基于2000—2014年文献和著作资料中的湖南省森林土壤剖面有机碳含量数据,湖南会同杉木林生态系统国家野外科学观测研究站近15年的实测数据,分析了湖南省主要森林类型土壤有机碳密度,结合1983年至2009年湖南省4次森林资源清查数据,研究...基于2000—2014年文献和著作资料中的湖南省森林土壤剖面有机碳含量数据,湖南会同杉木林生态系统国家野外科学观测研究站近15年的实测数据,分析了湖南省主要森林类型土壤有机碳密度,结合1983年至2009年湖南省4次森林资源清查数据,研究了湖南省森林土壤有机碳库储量的动态特征。结果表明:湖南省主要森林类型土壤有机碳算术平均含量在9.53—22.86g/kg之间,灌木林最高,土壤有机碳含量的分异主要发生在0—40 cm土层,0—80 cm土壤层有机碳密度在95.44—181.30 t C/hm2之间,平均为137.15 t C/hm2,主要分布在0—40 cm土层中,随土壤深度增加,各森林类型土壤有机碳密度的差异下降,受森林类型的影响减弱。从1983—1987年到2009年,湖南省乔木林土壤层(0—80 cm)有机碳库储量净增加了414.86×106t C,面积加权平均有机碳密度提高了10.98 t C/hm2,不同乔木林土壤层(0—80 cm)有机碳库储量的差异随着时间进程逐渐增大,主要分布在杉木林、松木林、阔叶林。天然林是湖南省乔木林土壤有机碳库储量的主要贡献者,人工林土壤有机碳储量正逐步提高,经济林、竹林、灌木林对湖南省森林土壤层(0—80 cm)有机碳库储量贡献不同,且动态变化趋势也不同。森林土壤层有机碳库储量的变化与各森林类型面积的变化密切相关,而各森林类型面积的增减,与各项林业政策的实施密切相关。因此,人类活动深刻影响森林土壤的碳汇功能。展开更多
Soils play a critical role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Fine roots are important component of a forest ecos...Soils play a critical role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Fine roots are important component of a forest ecosystem in terms of water and nutrient uptake. In this study the effects of thinning and litter fall removal on fine root production and soil organic carbon content were examined in 20-year-old Masson pine （Pinus resinosa） plantations in Huitong, Hunan Province of China in the growing seasons of 2004 and 2005. The results showed that fine root production was significantly lower in the thinning plots than in the control plots, with a decrease of 58% and 14% in 2004 and 2005 growing seasons, respectively. Litter fall removal significantly increased fine root production by 14% in 2004. Soil temperature （Tsoil） and soil moisture （Msoil） were higher in the thinning plots than those in the controls. Litter fall removal had significant effects on Tsoil and Msoil. Soil organic carbon content was higher in the thinning plots but was lower in the plots with litter fall removal compared with that in the controls. Our results also indicated that annual production of fine roots resulted in small carbon accumulation in the upper layers of the soil, and removal of tree by thinning resulted in a significant increase of carbon storage in Masson pine plantations.展开更多
The objectives of this study of pregnant women with asthma are 1) to describe their knowledge and attitudes of asthma in pregnancy and their self-efficacy in carrying out their self-management plan during pregnancy, 2...The objectives of this study of pregnant women with asthma are 1) to describe their knowledge and attitudes of asthma in pregnancy and their self-efficacy in carrying out their self-management plan during pregnancy, 2) to determine if their knowledge, attitudes, and self-efficacy changed as their pregnancy progressed, and 3) to ascertain the relationship between knowledge, attitudes, and self-esteem and age, education, trimester of pregnancy, weeks of pregnancy, the number of times pregnant and live births. Sixty-eight pregnant women who had an asthma diagnosis were given knowledge, attitudes and self-efficacy questionnaires initially during the point of first contact (first or second) trimester (Time I) and subsequently during the latter part of their pregnancy (third trimester) (Time II). A demographic data form was also administered at Times I and II. Data were collected in an urban academic medical clinic and analyzed using SPSS 17. Data analysis utilized frequencies, paired samples t tests, and linear regression. There were no significant differences between Time I and Time II in attitudes and self-efficacy. Significant differences were limited to the knowledge questionnaire (t = 4.370, p = 0.05). There was a significant relationship between education and knowledge. Pregnant women with asthma had gaps in their knowledge of asthma in pregnancy, although their knowledge increased as their pregnancy progressed from Time I to Time II. Also, the more education the women had, the better they understood asthma. Education for pregnant women with asthma is tailored to their needs and modified as necessary. Nurses are prepared to address this challenge.展开更多
Inorganic resources can be detrimental to the environment when exploited.In comparison,organic resources help balance the soil’s carbon and nitrogen(C/N)ratio,enhance soil fertility and benefit ecological protection....Inorganic resources can be detrimental to the environment when exploited.In comparison,organic resources help balance the soil’s carbon and nitrogen(C/N)ratio,enhance soil fertility and benefit ecological protection.Current climate crises,rapid urbanization,and fast population growth are causing many natural forests to be converted to agricultural and industrial lands to fulfill ever-increasing food and developmental requirements.Application of different bio-resources becomes necessary for sustainable productivity of available lands.This study explores the effects of various organic amendments on the growth,morpho-physiological and biochemical attributes of three leguminous tree species:Dalbergia sissoo,Vachellia nilotica,and Acacia ampliceps,concerning sustainable productivity.One-year-old healthy,disease-free,and homogenous seedlings were used as study material in a greenhouse pot experiment.Four organic amendments,i.e.,compost(CMP),cow dung(CD),poultry manure(PM),and biochar(BC),along with a control(CK)treatment,were applied.Results showed that all the organic amendments performed significantly better(P<0.05)than CK.CD produced the most significant results,followed by BC application,while PM influence was the least.Among all treatments and species,the maximum values of root length,root biomass,chlorophyll content,carotenoids,catalase,and total phenolic content were recorded under the CD treatment.Whereas for plant height and collar diameter,no big differences were observed between CD and BC(P=0.054).While comparing species,V.nilotica growth was significantly enhanced under organic amendments,followed by A.ampliceps.Combined and comparative results of studied parameters conclude that CD and BC were the most effective organic amendments,which greatly improved the growth of experimental leguminous tree species;this makes these two biofertilizers a powerful tool for sustainable agricultural productivity.Our study contributes toward an enhanced understanding of plant’s morpho-physiological responses,biochemical growth patterns,controls,and activities under different bio-fertilizers.展开更多
Climate change is expected to cause the alteration of litter production in forests, which may result in substantial changes in soil CO2 effiux （FCO2） process as litter represents a major pathway of carbon from veget...Climate change is expected to cause the alteration of litter production in forests, which may result in substantial changes in soil CO2 effiux （FCO2） process as litter represents a major pathway of carbon from vegetation to the soils. In this study, we conducted an aboveground litter manipulation experiment to examine the influence of litter addition and exclusion on soil FCO2 in Camphor tree, Masson pine, and mixed Camphor tree and Masson pine forests in central south China. Litter input manipulation included three treatments： nonqitter input （litter exclusion）, double litter input （litter addition）, and natural litter input （control）. On average, litter exclusion significantly reduced soil FCO2 rate by approximately 39%, 24% and 22% in Camphor tree forests, the Mixed forests, and Masson pine forests, respectively. On a yearly basis, double litter addition significantly increased soil CO2 by 12% in the Mixed forests （P=0.02） but not in both Camphor tree and Masson pine forests （P〉0.05）, when compared with their corre- sponding control treatments. However, litter addition increased soil FCO2 rates in the months of June-August in Camphor tree and Masson pine forests, coinciding with high soil temperature of summer conditions. Litter exclusion reduced soil FCO2 more than litter addition increased it in the study sites. Responses of soil respiration to litter input treatments varied with forest types. Litter input treatments did not alter the seasonal patterns of soil temperature and soil water content. Our results indicated that changes in aboveground litter as a result of global climate change and/or forest management have a great potential to alter soil respiration and soil carbon balance in forest ecosystems.展开更多
Anthropogenic activities have increased nitrogen(N)deposition in terrestrial ecosystems,which directly and indirectly affects soil biogeochemical processes,including soil respiration.However,the effects of the increas...Anthropogenic activities have increased nitrogen(N)deposition in terrestrial ecosystems,which directly and indirectly affects soil biogeochemical processes,including soil respiration.However,the effects of the increases in N availability on soil respiration are not fully understood.In this study,soil respiration was measured using an infrared gas analyzer system with soil chambers under four N treatments(0,5,15,and 30 g Nm^-2 year^-1 as control,low N(LN),moderate N(MN),and high N(HN),respectively)in camphor tree and slash pine forests in subtropical China.Results showed that soil respiration rates decreased by 37% in the camphor tree forest and 27% in the slash pine forest on average on an annual base,respectively,in the N-fertilized treatments when compared with the control.No significant differences were found in the soil respiration rate among the LN,MN,and HN treatments in both forest types as these fertilized plots reached an adequate N content zone.In addition,soil microbial biomass carbon(C)content and fine root biomass declined in N-treated plots compared to the control.Our results indicated that elevated N deposition might alter the tree growth pattern,C partitioning,and microbial activity,which further affect soil C sequestration by reducing soil respiration in subtropical forests of China.展开更多
The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better unde...The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better understand characteristics of soil CO2 flux （FCO2） in subtropical forests, soil FCO2 rates were quantified in five adjacent forest types （camphor tree forest, Masson pine forest, mixed camphor tree and Masson pine forest, Chinese sweet gum forest, and slash pine forest） at the Tianjiling National Park in Changsha, Hunan Province, in subtropical China, from January to December 2010. The influences of soil temperature （Tsoil）, volumetric soil water content （0soiI）, soil pH, soil organic carbon （SOC） and soil C/nitrogen （N） ratio on soil FCO2 rates were also investigated. The annual mean soil FCO2 rate varied with the forest types. The soil FCO2 rate was the highest in the camphor tree forest （3.53 ± 0.51 μmol m-2 s-I）, followed by, in order, the mixed, Masson pine, Chinese sweet gum, and slash pine forests （1.53 ± 0.25 μmol m-2 sl）. Soil FCO2 rates from the five forest types followed a similar seasonal pattern with the maximum values occurring in summer （July and August） and the minimum values during winter （December and January）. Soil FCO2 rates were correlated to Tsoil and 0soil, but the relationships were only significant for Tsoil. No correlations were found between soil FCO2 rates and other selected soil properties, such as soil pH, SOC, and C/N ratio, in the examined forest types. Our results indicated that soil FCO2 rates were much higher in the evergreen broadleaved forest than coniferous forest under the same microclimatic environment in the study region.展开更多
文摘基于2000—2014年文献和著作资料中的湖南省森林土壤剖面有机碳含量数据,湖南会同杉木林生态系统国家野外科学观测研究站近15年的实测数据,分析了湖南省主要森林类型土壤有机碳密度,结合1983年至2009年湖南省4次森林资源清查数据,研究了湖南省森林土壤有机碳库储量的动态特征。结果表明:湖南省主要森林类型土壤有机碳算术平均含量在9.53—22.86g/kg之间,灌木林最高,土壤有机碳含量的分异主要发生在0—40 cm土层,0—80 cm土壤层有机碳密度在95.44—181.30 t C/hm2之间,平均为137.15 t C/hm2,主要分布在0—40 cm土层中,随土壤深度增加,各森林类型土壤有机碳密度的差异下降,受森林类型的影响减弱。从1983—1987年到2009年,湖南省乔木林土壤层(0—80 cm)有机碳库储量净增加了414.86×106t C,面积加权平均有机碳密度提高了10.98 t C/hm2,不同乔木林土壤层(0—80 cm)有机碳库储量的差异随着时间进程逐渐增大,主要分布在杉木林、松木林、阔叶林。天然林是湖南省乔木林土壤有机碳库储量的主要贡献者,人工林土壤有机碳储量正逐步提高,经济林、竹林、灌木林对湖南省森林土壤层(0—80 cm)有机碳库储量贡献不同,且动态变化趋势也不同。森林土壤层有机碳库储量的变化与各森林类型面积的变化密切相关,而各森林类型面积的增减,与各项林业政策的实施密切相关。因此,人类活动深刻影响森林土壤的碳汇功能。
基金Supported by the "948" Grant of the National Forestry Administration of China (No.2007-4-19)the Special Grantof Chinese Forestry Public Benefits (Nos.200804030 and 2007-4-15)the Provincial Fund for Distinguished Young Scholars of Hunan, China (No.07JJ1004)
文摘Soils play a critical role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Fine roots are important component of a forest ecosystem in terms of water and nutrient uptake. In this study the effects of thinning and litter fall removal on fine root production and soil organic carbon content were examined in 20-year-old Masson pine （Pinus resinosa） plantations in Huitong, Hunan Province of China in the growing seasons of 2004 and 2005. The results showed that fine root production was significantly lower in the thinning plots than in the control plots, with a decrease of 58% and 14% in 2004 and 2005 growing seasons, respectively. Litter fall removal significantly increased fine root production by 14% in 2004. Soil temperature （Tsoil） and soil moisture （Msoil） were higher in the thinning plots than those in the controls. Litter fall removal had significant effects on Tsoil and Msoil. Soil organic carbon content was higher in the thinning plots but was lower in the plots with litter fall removal compared with that in the controls. Our results also indicated that annual production of fine roots resulted in small carbon accumulation in the upper layers of the soil, and removal of tree by thinning resulted in a significant increase of carbon storage in Masson pine plantations.
文摘The objectives of this study of pregnant women with asthma are 1) to describe their knowledge and attitudes of asthma in pregnancy and their self-efficacy in carrying out their self-management plan during pregnancy, 2) to determine if their knowledge, attitudes, and self-efficacy changed as their pregnancy progressed, and 3) to ascertain the relationship between knowledge, attitudes, and self-esteem and age, education, trimester of pregnancy, weeks of pregnancy, the number of times pregnant and live births. Sixty-eight pregnant women who had an asthma diagnosis were given knowledge, attitudes and self-efficacy questionnaires initially during the point of first contact (first or second) trimester (Time I) and subsequently during the latter part of their pregnancy (third trimester) (Time II). A demographic data form was also administered at Times I and II. Data were collected in an urban academic medical clinic and analyzed using SPSS 17. Data analysis utilized frequencies, paired samples t tests, and linear regression. There were no significant differences between Time I and Time II in attitudes and self-efficacy. Significant differences were limited to the knowledge questionnaire (t = 4.370, p = 0.05). There was a significant relationship between education and knowledge. Pregnant women with asthma had gaps in their knowledge of asthma in pregnancy, although their knowledge increased as their pregnancy progressed from Time I to Time II. Also, the more education the women had, the better they understood asthma. Education for pregnant women with asthma is tailored to their needs and modified as necessary. Nurses are prepared to address this challenge.
基金supported by funding from the Central South University of Forestry and Technology and the Hunan Province Educational Department Funding(No.70702-45200003).
文摘Inorganic resources can be detrimental to the environment when exploited.In comparison,organic resources help balance the soil’s carbon and nitrogen(C/N)ratio,enhance soil fertility and benefit ecological protection.Current climate crises,rapid urbanization,and fast population growth are causing many natural forests to be converted to agricultural and industrial lands to fulfill ever-increasing food and developmental requirements.Application of different bio-resources becomes necessary for sustainable productivity of available lands.This study explores the effects of various organic amendments on the growth,morpho-physiological and biochemical attributes of three leguminous tree species:Dalbergia sissoo,Vachellia nilotica,and Acacia ampliceps,concerning sustainable productivity.One-year-old healthy,disease-free,and homogenous seedlings were used as study material in a greenhouse pot experiment.Four organic amendments,i.e.,compost(CMP),cow dung(CD),poultry manure(PM),and biochar(BC),along with a control(CK)treatment,were applied.Results showed that all the organic amendments performed significantly better(P<0.05)than CK.CD produced the most significant results,followed by BC application,while PM influence was the least.Among all treatments and species,the maximum values of root length,root biomass,chlorophyll content,carotenoids,catalase,and total phenolic content were recorded under the CD treatment.Whereas for plant height and collar diameter,no big differences were observed between CD and BC(P=0.054).While comparing species,V.nilotica growth was significantly enhanced under organic amendments,followed by A.ampliceps.Combined and comparative results of studied parameters conclude that CD and BC were the most effective organic amendments,which greatly improved the growth of experimental leguminous tree species;this makes these two biofertilizers a powerful tool for sustainable agricultural productivity.Our study contributes toward an enhanced understanding of plant’s morpho-physiological responses,biochemical growth patterns,controls,and activities under different bio-fertilizers.
基金supported by the Chinese Forestry Specific Research Grant for Public Benefits(200804030)New Century Excellent Youth Program of the Min-istry of Education of China(NCET-10-0151)+2 种基金Science and Technology Bureau of Changsha City(K1003009-61)'Bai Ren'Scholar Program of Hunan ProvinceCentral South University of Forestry and Technology(0842)
文摘Climate change is expected to cause the alteration of litter production in forests, which may result in substantial changes in soil CO2 effiux （FCO2） process as litter represents a major pathway of carbon from vegetation to the soils. In this study, we conducted an aboveground litter manipulation experiment to examine the influence of litter addition and exclusion on soil FCO2 in Camphor tree, Masson pine, and mixed Camphor tree and Masson pine forests in central south China. Litter input manipulation included three treatments： nonqitter input （litter exclusion）, double litter input （litter addition）, and natural litter input （control）. On average, litter exclusion significantly reduced soil FCO2 rate by approximately 39%, 24% and 22% in Camphor tree forests, the Mixed forests, and Masson pine forests, respectively. On a yearly basis, double litter addition significantly increased soil CO2 by 12% in the Mixed forests （P=0.02） but not in both Camphor tree and Masson pine forests （P〉0.05）, when compared with their corre- sponding control treatments. However, litter addition increased soil FCO2 rates in the months of June-August in Camphor tree and Masson pine forests, coinciding with high soil temperature of summer conditions. Litter exclusion reduced soil FCO2 more than litter addition increased it in the study sites. Responses of soil respiration to litter input treatments varied with forest types. Litter input treatments did not alter the seasonal patterns of soil temperature and soil water content. Our results indicated that changes in aboveground litter as a result of global climate change and/or forest management have a great potential to alter soil respiration and soil carbon balance in forest ecosystems.
基金supported financially by the Chinese Forestry Specific Research Fund for Public Benefits (No.200804030)New Century Excellent Youth Program of the Ministry of Education of China (No.NCET-10-0151)+1 种基金‘100-Talents’ Scholar Program of Hunan Province, ChinaCentral South University of Forestry and Technology, China (No.0842)
文摘Anthropogenic activities have increased nitrogen(N)deposition in terrestrial ecosystems,which directly and indirectly affects soil biogeochemical processes,including soil respiration.However,the effects of the increases in N availability on soil respiration are not fully understood.In this study,soil respiration was measured using an infrared gas analyzer system with soil chambers under four N treatments(0,5,15,and 30 g Nm^-2 year^-1 as control,low N(LN),moderate N(MN),and high N(HN),respectively)in camphor tree and slash pine forests in subtropical China.Results showed that soil respiration rates decreased by 37% in the camphor tree forest and 27% in the slash pine forest on average on an annual base,respectively,in the N-fertilized treatments when compared with the control.No significant differences were found in the soil respiration rate among the LN,MN,and HN treatments in both forest types as these fertilized plots reached an adequate N content zone.In addition,soil microbial biomass carbon(C)content and fine root biomass declined in N-treated plots compared to the control.Our results indicated that elevated N deposition might alter the tree growth pattern,C partitioning,and microbial activity,which further affect soil C sequestration by reducing soil respiration in subtropical forests of China.
基金Supported by the National Forestry Public Welfare Research Program of China(Nos.201104005 and 200804030)the Program for New Century Excellent Talents in University of Ministry of Education of China(No.NCET-10-0151)+1 种基金the 100 Talents Program of Hunan Province,China(No.2011516)Central South University of Forestry and Technology,China(No.0842)
文摘The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better understand characteristics of soil CO2 flux （FCO2） in subtropical forests, soil FCO2 rates were quantified in five adjacent forest types （camphor tree forest, Masson pine forest, mixed camphor tree and Masson pine forest, Chinese sweet gum forest, and slash pine forest） at the Tianjiling National Park in Changsha, Hunan Province, in subtropical China, from January to December 2010. The influences of soil temperature （Tsoil）, volumetric soil water content （0soiI）, soil pH, soil organic carbon （SOC） and soil C/nitrogen （N） ratio on soil FCO2 rates were also investigated. The annual mean soil FCO2 rate varied with the forest types. The soil FCO2 rate was the highest in the camphor tree forest （3.53 ± 0.51 μmol m-2 s-I）, followed by, in order, the mixed, Masson pine, Chinese sweet gum, and slash pine forests （1.53 ± 0.25 μmol m-2 sl）. Soil FCO2 rates from the five forest types followed a similar seasonal pattern with the maximum values occurring in summer （July and August） and the minimum values during winter （December and January）. Soil FCO2 rates were correlated to Tsoil and 0soil, but the relationships were only significant for Tsoil. No correlations were found between soil FCO2 rates and other selected soil properties, such as soil pH, SOC, and C/N ratio, in the examined forest types. Our results indicated that soil FCO2 rates were much higher in the evergreen broadleaved forest than coniferous forest under the same microclimatic environment in the study region.
