The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles.For this purpose,the prepared coatings were applied to pine wood surfaces and weathered arti...The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles.For this purpose,the prepared coatings were applied to pine wood surfaces and weathered artificially.Subsequently,color and gloss of the coatings were measured before and after the weathering test.Field emission scanning electron microscopy(FE-SEM)micrographs prepared from the coatings showed that the average size of nano-particles in the polyurethane substrate was approximately 500 nm.Nuclear magnetic resonance(13C-NMR)spectroscopy showed that strong urethane bonds were formed in the nano-lignin-based polyurethane.Differential calorimetric analysis(DSC)test revealed that the glass-transition temperature(Tg)of lignin nanoparticles modified with diethylenetriamine(DETA)was 112.8℃ and Tg of lignin nano-particles modified with ethylenediamine(EDA)was 102.5℃,which is lower than the Tg of un-modified lignin(114.6℃)and lignin modified with DETA(126.8℃)and lignin modified with EDA(131.3℃).The coatings modified with lignin nano-particles had a greater change in gloss.The lignin nano-particles in the modified coating are trapping hydroxyl radicals which reduces photoactivity and yellowing of the polyurethane by about 3 times compared to unmodified polyurethane coatings.After weathering test,the nano-lignin-based coating had a rougher surface with a lower contact angle(0.78°)compared to the unmodified polyurethane coating(0.85°).展开更多
We carried out this research at Abu-Gaddaf Natural Forest Reserve (ANFR) which is located east of Blue Nile River, in Blue Nile State, Sudan. It aims at exploring tree composition assessing their diversity indices, an...We carried out this research at Abu-Gaddaf Natural Forest Reserve (ANFR) which is located east of Blue Nile River, in Blue Nile State, Sudan. It aims at exploring tree composition assessing their diversity indices, and ecological importance values. For survey of types and estimation of density of tree species in the forest, we randomly distributed 97 circular sample plots (0.1 hectare (ha)). In each sample plot we identified all trees to the species level, recorded their frequencies and computed species diversity and importance value indices (IVI). A total of 13 tree species, which belong to 12 genera and nine families, were identified in the tree layer of the forest. Mean tree density in ANFR was 116 trees/ha, composed mainly of Boswellia papyrifera (Del.) Hochst. (48), followed by Combretum hartmannianu (19) and Lannea fruticosa (18). Fabaceae was the most common family followed by Combretaceae and Malvaceae. B. papyrifera Delile Hochst was the most abundant while Acacia seyal was the least abundant species. Species richness (R = 1.71), evenness (E = 0.69), dominance (0.24) indices and Simpson’s Index of Diversity (D' = 0.76) suggest a moderate diversity, moderate numbers of individuals in each species and a moderate community stability. The research provides empirical results on diversity and ecological importance value of species, signifies the urging need to safeguard threatened species and to prioritize them for conservation, as well as the need to promote management of abundant species to provide multiple forest ecosystem services.展开更多
The Dongsithouane National Production Forest (DNPF) is one of the largest natural forest areas in Savannakhet, Lao PDR, which has been a vital support for the local community’s livelihood, Recently, significant chang...The Dongsithouane National Production Forest (DNPF) is one of the largest natural forest areas in Savannakhet, Lao PDR, which has been a vital support for the local community’s livelihood, Recently, significant changes in land use and land cover (LULC) have been observed in this area, leading to a reduction of natural forests. There were two separate methods of this study: firstly, to identify LULC changes across three different periods, spectral imagery from the Landsat 5 Thematic Mapper (TM) for the years 2001 and 2011, and the Landsat 8 Operational Land Imager (OLI) for 2021 were used as the primary data sources. The satellite images were preprocessed for various forest classes, including pretreatment of the top of atmosphere reflectance by using QGIS software’s semi-automatic classification plug-in (SCP), and ArcGIS was used for post-classification. A supervised classification approach was applied to the satellite images from 2001, 2011, and 2021 to generate diverse maps of LULC. Secondly, a household survey dataset was used to investigate influential factors. Approximately 220 households were interviewed in order to collect socio-economic information (including data on population growth, increased business activities, location of the area, agriculture land expansion, and need for settlement land). Household survey data was analyzed by using SPSS. Descriptive statistics, including frequency distributions and percentages, were applied to observe characteristics. Additionally, a binary logistic regression model was used to analyze the socioeconomic factors related to LULC change in DNPF. Key findings indicated a decline in natural forest areas within the study site. Specifically, both dry dipterocarp forest (−11.35%) and mixed deciduous forest (−0.18%) decreased from 2001 to 2021. The overall accuracy of the LULC maps was 94%, 86%, and 89% for the years 2001, 2011, and 2021 respectively. In contrast, agricultural land increased significantly by 155.70%, while built-up land, and water bodies increased by 65.54% and 35.33%, respectively. The results also highlighted a significant increase in construction land, up to 65.54%. Furthermore, the study found a correlation between agricultural expansion and a reduction of forest areas, along with an increase in built-up land along the forest areas’ boundaries. Timber exploitation and charcoal production also contributed to the decline in forest cover. The logistic regression model identified significant determinants of LULC change, including the area’s location, agricultural land expansion, increased business activity, and the need for settlement land. These factors have influenced the management of DNPF. Urgent sustainable management practices and actions, including forest ecosystem protection, village agricultural zoning, water source and watershed protection and public awareness, are required to preserve the forest areas of DNPF.展开更多
We investigated the effects of grazing on natural regeneration, quantity, and diversity of woody species and dominant herb species in Kheyroud forest in northern Iran. We sampled vegetation in 5m2 plots in custom unit...We investigated the effects of grazing on natural regeneration, quantity, and diversity of woody species and dominant herb species in Kheyroud forest in northern Iran. We sampled vegetation in 5m2 plots in custom units, which are demarcated resource areas traditionally used by local livestock producers. The authors quantified number of species, height of seedlings, and diameter of seedlings. Height classes were 0-30 cm, 30-130 cm, and 〉130 cm, and diameter classes were 0-2.5 cm, 2.5-5 cm and 5-7.5 cm. The density of seedlings declined with distance from corral until reaching the custom unit boundary. Most seedlings had diameters of 0-2.5 cm and heights of 0-30 cm. Predominant species, Carpinus betulus and Acer capadocicum, were in plots near the centers of custom units, Fagus orientalis, Acer velutinum, Quercus castanifolia species were dominant in plots near the custom unit boundary. Plant species such as Oplismenus undulatifolius, Euphorbia amygdaloides, Rubusfrutieos and Pteridium aquilinum were dominant in plots nearer to forest corral. Healthy seedlings were more numerous in plots nearest the corral, while defective and deformed seedlings were more abundant away from the corral. We conclude that grazing had negative effects on the quantity and quality of vegetative regeneration. Continuation of overgrazing will not only endanger the sustainability of forest ecosystems, but also will increase the challenge of sustainable forest management.展开更多
For developing nature-based silvicultural practices in a beech forest to promote, abundance, height, vitality, and preferred growth form, regenerated trees growing in gaps were compared with those under closed canopie...For developing nature-based silvicultural practices in a beech forest to promote, abundance, height, vitality, and preferred growth form, regenerated trees growing in gaps were compared with those under closed canopies. A systematic 50 ×50 m grid was plotted in a beech stand in the Kheyrud Experimental Forest for selecting trees to measure variables in gaps and under closed canopies. Abundance and mean height of regenerated beech trees were significantly higher in closed canopies than in canopy gaps. Beech seedlings with excurrent growth were significantly taller within regeneration patches under closed canopy. Moreover, regenerated trees with high vitality were more abundant in closed canopy areas than in gaps. Thus, beech regeneration should improve under closed canopies; hence, gaps in a near natural forest should be created only after adequate regeneration and appropriate growth under the parent tree in a closed canopy area is ensured. The results of this research have profound implications for the sustainable management of the forest and for ensuring sustainable beech regeneration. The presence of a closed canopy cover likely will reduce potential stresses on oriental beech regeneration.展开更多
The objective of this investigation was to introduce a cement-based composite of higher quality. For this purpose new hybrid nanocomposite from bagasse fiber,glass fiber and multi-wall carbon nanotubes（MWCNTs）were m...The objective of this investigation was to introduce a cement-based composite of higher quality. For this purpose new hybrid nanocomposite from bagasse fiber,glass fiber and multi-wall carbon nanotubes（MWCNTs）were manufactured. The physical and mechanical properties of the manufactured composites were measured according to standard methods. The properties of the manufactured hybrid nanocomposites were dramatically better than traditional composites. Also all the reinforced composites with carbon nanotube, glass fiber or bagasse fiber exhibited better properties rather than neat cement.The results indicated that bagasse fiber proved suitable for substitution of glass fiber as a reinforcing agent in the cement composites. The hybrid nanocomposite containing10 % glass fiber, 10 % bagasse fiber and 1.5 % MWCNTs was selected as the best compound.展开更多
Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms,especially carbon-carbon and carbon-hydrogen.These compounds are mainly used as reactants to make other polymers.Amon...Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms,especially carbon-carbon and carbon-hydrogen.These compounds are mainly used as reactants to make other polymers.Among biopolymers,lignin is regarded as the base of a new polymer in polyol construction.The present study aimed to investigate the effects of amine type(diethylenetriamine and ethylenediamine)on the modification of lignin-based polyols,so as to provide an alternative to petroleum polyols and,in turn,increase functional groups and reduce their harm to humans’health and the environment.To this aim,first,lignin was extracted from raw liquor.Next,the extracted lignin was reacted with diethylenetriamine(DETA)and ethylenediamine(EDA).Finally,the Mannich method was used for the reaction between amine lignin and propylene carbonate.The results of the Fourier Transform Infrared(FTIR)spectroscopy analysis showed that modification with DETA led to more structural change in lignin and peak 1100 indicates the presence of C–O bond related to urethane bonds in modified lignin.Moreover,adding propylene carbonate to aminated lignin did not result in much change in the results of the FTIR analysis.Additionally,urethane bonds can be seen in the results of GPC at 400℃–500℃.Furthermore,a slight decrease in thermal stability was observed in lignin modified with amine and propylene carbonate,compared to the raw lignin sample.展开更多
Arasbaran forests are located in East Azerbaijan （northwest Iran）. Increasing of socio-economic problems in this area causes destruction of biodiversity and structure of these forests. Using multipurpose trees such ...Arasbaran forests are located in East Azerbaijan （northwest Iran）. Increasing of socio-economic problems in this area causes destruction of biodiversity and structure of these forests. Using multipurpose trees such as cornelian cherry （Cornus mas L） to encourage villagers to produce forest by-products is a basic approach for preserving these forests. This species grows naturally in Arasbaran forests and the fruit is annually exploited using traditional harvest methods. This study aims to assess the ecological requirements of cornelian cherry and the important factors affecting its distribution. For this purpose, 40 circular sampling plots （300 m2） on various slope aspects were demarcated for sampling the occurrence of cornelian cherry in forest stands. DBH and crown cover percentage on north aspects were significantly greater than on other aspects and 4.5% of all trees were cornelian cherry in mature forest stands. North aspects had more seed-origin trees （standards） of cornelian cherry than coppiced trees, while west facing aspects had more coppiced than standard trees. This species had the highest regeneration rate in the sapling stage of 0–2.5 cm DBH. Thus, I recommend cultivation and development of cornelian cherry as a multi-purpose tree in the Arasbaran region on degraded forest lands on north and west aspects.展开更多
Recent studies on decentralized wetland governance in Uganda have focused mainly on the relationship between central and local governments. Less attention has been given to the relationship between agricultural system...Recent studies on decentralized wetland governance in Uganda have focused mainly on the relationship between central and local governments. Less attention has been given to the relationship between agricultural systems, local governments, and water bodies. This study aims at assessing decentralized wetlands governance in the upper river Rwizi and Iguluibi micro catchments, Lake Victoria Basin Uganda, in relation to farming practices. Qualitative and quantitative methods were used to provide a comprehensive understanding of the contribution of decentralized governance to the management of wetlands resources. Quantitative survey data were analyzed using descriptive summary statistics with the help of Statistical package for Social Sciences (SPSS) soft ware. Qualitative data analysis involved the categorization of verbal and behavioral data for purposes of classification with the use of Nvivo soft ware. Data were analyzed at two levels: the descriptive level of analysis which is the account of the data in terms of what was said, documented or observed with nothing assumed about it. The second level of analysis was interpretive, where data is transformed into what is meant by the responses and conclusions are drawn. All recorded interviews were transcribed into a written report. Findings revealed that decentralized wetlands governance has brought ecosystem services nearer to communities in form of community-based management planning. However, results indicated inadequate institutional capacity, knowledge gaps of existing legal frameworks, limited political support and accountability for local leaders, lack of cooperation and coordination, and inadequate funding. In all, the policy has not fully realized its intended outcomes.展开更多
The plantation of non-native species is one of the most expensive ecological restoration measures in arid and semi-arid areas,while its impacts on local communities are largely ignored.This study assessed the rate of ...The plantation of non-native species is one of the most expensive ecological restoration measures in arid and semi-arid areas,while its impacts on local communities are largely ignored.This study assessed the rate of change and the dynamic degree of the economic values of ecosystem services related to local conservation(water yield,stocking rate and aesthetic value)and preserving the future(carbon sequestration,soil protection,soil stability and habitat provision)to determine the restoration success of the plantation of non-native species Haloxylon ammodendron(C.A.Mey.)Bunge ex Fenzl(15-and 30-year-old)in parts of arid rangelands of Bardsir region,Kerman Province,Iran.We investigated the impacts of the two plantations on the seven ecosystem services and ecosystem structures(horizontal and vertical structures,vegetation composition and species diversity)based on field sampling and measurements at four sampling sites(i.e.,control,degraded,and 15-and 30-year-old plantation sites)in spring and summer of 2022.The restoration success of the plantation of non-native species was then examined by assessing the rate of change and the dynamic degree of the total economic value of all ecosystem services as well as the rate of change and the dynamic degree of the economic values of ecosystem services for the two groups(local conservation and preserving the future).Although the plantation of non-native species H.ammodendron enormously improved the vertical and horizontal structures of ecosystems,it failed to increase species diversity and richness fully.Further,despite the plantation of non-native species H.ammodendron had significantly increased the economic values of all ecosystem services,it was only quite successful in restoring carbon sequestration.Path analysis showed that plantation age had a significant impact on restoration success directly and indirectly(through changing ecosystem structures and services).The dynamic degree of the economic values of ecosystem services related to local conservation and preserving the future at the 15-and 30-year-old plantation sites indicated that the two plantations successfully restored the ecosystem services related to preserving the future.The presented method can help managers select the best restoration practices and predict their ecological-social success,especially for the plantation of high-risk non-native species in arid and semi-arid areas.展开更多
Lake Urmia,Northwest Iran,has confronted a drying procedure in recent years with losing 90%of its water body.The authorities concerned about desertification processes and possible dust events throughout the region.In ...Lake Urmia,Northwest Iran,has confronted a drying procedure in recent years with losing 90%of its water body.The authorities concerned about desertification processes and possible dust events throughout the region.In this regard,the Iranian Natural Resources and Watershed Management Organization has taken ecological measures to plant vegetation using salt cedar(Tamarix ramosissima Ledeb.)shrubs to combat desertification.This study aimed to investigate the vegetation and soil characteristics of natural and plantation stands of salt cedar on the western shores of Lake Urmia.To this end,7 transects were randomly selected with 15 shrubs in natural stands,and 7 transects were randomly selected with 15 shrubs in the plantation parts along the planting rows.Then,vegetative characteristics were examined.Also,soil samples were taken from the vicinity of the shrubs.The results indicated that there was no significant difference between the mean diameter at breast height(DBH)of salt cedar in natural sites.There was a significant difference between the mean number of sprouts per sprout-clumps,mean crown diameter,collar diameter,total height,and also between mean crown diameter and freshness of shrubs among different sites(P<0.05).It was also found that soil variables,such as clay content,organic matter,electrical conductivity(EC),Na^(+),specific absorption rate(SAR),Cl^(-),SO_(4)^(2-),Na^(+),K^(+),and PO_(4)^(2-) are the most significant variable parameters between studied sites.As the results shown,the values of EC,SAR,Na^(+),and Cl^(-)are 6 times higher in the planted stands than in the natural stands of T.ramosissima.Also,the colonization of T.ramosissima in the planted stands is unsuccessful by dramatic drop in the total height and average diameter.Considering the role of soil characteristics in explaining the variance of data and site separation,it seems that these indicators can be applied in executive plans as important indicators to identify suitable planting sites for combating desertification.展开更多
The influences of trait diversity(i.e.,the niche complementarity effect)and functional composition(i.e.,the mass ratio effect)on aboveground biomass(AGB)is a highly debated topic in forest ecology.Therefore,further st...The influences of trait diversity(i.e.,the niche complementarity effect)and functional composition(i.e.,the mass ratio effect)on aboveground biomass(AGB)is a highly debated topic in forest ecology.Therefore,further studies are needed to explore these mechanisms in unstudied forest ecosystems to enhance our understanding,and to provide guidelines for specific forest management.Here,we hypothesized that functional composition would drive AGB better than trait diversity and stem size inequality in the(sub-)tropical forests of Nepal.Using data from 101 forest plots,we tested 25 structural equation models(SEMs)to link elevation,stem DBH inequality,trait diversity(i.e.,trait richness,evenness,dispersion and divergence),functional composition[i.e.,community-weighted of maximum height mean(CWM of Hmax),specific leaf area(CWM of SLA),leaf dry matter content(CWM of LDMC),and wood density(CWM of WD)]and AGB.The best-fitted SEMs indicated that CWM of Hmax promoted AGB while overruling the impacts of trait diversity indices on AGB.However,low trait diversity indices were linked with higher AGB while overruling the effects of CWM of SLA,LDMC and WD on AGB.In addition,AGB decreased with increasing elevation,whereas stem size inequality did not influence AGB.Our results suggest that divergent species’functional strategies could shape AGB along an altitudinal gradient in tropical forests.We argue that forest management practices should include plant functional traits in the management plan for the co-benefits of biodiversity conservation and carbon sequestration that underpins human wellbeing.展开更多
Plants have always been exploited worldwide for food, medicines, shelter, and other purposes because they are readily available, affordable and acceptable to a large populace of the world. The study was conducted to g...Plants have always been exploited worldwide for food, medicines, shelter, and other purposes because they are readily available, affordable and acceptable to a large populace of the world. The study was conducted to gather information on the proximate composition of fresh and dry leaves of Pterocarpus erinaceus. The proximate composition of the leaf samples was determined using the standard methods of analysis of the Association of Official Analytical Chemists (AOAC). Proximate analysis of the fresh leaf samples of the plant shows a higher moisture content compared to the dry leaf samples. The total fat and total ash contents of the fresh leaf samples were however lower compared to values recorded for the dry leaf samples. The dry matter content of fresh leaf samples was also lower compared to that of the dry leaf samples. Fresh leaf samples again recorded the least crude protein content compared to dry leaf samples. Carbohydrates content in fresh leaf samples was higher compared to dry leaf samples. Generally, higher proximate values were recorded for dry leaf samples than for fresh leaves. Dry matter and moisture contents were detected in high quantities in both fresh and dry leaf samples of P. erinaceus. These results could be a justification for the multiple uses of the plant leaves across Sub-Saharan Africa. Further research should be carried out on the mineral, phytochemical and vitamin composition between the fresh and dry leaves of the plant.展开更多
Construction projects,including road construction,are very important.Therefore,a lot of money is spent on these projects every year.So,the lack of proper planning will increase the cost and cause irreparable damage to...Construction projects,including road construction,are very important.Therefore,a lot of money is spent on these projects every year.So,the lack of proper planning will increase the cost and cause irreparable damage to the country.The role of workshop management is one of the most important factors in increasing the cost of these types of projects.Generally,workshop management plays a very important role in improving the quality and quantity of projects and has an important place in the project implementation process.Therefore,this study evaluated the impact of workshop management on the progress of road construction projects on a case-by-case basis in road construction projects in Tehran province.According to the purpose of the research,this study was a descriptive-survey type.In addition,the tool used in this research was a questionnaire.The statistical population of this research included all experts and specialists in road construction projects,among whom 65 people were selected by snowball method.Then the collected data were analyzed using SPSS software.The results of this study showed that the management of the workshop and its role in the control and implementation of projects is a complex process,which can be implemented at high levels and effectively by combining scientific and experimental training.And a very important point in the discussion of workshop management is applying scientific management to the use of valuable experiences from others.Because management knowledge not only does not negate the use of these experiences,but also emphasizes the necessity of using them.In other words,improving the knowledge of workshop management is one of the requirements for the implementation of value engineering in construction projects,especially road construction,and it is very important.展开更多
Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of ...Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation practices.Numerous studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the watersheds.However,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located downstream.The surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 points.Suspended and bed sediments were sampled in the watershed outlet in two high and low water periods.Geochemical characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC Integra.The reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R software.The results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water periods.For bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,respectively.Land use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.展开更多
Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across c...Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across climatic gradients and slope aspects in arid and semi-arid ecosys-tems.In this study,using 60 composite soil samples,direct and indirect effects of climate factors and slope aspects on AMF diversity,composition and spore density were studied.The findings indicate that climate has a more direct influ-ence on soil properties(P<0.001)in comparison to slope aspect(P=0.449).In contrast,climate significantly affected AMF diversity and composition,with the highest diversity in dryer areas.Soil pH had the highest correlation with different facets of AMF diversity.Structural equation modeling(SEM)indicated that only a small part of the variation in AMF diversity and spore density could be explained by climate characteristics,slope aspect and soil properties.Based on SEM results,climate was the most important determinant of AMF diversity and spore density;slope aspect had a less critical role.The outputs suggest that variations in AMF diversity are derived by the direct effects of climate and the indirect effect of soil chemical properties.In addition,with increasing dryness,sporulation and AMF diversity increased.展开更多
This study aims to investigate grain quality and nutritional values of rice(Pokkali,a salt-tolerant cultivar;RD73,a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali,and KDML105,a moderately...This study aims to investigate grain quality and nutritional values of rice(Pokkali,a salt-tolerant cultivar;RD73,a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali,and KDML105,a moderately salt-susceptible cultivar)grown under non-saline(0.04–0.87 dS/m)and slightly saline(1.08–4.83 dS/m)field conditions.The results revealed that salinity caused significant reduction in grain size but significant increments in reducing sugar and total protein contents in the grains.Nevertheless,the amounts of starch in the grains of KDML105 and Pokkali rice genotypes were unaffected by the stress.The starch granule size distribution was also unaffected by salinity.Interestingly,only starch from Pokkali was significantly diminished in amylose content,from 19.18%to 16.99%.Accordingly,parameters relating to starch gelatinization,retrogradation,and pasting properties of KDML105 and RD73 were unaffected by salinity;only Pokkali showed a significant increase in percentage of retrogradation along with a significant reduction in gelatinization enthalpy.In the saline field,total phenolic content and antioxidant capacity in the grains of all rice cultivars tended to increase,particularly in Pokkali.On average,essential element contents in grains from the saline-treated plants showed a 33%,32%,32%,22%,20%,11%,and 10%increase in total P,N,K,Mg,Zn,Fe,and Ca content,respectively.Interestingly,total Fe content exhibited the greatest percentage of increments in KDML105(187%).Taken together,cultivation of rice in the slightly saline field did not alter its eating and cooking qualities,while enhanced some nutritional properties such as proteins,minerals,and secondary metabolites like phenolic compounds.展开更多
Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） a...Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） and cetylrimethyl ammonium bromide （CTAB） on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content （foc）. The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration （〈 100 mg/L）, the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene.展开更多
The contents and distribution of 20 polycyclic aromatic hydrocarbons （PAHs） and heterocyclic aromatic hydrocarbons （HAHs） were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high mole...The contents and distribution of 20 polycyclic aromatic hydrocarbons （PAHs） and heterocyclic aromatic hydrocarbons （HAHs） were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs （HMWPAHs） and the correlation between total organic carbon （TOC） and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil （〈 40 cm）, with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.展开更多
The effects of municipal sewage irrigation on the soil and black locust （Robinia pseudoacacia L.） tree were studied. For this purpose, two artificial black locust stands under irrigation of municipal sewage and well...The effects of municipal sewage irrigation on the soil and black locust （Robinia pseudoacacia L.） tree were studied. For this purpose, two artificial black locust stands under irrigation of municipal sewage and well water were selected in south of Tehran, Iran. Data were collected using technique of systematic random sampling with 4 replicates in each stand. It was found that the growth of black locust tree, as indicated by diameter at breast height, total height, crown length, average crown diameter, basal area and volume, in sewage irrigation stand was much higher than that of well water irrigation stand （P 〈 0.01）. Plant analysis indicated that concentrations of leaf nutrients （N, E K, Ca, Mg, Na, Fe, Mn, Cu and Zn） were greater in sewage-irrigated trees, without toxicity to the minerals of tree leaf, than those of well waterirrigated trees, and positively correlated with their respective value in soil. Ni, Cr and Pb were not detected in leaf samples. Application of sewage resulted in a 1.5-fold increase in the concentrations of soil nutrients, Ni, Cr and Pb. Among these minerals only Pb and Ni in some soil samples exceeded the toxicity limit. The increase in pH, electrical conductivity （EC） and organic carbon of soil was also observed in sewage irrigation. Results confirm that besides the use as irrigation water, municipal sewages are also a potential source of plant nutrients. However, significant accumulation of heavy metals such as Pb and Ni in soil needs to be monitored.展开更多
文摘The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles.For this purpose,the prepared coatings were applied to pine wood surfaces and weathered artificially.Subsequently,color and gloss of the coatings were measured before and after the weathering test.Field emission scanning electron microscopy(FE-SEM)micrographs prepared from the coatings showed that the average size of nano-particles in the polyurethane substrate was approximately 500 nm.Nuclear magnetic resonance(13C-NMR)spectroscopy showed that strong urethane bonds were formed in the nano-lignin-based polyurethane.Differential calorimetric analysis(DSC)test revealed that the glass-transition temperature(Tg)of lignin nanoparticles modified with diethylenetriamine(DETA)was 112.8℃ and Tg of lignin nano-particles modified with ethylenediamine(EDA)was 102.5℃,which is lower than the Tg of un-modified lignin(114.6℃)and lignin modified with DETA(126.8℃)and lignin modified with EDA(131.3℃).The coatings modified with lignin nano-particles had a greater change in gloss.The lignin nano-particles in the modified coating are trapping hydroxyl radicals which reduces photoactivity and yellowing of the polyurethane by about 3 times compared to unmodified polyurethane coatings.After weathering test,the nano-lignin-based coating had a rougher surface with a lower contact angle(0.78°)compared to the unmodified polyurethane coating(0.85°).
文摘We carried out this research at Abu-Gaddaf Natural Forest Reserve (ANFR) which is located east of Blue Nile River, in Blue Nile State, Sudan. It aims at exploring tree composition assessing their diversity indices, and ecological importance values. For survey of types and estimation of density of tree species in the forest, we randomly distributed 97 circular sample plots (0.1 hectare (ha)). In each sample plot we identified all trees to the species level, recorded their frequencies and computed species diversity and importance value indices (IVI). A total of 13 tree species, which belong to 12 genera and nine families, were identified in the tree layer of the forest. Mean tree density in ANFR was 116 trees/ha, composed mainly of Boswellia papyrifera (Del.) Hochst. (48), followed by Combretum hartmannianu (19) and Lannea fruticosa (18). Fabaceae was the most common family followed by Combretaceae and Malvaceae. B. papyrifera Delile Hochst was the most abundant while Acacia seyal was the least abundant species. Species richness (R = 1.71), evenness (E = 0.69), dominance (0.24) indices and Simpson’s Index of Diversity (D' = 0.76) suggest a moderate diversity, moderate numbers of individuals in each species and a moderate community stability. The research provides empirical results on diversity and ecological importance value of species, signifies the urging need to safeguard threatened species and to prioritize them for conservation, as well as the need to promote management of abundant species to provide multiple forest ecosystem services.
文摘The Dongsithouane National Production Forest (DNPF) is one of the largest natural forest areas in Savannakhet, Lao PDR, which has been a vital support for the local community’s livelihood, Recently, significant changes in land use and land cover (LULC) have been observed in this area, leading to a reduction of natural forests. There were two separate methods of this study: firstly, to identify LULC changes across three different periods, spectral imagery from the Landsat 5 Thematic Mapper (TM) for the years 2001 and 2011, and the Landsat 8 Operational Land Imager (OLI) for 2021 were used as the primary data sources. The satellite images were preprocessed for various forest classes, including pretreatment of the top of atmosphere reflectance by using QGIS software’s semi-automatic classification plug-in (SCP), and ArcGIS was used for post-classification. A supervised classification approach was applied to the satellite images from 2001, 2011, and 2021 to generate diverse maps of LULC. Secondly, a household survey dataset was used to investigate influential factors. Approximately 220 households were interviewed in order to collect socio-economic information (including data on population growth, increased business activities, location of the area, agriculture land expansion, and need for settlement land). Household survey data was analyzed by using SPSS. Descriptive statistics, including frequency distributions and percentages, were applied to observe characteristics. Additionally, a binary logistic regression model was used to analyze the socioeconomic factors related to LULC change in DNPF. Key findings indicated a decline in natural forest areas within the study site. Specifically, both dry dipterocarp forest (−11.35%) and mixed deciduous forest (−0.18%) decreased from 2001 to 2021. The overall accuracy of the LULC maps was 94%, 86%, and 89% for the years 2001, 2011, and 2021 respectively. In contrast, agricultural land increased significantly by 155.70%, while built-up land, and water bodies increased by 65.54% and 35.33%, respectively. The results also highlighted a significant increase in construction land, up to 65.54%. Furthermore, the study found a correlation between agricultural expansion and a reduction of forest areas, along with an increase in built-up land along the forest areas’ boundaries. Timber exploitation and charcoal production also contributed to the decline in forest cover. The logistic regression model identified significant determinants of LULC change, including the area’s location, agricultural land expansion, increased business activity, and the need for settlement land. These factors have influenced the management of DNPF. Urgent sustainable management practices and actions, including forest ecosystem protection, village agricultural zoning, water source and watershed protection and public awareness, are required to preserve the forest areas of DNPF.
文摘We investigated the effects of grazing on natural regeneration, quantity, and diversity of woody species and dominant herb species in Kheyroud forest in northern Iran. We sampled vegetation in 5m2 plots in custom units, which are demarcated resource areas traditionally used by local livestock producers. The authors quantified number of species, height of seedlings, and diameter of seedlings. Height classes were 0-30 cm, 30-130 cm, and 〉130 cm, and diameter classes were 0-2.5 cm, 2.5-5 cm and 5-7.5 cm. The density of seedlings declined with distance from corral until reaching the custom unit boundary. Most seedlings had diameters of 0-2.5 cm and heights of 0-30 cm. Predominant species, Carpinus betulus and Acer capadocicum, were in plots near the centers of custom units, Fagus orientalis, Acer velutinum, Quercus castanifolia species were dominant in plots near the custom unit boundary. Plant species such as Oplismenus undulatifolius, Euphorbia amygdaloides, Rubusfrutieos and Pteridium aquilinum were dominant in plots nearer to forest corral. Healthy seedlings were more numerous in plots nearest the corral, while defective and deformed seedlings were more abundant away from the corral. We conclude that grazing had negative effects on the quantity and quality of vegetative regeneration. Continuation of overgrazing will not only endanger the sustainability of forest ecosystems, but also will increase the challenge of sustainable forest management.
文摘For developing nature-based silvicultural practices in a beech forest to promote, abundance, height, vitality, and preferred growth form, regenerated trees growing in gaps were compared with those under closed canopies. A systematic 50 ×50 m grid was plotted in a beech stand in the Kheyrud Experimental Forest for selecting trees to measure variables in gaps and under closed canopies. Abundance and mean height of regenerated beech trees were significantly higher in closed canopies than in canopy gaps. Beech seedlings with excurrent growth were significantly taller within regeneration patches under closed canopy. Moreover, regenerated trees with high vitality were more abundant in closed canopy areas than in gaps. Thus, beech regeneration should improve under closed canopies; hence, gaps in a near natural forest should be created only after adequate regeneration and appropriate growth under the parent tree in a closed canopy area is ensured. The results of this research have profound implications for the sustainable management of the forest and for ensuring sustainable beech regeneration. The presence of a closed canopy cover likely will reduce potential stresses on oriental beech regeneration.
文摘The objective of this investigation was to introduce a cement-based composite of higher quality. For this purpose new hybrid nanocomposite from bagasse fiber,glass fiber and multi-wall carbon nanotubes（MWCNTs）were manufactured. The physical and mechanical properties of the manufactured composites were measured according to standard methods. The properties of the manufactured hybrid nanocomposites were dramatically better than traditional composites. Also all the reinforced composites with carbon nanotube, glass fiber or bagasse fiber exhibited better properties rather than neat cement.The results indicated that bagasse fiber proved suitable for substitution of glass fiber as a reinforcing agent in the cement composites. The hybrid nanocomposite containing10 % glass fiber, 10 % bagasse fiber and 1.5 % MWCNTs was selected as the best compound.
文摘Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms,especially carbon-carbon and carbon-hydrogen.These compounds are mainly used as reactants to make other polymers.Among biopolymers,lignin is regarded as the base of a new polymer in polyol construction.The present study aimed to investigate the effects of amine type(diethylenetriamine and ethylenediamine)on the modification of lignin-based polyols,so as to provide an alternative to petroleum polyols and,in turn,increase functional groups and reduce their harm to humans’health and the environment.To this aim,first,lignin was extracted from raw liquor.Next,the extracted lignin was reacted with diethylenetriamine(DETA)and ethylenediamine(EDA).Finally,the Mannich method was used for the reaction between amine lignin and propylene carbonate.The results of the Fourier Transform Infrared(FTIR)spectroscopy analysis showed that modification with DETA led to more structural change in lignin and peak 1100 indicates the presence of C–O bond related to urethane bonds in modified lignin.Moreover,adding propylene carbonate to aminated lignin did not result in much change in the results of the FTIR analysis.Additionally,urethane bonds can be seen in the results of GPC at 400℃–500℃.Furthermore,a slight decrease in thermal stability was observed in lignin modified with amine and propylene carbonate,compared to the raw lignin sample.
文摘Arasbaran forests are located in East Azerbaijan （northwest Iran）. Increasing of socio-economic problems in this area causes destruction of biodiversity and structure of these forests. Using multipurpose trees such as cornelian cherry （Cornus mas L） to encourage villagers to produce forest by-products is a basic approach for preserving these forests. This species grows naturally in Arasbaran forests and the fruit is annually exploited using traditional harvest methods. This study aims to assess the ecological requirements of cornelian cherry and the important factors affecting its distribution. For this purpose, 40 circular sampling plots （300 m2） on various slope aspects were demarcated for sampling the occurrence of cornelian cherry in forest stands. DBH and crown cover percentage on north aspects were significantly greater than on other aspects and 4.5% of all trees were cornelian cherry in mature forest stands. North aspects had more seed-origin trees （standards） of cornelian cherry than coppiced trees, while west facing aspects had more coppiced than standard trees. This species had the highest regeneration rate in the sapling stage of 0–2.5 cm DBH. Thus, I recommend cultivation and development of cornelian cherry as a multi-purpose tree in the Arasbaran region on degraded forest lands on north and west aspects.
文摘Recent studies on decentralized wetland governance in Uganda have focused mainly on the relationship between central and local governments. Less attention has been given to the relationship between agricultural systems, local governments, and water bodies. This study aims at assessing decentralized wetlands governance in the upper river Rwizi and Iguluibi micro catchments, Lake Victoria Basin Uganda, in relation to farming practices. Qualitative and quantitative methods were used to provide a comprehensive understanding of the contribution of decentralized governance to the management of wetlands resources. Quantitative survey data were analyzed using descriptive summary statistics with the help of Statistical package for Social Sciences (SPSS) soft ware. Qualitative data analysis involved the categorization of verbal and behavioral data for purposes of classification with the use of Nvivo soft ware. Data were analyzed at two levels: the descriptive level of analysis which is the account of the data in terms of what was said, documented or observed with nothing assumed about it. The second level of analysis was interpretive, where data is transformed into what is meant by the responses and conclusions are drawn. All recorded interviews were transcribed into a written report. Findings revealed that decentralized wetlands governance has brought ecosystem services nearer to communities in form of community-based management planning. However, results indicated inadequate institutional capacity, knowledge gaps of existing legal frameworks, limited political support and accountability for local leaders, lack of cooperation and coordination, and inadequate funding. In all, the policy has not fully realized its intended outcomes.
基金supported by the University of Jirof, Iran (4813-00-1)
文摘The plantation of non-native species is one of the most expensive ecological restoration measures in arid and semi-arid areas,while its impacts on local communities are largely ignored.This study assessed the rate of change and the dynamic degree of the economic values of ecosystem services related to local conservation(water yield,stocking rate and aesthetic value)and preserving the future(carbon sequestration,soil protection,soil stability and habitat provision)to determine the restoration success of the plantation of non-native species Haloxylon ammodendron(C.A.Mey.)Bunge ex Fenzl(15-and 30-year-old)in parts of arid rangelands of Bardsir region,Kerman Province,Iran.We investigated the impacts of the two plantations on the seven ecosystem services and ecosystem structures(horizontal and vertical structures,vegetation composition and species diversity)based on field sampling and measurements at four sampling sites(i.e.,control,degraded,and 15-and 30-year-old plantation sites)in spring and summer of 2022.The restoration success of the plantation of non-native species was then examined by assessing the rate of change and the dynamic degree of the total economic value of all ecosystem services as well as the rate of change and the dynamic degree of the economic values of ecosystem services for the two groups(local conservation and preserving the future).Although the plantation of non-native species H.ammodendron enormously improved the vertical and horizontal structures of ecosystems,it failed to increase species diversity and richness fully.Further,despite the plantation of non-native species H.ammodendron had significantly increased the economic values of all ecosystem services,it was only quite successful in restoring carbon sequestration.Path analysis showed that plantation age had a significant impact on restoration success directly and indirectly(through changing ecosystem structures and services).The dynamic degree of the economic values of ecosystem services related to local conservation and preserving the future at the 15-and 30-year-old plantation sites indicated that the two plantations successfully restored the ecosystem services related to preserving the future.The presented method can help managers select the best restoration practices and predict their ecological-social success,especially for the plantation of high-risk non-native species in arid and semi-arid areas.
基金financially supported by the Urmia University,Iran.
文摘Lake Urmia,Northwest Iran,has confronted a drying procedure in recent years with losing 90%of its water body.The authorities concerned about desertification processes and possible dust events throughout the region.In this regard,the Iranian Natural Resources and Watershed Management Organization has taken ecological measures to plant vegetation using salt cedar(Tamarix ramosissima Ledeb.)shrubs to combat desertification.This study aimed to investigate the vegetation and soil characteristics of natural and plantation stands of salt cedar on the western shores of Lake Urmia.To this end,7 transects were randomly selected with 15 shrubs in natural stands,and 7 transects were randomly selected with 15 shrubs in the plantation parts along the planting rows.Then,vegetative characteristics were examined.Also,soil samples were taken from the vicinity of the shrubs.The results indicated that there was no significant difference between the mean diameter at breast height(DBH)of salt cedar in natural sites.There was a significant difference between the mean number of sprouts per sprout-clumps,mean crown diameter,collar diameter,total height,and also between mean crown diameter and freshness of shrubs among different sites(P<0.05).It was also found that soil variables,such as clay content,organic matter,electrical conductivity(EC),Na^(+),specific absorption rate(SAR),Cl^(-),SO_(4)^(2-),Na^(+),K^(+),and PO_(4)^(2-) are the most significant variable parameters between studied sites.As the results shown,the values of EC,SAR,Na^(+),and Cl^(-)are 6 times higher in the planted stands than in the natural stands of T.ramosissima.Also,the colonization of T.ramosissima in the planted stands is unsuccessful by dramatic drop in the total height and average diameter.Considering the role of soil characteristics in explaining the variance of data and site separation,it seems that these indicators can be applied in executive plans as important indicators to identify suitable planting sites for combating desertification.
基金supported by the Jiangsu Science and Technology Special Project(Grant No.BX2019084)Research Startup Funding at Nanjing Forestry University(Grant No.163010230)the Faculty Startup Funding(to Arshad Ali)for establishing Forest Ecology Research Group at Hebei University(Special Project No.521100221033)。
文摘The influences of trait diversity(i.e.,the niche complementarity effect)and functional composition(i.e.,the mass ratio effect)on aboveground biomass(AGB)is a highly debated topic in forest ecology.Therefore,further studies are needed to explore these mechanisms in unstudied forest ecosystems to enhance our understanding,and to provide guidelines for specific forest management.Here,we hypothesized that functional composition would drive AGB better than trait diversity and stem size inequality in the(sub-)tropical forests of Nepal.Using data from 101 forest plots,we tested 25 structural equation models(SEMs)to link elevation,stem DBH inequality,trait diversity(i.e.,trait richness,evenness,dispersion and divergence),functional composition[i.e.,community-weighted of maximum height mean(CWM of Hmax),specific leaf area(CWM of SLA),leaf dry matter content(CWM of LDMC),and wood density(CWM of WD)]and AGB.The best-fitted SEMs indicated that CWM of Hmax promoted AGB while overruling the impacts of trait diversity indices on AGB.However,low trait diversity indices were linked with higher AGB while overruling the effects of CWM of SLA,LDMC and WD on AGB.In addition,AGB decreased with increasing elevation,whereas stem size inequality did not influence AGB.Our results suggest that divergent species’functional strategies could shape AGB along an altitudinal gradient in tropical forests.We argue that forest management practices should include plant functional traits in the management plan for the co-benefits of biodiversity conservation and carbon sequestration that underpins human wellbeing.
文摘Plants have always been exploited worldwide for food, medicines, shelter, and other purposes because they are readily available, affordable and acceptable to a large populace of the world. The study was conducted to gather information on the proximate composition of fresh and dry leaves of Pterocarpus erinaceus. The proximate composition of the leaf samples was determined using the standard methods of analysis of the Association of Official Analytical Chemists (AOAC). Proximate analysis of the fresh leaf samples of the plant shows a higher moisture content compared to the dry leaf samples. The total fat and total ash contents of the fresh leaf samples were however lower compared to values recorded for the dry leaf samples. The dry matter content of fresh leaf samples was also lower compared to that of the dry leaf samples. Fresh leaf samples again recorded the least crude protein content compared to dry leaf samples. Carbohydrates content in fresh leaf samples was higher compared to dry leaf samples. Generally, higher proximate values were recorded for dry leaf samples than for fresh leaves. Dry matter and moisture contents were detected in high quantities in both fresh and dry leaf samples of P. erinaceus. These results could be a justification for the multiple uses of the plant leaves across Sub-Saharan Africa. Further research should be carried out on the mineral, phytochemical and vitamin composition between the fresh and dry leaves of the plant.
文摘Construction projects,including road construction,are very important.Therefore,a lot of money is spent on these projects every year.So,the lack of proper planning will increase the cost and cause irreparable damage to the country.The role of workshop management is one of the most important factors in increasing the cost of these types of projects.Generally,workshop management plays a very important role in improving the quality and quantity of projects and has an important place in the project implementation process.Therefore,this study evaluated the impact of workshop management on the progress of road construction projects on a case-by-case basis in road construction projects in Tehran province.According to the purpose of the research,this study was a descriptive-survey type.In addition,the tool used in this research was a questionnaire.The statistical population of this research included all experts and specialists in road construction projects,among whom 65 people were selected by snowball method.Then the collected data were analyzed using SPSS software.The results of this study showed that the management of the workshop and its role in the control and implementation of projects is a complex process,which can be implemented at high levels and effectively by combining scientific and experimental training.And a very important point in the discussion of workshop management is applying scientific management to the use of valuable experiences from others.Because management knowledge not only does not negate the use of these experiences,but also emphasizes the necessity of using them.In other words,improving the knowledge of workshop management is one of the requirements for the implementation of value engineering in construction projects,especially road construction,and it is very important.
基金the doctoral dissertation of Nabiyeh Karimi with the financial support of Sari University of Agricultural Sciences and Natural Resources, Iran
文摘Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation practices.Numerous studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the watersheds.However,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located downstream.The surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 points.Suspended and bed sediments were sampled in the watershed outlet in two high and low water periods.Geochemical characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC Integra.The reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R software.The results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water periods.For bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,respectively.Land use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.
文摘Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across climatic gradients and slope aspects in arid and semi-arid ecosys-tems.In this study,using 60 composite soil samples,direct and indirect effects of climate factors and slope aspects on AMF diversity,composition and spore density were studied.The findings indicate that climate has a more direct influ-ence on soil properties(P<0.001)in comparison to slope aspect(P=0.449).In contrast,climate significantly affected AMF diversity and composition,with the highest diversity in dryer areas.Soil pH had the highest correlation with different facets of AMF diversity.Structural equation modeling(SEM)indicated that only a small part of the variation in AMF diversity and spore density could be explained by climate characteristics,slope aspect and soil properties.Based on SEM results,climate was the most important determinant of AMF diversity and spore density;slope aspect had a less critical role.The outputs suggest that variations in AMF diversity are derived by the direct effects of climate and the indirect effect of soil chemical properties.In addition,with increasing dryness,sporulation and AMF diversity increased.
基金supported by the National Research Council of Thailand(Grant No.NRCT813/2563)the Post-Doctoral Training,Khon Kaen University(Grant No.PD2565-02-02)。
文摘This study aims to investigate grain quality and nutritional values of rice(Pokkali,a salt-tolerant cultivar;RD73,a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali,and KDML105,a moderately salt-susceptible cultivar)grown under non-saline(0.04–0.87 dS/m)and slightly saline(1.08–4.83 dS/m)field conditions.The results revealed that salinity caused significant reduction in grain size but significant increments in reducing sugar and total protein contents in the grains.Nevertheless,the amounts of starch in the grains of KDML105 and Pokkali rice genotypes were unaffected by the stress.The starch granule size distribution was also unaffected by salinity.Interestingly,only starch from Pokkali was significantly diminished in amylose content,from 19.18%to 16.99%.Accordingly,parameters relating to starch gelatinization,retrogradation,and pasting properties of KDML105 and RD73 were unaffected by salinity;only Pokkali showed a significant increase in percentage of retrogradation along with a significant reduction in gelatinization enthalpy.In the saline field,total phenolic content and antioxidant capacity in the grains of all rice cultivars tended to increase,particularly in Pokkali.On average,essential element contents in grains from the saline-treated plants showed a 33%,32%,32%,22%,20%,11%,and 10%increase in total P,N,K,Mg,Zn,Fe,and Ca content,respectively.Interestingly,total Fe content exhibited the greatest percentage of increments in KDML105(187%).Taken together,cultivation of rice in the slightly saline field did not alter its eating and cooking qualities,while enhanced some nutritional properties such as proteins,minerals,and secondary metabolites like phenolic compounds.
基金supported by the National NaturalScience Foundation of China (No. 40372109)the National Basic Research Program (973) of China (No.2004CB418502).
文摘Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） and cetylrimethyl ammonium bromide （CTAB） on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content （foc）. The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration （〈 100 mg/L）, the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene.
基金supported by the National NaturalScience Foundation of China (No. 40473045)
文摘The contents and distribution of 20 polycyclic aromatic hydrocarbons （PAHs） and heterocyclic aromatic hydrocarbons （HAHs） were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs （HMWPAHs） and the correlation between total organic carbon （TOC） and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil （〈 40 cm）, with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.
基金supported by the Tarbiat Modares University Research Fundation
文摘The effects of municipal sewage irrigation on the soil and black locust （Robinia pseudoacacia L.） tree were studied. For this purpose, two artificial black locust stands under irrigation of municipal sewage and well water were selected in south of Tehran, Iran. Data were collected using technique of systematic random sampling with 4 replicates in each stand. It was found that the growth of black locust tree, as indicated by diameter at breast height, total height, crown length, average crown diameter, basal area and volume, in sewage irrigation stand was much higher than that of well water irrigation stand （P 〈 0.01）. Plant analysis indicated that concentrations of leaf nutrients （N, E K, Ca, Mg, Na, Fe, Mn, Cu and Zn） were greater in sewage-irrigated trees, without toxicity to the minerals of tree leaf, than those of well waterirrigated trees, and positively correlated with their respective value in soil. Ni, Cr and Pb were not detected in leaf samples. Application of sewage resulted in a 1.5-fold increase in the concentrations of soil nutrients, Ni, Cr and Pb. Among these minerals only Pb and Ni in some soil samples exceeded the toxicity limit. The increase in pH, electrical conductivity （EC） and organic carbon of soil was also observed in sewage irrigation. Results confirm that besides the use as irrigation water, municipal sewages are also a potential source of plant nutrients. However, significant accumulation of heavy metals such as Pb and Ni in soil needs to be monitored.
