Seven kinds of heavy metal accumulation of rubbish compost in turfgrass by EDTA chelating were investigated. With EDTA application, heavy metal accumulation by two species of turfgrass was increased significantly. The...Seven kinds of heavy metal accumulation of rubbish compost in turfgrass by EDTA chelating were investigated. With EDTA application, heavy metal accumulation by two species of turfgrass was increased significantly. The enrichment coefficients of Lolium perenne L（L） and Festuca arundinacea L（F） to Cr reached 9.4.5 and 6.15 respectively. In the range of EDTA dosages given, heavy metal accumulation in turfgrass increased with increasing EDTA level. There were significant differences in remediation of different metals by applying EDTA. L had high ability to accumulate Cr, Cd, Ni and Zn, showing better remediation to heavy metals of rubbish compost. In contrast, F showed high ability to accumulate Cr, Ni, Cu and Zn. Low EDTA level increased aboveground net primary production （ANP） of turfgrass, but EDTA would considerably inhibit it when EDTA was higher than 20 mmol/kg. The results demonstrated that the optimum dosage of EDTA for remediating heavy metals in rubbish compost by turfgrass was between 10 mmol/kg and 20 mmol/kg.展开更多
This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgras...This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgrass medium. Heavy metals in domestic rubbish were controlled by source screening before composting. The study consisted of a control with garden soil. The contents of main mineral elements and heavy metals in rubbish compost and control were determined by the method of ICP-AES. The results showed that heavy metal concentrations in rubbish were lower than those in garden soil, and little difference occurred between rubbish and garden soil in main mineral element concentrations. Based on this, it was concluded that rubbish compost was favorable for using as turfgrass medium and heavy metal control in rubbish by source screening was effective.展开更多
The role of turfgrasses in C and N cycling in the southeastern U.S. has not been well documented. The objectives of this research were to determine the characterization of chemical quality, clipping decomposition rate...The role of turfgrasses in C and N cycling in the southeastern U.S. has not been well documented. The objectives of this research were to determine the characterization of chemical quality, clipping decomposition rates, and C and N release from warm- and cool-season turfgrasses. The study was conducted for 46 weeks in 2012 in Auburn, AL. Four warm season turfgrasses were used included (bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy], centipedegrass (Eremochloa ophiuroides (Munro) Hack), St. Augustinegrass (Stenotaphrum secundatum (Walter) Kuntze), zoysiagrass (Zoysia japonica Steud.), and one cool season turfgrass (tall fescue (Festuca arundinacea Schreb)). Litter was placed into nylon bags at an oven dry rate of 3.6 Mg?ha?1. Litter bags were retrieved after 0, 1, 2, 4, 8, 16, 24, 32, and 46 weeks, and analyzed for total C and N. A double exponential decay model was used to describe mass, C, and N loss. Results indicated that tall fescue decomposition occurred rapidly compared to warm season turfgrasses. Litter mass loss measured after 46 weeks was determined to be 61.7%, 73.7%, 72.2%, 86.8%, and 45.4% in bermudagrass, centipedegrass, St. Augustinegrass, tall fescue, and zoysiagrass respectively. Zoysiagrass litter had a higher lignin concentration, while tall fescue had the lowest lignin. Over 46 weeks’ release of C was in the order: zoysiagrass > bermudagrass = centipedegrass = St. Augustinegrass > tall fescue, and release of N was in the order zoysiagrass > centipedegrass > bermudagrass = St. Augustinegrass > tall fescue. Our study concluded that, zosiagrass is a better choice for home lawns.展开更多
The development of a (layer of) thatch in turfgrass causes important changes to near-surface eco-hydrological processes. In this study, we investigated the effects of turfgrass thatch, specifically Kentucky bluegrass ...The development of a (layer of) thatch in turfgrass causes important changes to near-surface eco-hydrological processes. In this study, we investigated the effects of turfgrass thatch, specifically Kentucky bluegrass (Poa pratensis L.) and red fescue (Festuca rubra L.) on water infiltration, surface runoff, and soil moisture evaporation. The thatches were collected from the field for controlled experiments using packed soil columns under various rainfall conditions. Results indicated that the presence of thatch delayed the onset of infiltration compared with situations without a thatch at the soil surface. Infiltration was delayed for a longer period in thicker red fescue thatch than thinner Kentucky bluegrass thatch. The presence of a thatch reduced runoff by holding more water locally during the rainfall period and allowing a longer period of time for infiltration. Additionally, evaporative water loss was reduced with the presence of thatch than that of bare soil. Our results highlight that the presence of thatch changes the near-surface hydrological processes, which may help improve turf management practices in terms of thatch control and irrigation scheduling.展开更多
The paper aimed to study the effects of nitrogen fertilization on the yield and some plant characteristics of perennial ryegrass (Lolium perenne L.). The study was conducted at Agricultural Research and Application Ce...The paper aimed to study the effects of nitrogen fertilization on the yield and some plant characteristics of perennial ryegrass (Lolium perenne L.). The study was conducted at Agricultural Research and Application Center of the Faculty of Agriculture in Igdir University in 2013. In the experiment, eight levels of fertilizers: 0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0 and 70.0 kg N/ha per month were applied in perennial ryegrass (Lolium perenne L.) during the sixth growing season. A randomized complete block with three replications was used as the experimental design. Nitrogen application affected plant height, green grass yield, plant covering rate, canopy color and turfgrass quality values of perennial ryegrass positively. In both monthly and as the average of nitrogen application, times of application (spring, summer and fall) caused the most uniform turfgrass quality and establishment. Results indicated that although a significant impact was on the character investigated, such as the leaf length, green grass yield, plant cover ratio, canopy color and turfgrass quality, the doses of nitrogen fertilizer have created close to each other in groups. In the stand point of view of all characters, N1, N2 and N3 were located in first group, N4 and N5 in the second group, N6 and N7 in the third group, expect for control (N0). It can be concluded that 40.0-50.0 kg N/ha per month may be more suitable to be used in ryegrass production in the landscape.展开更多
The carbon （C） sequestration potential of turfgrass systems has been investigated and demonstrated from several studies. The role of these ecosystems in continental and Mediterranean climates though, is not yet clea...The carbon （C） sequestration potential of turfgrass systems has been investigated and demonstrated from several studies. The role of these ecosystems in continental and Mediterranean climates though, is not yet clearly understood because environmental limiting factors and management intensities can strongly influence the overall C budget. The aim of the present study is to improve the understanding of the mechanisms underlying C fluxes in a turfgrass ecosystem and to assess its C sequestration potential by estimating the annual C budget. NEE （Net Ecosystem Exchange） of turfgrass was calculated in its seasonal variation over one year, and compared between areas characterized by different degrees of maintenance. The C sequestration potential of the turfgrass was investigated in a golf course near Verona （Italy）, adopting a small-chamber enclosure approach. The measurements of gas exchanges between biosphere and atmosphere, permitted to estimate the NEE, as a function of different management intensities. The intensity of management seems to have influence on its C balance. This study needs further research to understand which maintenance variables are determinant on turfgrass C sequestration.展开更多
[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbo...[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbon nanomaterials on soil enzyme activity was studied by adding graphene, graphene oxide and carbon nanotubes to turfgrass soil. [Results] Compared with the control(CK), the activity of soil protease, sucrase, alkaline phosphatase and catalase was not significantly affected by carbon nanomaterials. Under the treatment of carbon nanotubes, urease activity was significantly lower than that of graphene and graphene oxide, and dehydrogenase activity was significantly lower than that of the CK, graphene and graphene oxide. [Conclusions] This study provides a theoretical basis for the safe application of carbon nanomaterials.展开更多
Natural organic fertilizers are receiving increased attention as a nutrient source for athletic turf fields. However, the performance of these fertilizers as an alternative to inorganic fertilizers is relatively untes...Natural organic fertilizers are receiving increased attention as a nutrient source for athletic turf fields. However, the performance of these fertilizers as an alternative to inorganic fertilizers is relatively untested. To address this issue, we initiated a study to evaluate turfgrass response to the use of pelletized poultry litter （PPL） as a nutrient source compared to inorganic fertilizer, and to compare core aeration and vibrating aeration. Four treatments were evaluated： synthetic fertilizer with vibrating aeration （VS）, synthetic fertilizer with core aeration （CS）, PPL with vibrating aeration （VP）, and PPL with core aeration （CP）. The PPL was applied at a nitrogen （N） rate equivalent to the synthetic fertilizer （assuming 50% availability of N）. Application of PPL did not produce significant changes in measured soil parameters during the 2.5 year study compared to the synthetic fertilizer. Minimal differences in tissue concentrations of Mn were observed. Remote sensing indicated that the CS treatment, which is the current management practice at the study site, produced the lowest turfgrass quality of all the treatments. Highest turf quality was achieved with the CP and VS treatments. Application of PPL resulted in greater turfgrass quality when compared to the same N rate of synthetic fertilizer, regardless of aeration method.展开更多
Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals, which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turf...Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals, which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turfgrass to rubbish compost were investigated following the addition of EDTA. The results showed that the addition of EDTA significantly increased heavy metal accumulation in Lolium perenne L. and Festuca arundinacea L. Most heavy metal concentrations in L. perenne increased with increasing EDTA supply. The concentrations of Cr, Mn, Ni, Cu, and Cd in L. perenne were highest following the addition of 30 mmol/kg EDTA and the concentrations of Cr and Ni at this point reached concentrations of 1 914.17 and 521.25 μg/g, respectively. When the EDTA level was 〈 20 mmol/kg, the accumulation of most heavy metals in F. arundinacea increased with increasing EDTA supply, but showed a tendency to decrease at EDTA concentrations 〉20 mmol/kg. The highest concentrations of Mn, Ni, Cu, and Zn in F. arundinacea reached 268.01, 110.94, 161.52 and 1 354.97 μg/g, respectively, following the addition of 20 mmol/kg EDTA. The EDTA-induced increase in the accumulation of heavy metals in turfgrass was plantand metal-specific. L. perenne had a relatively high ability to accumulate Cr, Ni, and Zn. The highest Zn concentration was 2 979.58 μg/g and, following the addition of EDTA, the concentrations of the three metals were increased 26.23, 20.03, and 10.49-fold, respectively, compared with control. However, F. arundinacea showed a high ability to accumulate Cr, with the highest concentration （596.02 μg/g） seen following the addition of 30 mmol/kg EDTA; the concentration of Cr increased 15.51-fold compared with control. With EDTA addition, ecological responses of both turfgrass species showed that EDTA at concentrations 〈10 mmol/kg increased seed germination and aboveground net primary production （ANP） of L. perenne and slightly inhibited those of F. arundinacea, but EDTA at concentrations 〉20 mmol/kg inhibited these parameters significantly for both species. Moreover, EDTA increased the chlorophyll and proline content at all concentrations tested. On the basis of the synthetic remediation index, the optimal EDTA concentration for turfgrass remediation of heavy metals in compost is approximately 10 mmol/kg.展开更多
随着城市人口密度的不断增长和城市化进程的加快,城市生态系统已成为影响全球气候变化的热点区域。但是,城市草地作为城市生态系统的重要组成部分,其对土壤—大气CO_(2)和CH_(4)交换过程的影响尚不明确。为此,本文依托北京城市绿地生态...随着城市人口密度的不断增长和城市化进程的加快,城市生态系统已成为影响全球气候变化的热点区域。但是,城市草地作为城市生态系统的重要组成部分,其对土壤—大气CO_(2)和CH_(4)交换过程的影响尚不明确。为此,本文依托北京城市绿地生态系统定位观测研究站,采用静态暗箱—气相色谱方法对三种典型城市草地类型[即以C_(4)草种(光合作用中CO_(2)被固定为三碳和四碳化合物)为主的暖季草地和以C_(3)草种(光合作用中CO_(2)被固定为三碳化合物)为主的冷季草地与林下地被]的土壤CO_(2)排放和CH_(4)吸收通量及其辅助环境因子进行了一个完整周年的田间原位观测研究。结果表明,三种城市草地类型的土壤CO_(2)排放和CH_(4)吸收通量在整个观测期内具有相似的季节变化动态。城市草地土壤CO_(2)排放的季节变化主要受土壤温度和土壤水分含量变化的影响,二者的协同作用可以解释土壤CO_(2)排放变化的77%~87%;而城市草地土壤CH_(4)吸收通量的变化主要受土壤水分含量的影响,且两者之间呈显著负相关关系。在全年尺度上,三种城市草地类型的土壤CO_(2)年排放量在12.1~15.2 t C ha^(-1)a^(-1)之间,其土壤CH_(4)年吸收量范围为3.71~4.27 kg C ha^(-1)a^(-1)。尽管城市草地非生长季的低温通常会抑制微生物活性而降低土壤呼吸和CH_(4)吸收强度,但结果显示非生长季土壤CO_(2)排放和CH_(4)吸收量分别占全年总量的10%~18%和39%~51%,突出了开展完整周年观测研究的重要性。对比三种城市草地类型,以C_(4)草种为主的暖季草地相较于冷季草地和林下地被(二者均以C_(3)草种为主)具有明显较高的土壤CO_(2)年排放量,同时显著降低了土壤CH_(4)年吸收量,这与各草地植被特性以及土壤性质的差异有关。综上,该研究结果表明种植C_(3)草种有利于城市草地土壤—大气CO_(2)和CH_(4)交换过程的减排增汇,这将有助于合理规划和利用城市草地,以缓解快速城市化对气候变化所带来的影响。展开更多
基金The National Natural Science Foundation of China(No.59878033) and Tianjin Science and Technology Development Program(No.043100611)
文摘Seven kinds of heavy metal accumulation of rubbish compost in turfgrass by EDTA chelating were investigated. With EDTA application, heavy metal accumulation by two species of turfgrass was increased significantly. The enrichment coefficients of Lolium perenne L（L） and Festuca arundinacea L（F） to Cr reached 9.4.5 and 6.15 respectively. In the range of EDTA dosages given, heavy metal accumulation in turfgrass increased with increasing EDTA level. There were significant differences in remediation of different metals by applying EDTA. L had high ability to accumulate Cr, Cd, Ni and Zn, showing better remediation to heavy metals of rubbish compost. In contrast, F showed high ability to accumulate Cr, Ni, Cu and Zn. Low EDTA level increased aboveground net primary production （ANP） of turfgrass, but EDTA would considerably inhibit it when EDTA was higher than 20 mmol/kg. The results demonstrated that the optimum dosage of EDTA for remediating heavy metals in rubbish compost by turfgrass was between 10 mmol/kg and 20 mmol/kg.
基金NationalNaturalScienceFoundation (59878033)Tianjin Science and Technology Developm entProgram (043100611).
文摘This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgrass medium. Heavy metals in domestic rubbish were controlled by source screening before composting. The study consisted of a control with garden soil. The contents of main mineral elements and heavy metals in rubbish compost and control were determined by the method of ICP-AES. The results showed that heavy metal concentrations in rubbish were lower than those in garden soil, and little difference occurred between rubbish and garden soil in main mineral element concentrations. Based on this, it was concluded that rubbish compost was favorable for using as turfgrass medium and heavy metal control in rubbish by source screening was effective.
文摘The role of turfgrasses in C and N cycling in the southeastern U.S. has not been well documented. The objectives of this research were to determine the characterization of chemical quality, clipping decomposition rates, and C and N release from warm- and cool-season turfgrasses. The study was conducted for 46 weeks in 2012 in Auburn, AL. Four warm season turfgrasses were used included (bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy], centipedegrass (Eremochloa ophiuroides (Munro) Hack), St. Augustinegrass (Stenotaphrum secundatum (Walter) Kuntze), zoysiagrass (Zoysia japonica Steud.), and one cool season turfgrass (tall fescue (Festuca arundinacea Schreb)). Litter was placed into nylon bags at an oven dry rate of 3.6 Mg?ha?1. Litter bags were retrieved after 0, 1, 2, 4, 8, 16, 24, 32, and 46 weeks, and analyzed for total C and N. A double exponential decay model was used to describe mass, C, and N loss. Results indicated that tall fescue decomposition occurred rapidly compared to warm season turfgrasses. Litter mass loss measured after 46 weeks was determined to be 61.7%, 73.7%, 72.2%, 86.8%, and 45.4% in bermudagrass, centipedegrass, St. Augustinegrass, tall fescue, and zoysiagrass respectively. Zoysiagrass litter had a higher lignin concentration, while tall fescue had the lowest lignin. Over 46 weeks’ release of C was in the order: zoysiagrass > bermudagrass = centipedegrass = St. Augustinegrass > tall fescue, and release of N was in the order zoysiagrass > centipedegrass > bermudagrass = St. Augustinegrass > tall fescue. Our study concluded that, zosiagrass is a better choice for home lawns.
文摘The development of a (layer of) thatch in turfgrass causes important changes to near-surface eco-hydrological processes. In this study, we investigated the effects of turfgrass thatch, specifically Kentucky bluegrass (Poa pratensis L.) and red fescue (Festuca rubra L.) on water infiltration, surface runoff, and soil moisture evaporation. The thatches were collected from the field for controlled experiments using packed soil columns under various rainfall conditions. Results indicated that the presence of thatch delayed the onset of infiltration compared with situations without a thatch at the soil surface. Infiltration was delayed for a longer period in thicker red fescue thatch than thinner Kentucky bluegrass thatch. The presence of a thatch reduced runoff by holding more water locally during the rainfall period and allowing a longer period of time for infiltration. Additionally, evaporative water loss was reduced with the presence of thatch than that of bare soil. Our results highlight that the presence of thatch changes the near-surface hydrological processes, which may help improve turf management practices in terms of thatch control and irrigation scheduling.
文摘The paper aimed to study the effects of nitrogen fertilization on the yield and some plant characteristics of perennial ryegrass (Lolium perenne L.). The study was conducted at Agricultural Research and Application Center of the Faculty of Agriculture in Igdir University in 2013. In the experiment, eight levels of fertilizers: 0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0 and 70.0 kg N/ha per month were applied in perennial ryegrass (Lolium perenne L.) during the sixth growing season. A randomized complete block with three replications was used as the experimental design. Nitrogen application affected plant height, green grass yield, plant covering rate, canopy color and turfgrass quality values of perennial ryegrass positively. In both monthly and as the average of nitrogen application, times of application (spring, summer and fall) caused the most uniform turfgrass quality and establishment. Results indicated that although a significant impact was on the character investigated, such as the leaf length, green grass yield, plant cover ratio, canopy color and turfgrass quality, the doses of nitrogen fertilizer have created close to each other in groups. In the stand point of view of all characters, N1, N2 and N3 were located in first group, N4 and N5 in the second group, N6 and N7 in the third group, expect for control (N0). It can be concluded that 40.0-50.0 kg N/ha per month may be more suitable to be used in ryegrass production in the landscape.
文摘The carbon （C） sequestration potential of turfgrass systems has been investigated and demonstrated from several studies. The role of these ecosystems in continental and Mediterranean climates though, is not yet clearly understood because environmental limiting factors and management intensities can strongly influence the overall C budget. The aim of the present study is to improve the understanding of the mechanisms underlying C fluxes in a turfgrass ecosystem and to assess its C sequestration potential by estimating the annual C budget. NEE （Net Ecosystem Exchange） of turfgrass was calculated in its seasonal variation over one year, and compared between areas characterized by different degrees of maintenance. The C sequestration potential of the turfgrass was investigated in a golf course near Verona （Italy）, adopting a small-chamber enclosure approach. The measurements of gas exchanges between biosphere and atmosphere, permitted to estimate the NEE, as a function of different management intensities. The intensity of management seems to have influence on its C balance. This study needs further research to understand which maintenance variables are determinant on turfgrass C sequestration.
基金Supported by National Natural Science Foundation of China (31870484)。
文摘[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbon nanomaterials on soil enzyme activity was studied by adding graphene, graphene oxide and carbon nanotubes to turfgrass soil. [Results] Compared with the control(CK), the activity of soil protease, sucrase, alkaline phosphatase and catalase was not significantly affected by carbon nanomaterials. Under the treatment of carbon nanotubes, urease activity was significantly lower than that of graphene and graphene oxide, and dehydrogenase activity was significantly lower than that of the CK, graphene and graphene oxide. [Conclusions] This study provides a theoretical basis for the safe application of carbon nanomaterials.
文摘Natural organic fertilizers are receiving increased attention as a nutrient source for athletic turf fields. However, the performance of these fertilizers as an alternative to inorganic fertilizers is relatively untested. To address this issue, we initiated a study to evaluate turfgrass response to the use of pelletized poultry litter （PPL） as a nutrient source compared to inorganic fertilizer, and to compare core aeration and vibrating aeration. Four treatments were evaluated： synthetic fertilizer with vibrating aeration （VS）, synthetic fertilizer with core aeration （CS）, PPL with vibrating aeration （VP）, and PPL with core aeration （CP）. The PPL was applied at a nitrogen （N） rate equivalent to the synthetic fertilizer （assuming 50% availability of N）. Application of PPL did not produce significant changes in measured soil parameters during the 2.5 year study compared to the synthetic fertilizer. Minimal differences in tissue concentrations of Mn were observed. Remote sensing indicated that the CS treatment, which is the current management practice at the study site, produced the lowest turfgrass quality of all the treatments. Highest turf quality was achieved with the CP and VS treatments. Application of PPL resulted in greater turfgrass quality when compared to the same N rate of synthetic fertilizer, regardless of aeration method.
文摘Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals, which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turfgrass to rubbish compost were investigated following the addition of EDTA. The results showed that the addition of EDTA significantly increased heavy metal accumulation in Lolium perenne L. and Festuca arundinacea L. Most heavy metal concentrations in L. perenne increased with increasing EDTA supply. The concentrations of Cr, Mn, Ni, Cu, and Cd in L. perenne were highest following the addition of 30 mmol/kg EDTA and the concentrations of Cr and Ni at this point reached concentrations of 1 914.17 and 521.25 μg/g, respectively. When the EDTA level was 〈 20 mmol/kg, the accumulation of most heavy metals in F. arundinacea increased with increasing EDTA supply, but showed a tendency to decrease at EDTA concentrations 〉20 mmol/kg. The highest concentrations of Mn, Ni, Cu, and Zn in F. arundinacea reached 268.01, 110.94, 161.52 and 1 354.97 μg/g, respectively, following the addition of 20 mmol/kg EDTA. The EDTA-induced increase in the accumulation of heavy metals in turfgrass was plantand metal-specific. L. perenne had a relatively high ability to accumulate Cr, Ni, and Zn. The highest Zn concentration was 2 979.58 μg/g and, following the addition of EDTA, the concentrations of the three metals were increased 26.23, 20.03, and 10.49-fold, respectively, compared with control. However, F. arundinacea showed a high ability to accumulate Cr, with the highest concentration （596.02 μg/g） seen following the addition of 30 mmol/kg EDTA; the concentration of Cr increased 15.51-fold compared with control. With EDTA addition, ecological responses of both turfgrass species showed that EDTA at concentrations 〈10 mmol/kg increased seed germination and aboveground net primary production （ANP） of L. perenne and slightly inhibited those of F. arundinacea, but EDTA at concentrations 〉20 mmol/kg inhibited these parameters significantly for both species. Moreover, EDTA increased the chlorophyll and proline content at all concentrations tested. On the basis of the synthetic remediation index, the optimal EDTA concentration for turfgrass remediation of heavy metals in compost is approximately 10 mmol/kg.
文摘随着城市人口密度的不断增长和城市化进程的加快,城市生态系统已成为影响全球气候变化的热点区域。但是,城市草地作为城市生态系统的重要组成部分,其对土壤—大气CO_(2)和CH_(4)交换过程的影响尚不明确。为此,本文依托北京城市绿地生态系统定位观测研究站,采用静态暗箱—气相色谱方法对三种典型城市草地类型[即以C_(4)草种(光合作用中CO_(2)被固定为三碳和四碳化合物)为主的暖季草地和以C_(3)草种(光合作用中CO_(2)被固定为三碳化合物)为主的冷季草地与林下地被]的土壤CO_(2)排放和CH_(4)吸收通量及其辅助环境因子进行了一个完整周年的田间原位观测研究。结果表明,三种城市草地类型的土壤CO_(2)排放和CH_(4)吸收通量在整个观测期内具有相似的季节变化动态。城市草地土壤CO_(2)排放的季节变化主要受土壤温度和土壤水分含量变化的影响,二者的协同作用可以解释土壤CO_(2)排放变化的77%~87%;而城市草地土壤CH_(4)吸收通量的变化主要受土壤水分含量的影响,且两者之间呈显著负相关关系。在全年尺度上,三种城市草地类型的土壤CO_(2)年排放量在12.1~15.2 t C ha^(-1)a^(-1)之间,其土壤CH_(4)年吸收量范围为3.71~4.27 kg C ha^(-1)a^(-1)。尽管城市草地非生长季的低温通常会抑制微生物活性而降低土壤呼吸和CH_(4)吸收强度,但结果显示非生长季土壤CO_(2)排放和CH_(4)吸收量分别占全年总量的10%~18%和39%~51%,突出了开展完整周年观测研究的重要性。对比三种城市草地类型,以C_(4)草种为主的暖季草地相较于冷季草地和林下地被(二者均以C_(3)草种为主)具有明显较高的土壤CO_(2)年排放量,同时显著降低了土壤CH_(4)年吸收量,这与各草地植被特性以及土壤性质的差异有关。综上,该研究结果表明种植C_(3)草种有利于城市草地土壤—大气CO_(2)和CH_(4)交换过程的减排增汇,这将有助于合理规划和利用城市草地,以缓解快速城市化对气候变化所带来的影响。
文摘为研究不同发展演替阶段草坪生态系统结构和功能之间的相关关系,以狗牙根[Cynodon dactylon(L.)Persoon]、匍匐剪股颖(Agrostis stolonifera L.)、多年生黑麦草(Lolium perenne L.)、野牛草[Buchloe dactyloides(Nutt.)Engelm.]、高羊茅(Festuca elata Keng ex E. B. Alexeev)和白花三叶草(Trifolium repens L.)为研究对象,设置保持自然状态和人工去杂两种试验处理,调查其不同发展演替阶段植物物种多样性和生长量的变化。结果表明,不同发展演替阶段和不同试验处理中,草坪生态系统植物物种多样性和生长量之间的相关关系各异:初期,两者之间在6种草坪、2种试验处理中均呈线性正相关关系;中期,两者之间在保持自然状态试验处理中呈单峰曲线相关关系,在人工去杂试验处理中无明显相关关系;后期,两者之间在所有保持自然状态试验处理中呈单峰曲线相关关系,在50%的人工去杂试验处理中呈线性负相关关系,而剩下的50%则无明显相关关系。
