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地理教学语言的“地理性” 被引量:3
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作者 陈大路 《黑龙江教育(中学版)》 2004年第1期44-45,共2页
学科语言必须有自己学科的特性,地理教学语言也不例外。深入研究地理教学语言的学科特性——地理性,是提高地理教学质量的重要途径之一。地理教学语言的学科特性,主要表现在以下几方面。
关键词 地理教学 教学语言 “地理性” 教学质量 形体语言 德育 中学
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Genetic variations of wood properties and growth characters of Ko-rean pines from different provenances 被引量:4
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作者 王慧梅 夏德安 +1 位作者 王文杰 杨书文 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第4期277-280,337,共4页
Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatom... Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude. 展开更多
关键词 Korean pine Provenance trial Wood properties Geographical variation Genetic variation
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Genetic Diversity of Achnatherum Splendens 被引量:8
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作者 徐海霞 张霞 +2 位作者 王绍明 阎平 杜金洲 《Agricultural Science & Technology》 CAS 2008年第1期21-23,28,共4页
[Objective] Study on the genetic diversities of A.splendens from different areas of xinjiang. [Method] The genetic diversities among seven populations and within two populations were analyzed by RAPD. [Result] Genetic... [Objective] Study on the genetic diversities of A.splendens from different areas of xinjiang. [Method] The genetic diversities among seven populations and within two populations were analyzed by RAPD. [Result] Genetic clustering results presented that the relationships among populations of A. splendens are directly related with geographic positions, and within population are related with habitats. [Conclusion] RAPD technique can be used to study genetic diversity of A. splendens. 展开更多
关键词 Achnatherum splendens RAPD Genetic diversity
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Interspecific Transition Among Caragana microphylla, C. davazamcii and C. korshinskii Along Geographic Gradient. Ⅱ. Characteristics of Photosynthesis and Water Metabolism 被引量:13
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作者 马成仓 高玉葆 +1 位作者 郭宏宇 王金龙 《Acta Botanica Sinica》 CSCD 2003年第10期1228-1237,共10页
The characteristics of photosynthesis and water metabolism of Caragana microphylla Lam.,C. davazamcii Sancz. and C. korshinskii Kom. populations in different sites (117.6o-105.7o E, 44.6o-38.8o N)were studied. (1) Fro... The characteristics of photosynthesis and water metabolism of Caragana microphylla Lam.,C. davazamcii Sancz. and C. korshinskii Kom. populations in different sites (117.6o-105.7o E, 44.6o-38.8o N)were studied. (1) From the east to the west, the responses of the three species to photosyntheticallyavailable radiation (PAR) in net photosynthesis rate increased, the relative humidity of the air whichcorresponded to the occurrence of maximum photosynthesis rate decreased, and the corresponding airtemperature increased. Along the same gradient, the before-noon superiority of the photosynthesis be-came evident, and the photosynthesis rate and the light use efficiency (LUE ) increased, while the transp-iration rate decreased, thus the water use efficiency (WUE ) increased notably, and the leaf water contentdecreased gradually. From the east to the west, the plants took a water-saving strategy step by step withhigher photosynthesis rate and lower transpiration rate. These physiological changes in the plants wereadaptable to the conditions of light, temperature and humidity in the habitat of the plants, and might be thebiological foundation for the geographical transition among C. microphylla , C. davazamcii and C. korshinskii.(2) The adaptation of photosynthetic system of C. microphylla , C. davazamcii and C. korshinskii to PAR, airhumidity and temperature exhibited the interspecific continuity, which was consistent with theenvironmental gradient. In different species and different sites, the diurnal changes of net photosynthesisrate, the daily cumulative value of net photosynthesis, the diurnal changes of transpiration rate, the dailycumulative value of transpiration, the water use efficiency and the diurnal changes of leaf water contentvaried with longitudinal descent (from the east to the west). The characteristics of photosynthesis andwater metabolism indicated that the geographical transition among C. microphylla , C. davazamcii and C.korshinskii was in gradual change, and these three species formed a geographical cline. 展开更多
关键词 Caragana microphylla C. davazamcii C. korshinskii geographical transition PHOTOSYNTHESIS water metabolism
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A generalized viscoelastic Biot/squirt model for clay-bearing sandstones in a wide range of permeabilities 被引量:7
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作者 聂建新 杨顶辉 杨慧珠 《Applied Geophysics》 SCIE CSCD 2008年第4期249-260,共12页
To simultaneously take into account the Biot-flow mechanism, the squirt-flow mechanism, and the frame-viscoelasticity mechanism, a generalized viscoelastic BISQ (Biot/squirt) model is developed for wave propagation ... To simultaneously take into account the Biot-flow mechanism, the squirt-flow mechanism, and the frame-viscoelasticity mechanism, a generalized viscoelastic BISQ (Biot/squirt) model is developed for wave propagation in clay-bearing sandstones based on Dvorkin's elastic BISQ model. The present model is extended to a wide range of permeabilities (k 〉 0.05 mD) by introducing a dimensionless correction factor for viscoelastic parameters, defined as a function of the permeability and the clay content. We describe the frame's stress-strain relationship of the clay-bearing sandstones by the differential constitutive equations of generalized viscoelasticity and then derive the viscoelastic-wave dynamic equations. With the assumption of a plane-wave solution, we finally yield the phase velocities and the attenuation coefficients by solving the dynamic wave equations in the frequency and wave number domain. The comparison of numerical results and experimental data shows that the generalized viscoelastic BISQ model is applicable for modeling the wave propagation in most of the sandstones mainly bearing kaolinite clay. 展开更多
关键词 VISCOELASTICITY BISQ model clay-bearing sandstones phase velocity attenuationcoefficient
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Interspecific Transition Among Caragana microphylla, C. davazamcii and C. korshinskii Along Geographic Gradient. Ⅰ. Ecological and RAPD Evidence 被引量:12
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作者 马成仓 高玉葆 +2 位作者 刘惠芬 王金龙 郭宏宇 《Acta Botanica Sinica》 CSCD 2003年第10期1218-1227,共10页
The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau.... The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau. The present study on population distribution, taxonomy, morphology, development andgenetic structure demonstrated that the geographical distribution of these three species was successiveand in gradual change, thus forming a geographical cline which extended from the east to the west of NeiMongol Plateau. With an analysis of climate change over time, it was considered that the formation of thisgeographical cline was a result of plant adaptation to its natural environment. 展开更多
关键词 Caragana microphylla C. davazamcii C. korshinskii interspecific transition alonggeographical gradient Morphology TAXONOMY RAPD
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Variation of Nitrogen Uptake and Utilization Efficiency of Mid-Season Hybrid Rice at Different Ecological Sites under Different Nitrogen Application Levels 被引量:3
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作者 徐富贤 熊洪 +4 位作者 张林 郭晓艺 朱永川 周兴兵 刘茂 《Agricultural Science & Technology》 CAS 2011年第7期1001-1009,1012,共10页
[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and ut... [Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice.[Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials,field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009.A total of four nitrogen application levels were set as follows:by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer,extra 0,90,150 and 210 kg/hm2 of nitrogen fertilizer(in which,base fertilizer,base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%,20% and 20%.) was applied,respectively.In the split-plot design,fertilizer was considered as the main factor while rice variety was taken as the secondary factor.A total of eight treatments were set with three replications.[Result] Highly significant differences of grain yield were found among seven locations,two varieties,four nitrogen application levels,interactions of site × variety and site × nitrogen application level,but the interaction of variety ×nitrogen application level had no significant influence on rice yield.There were highly significant effects of site,varieties and nitrogen application level on dry matter production,nitrogen content,nitrogen utilization efficiency.Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found;and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites,chemical quality of soil and the levels of nitrogen application.[Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation. 展开更多
关键词 Mid-season hybrid rice Ecological site Soil chemical characteristics Nitrogen application level Nitrogen uptake and utilization efficiency
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Gas sand distribution prediction by prestack elastic inversion based on rock physics modeling and analysis 被引量:5
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作者 贺芙邦 游俊 陈开远 《Applied Geophysics》 SCIE CSCD 2011年第3期197-205,240,共10页
Seismic inversion is one of the most widely used technologies for reservoir prediction. Many good results have been obtained but sometimes it fails to differentiate the lithologies and identify the fluids. However, se... Seismic inversion is one of the most widely used technologies for reservoir prediction. Many good results have been obtained but sometimes it fails to differentiate the lithologies and identify the fluids. However, seismic prestack elastic inversion based on rock physics modeling and analysis introduced in this paper is a significant method that can help seismic inversion and interpretation reach a new quantitative (or semi-quantitative) level from traditional qualitative interpretation. By doing rock physics modeling and forward perturbation analysis, we can quantitatively analyze the essential relationships between rock properties and seismic responses and try to find the sensitive elastic properties to the lithology, porosity, fluid type, and reservoir saturation. Finally, standard rock physics templates (RPT) can be built for specific reservoirs to guide seismic inversion interpretation results for reservoir characterization and fluids identification purpose. The gas sand distribution results of the case study in this paper proves that this method has unparalleled advantages over traditional post-stack methods, by which we can perform reservoir characterization and seismic data interpretation more quantitatively and efficiently. 展开更多
关键词 Rock physics seismic response elastic parameters elastic inversion reservoir characterization MODELING
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Exploration of the spatial pattern of urban residential land use with geographically weighted regression technique: a case study of Nanjing,China 被引量:1
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作者 胡明星 吴江 朱选 《Journal of Southeast University(English Edition)》 EI CAS 2015年第1期149-156,共8页
As the traditional methods and technical means cannot meet the quantitative research needs of the urban land use patterns, quantitative research methods for the urban land use pattern are established via the GIS (geo... As the traditional methods and technical means cannot meet the quantitative research needs of the urban land use patterns, quantitative research methods for the urban land use pattern are established via the GIS (geographic information system ) technique combined with the related theories and models. Taking the city of Nanjing as an example, a spatial database of urban land use and other environmental and socio-economic data is constructed. A multiple linear regression model is developed to determine the statistically significant factors affecting the residential land use distributions. To explain the spatial variations of urban land use patterns, the geographically weighted regression (GWR) is employed to establish spatial associations between these significant factors and the distribution of urban residential land use. The results demonstrate that the GWR can provide an effective approach to the exploration of the urban land use spatial patterns and also provide useful spatial information for planning residential development and other types of urban land use. 展开更多
关键词 urban residential land use GIS (geographic information system) multiple linear regression geographically weighted regression
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New seismic attribute:Fractal scaling exponent based on gray detrended fluctuation analysis 被引量:1
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作者 黄亚平 耿建华 郭彤楼 《Applied Geophysics》 SCIE CSCD 2015年第3期343-352,467,共11页
Seismic attributes have been widely used in oil and gas exploration and development. However, owing to the complexity of seismic wave propagation in subsurface media, the limitations of the seismic data acquisition sy... Seismic attributes have been widely used in oil and gas exploration and development. However, owing to the complexity of seismic wave propagation in subsurface media, the limitations of the seismic data acquisition system, and noise interference, seismic attributes for seismic data interpretation have uncertainties. Especially, the antinoise ability of seismic attributes directly affects the reliability of seismic interpretations. Gray system theory is used in time series to minimize data randomness and increase data regularity. Detrended fluctuation analysis (DFA) can effectively reduce extrinsic data tendencies. In this study, by combining gray system theory and DFA, we propose a new method called gray detrended fluctuation analysis (GDFA) for calculating the fractal scaling exponent. We consider nonlinear time series generated by the Weierstrass function and add random noise to actual seismic data. Moreover, we discuss the antinoise ability of the fractal scaling exponent based on GDFA. The results suggest that the fractal scaling exponent calculated using the proposed method has good antinoise ability. We apply the proposed method to 3D poststack migration seismic data from southern China and compare fractal scaling exponents calculated using DFA and GDFA. The results suggest that the use of the GDFA-calculated fractal scaling exponent as a seismic attribute can match the known distribution of sedimentary facies. 展开更多
关键词 Seismic attribute gray system theory detrended fluctuation analysis fractal scaling exponent
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Effects of Plastic Film Mulching on Physical Characters of Soil and Yield and Yield Components of Sweet Potato 被引量:5
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作者 张超凡 黄艳岚 +2 位作者 周虹 张亚 张道微 《Agricultural Science & Technology》 CAS 2015年第11期2379-2385,2393,共8页
Field experiments were carried out to study the effects of plastic film mulching on soil physical characters, including soil temperature, soil moisture content and soil bulk density, and yield and yield components of ... Field experiments were carried out to study the effects of plastic film mulching on soil physical characters, including soil temperature, soil moisture content and soil bulk density, and yield and yield components of sweet potato. The results showed that plastic filming mulching increased soil temperature. Considering the soil temperature-increasing effect, the treatments ranked as black plastic film treatment 〉 white plastic film treatment 〉 control. However, with the deepening of soil layer, the warming effect of plastic film mulching was weakened. Black or white plastic film mulching was conducive to low T/R value, especially in the early growth stage of sweet potato. Plastic film mulching significantly improved the storage root yield of sweet potato. In terms of yield-improving effect, the treatments ranked as black plastic film treatment 〉 white plastic film treatment 〉 control. The storage root num- ber per plant showed a downward trend, but the weight of single storage root was increased. 展开更多
关键词 Plastic film mulching Sweet potato Soil physical characters YIELD Growth and development
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Application of seismic multi-attribute fusion method based on D-S evidence theory in prediction of CBM-enriched area 被引量:1
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作者 祁雪梅 张绍聪 《Applied Geophysics》 SCIE CSCD 2012年第1期80-86,116,117,共9页
D-S evidence theory provides a good approach to fuse uncertain inlbrmation. In this article, we introduce seismic multi-attribute fusion based on D-S evidence theory to predict the coalbed methane (CBM) concentrated... D-S evidence theory provides a good approach to fuse uncertain inlbrmation. In this article, we introduce seismic multi-attribute fusion based on D-S evidence theory to predict the coalbed methane (CBM) concentrated areas. First, we choose seismic attributes that are most sensitive to CBM content changes with the guidance of CBM content measured at well sites. Then the selected seismic attributes are fused using D-S evidence theory and the fusion results are used to predict CBM-enriched area. The application shows that the predicted CBM content and the measured values are basically consistent. The results indicate that using D-S evidence theory in seismic multi-attribute fusion to predict CBM-enriched areas is feasible. 展开更多
关键词 D-S evidence theory CBM seismic attributes thsion
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Geographic variation and provenance selection for bamboo wood properties in Bambusa chungii 被引量:3
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作者 杨秀艳 傅懋毅 +1 位作者 谢锦忠 李正才 《Journal of Forestry Research》 SCIE CAS CSCD 2009年第A3期261-267,287,共9页
Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed... Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences between fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in elevation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis. 展开更多
关键词 Bambusa chungii bamboo wood property pulp-bamboo geographic variation provenance selection
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Studies of Soil Physical Property on Different Abandoned Lands in the Minqin Oasis,Downstream of the Shiyang River 被引量:1
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作者 郭春秀 王理德 +6 位作者 韩福贵 马剑平 何芳兰 刘淑娟 王方琳 张莹花 魏林源 《Agricultural Science & Technology》 CAS 2015年第5期1014-1018,共5页
The vast area of farmland was abandoned at downstream of the Shiyang River because of decreased water recourse. To ensure the ecological safety of Minqin Oasis and to provide management basis for the abandoned land, s... The vast area of farmland was abandoned at downstream of the Shiyang River because of decreased water recourse. To ensure the ecological safety of Minqin Oasis and to provide management basis for the abandoned land, soil physical properties were observed and studied. The authors analyzed land with abandonment time of 1 year, 2 years, 3 years, 4 years, 5 years, 8 years, 15 years, 24 years and 31 years. Samples were took at the 0-40 cm layer of soil to measure the bulk density, porosity and grain composition of soil in the different abandoned lands. Results showed that the tendency of clay content was decreasing, conversely, the fine sand increased at the layer of 0-10 cm of different abandoned lands.The changes of grain content reached a peak at the fourth year after the land was abandoned, then varied slightly. The variation of grain content of abandoned land was obvious with the extension of the abandonment year. The soil bulk density decreased and porosity increased with the extension of the abandonment year. The difference of porosity and soil bulk density at the range of 0-40 cm of different abandoned land decreased after the land abandoned for 3 years. The quality of soil was decreased, while the soil permeability was improved. The soil physical properties changed obviously in 3 to 4 years after abandonment, so it is the key time for land management. 展开更多
关键词 Minqin Oasis Abandoned land Abandoned years Soil physical properties
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Effects of Artificial Vegetation Restoration on Soil Physicochemical Properties in Southern Edge of Mu Us Sandy Land 被引量:3
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作者 杨越 孙宏 +3 位作者 韩永娇 武智勇 宋双双 赵瑞 《Agricultural Science & Technology》 CAS 2014年第4期648-652,691,共6页
[Objective] This study aimed to investigate the artificial vegetations on soil physicochemical properties of sandy land. [Method] The soil physicochemical proper- ties in five representative lands respectively covered... [Objective] This study aimed to investigate the artificial vegetations on soil physicochemical properties of sandy land. [Method] The soil physicochemical proper- ties in five representative lands respectively covered by Artemisia ordosica, Salix cheilophila, Hedysarum scoparium, Populus simonii and Amorpha fruticosa, all of which were planted artificially at the same year were measured in the present study, using a bare soil as the control. [Result] Artificial vegetation improved the soil physicochemical properties by different extents in the lands covered by different plants. The soil physicochemical properties such as bulk density under A. Fruticosa and H. Scoparium were improved greatly. The frequency distribution of soil particle size under artificial vegetations exhibited a bimodal curve. The average soil particle size under A. fruticosa was the smallest, and the soil was very poorly sorted. The soil nutrients in the sandy land were not significantly improved by artificial vegeta- tion. [Conclusion] Artificial vegetation has a certain impact on soil properties in sandy land, as it greatly improves the soil physical properties but not the chemical properties. 展开更多
关键词 Artificial vegetation restoration Soil physicochemical properties Mu Us sandy land
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Application of Comprehensive Geophysical Techniques to Predict Carbonate Fractured Reservoirs inQingxi Oilfield 被引量:1
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作者 师永民 撒利明 +3 位作者 陈广坡 田鑫 李虹 王斌婷 《Applied Geophysics》 SCIE CSCD 2005年第2期119-126,F0003,共9页
Inter-crystalline pores, cavities, and fractures created from diagenetic shrinkage of dolomite are inter-connected each other, forming fine oil- and gas-bearing reservoirs. It is hard to predict these complex fracture... Inter-crystalline pores, cavities, and fractures created from diagenetic shrinkage of dolomite are inter-connected each other, forming fine oil- and gas-bearing reservoirs. It is hard to predict these complex fracture-cavity reservoirs because of their random distribution, different growth timing, and so on. Taking the lacustrine dolomite fracture-pore reservoir in the Lower Cretaceous Xiagou Formation in the Qingxi oilfield within the Jiuquan basin as an example, we put forward a comprehensive geophysical method to predict carbonate fractures. 展开更多
关键词 Qingxi oilfield imaging logging waveform analysis tectonic stress field CARBONATE and fracture prediction
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Studies of Soil Physical Properties and Community Characteristics of Different Abandoned Lands in the Minqin Oasis,Downstream of the Shiyang River
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作者 郭春秀 何芳兰 +6 位作者 马剑平 安富博 马俊梅 袁宏波 赵鹏 刘克彪 申国峰 《Agricultural Science & Technology》 CAS 2016年第7期1697-1701,共5页
[Objective] The aim was to explore physical properties and community characteristics of abandoned lands in different years in Minqin Oasis, downstream of the Shiyang River, [Method] The evolution of environment and pl... [Objective] The aim was to explore physical properties and community characteristics of abandoned lands in different years in Minqin Oasis, downstream of the Shiyang River, [Method] The evolution of environment and plant community characteristics in different abandoned lands were analyzed after abandonment for 1, 2, 3, 4, 5, 8, 15, 24 and 31 years, and the plant community characteristics, water content, bulk density, porosity and mechanical composition of soil in the different a- bandoned lands were also researched in the Minqin Oasis, downstream of the Shiyang River. [Result] Plant of 32 species spread over 14 family live through fifty years appeared in abandoned lands in the study area. Shrubs was 6 species, herbs was 26 species among them, which were 18.75%, 81.25% respectively. The goose- foot family (6 species), the composite family(4 species),the grass family(4 species), caltrop family(3 species) were 53.13% among them. Within the range of 0-40 cm of different abandoned Land, the soil moisture content showed a trend of first increase and then decrease with the increase of soil depth changes in soil bulk density and porosity of less obvious. In the range of 0-40 cm soil depth, the largest proportion of fine sand, followed by silt and clay and the smallest proportion of coarse sand in every plot, but the proportion of the each silt size varies little with the years aban- doned. [Conclusion] The research provides references for vegetation reconstruction and eco-environment construction in abandoned lands in downstream of Shiyang River. 展开更多
关键词 Minqin Oasis Abandoned land Years abandoned Soil physical proper- ties Vegetation characteristics
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Study on the Feasibility of the Calculation Methods of Consolidating Rural Residential Land into Arable Land in China
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作者 何英彬 陈佑启 +2 位作者 姚艳敏 许新国 李志斌 《Journal of Landscape Research》 2009年第9期55-58,共4页
Since the increasing demand for arable land and low efficient and disordered use of rural residential land,land consolidation for rural settlement has become a hot issue in China.Many Chinese scientists studied the to... Since the increasing demand for arable land and low efficient and disordered use of rural residential land,land consolidation for rural settlement has become a hot issue in China.Many Chinese scientists studied the topic from different angles.However,there is no reference systematically summarizing and discussing feasibility of consolidating rural residential land into arable land.The authors listed and analyzed the calculation methods of consolidating rural residential land into arable land,and discussed the feasibility and reasonability of those methods.Moreover,this paper put forward the study orientation in this regard for providing references for relevant researches. 展开更多
关键词 Rural residential land Land consolidation METHODOLOGY POTENTIALITY FEASIBILITY
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Soil Physical and Chemical Properties of Five Subtropical Forests in Lingao of Hainan
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作者 薛杨 宿少锋 +1 位作者 王小燕 林之盼 《Agricultural Science & Technology》 CAS 2017年第8期1459-1464,共6页
With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosi... With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosity was the highest in the Casuarina equisetifolia forest (46.168%), but the lowest in the Encalyptus robusta forest (39.46%). The soil capillary porosity was the highest in the Acacia mangium forest (22.57%), but the lowest in the secondary forest (18.95%). The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic (pH 4.5-5.5), and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents (with a mean value of 2.29 mg/kg) and ammonium N contents (with a mean value of 3.93 mg/kg). For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend. 展开更多
关键词 Lingao County Coastal platform Different forest types Soil physical and chemical properties COMPARISON
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A NEW TECHNIQUE FOR PREDICTING DISTRIBUTION OF TERRESTRIAL VERTEBRATES USING INFERENTIAL MODELING 被引量:2
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作者 陈国君 A.Townsend Peterson 《Zoological Research》 CAS CSCD 2000年第3期231-237,共7页
A new technique for predicting species' geographic distribution is described.The approach involves 3 steps:①setting up geographic base data;②collecting and georeferencing distributional points;③modeling ecologi... A new technique for predicting species' geographic distribution is described.The approach involves 3 steps:①setting up geographic base data;②collecting and georeferencing distributional points;③modeling ecological niches using the biodiversity species workshop implementation of the genetic algorithm for rule set prediction (GARP).To illustrate these procedures,an example based on the Brown Eared Pheasant (Crossoptilon mantchuricum) is developed.This technique constitutes a useful tool for assessing geographic distribution for questions of ecology,biogeography,systematics,and conservation biology. 展开更多
关键词 Geographic information systems Genetic algorithm for rule set prediction DISTRIBUTION Ecological niche
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