed at Station 3138. The pulse periods ranged from 2.3 to 14.5 s, with the longest pulse period of 14.5 s observed at Station 3116. The amplitude and period of the pulses observed during this earthquake were comparable to those of similar-magnitude global earthquakes. The amplitude of the pulses decreased significantly with increasing fault distance, whereas the pulse period was not significantly affected by the fault distance. (3) Compared with non-pulse records, the velocity pulse records had a pronounced amplification effect on the acceleration response spectra near the pulse period, with factors ranging from 2.1 to 5.8. The larger velocity pulses also significantly amplified the velocity response spectra, particularly over the long periods. This significant amplification effect of the pulses on the response spectra leads to empirical models underestimating the long-period earthquake ground motion.  相似文献   

GIS技术在城市地下水重金属浓度识别与分级中的应用（英文）     

Sobia Ashraf  Farhat Abbas  Muhammad Ibrahim  Umer Rashid  Shoaib Khalid  Hammad Raza Ahmad  Khalid Rehman Hakeem  Tahir Majeed 《地理学报(英文版)》2015,(2):225-235

Groundwater is the most appropriate and widely used source of drinking water,which is increasingly threatened by pollution from industrial and agricultural activities.To check the severity of the problem,156 groundwater samples were collected from various depths(60-110 ft) of 52 different localities in Faisalabad city,the third largest metropolis in Pakistan,and analyzed for the metals(Zn,Cu,Cd,Ni,Pb,Mn and Fe) concentration in 2009.Quantification was done by using Flame Atomic Absorption Spectrophotometer technique and the results were compared with WHO standards for drinking water quality.Results showed that the levels of Cu,Mn and Fe were below the WHO standards while the concentrations of Zn,Cd,Ni and Pb were above the recommended levels of safe drinking water.Correlation analysis among the occurrence of these heavy metals revealed a highly significant and positive correlation of Mn with Zn and Fe.A significant and positive correlation of Cd was also found with Cu and groundwater depth showing that there is strong association between Cu-Cd pair and that the Cd concentration varies with depth of groundwater in the study area.Regional patterns of heavy metals occurrence were mapped using Geographical Information System(GIS) for the identification and demarcation of risk areas.The concentration maps may be used by policymakers of the city to mitigate groundwater pollution.  相似文献   

Use of Intelligent Methods to Design Effective Pattern Parameters of Mine Blasting to Minimize Flyrock Distance     

Zhou  Jian  Koopialipoor  Mohammadreza  Murlidhar  Bhatawdekar Ramesh  Fatemi  Seyed Alireza  Tahir  M. M.  Jahed Armaghani  Danial  Li  Chuanqi 《Natural Resources Research》2020,29(2):625-639

Flyrock is one of the most important environmental issues in mine blasting, which can affect equipment, people and could cause fatal accidents. Therefore, minimization of this environmental issue of blasting must be considered as the ultimate objective of many rock removal projects. This paper describes a new minimization procedure of flyrock using intelligent approaches, i.e., artificial neural network (ANN) and particle swarm optimization (PSO) algorithms. The most effective factors of flyrock were used as model inputs while the output of the system was set as flyrock distance. In the initial stage, an ANN model was constructed and proposed with high degree of accuracy. Then, two different strategies according to ideal and engineering condition designs were considered and implemented using PSO algorithm. The two main parameters of PSO algorithm for optimal design were obtained as 50 for number of particle and 1000 for number of iteration. Flyrock values were reduced in ideal condition to 34 m; while in engineering condition, this value was reduced to 109 m. In addition, an appropriate blasting pattern was proposed. It can be concluded that using the proposed techniques and patterns, flyrock risks in the studied mine can be significantly minimized and controlled.

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An assessment of the potential impact of climate change on flood risk in Mumbai   总被引：2，自引：1，他引：1  

Nicola Ranger  St��phane Hallegatte  Sumana Bhattacharya  Murthy Bachu  Satya Priya  K. Dhore  Farhat Rafique  P. Mathur  Nicolas Naville  Fanny Henriet  Celine Herweijer  Sanjib Pohit  Jan Corfee-Morlot 《Climatic change》2011,104(1):139-167

Managing risks from extreme events will be a crucial component of climate change adaptation. In this study, we demonstrate an approach to assess future risks and quantify the benefits of adaptation options at a city-scale, with application to flood risk in Mumbai. In 2005, Mumbai experienced unprecedented flooding, causing direct economic damages estimated at almost two billion USD and 500 fatalities. Our findings suggest that by the 2080s, in a SRES A2 scenario, an ??upper bound?? climate scenario could see the likelihood of a 2005-like event more than double. We estimate that total losses (direct plus indirect) associated with a 1-in-100 year event could triple compared with current situation (to $690?C$1,890 million USD), due to climate change alone. Continued rapid urbanisation could further increase the risk level. The analysis also demonstrates that adaptation could significantly reduce future losses; for example, estimates suggest that by improving the drainage system in Mumbai, losses associated with a 1-in-100 year flood event today could be reduced by as much as 70%.,We show that assessing the indirect costs of extreme events is an important component of an adaptation assessment, both in ensuring the analysis captures the full economic benefits of adaptation and also identifying options that can help to manage indirect risks of disasters. For example, we show that by extending insurance to 100% penetration, the indirect effects of flooding could be almost halved. We conclude that, while this study explores only the upper-bound climate scenario, the risk-assessment core demonstrated in this study could form an important quantitative tool in developing city-scale adaptation strategies. We provide a discussion of sources of uncertainty and risk-based tools could be linked with decision-making approaches to inform adaptation plans that are robust to climate change.  相似文献