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| 1 | Challenge and Opportunity in Improving Fertilizer-nitrogen Use Efficiency of Irrigated Rice in China显示文摘Today, about 30% of world nitrogen (N) fertilizer is consumed by China. Rice crops in China consume about 37% of the total N fertilizer used for rice production in the world. Average rate of N application for rice production in China is high and fertilizer-N use efficiency is low compared with other major rice growing countries. Research progresses have been made internationally and domestically on the application method, fertilizer-N sources, computer-based decision support systems, and real-time N management in order to reduce N losses and increase fertilizer-N use efficiency. In addition to continuous increase in N rate and lack of adoption of new knowledge and technology in N management by farmers, we hypothesize that high indigenous soil N supply, adoption of hybrid and super rice cultivars, improper timing of N application, and practice of mid-season drainage could be the causes for the low fertilizer-N use efficiency in China. Future research work on improving fertilizer-N use efficiency of rice crop in China should focus more on improving cultivar's N responsiveness, optimizing the timing and rate of N application based on crop N status, and achieving optimal soil N supply capacity. | Roland Buresh Christian Witt | 2002 | Agricultural Sciences in China2002，1，7： | 86 |
| 2 | Ideotype root architecture for efficient nitrogen acquisition by maize in intensive cropping systems显示文摘The use of nitrogen(N) fertilizers has contributed to the production of a food supply sufficient for both animals and humans despite some negative environmental impact.Sustaining food production by increasing N use efficiency in intensive cropping systems has become a major concern for scientists,environmental groups,and agricultural policymakers worldwide.In high-yielding maize systems the major method of N loss is nitrate leaching.In this review paper,the characteristic of nitrate movement in the soil,N uptake by maize as well as the regulation of root growth by soil N availability are discussed.We suggest that an ideotype root architecture for efficient N acquisition in maize should include(i) deeper roots with high activity that are able to uptake nitrate before it moves downward into deep soil;(ii) vigorous lateral root growth under high N input conditions so as to increase spatial N availability in the soil;and(iii) strong response of lateral root growth to localized nitrogen supply so as to utilize unevenly distributed nitrate especially under limited N conditions. | MI GuoHua,CHEN FanJun,WU QiuPing,LAI NingWei,YUAN LiXing & ZHANG FuSuo* Key Laboratory of Plant Nutrition,MOA Key Laboratory of Plant-Soil Interaction,MOE College of Resources and Environmental Science,China Agricultural University,Beijing 100193,China | 2010 | Science China(Life Sciences)2010，53，12： | 35 |
| 3 | Land use change and carbon cycle in arid and semi-arid lands of East and Central Asia显示文摘Dramatic changes in land use have occurred in arid and semi-arid landsof Asia during the 20th century. Grassland conversion into croplands and ecosystem degradation is widespread due to the high growth rate of human population and political reforms of pastoral systems. Rangeland degradation made many parts of this region vulnerable to environmental and political changes. The collapse of the livestock sector in some states of central Asia, expansion of livestock inChina and intensive degradation of grasslands in China are examples of the responses of pastoral systems to these changes over the past decades. Carbon dynamics in this region is highly variable in space and time. Land use/cover changes with widespread reduction of forest and grasslands increased carbon emission from the region. | Togtohyn Chuluun Dennis Ojima | 2002 | Science China(Life Sciences)2002，45，z1： | 34 |
| 4 | The effect of land use structure on the distribution of soil nutrients in the hilly area of the Loess Plateau,China显示文摘The irrational land use is one of the main reasons for the soil erosion and nutrient loss in the loess hilly area of China. In this project, 4 types of typical land use structure of sustain ment for about 15 years in the loess hill slope are selected to study the effect of land use structure on the distribution of soil nutrients. From hill bottom to hill top, the patterns of land use types are:, grassland-slope farmland-forest, slope farmland-grassland-forest, terrace-grassland-forest and slope farmland-forest-grassland. By measuring the contents of the total N, total P, available N, available P and organic matter of soils, the results show that the land use structure types of slope farmland-grassland-forest and terrace-grassland-forest have a better capacity to maintain the soil nutrients. | Bojie Fu Keming Ma Huafeng Zhou Liding Chen | 1999 | Chinese Science Bulletin1999，44，8： | 32 |
| 5 | Rural vitalization in China:A perspective of land consolidation显示文摘The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population,land and industry.As one of the prerequisites,land resources is required to be optimally allocated via land consolidation.Con seque ntly,la nd con solidati on con tributes greatly to population agglomeration,industrial developme nt and resources support under the con text of combati ng rural decline.Based on the key eleme nts affecting rural development,this paper elaborates the con no tation of rural vitalization and land consolidation in the new era as well as their relationships.Furthermore,the paper analyzes the alternative paths for achieving rural vitalization via land consolidation,and discusses the future directions of land consolidation and rural vitalization.The conclusions are drawn as follows:(1)To cope with the loss and decline of the intrinsic elements in rural areas,rural vitalization is a development strategy aimed at realizing economic,political,cultural and ecological rejuvenation in rural area by reshaping socio?economic morphology and spatial pattern in rural territory.(2)From the perspective of rural vitalization,land consolidation is endowed with new connotation,which should not only target at activating the key elements of rural development,but also place emphasis on coordimating material space and spirit core as well as integrating the restructuring of the physical space and the rural gov?ernance system.(3)Land consolidation should be compatible with regional natural conditions and the current stage of socio-economic development.According to the principle of regional planning and classification strategy,the appropriate models and paths should be adopted to promote the benign interactions of population,land and industry based on engineering techniques and ecological means.(4)Under the background of national strategy of rural vitaliza?tion,it is n ecessary to reshape the value orientati on of la nd con solidation based on a scie tific understanding of urban-rural relations and rural territorial functions,coordinate land consolidation planning and rural vitalization planning under the unified spatial planning system,and explore the new model combining land consolidation and multifunctional agriculture. | LONG Hualou ZHANG Yingnan TU Shuangshuang | 2019 | Journal of Geographical Sciences2019，29，4： | 33 |
| 6 | HCV-RNA positivity in peripheral blood mononuclear cells of patients with chronic HCV-infection: does it really mean viral replication?显示文摘AIM To analyze the association of HCV-RNA with peripheral blood mononuclear cells (PBMC)and to answer the question whether HCV-RNA positivity in PBMC is due to viral replication,METHODS HCV-RNA was monitored in serumand PBMC preparations from 15 patients with chronic HCV infection before, during and after an IFN-α therapy using a nested RT/ PCRtechnique. In a second approach, PBMC from healthy donors were incubated in HCV positive plasma.RESULTS In the IFN-α responding patients,HCV-RNA disappeared first from total RNApreparations of PBMC and then from serum. In contrast, in relapsing patients, HCV-RNAreappeared first in serum and then in PBMC. A quantitative analysis of the HCV-RNAconcentration in serum was performed before and after transition from detectable to nondetectable HCV-RNA in PBMC-RNA and vice versa. When HCV-RNA was detectable in PBMCpreparations, the HCV concentration in serum was significantly higher than the serum HCV-RNA concentration when HCV-RNA in PBMC was not detectable. Furthermore, at no time during the observation period was HCV specific RNA observed in PBMC, if HCV-RNA in serum was under the detection limit. Incubation of PBMCfrom healthy donors with several dilutions of HCV positive plasma for two hours showed a concentration-dependent PCR-positivity for HCV-RNA in reisolated PBMC.CONCLUSION The detectability of HCV-RNA in total RNA from PBMC seems to depend on the HCV concentration in serum. Contamination or passive adsorption by circulating virus could be the reason for detection of HCV-RNA in PBMCpreparations of chronically infected patients. | Volker Meier Sabine Mihm Perdita Wietzke-Braun Guliano Ramadori | 2001 | World Journal of Gastroenterology2001，7，2： | 29 |
| 7 | Land use changes and their relations with carbon cycles over the past 300 a in China显示文摘Land use and land cover in China have changed greatly during the past 300 a, indicated by the rapid abrupt decrease of forest land area and the rapid increase of cropland area, which can affect terrestrial carbon cycle greatly. The first-hand materials are used to analyze main characteristics for land use and land cover changes in China during the study period. The following conclusions can be drawn from this study. The cropland area in China kept increasing from 60.78×106 hm2 in 1661 to 96.09×106 hm2 in 1998. Correspondingly, the forest land area decreased from 248.13×106 hm2 in 1700 to 109.01×106 hm2 in 1949. Affected by such changes, the terrestrial ecosystem carbon storage decreased in the mean time. Car-bon lost from land use and land cover changes mainly consist of the loss from vegetation biomass and soil. In the past 300 a, about 3.70 PgC was lost from vegetation biomass, and emissions from soil ranged from 0.80 to 5.84 PgC. The moderate evaluation of soil losses was 2.48 PgC. The total loss from vegetation and soil was between 4.50 and 9.54 PgC. The moderate and optimum evaluation was 6.18 PgC. Such carbon losses distribution varied spatially from region to region. Carbon lost more significantly in Northeast China and Southwest China than in other regions, because losses of forest land in these two regions were far greater than in the other regions during the past 300 a. And losses of carbon in the other regions were also definite, such as Inner Mongolia, the western part of South China, the Xinjiang Uygur Autonomous Region, and the Qinghai-Tibet Plateau. But the carbon lost very little from the traditional agricultural regions in China, such as North China and East China. Studies on the relationship between land use and land cover change and carbon cycle in China show that the land use activities, especially those related to agriculture and forest management, began to affect terrestrial carbon storage positively in recent years. | GE QuanSheng DAI JunHu HE FanNeng PAN Yuan WANG MengMai | 2008 | Science China Earth Sciences2008，51，6： | 30 |
| 8 | Protective mechanism of desiccation tolerance in Reaumuria soongorica: Leaf abscission and sucrose accumulation in the stem显示文摘Reaumuria soongorica (Pall.) Maxim., a perennial semi-shrub, is widely found in semi-arid areas in northwestern China and can survive severe desiccation of its vegetative organs. In order to study the protective mechanism of desiccation tolerance in R. soongorica, diurnal patterns of net photosynthetic rate (Pn), water use efficiency (WUE) and chlorophyll fluorescence parameters of Photosystem II (PSII), and sugar content in the source leaf and stem were investigated in 6-year-old plants during progressive soil drought imposed by the cessation of watering. The results showed that R. soongorica was char-acterized by very low leaf water potential, high WUE, photosynthesis and high accumulation of sucrose in the stem and leaf abscission under desiccation. The maximum Pn increased at first and then de-clined during drought, but intrinsic WUE increased remarkably in the morning with increasing drought stress. The maximal photochemical efficiency of PSII (Fv/Fm) and the quantum efficiency of noncyclic electric transport of PSII(ΦPSII) decreased significantly under water stress and exhibited an obvious phenomenon of photoinhibition at noon. Drought stressed plants maintained a higher capacity of dis-sipation of the excitation energy (measured as NPQ) with the increasing intensity of stress. Conditions of progressive drought promoted sucrose and starch accumulation in the stems but not in the leaves. However, when leaf water potential was less than –21.3 MPa, the plant leaves died and then abscised. But the stem photosynthesis remained and, afterward the plants entered the dormant state. Upon re-watering, the shoots reactivated and the plants developed new leaves. Therefore, R. soongorica has the ability to reduce water loss through leaf abscission and maintain the vigor of the stem cells to survive desiccation. | LIU YuBing1,2, ZHANG TengGuo1, LI XingRong2 & WANG Gang1 1 School of Life Sciences, Lanzhou University, Lanzhou 730000, China 2 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China | 2007 | Science China(Life Sciences)2007，50，1： | 27 |
| 9 | Cereal area and nitrogen use efficiency are drivers of future nitrogen fertilizer consumption显示文摘At a global scale, cereal yields and fertilizer N consumption have increased in a near-linear fashion during the past 40 years and are highly correlated with one another. However,large differences exist in historical trends of N fertilizer usage and nitrogen use efficiency (NUE)among regions, countries, and crops. The reasons for these differences must be understood to estimate future N fertilizer requirements. Global nitrogen needs will depend on: (i) changes in cropped cereal area and the associated yield increases required to meet increasing cereal demand from population and income growth, and (ii) changes in NUE at the farm level. Our analysis indicates that the anticipated 38% increase in global cereal demand by 2025 can be met by a 30% increase in N use on cereals, provided that the steady decline in cereal harvest area is halted and the yield response to applied N can be increased by 20%. If losses of cereal cropping area continue at the rate of the past 20 years (-0.33% per year) and NUE cannot be increased substantially, a 60% increase in global N use on cereals would be required to meet cereal demand. Interventions to increase NUE and reduce N losses to the environment must be accomplished at the farm- or field-scale through a combination of improved technologies and carefully crafted local policies that contribute to the adoption of improved N management; uniform regional or national directives are unlikey to be effective at both sustaining yield increases and improving NUE. Examples from several countries show that increases in NUE at rates of 1% per year or more can be achieved if adequate investments are made in research and extension. Failure to arrest the decrease in cereal crop area and to improve NUE in the world's most important agricultural systems will likely cause severe damage to environmental services at local, regional, and global scales due to a large increase in reactive N load in the environment. | Achim Dobermann Kenneth G.Cassman | 2005 | Science China(Life Sciences)2005，48，z2： | 24 |
| 10 | Treatment of corticosteroid-resistant ulcerative colitis with oral low molecular weight heparin显示文摘 | Cui HF Jiang XL | 1999 | World Journal of Gastroenterology1999，5，5： | 24 |
| 11 | Cancer prevention and control: alarming challenges in China显示文摘China is geographically the third largest country in the world and the most populated low-to-middle-income country. Cancer incidence and mortality rates for some cancers in the USA and European countries have steadily decreased over the last decades, whereas the incidence and mortality of certain cancers in China have been increasing at an alarming speed. Rapid industrialization and urbanization in China have been accompanied by incredible changes in lifestyle and environment combined with an aging population. Mortality caused by lung, colorectal and breast cancers has been steadily increasing, whereas cancer mortality from gastric, esophageal and cervical tumors has tended to decrease. Similar to what has occurred in the United States, unhealthy lifestyles in China, including heavy smoking and poor diet combined with pollution, have contributed to increased cancer risk. China is facing many challenges in cancer treatment and prevention for the general population. The major areas that need to be addressed in the control of cancer in China include cancers associated with environmental pollution,tobacco use, occupational carcinogens, infection, excessive alcohol consumption, dietary deficiencies and obesity. In this perspective, we review the problems in each area and suggest ideas for future directions in cancer research and strategies and actions to reduce the incidence of cancer in China. | Ann M.Bode Zigang Dong Hongyang Wang | 2016 | National Science Review2016，3，1： | 22 |
| 12 | Land use effects on climate in China as simulated by a regional climate model显示文摘A regional climate model (RegCM3) nested within ERA40 re-analyzed data is used to investigate the climate effects of land use change over China. Two 15-year simulations (1987―2001), one with current land use and the other with potential vegetation cover without human intervention, are conducted for a domain encompassing China. The climate impacts of land use change are assessed from the difference between the two simulations. Results show that the current land use (modified by anthropogenic ac- tivities) influences local climate as simulated by the model through the reinforcement of the monsoon circulation in both the winter and summer seasons and through changes of the surface energy budget. In winter, land use change leads to reduced precipitation and decreased surface air temperature south of the Yangtze River, and increased precipitation north of the Yangtze River. Land use change signifi- cantly affects summer climate in southern China, yielding increased precipitation over the region, de- creased temperature along the Yangtze River and increased temperature in the South China area (south-end of China). In summer, a reduction of precipitation over northern China and a temperature rise over Northwest China are also simulated. Both daily maximum and minimum temperatures are affected in the simulations. In general, the current land use in China leads to enhanced mean annual precipitation and decreased annual temperature over south China along with decreased precipitation over North China. | J.S.PAL F.GIORGI | 2007 | Science China Earth Sciences2007，50，4： | 21 |
| 13 | Delayed sowing can increase lodging resistance while maintaining grain yield and nitrogen use efficiency in winter wheat显示文摘Lodging resistance of winter wheat(Trnticum aestivum L.) can be increased by late sowing.However, whether grain yield and nitrogen use efficiency(NUE) can be maintained with delayed sowing remains unknown. During the 2013-2014 and 2014-2015 growing seasons, two winter wheat cultivars were sown on three dates(early sowing on October 1, normal so,wing on October8, and late sowing on October 15) to investigate the responses of lodging resistance, grain yield,and NUE to sowing date. No significant differences in lodging resistance, grain yield, or NUE between early and normal sowing were observed. Averaging over the two cultivars and years,postponing the sowing date significantly increased lodging resistance by 53.6% and 49.6%compared with that following early and normal sowing, respectively. Lodging resistance was improved mainly through a reduction in the culm height at the center of gravity and an increase in the tensile strength of the base internode. Late sowing resulted in similar grain yield as well as kernel weight and number of kernels per square meter, compared to early and normal sowing.Averaging over the two cultivars and years, delayed sowing resulted in a reduction in nitrogen uptake efficiency(UPE) by 11.0% and 9.9% compared to early and normal sowing, respectively,owing to reduced root length density and dry matter accumulation before anthesis. An average increase in nitrogen utilization efficiency(UTE) of 12.9% and 11.2% compared to early and normal sowing, respectively, was observed with late sowing owing to a reduction in the grain nitrogen concentration. The increase in UTE offset the reduction in UPE, resulting in equal NUEs among all sowing dates. Thus, sowing later than normal could increase lodging resistance while maintaining grain yield and NUE. | Xinglong Dai Yuechao Wang Xiuchun Dong Taifeng Qian Lijun Yin Shuxin Dong Jinpeng Chu Mingrong He | 2017 | The Crop Journal2017，5，6： | 21 |
| 14 | AUA框架下的语言测试开发者与使用者之责任研究——兼论英语专业四、八级考试设计显示文摘当前语言测试研究重点已转向测试使用公平性论证。为确保语言测评开发与使用的公平性,测评开发者与使用者责任的起点和终点在哪里?如何将测评开发与使用责任做出明确区分?针对上述问题,本文试图运用AUA(Assessment Use Argument)框架阐述测评开发者与使用者的责任,探讨不同利益相关者在测评开发和使用过程中的互动方式,并且联系TEM测评开发与使用进行前瞻性的思考。 | 徐启龙 | 2013 | 外语电化教学2013，，6： | 20 |
| 15 | Climate change, water resources and sustainable development in the arid and semi-arid lands of Central Asia in the past 30 years显示文摘The countries of Central Asia are collectively known as the five '-stans': Uzbekistan, Kyrgyzstan, Turkmenistan, Tajikistan and Kazakhstan. In recent times, the Central Asian region has been affected by the shrinkage of the Aral Sea, widespread desertification, soil salinization, biodiversity loss, frequent sand storms, and many other ecological disasters. This paper is a review article based upon the collection, identification and collation of previous studies of environmental changes and regional developments in Central Asia in the past 30 years. Most recent studies have reached a consensus that the temperature rise in Central Asia is occurring faster than the global average. This warming trend will not only result in a higher evaporation in the basin oases, but also to a significant retreat of glaciers in the mountainous areas. Water is the key to sustainable development in the arid and semi-arid regions in Central Asia. The uneven distribution, over consumption, and pollution of water resources in Central Asia have caused severe water supply problems, which have been affecting regional harmony and development for the past 30 years. The widespread and significant land use changes in the 1990 s could be used to improve our understanding of natural variability and human interaction in the region. There has been a positive trend of trans-border cooperation among the Central Asian countries in recent years. International attention has grown and research projects have been initiated to provide water and ecosystem protection in Central Asia. However, the agreements that have been reached might not be able to deliver practical action in time to prevent severe ecological disasters. Water management should be based on hydrographic borders and ministries should be able to make timely decisions without political intervention. Fully integrated management of water resources, land use and industrial development is essential in Central Asia. The ecological crisis should provide sufficient motivation to reach a consensus on unified water management throughout the region. | YU Yang PI Yuanyue YU Xiang TA Zhijie SUN Lingxiao Markus DISSE ZENG Fanjiang LI Yaoming CHEN Xi YU Ruide | 2019 | Journal of Arid Land2019，11，1： | 20 |
| 16 | Modeling the relationship of land use change and some geophysical indicators for the interlock area of farming and pasturing in China显示文摘This paper discusses land-use changes in the interlock area of farming and pasturing (IAFP)in northern China. It presents detailed analyses of land-use features in the IAFP, which are controlled by the macro geomorphic units and geophysical conditions-constraints or advantages. Additionally, it selects some indicators, according to the availability in acquiring and processing their quantitative data, to analyze the canonical correlations between the typical conversion of grassland and geophysical conditions. The preliminary study indicates that the physical conditions are of great advantages to the development of grassland. There exists significant correlation between land use change and some geophysical conditions. | DENG Xiangzheng, LIU Jiyuan, ZHUANG Dafang, ZHAN Jinyan, ZHAO Tao(Inst. of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China) | 2002 | Journal of Geographical Sciences2002，12，4： | 19 |
| 17 | Combination of 'low-dose' ribavirin and interferon alfa-2a therapy followed by interferon alfa-2a monotherapy in chronic HCV-infected nonresponders and relapsers after interferon alfa-2a monotherapy显示文摘AIM To report on the efficacy, safety and tolerability of interferon alfa-2a combined with a 'low dose' of ribavirin for relapsers and non responders to alpha interferon monotherapy.METHODS Thirty-four chronic hepatitis C virus-infected non-responders to interferon alfa2a monotherapy (a course of at least 3 months treatment) and 13 relapsers to interferon alfa 2a monotherapy (a dose of 3 to 6 million units three times per week for at least 20 weeks but not more than 18 months) were treated with the same dose of interferon alfa-2a used before (3 to 6 million units three times per week) and ribavirin (10 mg/ kg daily) for 6 months. In complete responders, interferon alfa-2a was administered for further 6 months at the same dose used before as monotherapy.RESULTS Seven (20.6%) of 34 non-responders stopped the combined therapy due to adverse events, including two patients with histological and clinical Child A cirrhosis. In 17/27 (63%)non-responders, the combined therapy was stopped after three months because of non-response. Ten of the 27 non-responders completed the 1;2-month treatment course. At a mean follow up of 28 months (16- 37 months)after the treatment, 4/10 (15%) previous non-responders still remained complete responders,All 13 previous relapsers completed the 12-month treatment course. At a mean follow up of 22months (9 - 36 months) after treatment, 6/13(46%) the previous relapsers were stillsustained complete responders.CONCLUSION Our treatment schedule of the combined therapy for 6 months of interferon alfa2a with a low dose of ribavirin (10 mg/kg/day)followed by 6 months of interferon alfa-2amonotherapy is able to induce a sustainedcomplete response rate in 15% of non-responders and 46% of relapsers with chronic hepatitis C virus-related liver diseases comparable to those obtained with the standarddoses of ribavirin 1000 - 1200 mg/day.Randomized prospective controlled trials using lower total amounts of ribavirin in combination with interferon should be performed. | Perdita Wietzke-Braun Volker Meier Felix Braun Giuliano Ramadori | 2001 | World Journal of Gastroenterology2001，7，2： | 19 |
| 18 | Role of microRNAs in alcohol-induced liver disorders and non-alcoholic fatty liver disease显示文摘MicroRNAs(miRNAs) are small non-coding RNAs that regulate multiple physiological and pathological functions through the modulation of gene expression at the post-transcriptional level. Accumulating evidence has established a role for miRNAs in the development and pathogenesis of liver disease. Specifically, a large number of studies have assessed the role of miRNAsin alcoholic liver disease(ALD) and non-alcoholic fatty liver disease(NAFLD), two diseases that share common underlying mechanisms and pathological characteristics. The purpose of the current review is to summarize and update the body of literature investigating the role of miRNAs in liver disease. In addition, the potential use of miRNAs as biomarkers and/or therapeutic targets is discussed. Among all miRNAs analyzed, miR-34 a, miR-122 and miR-155 are most involved in the pathogenesis of NAFLD. Of note, these three miRNAs have also been implicated in ALD, reinforcing a common disease mechanism between these two entities and the pleiotropic effects of specific miRNAs. Currently, no single miRNA or panel of miRNAs has been identified for the detection of, or staging of ALD or NAFLD. While promising results have been shown in murine models, no therapeutic based-miRNA agents have been developed for use in humans with liver disease. | Jorge-Luis Torres Ignacio Novo-Veleiro Laura Manzanedo Lucía Alvela-Suárez Ronald Macías Francisco-Javier Laso Miguel Marcos | 2018 | World Journal of Gastroenterology2018，24，36： | 19 |
| 19 | The influence of land use change on the spatial–temporal variability of habitat quality between 1990 and 2010 in Northeast China显示文摘Land use changes are a direct consequence of interactions between humans and nature.Analysing the spatial and temporal changes in habitat quality brought about by land use change can provide a scientific basis for ecological protection and land planning.Based on the analysis of land use change from 1990 to 2010 in Northeast China,we used the InVEST(integrated valuation of ecosystem services and trade-offs)module to evaluate habitat quality based on watershed subdivision.The results show that:(1)the main land use changes from 1990 to 2010 were the transition from grasslands and forest lands to agricultural lands,which led to a decrease in connectivity of landscape and an increase in fragmentation;(2)areas of high habitat quality were distributed north of the Greater Khingan Mountains,the region of the Lesser Khingan Mountains and east of the Changbai Mountains,while the central plain had low habitat quality;(3)agricultural lands had the largest effect on habitat degradation among all habitat threats.During these 2 decades,the contribution of agricultural lands to habitat degradation were 43.4%in 1990,44.6%in 2000 and 43.9%in 2010;and,(4)at a landscape scale,patch density and splitting index present noticeable negative correlations with habitat quality index.Habitat quality was significantly affected by landscape fragmentation and decreased connectivity. | Limin Dai Shanlin Li Bernard J.Lewis Jian Wu Dapao Yu Wangming Zhou Li Zhou Shengnan Wu | 2019 | Journal of Forestry Research2019，30，6： | 18 |
| 20 | Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat显示文摘Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems. | TIAN Zhong-wei LIU Xiao-xue GU Shi-lu YU Jin-hong ZHANG Lei ZHANG Wei-wei JIANG Dong CAO Wei-xing DAI Ting-bo | 2018 | Journal of Integrative Agriculture2018，17，12： | 18 |
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