Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity (BSP) is the production...Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity (BSP) is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr (1990-2011) long-term experimental data on black soil (Typic hapludoll) in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer (DSSAT)-CERES-Maize model was applied to simulate the yield by BSP of spring maize (Zea mays L.) to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined: (1) no-fertilization control (control); (2) chemical nitrogen, phosphorus, and potassium (NPK); (3) NPK plus farmyard manure (NPKM); (4) 1.5 time of NPKM (1.5NPKM) and (5) NPK plus straw (NPKS). Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value (in 1992), but not significant under NPK (26.9% increase) and the control (8.9% decrease). The contribution percentage of BSP showed a significant rising trend (P〈0.05) under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM〉NPKM〉NPK〉NPKS, indicating that organic manure combined with chemical fertilizers (I.5NPKM and NPKM) could more effectively increase BSP compared with the inorganic fertilizer application alone (NPK) in the black soil. This study showed that soil organic matter (SOM) was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization (NPKM or NPKS) not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization (NPKM or NPKS) should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.展开更多
The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity(BSP). In this study, BSP is defined as the productive ca...The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity(BSP). In this study, BSP is defined as the productive capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local field management. Based on 19-yr data of the long-term agronomic experiments(1989–2008) on a fluvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer(DSSAT ver. 4.0) crop growth model was used to simulate yields by BSP of winter wheat(Triticum aestivium L.) and summer maize(Zea mays L.) to examine the relationship between BSP and soil organic carbon(SOC) under long-term fertilization. Five treatments were included:(1) no fertilization(control),(2) nitrogen, phosphorus and potassium fertilizers(NPK),(3) NPK plus manure(NPKM),(4) 1.5 times of NPKM(1.5NPKM), and(5) NPK plus straw(NPKS). After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution percentage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the fluvo-aquic soil. There were significant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize(P〈0.01), and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha^(–1) when SOC stock increased 1 t C ha^(–1). Thus, increased SOC accumulation is a crucial way for increasing BSP in fluvo-aquic soil. The manure or straw combined application with chemical fertilizers significantly enhanced BSP compared to the application of chemical fertilizers alone.展开更多
The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ab...The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.展开更多
In this research, fi ve plots are selected based on stand storage and productivity of planted forest of Larix kaempferi (Japanese larch) as well as their relationship with factors such as forest age, site condition an...In this research, fi ve plots are selected based on stand storage and productivity of planted forest of Larix kaempferi (Japanese larch) as well as their relationship with factors such as forest age, site condition and stand den-sity. Through standard plot investigation and method of trunk analysis, systematic research is conducted on storage and productivity of the planted forest and their relationship with site condition. As shown in the research, produc-tivity of planted forest of Larix kaempferi in low latitude area is higher than that in high latitude area while stand productivity is higher in slight acid soil. Contents of potassium element in the soil have considerable in? uence on productivity of the Larix kaempferi forest.展开更多
According to the relationship between Toona sinensis Roem stand volume,productivity and forest age,site conditions,stand density and other factors,through selecting 8 representative cities or counties,using standard i...According to the relationship between Toona sinensis Roem stand volume,productivity and forest age,site conditions,stand density and other factors,through selecting 8 representative cities or counties,using standard investigation and stem analysis method,this paper makes relatively systematic research about the Toona sinensis Roem plantation accumulation,productivity,and the relationship between them and site conditions.Through comparative analysis indicators of multiple site conditions,this paper expects to give a more comprehensive picture about the source of accumulation and productivity difference.展开更多
China’s booming economy and the growing demand of urban middle class are creating a favorable situation for the development of domestic cultural and creative industry.The consumption pattern has changed and families ...China’s booming economy and the growing demand of urban middle class are creating a favorable situation for the development of domestic cultural and creative industry.The consumption pattern has changed and families spend more outlay on cultural products and services.Within this flourishing industry,many museums caught development opportunities and began to get profit through successfully promoting their own cultural and creative products.However,it is unusual that Emperor Qinshihuang’s Mausoleum Site Museum,enjoying high social status and a reputation for world cultural heritage as well as a national 5A level tourist attraction,regretfully,did not achieve noticeable achievements in this area.Therefore,based on STP theory,the purpose of this paper is to study the reasons why this museum fails to fulfill its potential in promising cultural and creative industry and give some suggestions to the development and promotion of its cultural and creative goods.展开更多
Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values...Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity potential.The site index values of these tree species were derived in South Korea using the Chapman-Richards equation.These values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South Korea.The prediction accuracy of this model was evaluated using the root mean square error.The results show that the prediction accuracy was high,with a root mean square error of~1m.Moreover,the importance of the variables related to climate and geography was generally high.The proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North Korea.The differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South Korea.This model is based on the determination of the suitability of tree species in restoration efforts.Therefore,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.展开更多
潜热通量产品的验证与分析对于研究气候变化及能量循环具有重要意义。全球陆表高分辨率蒸散产品(high resolution global lAnd surface evapotranspiration product,Hi-GLASS ET)融合了5种传统蒸散算法,能够生产出较高精度的陆表潜热通...潜热通量产品的验证与分析对于研究气候变化及能量循环具有重要意义。全球陆表高分辨率蒸散产品(high resolution global lAnd surface evapotranspiration product,Hi-GLASS ET)融合了5种传统蒸散算法,能够生产出较高精度的陆表潜热通量产品,但目前没有针对此产品的验证研究。利用Ameriflux通量观测站点的潜热通量观测值与相应的Hi-GLASS陆表潜热通量产品估算值进行对比,获取多组有效验证数据。验证结果显示,所选站点实际观测值与产品估算值的决定系数(R 2)为0.6,均方根误差(RMSE)为34.4 W/m^(2),平均偏差(Bias)为-13.4 W/m^(2),克林-古普塔效率(Kling-Gupta efficiency,KGE)为0.49,Hi-GLASS潜热通量产品具有较高的精度,算法的拟合结果较好;此外,空间分布也表明Hi-GLASS陆表潜热通量产品符合正常的自然规律。由于数据获取的局限性,仅采用了美国地区18个站点数据对产品进行验证,在其他地区仍需进一步验证。展开更多
[目的]把握生产建设项目废弃地植被恢复的发展历程及现阶段的研究热点问题,推进该研究领域的发展。[方法]以Web of Science数据库及CNKI数据库文献为基础,使用CiteSpace软件的文献计量方法对文献进行了分析。[结果](1)生产建设项目废弃...[目的]把握生产建设项目废弃地植被恢复的发展历程及现阶段的研究热点问题,推进该研究领域的发展。[方法]以Web of Science数据库及CNKI数据库文献为基础,使用CiteSpace软件的文献计量方法对文献进行了分析。[结果](1)生产建设项目废弃地植被恢复研究受到国内外研究者的共同关注,中国、印度和美国为主要发文国家。在国际上,印度科学与工业研究理事会(CSIR)和中国科学院是相关文章发表最多的机构,国内机构中发文量排名居榜首的是北京林业大学。(2)目前国际研究的知识群组主要分布在生态修复技术、生物多样性、生态恢复质量评价等方面。国内研究侧重于恢复生态系统结构、植被恢复模式和土壤质量评价体系等方面。(3)根据关键词突现分析,“生态系统服务”“植被恢复”“煤矿弃土”等是目前国际研究的热点;国内近年研究则聚焦于“生态恢复”“景观设计”“规划设计”等方面。[结论]目前的研究多为短期试验,鲜有针对大范围下整个恢复过程的研究,全面重建生态系统功能的研究尚不完善,未来的研究热点聚焦于在进行植被修复时考虑生态和景观综合效益,重视生态系统服务和景观设计。展开更多
为更好地理解格点融合实况数据与观测数据的差异和代表性,利用甘肃兰州和武威两地站点的观测数据对中国气象局陆面数据同化系统(CMA Land Data Assimilation System,CLDAS)地面2 m气温融合产品进行检验评估及偏差订正。结果表明:(1)逐...为更好地理解格点融合实况数据与观测数据的差异和代表性,利用甘肃兰州和武威两地站点的观测数据对中国气象局陆面数据同化系统(CMA Land Data Assimilation System,CLDAS)地面2 m气温融合产品进行检验评估及偏差订正。结果表明:(1)逐小时气温和日最低气温融合产品的平均误差总体为负值,较实际气温偏低,且在2500 m以下误差随海拔上升而减小;日最高气温融合产品平均误差在海拔1500 m附近为负值,1500 m以上误差变为正值且随海拔升高而增大;日最高和最低气温误差较逐小时气温误差偏大,但平均误差均在2℃以内。(2)通过近网格点检验,发现逐小时CLDAS气温产品白天与实况相近,夜间较实况偏低0.2℃;日平均气温CLDAS融合产品总体较实况偏低1℃,兰州城区产品偏差相对较小;30℃以上高温天数融合产品与实况分布基本一致,但在兰州城区,CLDAS融合产品的高温天数较观测天数偏少。(3)线性回归法和递减平均法对CLDAS气温融合产品都有一定的订正效果,递减平均法订正效果更优且在高海拔地区订正效果更明显。CLDAS气温实况融合产品在兰州和武威两地能较好地反映气温变化特征,但日最高、最低气温误差较逐小时气温大,且在复杂地形下误差相对较大。展开更多
基金supported by the National 973 Program of China (2011CB100501)the National 863 Program of China(2013AA102901)+1 种基金the Special Fund for Agro-Scientific Research in the Public Interest, China (201203077)the Science and Technology Project for Grain Production, China (2011BAD16B15)
文摘Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity (BSP) is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr (1990-2011) long-term experimental data on black soil (Typic hapludoll) in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer (DSSAT)-CERES-Maize model was applied to simulate the yield by BSP of spring maize (Zea mays L.) to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined: (1) no-fertilization control (control); (2) chemical nitrogen, phosphorus, and potassium (NPK); (3) NPK plus farmyard manure (NPKM); (4) 1.5 time of NPKM (1.5NPKM) and (5) NPK plus straw (NPKS). Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value (in 1992), but not significant under NPK (26.9% increase) and the control (8.9% decrease). The contribution percentage of BSP showed a significant rising trend (P〈0.05) under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM〉NPKM〉NPK〉NPKS, indicating that organic manure combined with chemical fertilizers (I.5NPKM and NPKM) could more effectively increase BSP compared with the inorganic fertilizer application alone (NPK) in the black soil. This study showed that soil organic matter (SOM) was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization (NPKM or NPKS) not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization (NPKM or NPKS) should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.
基金supported by the National Basic Research Program of China(973 Program,2011CB100501)the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2015BAD22B03)+1 种基金the National High-Tech R&D Program of China(2013AA102901)the Special Fund for Agro-scientific Research in the Public Interest,China(201203077)
文摘The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity(BSP). In this study, BSP is defined as the productive capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local field management. Based on 19-yr data of the long-term agronomic experiments(1989–2008) on a fluvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer(DSSAT ver. 4.0) crop growth model was used to simulate yields by BSP of winter wheat(Triticum aestivium L.) and summer maize(Zea mays L.) to examine the relationship between BSP and soil organic carbon(SOC) under long-term fertilization. Five treatments were included:(1) no fertilization(control),(2) nitrogen, phosphorus and potassium fertilizers(NPK),(3) NPK plus manure(NPKM),(4) 1.5 times of NPKM(1.5NPKM), and(5) NPK plus straw(NPKS). After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution percentage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the fluvo-aquic soil. There were significant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize(P〈0.01), and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha^(–1) when SOC stock increased 1 t C ha^(–1). Thus, increased SOC accumulation is a crucial way for increasing BSP in fluvo-aquic soil. The manure or straw combined application with chemical fertilizers significantly enhanced BSP compared to the application of chemical fertilizers alone.
基金financially supported by the National Natural Science Foundation of China with grant number of 22172082 and 21978137。
文摘The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.
文摘In this research, fi ve plots are selected based on stand storage and productivity of planted forest of Larix kaempferi (Japanese larch) as well as their relationship with factors such as forest age, site condition and stand den-sity. Through standard plot investigation and method of trunk analysis, systematic research is conducted on storage and productivity of the planted forest and their relationship with site condition. As shown in the research, produc-tivity of planted forest of Larix kaempferi in low latitude area is higher than that in high latitude area while stand productivity is higher in slight acid soil. Contents of potassium element in the soil have considerable in? uence on productivity of the Larix kaempferi forest.
文摘According to the relationship between Toona sinensis Roem stand volume,productivity and forest age,site conditions,stand density and other factors,through selecting 8 representative cities or counties,using standard investigation and stem analysis method,this paper makes relatively systematic research about the Toona sinensis Roem plantation accumulation,productivity,and the relationship between them and site conditions.Through comparative analysis indicators of multiple site conditions,this paper expects to give a more comprehensive picture about the source of accumulation and productivity difference.
基金This paper is funded by the Innovation and Entrepreneurship Training Program for college students in Guangdong Province(No.2019126220004).
文摘China’s booming economy and the growing demand of urban middle class are creating a favorable situation for the development of domestic cultural and creative industry.The consumption pattern has changed and families spend more outlay on cultural products and services.Within this flourishing industry,many museums caught development opportunities and began to get profit through successfully promoting their own cultural and creative products.However,it is unusual that Emperor Qinshihuang’s Mausoleum Site Museum,enjoying high social status and a reputation for world cultural heritage as well as a national 5A level tourist attraction,regretfully,did not achieve noticeable achievements in this area.Therefore,based on STP theory,the purpose of this paper is to study the reasons why this museum fails to fulfill its potential in promising cultural and creative industry and give some suggestions to the development and promotion of its cultural and creative goods.
基金supported by the National Institute of Forest Science(Project No.FM0800-2019-05)。
文摘Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity potential.The site index values of these tree species were derived in South Korea using the Chapman-Richards equation.These values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South Korea.The prediction accuracy of this model was evaluated using the root mean square error.The results show that the prediction accuracy was high,with a root mean square error of~1m.Moreover,the importance of the variables related to climate and geography was generally high.The proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North Korea.The differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South Korea.This model is based on the determination of the suitability of tree species in restoration efforts.Therefore,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.
文摘[目的]把握生产建设项目废弃地植被恢复的发展历程及现阶段的研究热点问题,推进该研究领域的发展。[方法]以Web of Science数据库及CNKI数据库文献为基础,使用CiteSpace软件的文献计量方法对文献进行了分析。[结果](1)生产建设项目废弃地植被恢复研究受到国内外研究者的共同关注,中国、印度和美国为主要发文国家。在国际上,印度科学与工业研究理事会(CSIR)和中国科学院是相关文章发表最多的机构,国内机构中发文量排名居榜首的是北京林业大学。(2)目前国际研究的知识群组主要分布在生态修复技术、生物多样性、生态恢复质量评价等方面。国内研究侧重于恢复生态系统结构、植被恢复模式和土壤质量评价体系等方面。(3)根据关键词突现分析,“生态系统服务”“植被恢复”“煤矿弃土”等是目前国际研究的热点;国内近年研究则聚焦于“生态恢复”“景观设计”“规划设计”等方面。[结论]目前的研究多为短期试验,鲜有针对大范围下整个恢复过程的研究,全面重建生态系统功能的研究尚不完善,未来的研究热点聚焦于在进行植被修复时考虑生态和景观综合效益,重视生态系统服务和景观设计。
文摘为更好地理解格点融合实况数据与观测数据的差异和代表性,利用甘肃兰州和武威两地站点的观测数据对中国气象局陆面数据同化系统(CMA Land Data Assimilation System,CLDAS)地面2 m气温融合产品进行检验评估及偏差订正。结果表明:(1)逐小时气温和日最低气温融合产品的平均误差总体为负值,较实际气温偏低,且在2500 m以下误差随海拔上升而减小;日最高气温融合产品平均误差在海拔1500 m附近为负值,1500 m以上误差变为正值且随海拔升高而增大;日最高和最低气温误差较逐小时气温误差偏大,但平均误差均在2℃以内。(2)通过近网格点检验,发现逐小时CLDAS气温产品白天与实况相近,夜间较实况偏低0.2℃;日平均气温CLDAS融合产品总体较实况偏低1℃,兰州城区产品偏差相对较小;30℃以上高温天数融合产品与实况分布基本一致,但在兰州城区,CLDAS融合产品的高温天数较观测天数偏少。(3)线性回归法和递减平均法对CLDAS气温融合产品都有一定的订正效果,递减平均法订正效果更优且在高海拔地区订正效果更明显。CLDAS气温实况融合产品在兰州和武威两地能较好地反映气温变化特征,但日最高、最低气温误差较逐小时气温大,且在复杂地形下误差相对较大。