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国玉伤痛宁软膏的研制及临床应用 被引量:1
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作者 李杰 周煌辉 唐国建 《湖南中医药导报》 2001年第8期399-400,共2页
作者介绍了国玉伤痛宁软膏的制备方法及质量标准。同时运用本品治疗损伤病例 149例 ,并与云南白药治疗的 82例作了对照 ,结果治疗组治愈率为 65 .1% ,总有效率为 95 .3% ;对照组治愈率为 37.8% ,总有效率为 85 .34 % ,两组差异有显著性... 作者介绍了国玉伤痛宁软膏的制备方法及质量标准。同时运用本品治疗损伤病例 149例 ,并与云南白药治疗的 82例作了对照 ,结果治疗组治愈率为 65 .1% ,总有效率为 95 .3% ;对照组治愈率为 37.8% ,总有效率为 85 .34 % ,两组差异有显著性差异 (P >0 .0 5 ) ,说明国玉伤痛宁软膏是一种较好的制剂。 展开更多
关键词 国玉伤痛宁 制备 质量标准 临床应用 中药
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史前新疆和田玉制品现状探讨
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作者 黄东海 《中国民族博览》 2016年第3期214-216,共3页
新疆和田玉是我国的国玉,是世界上最顶级的软玉。如何客观,公正对待史前和田玉制品工具发现,保护情况,保护现有潜在和田玉文物资源,是全民刻不容缓的重要问题。
关键词 新疆 史前文化 国玉 和田玉 软玉
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Fate of ^(15)N-Labeled Urea Under a Winter Wheat-Summer Maize Rotation on the North China Plain 被引量:44
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作者 JU Xiao-Tang LIU Xue-Jun +1 位作者 PAN Jia-Rong ZHANG Fu-Suo 《Pedosphere》 SCIE CAS CSCD 2007年第1期52-61,共10页
A field experiment was conducted to investigate the fate of ^15N-labeled urea and its residual effect under the winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation system on the North China... A field experiment was conducted to investigate the fate of ^15N-labeled urea and its residual effect under the winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation system on the North China Plain. Compared to a conventional application rate of 360 kg N ha^-1 (N360), a reduced rate of 120 kg N ha^-1 (N120) led to a significant increase (P 〈 0.05) in wheat yield and no significant differences were found for maize. However, in the 0-100 cm soil profile at harvest, compared with N360, N120 led to significant decreases (P 〈 0.05) of percent residual N and percent unaccounted-for N, which possibly reflected losses from the managed system. Of the residual fertilizer N in the soil profile, 25.6%-44.7% and 20.7%-38.2% for N120 and N360, respectively, were in the organic N pool, whereas 0.3%-3.0% and 11.2%-24.4%, correspondingly, were in the nitrate pool, indicating a higher potential for leaching loss associated with application at the conventional rate. Recovery of residual N in the soil profile by succeeding crops was less than 7.5% of the applied N. For N120, total soil N balance was negative; however, there was still considerable mineral N (NH4^+-N and NO3^--N) in the soil profile after harvest. Therefore, N120 could be considered ngronomically acceptable in the short run, but for long-term sustainability, the N rate should be recommended based on a soil mineral N test and a plant tissue nitrate test to maintain the soil fertility. 展开更多
关键词 ^15N-labeled urea nitrogen recovery nitrogen residual effect North China Plain winter wheat-summer maize rotation
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Comparison of Corn Production Costs in China,the U.S. and Brazil and Its Implications 被引量:3
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作者 钱福凤 杨军 Danielle Alencar ParenteTorres 《Agricultural Science & Technology》 CAS 2016年第3期731-736,共6页
This paper analyzes the corn production cost in China, the U.S. and Brazil from 1997 to 2014. According to the results,(1) corn production cost in China is the highest among these three countries;(2) the rapid gro... This paper analyzes the corn production cost in China, the U.S. and Brazil from 1997 to 2014. According to the results,(1) corn production cost in China is the highest among these three countries;(2) the rapid growth of labor cost and land cost is the major factor that promotes the increase of total corn production cost in China;(3) the level of agricultural mechanization in China has been gradually improving, and the gap between agricultural mechanization levels in China and other two countries is constantly narrowing;(4) differing from the U.S. and Brazil,China exhibits a "high input, low output" agricultural production mode. Based on the above analyses, corresponding suggestions have been presented to reduce corn production cost in China. 展开更多
关键词 CORN Production cost China the U.S Brazil
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Groundwater Contamination with NO_3-N in a Wheat-Corn Cropping System in the North China Plain 被引量:20
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作者 ZHAO Bing-Zi ZHANG Jia-Bao +3 位作者 M. FLURY ZHU An-Ning JIANG Qi-Ao BI Jin-Wei 《Pedosphere》 SCIE CAS CSCD 2007年第6期721-731,共11页
The North China Plain,where summer corn(Zea mays L.)and winter wheat(Triticum aestivum L.)are the major crops grown,is a major agricultural area in China.Permeable soils make the region susceptible to groundwater poll... The North China Plain,where summer corn(Zea mays L.)and winter wheat(Triticum aestivum L.)are the major crops grown,is a major agricultural area in China.Permeable soils make the region susceptible to groundwater pollution by NO_3-N,which is applied to fields in large amounts of more than 400 kg NO_3-N ha^(-1)as fertilizer.A field experiment was established in 2002 to examine the relationship among N fertilization rate,soil NO_3-N,and NO_3-N groundwater contamination.Two adjacent fields were fertilized with local farmers' N fertilization rate(LN)and double the normal application rate(HN),respectively,and managed under otherwise identical conditions.The fields were under a traditional summer corn/winter wheat rotation.Over a 22-month period,we monitored NO_3-N concentrations in both bulk soil and soil pore water in 20-40 cm increments up to 180 cm depth.We also monitored NO_3-N concentrations in groundwater and the depth of the groundwater table.No significant differences in soil NO_3-N were observed between the LN and HN treatment.We identified NO_3-N plumes moving downward through the soil profile.The HN treatment resulted in significantly higher groundwater NO_3-N,relative to the LN treatment,with groundwater NO_3-N consistently exceeding the maximum safe level of 10 mg L^(-1),but groundwater NO_3-N above the maximum safe level was also observed in the LN treatment after heavy rain.Heavy rain in June,July,and August 2003 caused increased NO_3-N leaching through the soil and elevated NO_3-N concentrations in the groundwater.Concurrent rise of the groundwater table into NO_3-N- rich soil layers also contributed to the increased NO_3-N concentrations in the groundwater.Our results indicate that under conditions of average rainfall,soil NO_3-N was accumulated in the soil profile.The subsequent significantly higher- than-average rainfalls continuously flushed the soil NO_3-N into deeper layers and raised the groundwater table,which caused continuous groundwater contamination with NO_3-N.The results suggest that under common farming practices in the North China Plain,groundwater contamination with NO_3-N was likely,especially during heavy rainfalls,and the degree of groundwater contamination appeared to be proportional to the N application rates.Decreasing fertilization rates, splitting fertilizer inputs,and optimizing irrigation scheduling had potential to reduce groundwater NO_3-N contamination. 展开更多
关键词 field experiment groundwater contamination NO3-N wheat-corn cropping system
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Spatial Variability of Soil Organic Carbon Under Maize Monoculture in the Song-Nen Plain, Northeast China 被引量:19
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作者 WANG Zong-Ming , ZHANG Bai, SONG Kai-Shan, LIU Dian-Wei and REN Chun-Ying Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun 130012 (China) 《Pedosphere》 SCIE CAS CSCD 2010年第1期80-89,共10页
Soil organic carbon (SOC) and its relationship with landscape attributes are important for evaluating current regional, continental, and global carbon stores. Data of SOC in surface soils (0–20 cm) of four main soils... Soil organic carbon (SOC) and its relationship with landscape attributes are important for evaluating current regional, continental, and global carbon stores. Data of SOC in surface soils (0–20 cm) of four main soils, Cambisol, Arenosol, Phaeozem, and Chernozem, were collected at 451 locations in Nongan County under maize monoculture in the Song-Nen Plain, Northeast China. The spatial characteristics of soil organic carbon were studied, using geographic information systems (GIS) and geostatistics. Effects of other soil physical and chemical properties, elevation, slope, and soil type on SOC were explored. SOC concentrations followed a normal distribution, with an arithmetic mean of 14.91 g kg-1 . The experimental variogram of SOC was fitted with a spherical model. There were significant correlations between soil organic carbon and bulk density (r =-0.374**), pH (r = 0.549**), total nitrogen (r = 0.781**), extractable phosphorus (r =-0.109*), exchangeable potassium (r = 0.565**), and cation exchange capacity (r = 0.313**). Generally, lower SOC concentrations were significantly associated with high elevation (r =-0.429**). Soil organic carbon was significantly negatively correlated with slope gradient (r =-0.195**). Samples of the Cambisol statistically had the highest SOC concentrations, and samples of the Arenosol had the lowest SOC value. 展开更多
关键词 GEOSTATISTICS slope soil bulk density spatial distribution
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Long-Term Effect of No-Tillage on Soil Organic Carbon Fractions in a Continuous Maize Cropping System of Northeast China 被引量:27
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作者 HUANG Shan SUN Yan-Ni +2 位作者 RUI Wen-Yi LIU Wu-Ren ZHANG Wei-Jian 《Pedosphere》 SCIE CAS CSCD 2010年第3期285-292,共8页
Increasing evidence has shown that conservation tillage is an effective agricultural practice to increase carbon (C) sequestration in soils. In order to understand the mechanisms underlying the responses of soil org... Increasing evidence has shown that conservation tillage is an effective agricultural practice to increase carbon (C) sequestration in soils. In order to understand the mechanisms underlying the responses of soil organic carbon (SOC) to tillage regimes, physical fractionation techniques were employed to evaluate the effect of long-term no-tillage (NT) on soil aggregation and SOC fractions. Results showed that NT increased the concentration of total SOC by 18.1% compared with conventional tillage (CT) under a long-term maize (Zea mays L.) cropping system in Northeast China. The proportion of soil large macroaggregates (〉 2 000 μm) was higher in NT than that in CT, while small macroaggregates (250-2 000μm) showed an opposite trend. Therefore, the total proportion of macroaggregates (〉 2 000 and 250-2 000μm) was not affected by tillage management. However, C concentrations of macroaggregates on a whole soil basis were higher under NT relative to CT, indicating that both the amount of aggregation and aggregate turnover affected C stabilization. Carbon concentrations of intra-aggregate particulate organic matter associated with microaggregates (iPOM-m) and microaggregates occluded within macroaggregates (iPOM-mM) in NT were 1.6 and 1.8 times greater than those in CT, respectively. Carbon proportions of iPOM-n and iPOM-mM in the total SOC increased from 5.4% and 6.3% in CT to 7.2% and 9.7% in NT, respectively. Furthermore, the difference in the microaggregate protected C (i. e., iPOM-m and iPOM-mM) between NT and CT could explain 45.4% of the difference in the whole SOC. The above results indicate that NT stimulates C accumulation within microaggregates which then are further acted upon in the soil to form macroaggregates. The shift of SOC within microaggregates is beneficial for long-term C sequestration in soil. We also corroborate that the microaggregate protected C is useful as a pool for assessing the impact of tillage management on SOC storage. 展开更多
关键词 carbon sequestration conservation tillage particulate organic matter physical fractionation soil aggregates
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Molecular Characterization of Segments S7 to S10 of a Southern Rice Black-streaked Dwarf Virus Isolate from Maize in Northern China 被引量:28
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作者 Xiao Yin Fei-fei Xu +3 位作者 Fang-qiang Zheng Xiang-dong LI Bao-shen Liu Chun-qing Zhang 《Virologica Sinica》 SCIE CAS CSCD 2011年第1期47-53,共7页
Southern rice black-streaked dwarf virus (SRBSDV) is a novel Fijivirus prevalent in rice in southern and central China,and northern Vietnam. Its genome has 10 segments of double-stranded RNA named S1 to S10 according ... Southern rice black-streaked dwarf virus (SRBSDV) is a novel Fijivirus prevalent in rice in southern and central China,and northern Vietnam. Its genome has 10 segments of double-stranded RNA named S1 to S10 according to their size. An isolate of SRBSDV,JNi4,was obtained from naturally infected maize plants from Ji'ning,Shandong province,in the 2008 maize season. Segments S7 to S10 of JNi4 share nucleotide identities of 72.6%-73.1%,72.3%-73%,73.9%-74.5% and 77.3%-79%,respectively,with corresponding segments of Rice black-streaked dwarf virus isolates,and identities of 99.7%,99.1%-99.7%,98.9%-99.5%,and 98.6%-99.2% with those of SRBSDV isolates HN and GD. JNi4 forms a separate branch with GD and HN in the phylogenetic trees constructed with genomic sequences of S7 to S10. These results confirm the proposed taxonomic status of SRBSDV as a distinct species of the genus Fijivirus and indicate that JNi4 is an isolate of SRBSDV. Shandong is so far the northernmost region where SRBSDV is found in China. 展开更多
关键词 Southern rice black-streaked dwarf virus (SRBSDV) Maize rough dwarf disease (MRD) Identity Phylogenetic analysis
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Applicability of Cytoplasmic Male Sterility (CMS) as a Reliable Biological Confinement Method for the Cultivation of Genetically Modified Maize in Germany
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作者 Heidrun Biickmann Alexandra Hiisken Joachim Schiemann 《Journal of Agricultural Science and Technology(A)》 2013年第5期385-403,共19页
The cultivation of genetically modified (GM) plants requires the reduction of an unwanted spread of genes (biological confinement). Cytoplasmic male sterility (CMS) inhibits the development of functional pollen,... The cultivation of genetically modified (GM) plants requires the reduction of an unwanted spread of genes (biological confinement). Cytoplasmic male sterility (CMS) inhibits the development of functional pollen, but nuclear restorer (RJ) genes and environmental impacts can restore the fertility. The aim of this study was to verify whether CMS in maize hybrids is a reliable confinement method for the prospective cultivation of GM maize in Germany. Two-year field experiments in three different environments were conducted with three CMS maize hybrids which vary in the CMS stability, one conventional maize variety (all yellow kernels) and white maize as pollen recipient. Tassel characteristics, pollen vitality and cross-pollination rates were investigated. The CMS stability was dependent on the genotype and the specific weather conditions per year and location. In all maize hybrids CMS was unstable. One CMS maize hybrid showed a high level of CMS stability and very low cross-pollination rates in any case (〈 1%). The two other CMS maize hybrids developed more fluctuant and fertile tassels with few or many pollen, respectively. Compared with a conventional and fully fertile maize variety, cross-pollination of all CMS maize hybrids was strongly reduced (84%-99%). In conclusion, the CMS trait can be proposed as a useful biological confinement method to reduce pollen-mediated gene flow from GM maize. 展开更多
关键词 CMS pollen release biological confinement cross-pollination reduction GM maize (Zea mays L.).
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Stem Borer Species Composition on Maize and Two Non-Cereal Hosts in the Forest Zone of Kisangani, DRC
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作者 Onesime Mubenga Kankonda Dudu Akaibe +2 位作者 Walangululu Massamba George Otieno Ong'amo Bruno-Pierre Le Ru 《Journal of Agricultural Science and Technology(A)》 2014年第10期822-829,共8页
Lepidopteran stem borers are the most damaging pests of maize in Sub-Saharan Africa. Despite the growing importance of maize in the forest zone of Democratic Republic of Congo, no data is available regarding stem bore... Lepidopteran stem borers are the most damaging pests of maize in Sub-Saharan Africa. Despite the growing importance of maize in the forest zone of Democratic Republic of Congo, no data is available regarding stem borer pest species present and their relative importance. It is thus important to gather information likely to guide future research in this area. This study was undertaken to catalogue stem borer pest species identity and assess their relative infestation levels on maize. Surveys were carried out in wild and cultivated habitats in Kisangani. Five species were collected on maize, i.e., Sesamia calamistis Hampson (1910), Eldana saccharina Walker (1865), Busseola fusca Fuller (1901), Chilo sp. Strand (1913), and Mussidia nigrivenella Ragonot (1888). In the wild habitats, Poenoma serrata Hampson, B. fusca and S. calamistis were collected on Pennisetum purpureum whereas Chilo sp. was collected on Panicum maximum. Our results suggest that P. maximum might affect the population dynamics of Chilo sp. whereas P. purpureum is expected not to influence the population dynamics of other stem borers owing to its scarcity in the interior of the forest. 展开更多
关键词 Stem borers MAIZE Busseolafusca Chilo sp. Eldana saccharina forest zone Kisangani.
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Evaluation and Performance of the APSIM Crop Growth Model for German Winter Wheat, Maize and Fieldpea Varieties in Monocropping and Intercropping Systems 被引量:1
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作者 H. Knorzer R. Lawes +2 位作者 M. Robertson S. Graeff-Honninger W. Claupein 《Journal of Agricultural Science and Technology(B)》 2011年第5期698-717,共20页
Competition for solar radiation between plants grown in multi-species cropping systems can severely limit crop production of individual species within that system. There are various approaches for modeling light inter... Competition for solar radiation between plants grown in multi-species cropping systems can severely limit crop production of individual species within that system. There are various approaches for modeling light interception within mixed-cropping and row or strip intercropping systems. To extend the knowledge about model behavior and different model approaches under interspecific competition conditions, the Agricultural Production Systems Simulator (APSIM) was evaluated and calibrated for field experiments previously described and simulated by the Decision Support System for Agrotechnology Transfer (DSSAT). Initially the APSIM plant model was successfully modified to simulate wheat, maize and fieldpea monocultures in the European agro-ecological zone. Once calibrated, the APSIM model was then used to simulate a strip relay intercropping maize/wheat and maize/fieldpea system. In DSSAT, a shading algorithm was introduced to modify the daily weather input in order to take competition for solar radiation into account. In contrast, APSIM simulates interspecific competition using a modified Beer's law for multi-component canopy conditions. After a re-evaluation of the model regarding a minimum change of crop coefficients and variables, APSIM was able to simulate dry matter and grain yield of German maize, wheat and fieldpea varieties adequately. However, APSIM is a point-based model, and many of the processes that influence strip cropping cannot be accommodated by adjusting Beer's Law alone. So far none of the tested frameworks successfully modeled strip or relay intercropping. The processes governing growth in the numerous and very diversifying intercropping systems are complex and at this point in time have not been captured in sufficient detail. 展开更多
关键词 APSIM competition DSSAT INTERCROPPING modeling solar radiation
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Shaking Intensity Distribution of the April 14,2010 Yushu,China Earthquake
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作者 Chen Kun Yu Yanxiang Gao Mengtan 《Earthquake Research in China》 2010年第3期394-397,共4页
Two hours after the 2010 Yushu Earthquake, the shaking intensity distribution was obtained using the ShakeMap Rapid Generation System Based on Site Effects, developed by the author, which integrates the information of... Two hours after the 2010 Yushu Earthquake, the shaking intensity distribution was obtained using the ShakeMap Rapid Generation System Based on Site Effects, developed by the author, which integrates the information of tectonic settings, the strike and scale of causative faults, focal mechanism solutions, fault rupture process and attenuation relationship in Western China, as well as local site effects. The results are as follows: (1) The major axis of shaking intensity distribution is directed NW-SE, parallel to the Yushu fault; (2) The meizoseismal area reaches an intensity IX and covers 300km^2; (3) The intensity IX area is mainly distributed in the area 40km southeast and 15km northwest of the epicenter along the causative fault; (4) Due to local soil conditions, the northwestern part of the area with intensity IX on bedrock shows an intensity Ⅷ when converting from the bedrock to the soil; (5) Areas with intensity Ⅷ, VII, VI measure 3,000km^2, 8,000km^2, and 24,000km^2, respectively. 展开更多
关键词 ShakeMap Shaking Intensity Yushu Earthquake
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Assessing the Impact of Year 2012 Drought on Corn Yield in the US Corn Belt Using Precipitation Data
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作者 Joe Wan Michael Qu +2 位作者 Xianjun Hao Ray Motha John J. Qu 《Journal of Earth Science and Engineering》 2015年第6期333-337,共5页
Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Bel... Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Belt by integrating county-level crop yield data from the USDA NASS Quick Stats database and precipitation data from the NCDC GHCN-Daily database. It is found that precipitation over an 8-week period in corn growth stages is critical for corn yield, the logarithm of precipitation during the period explained 55% of corn yield variation. The results indicated the importance of water supply in corn silking stage, and provided an approach to assess the impacts of drought on corn yield quantitatively. 展开更多
关键词 CORN DROUGHT YIELD PRECIPITATION Corn Belt.
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Maize-rice cropping systems in Bangladesh: Status and research needs 被引量:3
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作者 M. Yusuf Ali S. R. Waddington +2 位作者 J. Timsina D. Hodson J. Dixon 《Journal of Agricultural Science and Technology》 2009年第6期35-53,共19页
Maize-rice cropping systems are expanding in Bangladesh. Hybrid maize has increasing demand and value, particularly for poultry feed, while rice remains the traditional dominant starch staple food. Bangladesh maize yi... Maize-rice cropping systems are expanding in Bangladesh. Hybrid maize has increasing demand and value, particularly for poultry feed, while rice remains the traditional dominant starch staple food. Bangladesh maize yields (with average farm yields around 5.7 t·ha^-1) are among the highest found in Asia. Cool winter (Rabi) season maize followed by T. Aman (monsoon) rice is the major cropping system; however it is now becoming diversified with many other crops including potato. Financially, hybrid maize is far more profitable than boro (irrigated) rice, wheat, or most other competing winter season Rabi crops. Although maize is relatively problem-free in Bangladesh, some constraints are intensifying with increased concern over input supply and soil-related environmental sustainability. An array of new technologies for sustainable intensive maize production systems is emerging in Bangladesh and some are being promoted and adopted. Continued sustainability of hybrid maize production in Bangladesh depends on optimization of planting time, quality seed of appropriate hybrids, balanced use of nutrient inputs along with soil fertility conservation and other management, for which further research would be high priority. 展开更多
关键词 maize-rice BANGLADESH problems and risks promising technologies research needs
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Evapotranspiration and ratio of soil evaporation to evapotranspiration of winter wheat and maize in north China
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作者 Zheng Wei Yu Liu +1 位作者 Di Xu Jiabing Cai 《International Journal of Technology Management》 2013年第2期100-103,共4页
Evapotranspiration (ETc) is an important quantity for hydrological cycle. This study shows evapotranspiration, the ratio of evaporation to evapotranspiration (E/ETc) of winter wheat and maize in north China. Sever... Evapotranspiration (ETc) is an important quantity for hydrological cycle. This study shows evapotranspiration, the ratio of evaporation to evapotranspiration (E/ETc) of winter wheat and maize in north China. Several relationships, namely, E/ET0 and soil surface moisture, E/ET0 and leaf area index (LAI), are also analyzed. The average seasonal ETc values for winter wheat, maize (2008) and maize (2009) are 431.21,456.3 and 341.4mm. The value of E/ET0 varied from 1 at initial growth stage to 0.295 at the later growth for winter wheat, and from 1 to 0.492, from 1 to 0.566 for maize (2008) and maize (2009). The relationship between E/ET0 and surface soil water content, and E/ET0 and LAI are fitted to a quadratic parabola equation with significant correlation coefficients, respectively, for wheat and maize. These results should help the precise planning and efficient management of irrigation for these crops in this region. 展开更多
关键词 EVAPOTRANSPIRATION soil evaporation surface soil water content winter wheat MAIZE
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Impediments to New Improved Maize Variety Testing and Release in Selected Countries in Sub-Saharan Africa
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作者 P. S. Setimela B. Badu-Apraku W. Mwangi 《Journal of Agricultural Science and Technology》 2010年第6期79-85,共7页
Before farmers can benefit from new improved maize varieties with novel genetic information, new maize varieties have to undergo performance testing, registration and approval. The registration procedures require that... Before farmers can benefit from new improved maize varieties with novel genetic information, new maize varieties have to undergo performance testing, registration and approval. The registration procedures require that new maize varieties must pass the tests for value for cultivation and use (VCU) and standardized tests for distinctness, uniformity and stability (DUS). To meet the minimum requirements for variety release, public and private sector maize breeding programs routinely assemble breeding nurseries and evaluate variety performance in National and Regional Performance Trials (NRPT) with the objective of generating important agronomic data to identify the best maize varieties for release. In spite of intensive variety evaluation in regional and national trials, only few maize varieties have been registered and released annually in sub-Saharan Africa (SSA) denying farmers access to new improved varieties. The purpose of this study was to identify constraints hampering the registration and release of elite maize gennplasm and make recommends on how to quicken the deployment of elite germplasm to smallholders' farmers. A survey was conducted on the varietal testing and release systems in 14 selected countries (Angola, Benin, Ethiopia, Malawi, Ghana, Mali, Mozambique, Nigeria, Tanzania, Kenya, South Africa, Uganda, Zambia, and Zimbabwe) in SSA. The results from the study show that regulations on variety testing and release procedures in the various countries are overlapping and rigid hindering the deployment and commercialization of new improved maize germplasm. The study also showed that varietal release rates fluctuated between countries with South Africa having the highest number of varietal release rates per year and some countries failing to release a single variety per year. 展开更多
关键词 DUS maize VCU variety release seed regulations improved varieties.
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罗振玉“逼债”说之源流及其与王国维经济关系考论 被引量:5
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作者 彭玉平 《北京大学学报(哲学社会科学版)》 CSSCI 北大核心 2022年第1期95-107,共13页
王国维自沉颐和园之年,正是位居天津张园的逊清小朝廷政治斗争激烈之时,以溥仪深相赏识的王国维之死作为契机排斥异己,成为郑孝胥等人的政治谋略。罗振玉“逼债”王国维之说就是在郑孝胥的策划下,经史达、郭沫若、溥仪、周君适等人递相... 王国维自沉颐和园之年,正是位居天津张园的逊清小朝廷政治斗争激烈之时,以溥仪深相赏识的王国维之死作为契机排斥异己,成为郑孝胥等人的政治谋略。罗振玉“逼债”王国维之说就是在郑孝胥的策划下,经史达、郭沫若、溥仪、周君适等人递相祖述并加诡异想象,而使这一谣言一时竟然成为“公论”。而王国维之女王东明则认为王国维之死与王潜明早逝有关,明确说明无关乎罗振玉之逼债。检王国维与罗振玉近三十年相知相交的经历,虽然在王国维1916年从日本回国后,两人通信多有对古物、书画的买卖之事,但王国维主要提供信息以供罗振玉参酌,罗买与王买分得清清楚楚。罗振玉确实对王国维一家经济多有支持,但其主要方式是为王国维提供以劳务、职业或职务而获取报酬的机会。罗振玉视王国维为天挺之才,深感若令其旁皇生计乃是自己的耻辱,所以用各种方式缓解王家的经济困难,其主要目的是让王国维勿劳分心专力学术,以精深之学术延续中国学术之辉煌,罗振玉的胸襟与格局之高由此可见一斑。罗、王经济关系的底蕴在学术,这是现代学术史上值得书写的一章。 展开更多
关键词 罗振玉 王国维 郑孝胥 “逼债” 经济关系
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另一侧的潜流:清末国学变迁与章太炎的明治汉学批判
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作者 彭春凌 《北京大学学报(哲学社会科学版)》 CSSCI 北大核心 2020年第6期88-97,共10页
20世纪初,海外特别是明治汉学的波澜与中国国学界的跃动,事件层层叠叠,表现出互相倚依、内外牵扯的二重奏样态。1911年《学林》所载章太炎《与农科大学教习罗振玉书》,猛烈抨击明治汉学,乃近代中日文化交流史上的关键文本。往往被忽视... 20世纪初,海外特别是明治汉学的波澜与中国国学界的跃动,事件层层叠叠,表现出互相倚依、内外牵扯的二重奏样态。1911年《学林》所载章太炎《与农科大学教习罗振玉书》,猛烈抨击明治汉学,乃近代中日文化交流史上的关键文本。往往被忽视的另一侧,即中国国学界内部之演变,助推了章太炎的明治汉学批判。无论是抨击褒奖日本汉学的风气,还是质疑以新出土文物为重心的学术潮流,章太炎的相关言论,可溯自《国粹学报》。俞樾与岛田翰,才是他批判文章中未录其名,但内心实则紧张的人物。“依自不依他”,作为章太炎的伦理和学术立场,也反映了古物流失过程中,中国知识人通过坚信内心的实在圆满来应对外在事物变迁流转的共同心态。“故闻”与“古物”之学的纷争,蕴含了章太炎论衡“国故”与罗振玉“古器物之学”各自的关切。两人均视对方为争夺“国学”话语权的对手。《学林》与《国学丛刊》的创刊和隔空论争,意味着他们分别另起炉灶。从《国粹学报》到《与罗振玉书》的相关事件和言论,有助于我们理解在西力东侵、东学寝盛的背景下,中国国学界所经历的这段心态调整、人事变迁,学术竞争与转轨的动态历史。 展开更多
关键词 章太炎 罗振玉 《国粹学报》 明治汉学
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Root growth in response to nitrogen supply in Chinese maize hybrids released between 1973 and 2009 被引量:15
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作者 WU QiuPing CHEN FanJun +3 位作者 CHEN YanLing YUAN LiXing ZHANG FuSuo MI GuoHua 《Science China(Life Sciences)》 SCIE CAS 2011年第7期642-650,共9页
Root growth has a fundamental role in nitrogen (N) use efficiency. Nevertheless, little is known about how modem breeding progress has affected root growth and its responses to N supply. The root and shoot growth of... Root growth has a fundamental role in nitrogen (N) use efficiency. Nevertheless, little is known about how modem breeding progress has affected root growth and its responses to N supply. The root and shoot growth of a core set of 11 representative Chinese maize (Zea mays L.) hybrids released between 1973 and 2009 were investigated under high N (4 mmol L^-1, HN) and low N (0.04 mmol L^-1, LN) levels in a solution culture system. Compared with LN, HN treatment decreased root dry weight (RDW), the root: shoot ratio (R/S), and the relative growth rate for root dry weight (RGRroot), but increased the total root length (TRL) and the total lateral root length (LRL). The total axial root length (ARL) per plant was reduced under HN, mostly in hybrids released before the 1990s. The number of seminal roots (SRN) was largely unaffected by different N levels. More recently released hybrids showed higher relative growth rates in the shoot under both HN and LN. However, the roots only showed increased RGR under HN treatment. Correspondingly, there was a positive linear relationship with the year of hybrid release for TRL, LRL and ARL under HN treatment. Together, these results suggest that while shoot growth of maize has improved, its root growth has only improved under high N conditions over the last 36 years of selective breeding in China. Improving root growth under LN conditions may be necessary to increase the N use efficiency of maize. 展开更多
关键词 ROOT R/S ratio NITROGEN relative growth rate maize breeding
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Effect of Long-Term Potassium Fertilization on Crop Yield and Potassium Efficiency and Balance Under Wheat-Maize Rotation in China 被引量:24
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作者 ZHANG Hui-Min YANG Xue-Yun +4 位作者 HE Xin-Hua XU Ming-Gang HUANG Shao-Min LIU Hua WANG Bo-Ren 《Pedosphere》 SCIE CAS CSCD 2011年第2期154-163,共10页
Sustainable potassium (K) management at different soil sites requires understanding the relationships between crop productivity and long-term K fertilizations on a regional or national scale. We analyzed responses o... Sustainable potassium (K) management at different soil sites requires understanding the relationships between crop productivity and long-term K fertilizations on a regional or national scale. We analyzed responses of grain yield of wheat (Triticum aestivurn L.) and maize (Zea mays L.), K efficiency, and partial balance (difference between K input through fertilizer and K output in the aboveground biomass) during 15- (1990-2005) or 18-year (1990-2008) K fertilizations at five distinctive agroecologicai zones across China. Compared to the inorganic nitrogen (N) and phosphorus (P) fertilization, the inorganic NPK fertilization significantly increased grain yields of wheat (21%) and maize (16% 72%) at Qiyang and Changping, where soils have low exchangeable and non-exchangeable K contents, but not at Uriimqi, Yangling and Zhengzhou, where soils have a high exchangeable and non-exchangeable K and/or low N/K ratio in crop plants. Compared to the inorganic NPK fertilization, the inorganic NPK (30% N) and organic manure (70~~ N) fertilization (NPKM) increased grain yields of wheat (14%-40%) and maize (9%-6170) at four sites, but not at Zhengzhou. For a productivity of wheat at 2-5 t ha-1 or maize at 3-6 t ha 1, 13-26 or 9-17 kg K ha 1 were required to produce 1.0 t wheat or maize. The NP fertilization resulted in the lowest negative partial K balance and accumulated 52 kg K ha-1 year-1 less than the NPK fertilization, which accumulated 28 kg ha 1 year-1 less K than the NPKM fertilization. A re-evaluation of the site-specific fertilization effects on N/K ratio in crop plants and soil K accumulation under current NPK and NPKM t'ertilization is urgently needed to increase both crop yield and K use efficiency at different agroecologicai zones across China. 展开更多
关键词 exchangeable K internal K use efficiency K harvest index K uptake non-exchangeable K
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