Based on the results of nine Coupled Model Intercomparison Project Phase 5 (CMIP5) coupling models, the temperature and precipitation data of 114 stations in Northeast China were compared and analyzed. The simulation ...Based on the results of nine Coupled Model Intercomparison Project Phase 5 (CMIP5) coupling models, the temperature and precipitation data of 114 stations in Northeast China were compared and analyzed. The simulation effect of CMIP5 model on precipitation and temperature in Northeast China was evaluated. The research shows that the Geophysical Fluid Dynamics Laboratory Earth System Models (GGFDL-ESM2G) have the best simulation effect on precipitation and temperature in Northeast China. Based on the SPEI index, the relationship between the drought trend of maize growing season and the yield change rate of maize in Northeast China was analyzed, and the future drought (2020-2050) and corn yield in Northeast China were estimated. The cumulative Standardized Precipitation Evapotranspiration Index (SPEI) analysis of the northeast maize growing season (May-September) shows that the drought in the northeastern region showed an intensifying trend from 1980 to 2010, especially in the first ten years of the 21st century. The cumulative SPEI index has a significant positive correlation with the yield of maize in Northeast China, and has a certain indicator effect on the yield of maize in Northeast China. The three scenarios of GFDL-ESM2G model show that under the three scenarios of Representative Concentration Pathways (RCP), the warming in Northeast China is significant;under the RCP4.5 scenario, the precipitation in Northeast China is increasing;in the RCP2.6 and RCP8.5 climate scenarios, precipitation is presented and reduces the trend of drought. Estimates of drought trends in Northeast China show that under the RCP4.5 climate scenario, the drought in Northeast China showed a slowing trend from 2020 to 2050. Under the RCP2.6 and RCP8.5 climate scenarios, the drought in Northeast China showed an increasing trend. Under the RCP2.6 and RCP8.5 climate scenarios, the yield change rate of maize in Northeast China showed a downward trend, indicating that climate warming caused the drought in Northeast China to increase, which had a negative impact on corn yield increase. In severe drought years, drought may cause northeast corn production seriously reduced. However, under the RCP4.5 scenario, drought has little effect on corn yield.展开更多
The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation...The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.展开更多
为了明确当前国际氮肥施用研究领域的研究热点、发展态势,文章基于ISI Web of Science数据库,采用文献计量学方法,根据发文量、发文机构、发文期刊以及论文被引频次等指标,对全球发表于1957─2014年8月的关于农田施氮的SCI文献进行了数...为了明确当前国际氮肥施用研究领域的研究热点、发展态势,文章基于ISI Web of Science数据库,采用文献计量学方法,根据发文量、发文机构、发文期刊以及论文被引频次等指标,对全球发表于1957─2014年8月的关于农田施氮的SCI文献进行了数量和质量分析。结果显示,与农田施氮研究相关的SCI论文共有7 460篇,主要集中在氮肥施用对作物产量、大气环境以及水体质量的影响等3个方面。近5年来,该领域发文量迅速增加,年均发文量均在400篇以上。欧美发达国家研究起步早、基础好、水平高,尤其美国优势明显,共计发文1 893篇,其中美国农业部是发文量最多的机构;中国虽起步较晚,但发展迅速,目前总发文量已排到全球第2位(784篇),中国科学院和中国农业大学发文量排在全球第3和第4位,南京农业大学和中国农业科学院发文量也排在了全球前25位。刊发该领域文章最多的期刊以及被引频次超过300的论文均出自欧美国家,中国学者的研究成果也得到了国际认可,有2篇文章被引频次在270以上,但中国仍缺少有影响力的主流国际期刊。因此,尽管中国在该领域的研究实力近年来不断增加,但仍需要加快培养一批有影响力的主流国际期刊,促进产出更多的优秀成果。此外,农田氮肥施用对作物产量和环境质量的影响仍将是未来研究的主要内容,而确定兼顾氮肥农学效应与环境效应的农田适宜施氮量将是未来研究的重点。展开更多
文摘Based on the results of nine Coupled Model Intercomparison Project Phase 5 (CMIP5) coupling models, the temperature and precipitation data of 114 stations in Northeast China were compared and analyzed. The simulation effect of CMIP5 model on precipitation and temperature in Northeast China was evaluated. The research shows that the Geophysical Fluid Dynamics Laboratory Earth System Models (GGFDL-ESM2G) have the best simulation effect on precipitation and temperature in Northeast China. Based on the SPEI index, the relationship between the drought trend of maize growing season and the yield change rate of maize in Northeast China was analyzed, and the future drought (2020-2050) and corn yield in Northeast China were estimated. The cumulative Standardized Precipitation Evapotranspiration Index (SPEI) analysis of the northeast maize growing season (May-September) shows that the drought in the northeastern region showed an intensifying trend from 1980 to 2010, especially in the first ten years of the 21st century. The cumulative SPEI index has a significant positive correlation with the yield of maize in Northeast China, and has a certain indicator effect on the yield of maize in Northeast China. The three scenarios of GFDL-ESM2G model show that under the three scenarios of Representative Concentration Pathways (RCP), the warming in Northeast China is significant;under the RCP4.5 scenario, the precipitation in Northeast China is increasing;in the RCP2.6 and RCP8.5 climate scenarios, precipitation is presented and reduces the trend of drought. Estimates of drought trends in Northeast China show that under the RCP4.5 climate scenario, the drought in Northeast China showed a slowing trend from 2020 to 2050. Under the RCP2.6 and RCP8.5 climate scenarios, the drought in Northeast China showed an increasing trend. Under the RCP2.6 and RCP8.5 climate scenarios, the yield change rate of maize in Northeast China showed a downward trend, indicating that climate warming caused the drought in Northeast China to increase, which had a negative impact on corn yield increase. In severe drought years, drought may cause northeast corn production seriously reduced. However, under the RCP4.5 scenario, drought has little effect on corn yield.
基金supported by the National Natural Science Foundation of China (51239009, 41171034)Shaanxi Provincial Natural Science Foundation of China (Key) Project (2013JZ012)+1 种基金Shaanxi Provincial Key Laboratory Project of Department of Education (14JS059)Shaanxi Provincial Water Conservancy Science and Technology Project (2016slkj-11)
文摘The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.
文摘为了明确当前国际氮肥施用研究领域的研究热点、发展态势,文章基于ISI Web of Science数据库,采用文献计量学方法,根据发文量、发文机构、发文期刊以及论文被引频次等指标,对全球发表于1957─2014年8月的关于农田施氮的SCI文献进行了数量和质量分析。结果显示,与农田施氮研究相关的SCI论文共有7 460篇,主要集中在氮肥施用对作物产量、大气环境以及水体质量的影响等3个方面。近5年来,该领域发文量迅速增加,年均发文量均在400篇以上。欧美发达国家研究起步早、基础好、水平高,尤其美国优势明显,共计发文1 893篇,其中美国农业部是发文量最多的机构;中国虽起步较晚,但发展迅速,目前总发文量已排到全球第2位(784篇),中国科学院和中国农业大学发文量排在全球第3和第4位,南京农业大学和中国农业科学院发文量也排在了全球前25位。刊发该领域文章最多的期刊以及被引频次超过300的论文均出自欧美国家,中国学者的研究成果也得到了国际认可,有2篇文章被引频次在270以上,但中国仍缺少有影响力的主流国际期刊。因此,尽管中国在该领域的研究实力近年来不断增加,但仍需要加快培养一批有影响力的主流国际期刊,促进产出更多的优秀成果。此外,农田氮肥施用对作物产量和环境质量的影响仍将是未来研究的主要内容,而确定兼顾氮肥农学效应与环境效应的农田适宜施氮量将是未来研究的重点。
