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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Dynamika půdního uhlíku a vybraných půdních charakteristik v subpovodích modelového území Stropnice / Dynamism of soil carbon and selective soil characteristics in model landscape Stropnice subcatchments

BODLÁK, Lubomír January 2011 (has links)
The aim of the theses was to describe soil organic matter changes in model landscape Stropnice subcatchments that have different biotopes and agricultural and forest management.Particular aims were: 1) to determine the link between landuse, soil environment changes and catchment matter losses. 2)to experimentally prove the water regime impact on carbon and other substances losses during and between vegetation seasons.
12

Biologically relevant characteristics of dissolved organic carbon (DOC) from soil

Bowen, Susan January 2006 (has links)
Of the organic matter in soils typically < 1% by weight is dissolved in the soil solution (dissolved organic matter; DOM). DOM is a continuum of molecules of various sizes and chemical structures which has largely been operationally defined as the fraction of total organic carbon in an aqueous solution that passes through a 0.45 µm filter. Although only representing a relatively small proportion, it represents the most mobile part of soil organic carbon and is probably enriched with highly labile compounds. DOM acts as a source of nutrients for both soil and aquatic micro-organisms, influences the fate and transport of organic and inorganic contaminants, presents a potential water treatment problem and may indicate the mobilisation rate of key terrestrial carbon stores. The objective of this research was to ascertain some of the biologically relevant characteristics of soil DOM and specifically to determine: (1) the influence of method and time of extraction of DOM from the soil on its biochemical composition and concentration; (2) the dynamics of DOM biodegradation; and, (3) the effects of repeated applications of trace amounts of DOM on the rate of soil carbon mineralization. To examine the influence of method and time of extraction on the composition and concentration of DOM, soil solution was collected from a raised peat bog in Central Scotland using water extraction, field suction lysimetry, and centrifugation techniques on a bimonthly basis over the period of a year (Aug 2003 – Jun 2004). Samples were analysed for dissolved organic carbon (DOC), dissolved organic nitrogen (DON), protein, carbohydrate and amino acid content. For all of the sampled months except June the biochemical composition of DOC varied with extraction method, suggesting the biological, chemical and/or physical influences on DOC production and loss are different within the differently sized soil pores. Water-extractable DOC generally contained the greatest proportion of carbohydrate, protein and/or amino acid of the three extraction methods. Time of extraction had a significant effect on the composition of water- and suction-extracted DOC: the total % carbohydrate + protein + amino acid C was significantly higher in Oct than Dec, Feb and Jun for water-extracted DOC and significantly greater in Dec than Aug, Apr and Jun for suction-extracted DOC. There was no significant change in the total % carbohydrate + protein + amino acid C of centrifuge-extracted DOC during the sampled year. Time of extraction also had a significant effect on the % protein + amino acid N in water- and centrifuge-extracted DON: Oct levels were significantly higher than Feb for water-extracted DON and significantly higher in Aug and Apr for centrifuge-extracted DON. Concentrations of total DOC and total DON were also found to be dependent on time of extraction. DOC concentrations showed a similar pattern of variation over the year for all methods of extraction, with concentrations relatively constant for most of the year, rising in April to reach a peak in Jun. DON concentrations in water- and centrifuge-extracted DON peaked later, in Aug. There were no significant seasonal changes in the concentration of suction-extracted DON. A lack of correlation between DOC and DON concentrations suggested that DOC and DON production and/or loss are under different controls. Laboratory-based incubation experiments were carried out to examine the dynamics of DOC biodegradation. Over a 70 day incubation period at 20oC, the DOM from two types of peat (raised and blanket) and four samples of a mineral soil (calcaric gleysol), each previously exposed to a different management strategy, were found to be comprised of a rapidly degradable pools (half-life: 3 – 8 days) and a more stable pool (half-life: 0.4 to 6 years). For all soil types/treatments, excepting raised peat, the total net loss of DOC from the culture medium was greater than could be accounted for by the process of mineralization alone. A comparison between net loss of DOC and loss of DOC to CO2 and microbial biomass determined by direct microscopy suggested that at least some of the differences between DOC mineralised and net DOC loss were due to microbial assimilation and release. Changes in the microbial biomass during the decomposition process showed proliferation followed by decline over 15 days. The protein and carbohydrate fractions showed a complex pattern of both degradation and production throughout the incubation. The effects of repeated applications of trace amounts of litter-derived DOC on the rate of carbon mineralization over a 35 day period were investigated in a laboratory based incubation experiment. The addition of trace amounts of litter-derived DOC every 7 and 10.5 days appeared to ‘trigger’ microbial activity causing an increase in CO2 mineralisation such that extra C mineralised exceeded DOC additions by more than 2 fold. Acceleration in the rate of extra C mineralised 7 days after the second addition suggested that either the microbial production of enzymes responsible for biodegradation and/or an increase in microbial biomass, are only initiated once a critical concentration of a specific substrate or substrates has been achieved. The addition of ‘DOC + nutrients’ every 3.5 days had no effect on the total rate of mineralization. To date DOC has tended to be operationally defined according to its chemical and physical properties. An understanding of the composition, production and loss of DOC from a biological perspective is essential if we are to be able to predict the effects of environmental change on the rate of mineralization of soil organic matter. This research has shown that the pools of DOC extracted, using three different methods commonly used in current research, are biochemically distinct and respond differently to the seasons. This suggests some degree of compartmentalisation of biological processes within the soil matrix. The observed similarities between the characteristics of the decomposition dynamics of both peatland and agricultural DOC suggests that either there is little difference in substrate quality between the two systems or that the microbial community have adapted in each case to maximise their utilisation of the available substrate. The dependency of the concentration and biochemical composition of DOC on the seasons requires further work to ascertain which biotic and/or abiotic factors are exerting control. Published research has focussed on factors such as temperature, wet/dry cycles, and freeze/thawing. The effect of the frequency of doses of trace amounts of DOC on increasing the rate of soil organic C mineralization, evident from this research, suggests that the interval between periods of rainfall may be relevant. It also emphasises how it can be useful to use knowledge of a biological process as the starting point in determining which factors may be exerting control on DOC production and loss.
13

Propriedades físicas do solo e matéria orgânica em sistemas de plantio direto e cultivo mínimo / Organic matter regarding physical properties of soil on no-tillage and minimum tillage systems

Laurindo, Marlene Cristina de Oliveira 24 July 2006 (has links)
Made available in DSpace on 2017-07-10T19:25:23Z (GMT). No. of bitstreams: 1 Marlene Cristina de Oliveira.pdf: 350427 bytes, checksum: 54e199625b367e5a49ad9dad08f19863 (MD5) Previous issue date: 2006-07-24 / The physical properties on No-Tillage (NT) and Minimum Tillage (MT) management systems were analyzed in a Rhodic Kandiudox soil from an experimental area in Foz do Iguaçu, Westerner of Paraná, whose wheat production term has been of five years under NT system. Samples were collected before wheat seeding and after its crop to record the particles densities, soil density, total porosity, textural density and organic carbon content from soil, regarding these depths: 0-5; 5-10; 10-15 and 15-20 cm. Textural density supported the answers for determining values of soil density on its limit of saturation phase as well as on its water retention limit, related to friability range and to the best aggregate stability to each analyzed depth. The NT system showed greater content of organic carbon, as well as greater soil density. The results regarding particles density increased with depth, as well as total porosity while MT system showed greater answers of porosity on upper layers, even though it contributed on reducing porosity from 10-15 and 15-20 cm layers of depths. / Propriedades físicas em sistemas de manejo plantio direto (PD) e cultivo mínimo (CM) foram avaliadas em área experimental de Terra Roxa Estruturada localizada no município de Foz do Iguaçu, região Oeste do Paraná, com histórico de cinco anos de plantio de trigo sob PD. As amostras foram coletadas antes da semeadura do trigo e após a colheita para determinação de densidade de partículas, densidade do solo, porosidade total, densidade textural e teor de carbono orgânico do solo nas profundidades de 0-5, 5-10, 10-15 e 15-20 cm. Através da densidade textural se determinou os valores de densidade do solo no estado de limite de saturação e no limite de retenção de água, correspondente a faixa de friabilidade e maior estabilidade de agregados para cada profundidade analisada. O sistema de PD apresentou maior teor de carbono orgânico e maior densidade do solo. Os valores de densidade de partículas aumentaram com a profundidade, bem como a porosidade total. O sistema CM apresentou maiores valores de porosidade nas camadas superficiais, porém contribuiu para redução da porosidade nas camadas de 10-15 e de 15-20cm de profundidade.
14

Propriedades físicas do solo e matéria orgânica em sistemas de plantio direto e cultivo mínimo / Organic matter regarding physical properties of soil on no-tillage and minimum tillage systems

Laurindo, Marlene Cristina de Oliveira 24 July 2006 (has links)
Made available in DSpace on 2017-05-12T14:48:46Z (GMT). No. of bitstreams: 1 Marlene Cristina de Oliveira.pdf: 350427 bytes, checksum: 54e199625b367e5a49ad9dad08f19863 (MD5) Previous issue date: 2006-07-24 / The physical properties on No-Tillage (NT) and Minimum Tillage (MT) management systems were analyzed in a Rhodic Kandiudox soil from an experimental area in Foz do Iguaçu, Westerner of Paraná, whose wheat production term has been of five years under NT system. Samples were collected before wheat seeding and after its crop to record the particles densities, soil density, total porosity, textural density and organic carbon content from soil, regarding these depths: 0-5; 5-10; 10-15 and 15-20 cm. Textural density supported the answers for determining values of soil density on its limit of saturation phase as well as on its water retention limit, related to friability range and to the best aggregate stability to each analyzed depth. The NT system showed greater content of organic carbon, as well as greater soil density. The results regarding particles density increased with depth, as well as total porosity while MT system showed greater answers of porosity on upper layers, even though it contributed on reducing porosity from 10-15 and 15-20 cm layers of depths. / Propriedades físicas em sistemas de manejo plantio direto (PD) e cultivo mínimo (CM) foram avaliadas em área experimental de Terra Roxa Estruturada localizada no município de Foz do Iguaçu, região Oeste do Paraná, com histórico de cinco anos de plantio de trigo sob PD. As amostras foram coletadas antes da semeadura do trigo e após a colheita para determinação de densidade de partículas, densidade do solo, porosidade total, densidade textural e teor de carbono orgânico do solo nas profundidades de 0-5, 5-10, 10-15 e 15-20 cm. Através da densidade textural se determinou os valores de densidade do solo no estado de limite de saturação e no limite de retenção de água, correspondente a faixa de friabilidade e maior estabilidade de agregados para cada profundidade analisada. O sistema de PD apresentou maior teor de carbono orgânico e maior densidade do solo. Os valores de densidade de partículas aumentaram com a profundidade, bem como a porosidade total. O sistema CM apresentou maiores valores de porosidade nas camadas superficiais, porém contribuiu para redução da porosidade nas camadas de 10-15 e de 15-20cm de profundidade.
15

From trees to soil: microbial and spatial mediation of tree diversity effects on carbon cycling in subtropical Chinese forests

Beugnon, Rémy 09 February 2022 (has links)
The loss of biodiversity is affecting all ecosystems on Earth, one of the greatest threats to biodiversity being climate change. Forests have been highlighted for the potential to mitigate climate change by storing carbon above- and belowground in soils. In this thesis, I studied the effects of tree diversity on carbon cycling in subtropical Chinese forests. I aimed to explore the mechanisms behind tree diversity effects on carbon cycling by focusing on microbial-based processes and the consequences of tree diversity-induced spatial heterogeneity. First, my colleagues and I tested the effects of tree diversity on litterfall spatial patterns and the consequences for litter decomposition and quantified the importance of microbial community in decomposition processes. Second, we explored the effects of tree diversity on relationships between soil microbial facets and soil microbial functions. Third, we tested the effects of tree diversity on soil microbial biomass and carbon concentrations, and their mediation by biotic and abiotic conditions. Finally, we explored the consequences of diversifying forests for re-/afforestation initiatives and plantations to reduce atmospheric carbon levels, and the benefits of diversity for mitigating the effects of climate change on ecosystems and human well-being. We highlighted the positive effects of tree diversity on tree productivity. By increasing the amount and diversity of litterfall, tree diversity increased litter decomposition and subsequently the assimilation of tree products into the forest soils. Our investigation has shown the key role of microbial communities for forests carbon dynamics by carrying out litter decomposition, soil heterotrophic respiration, and soil carbon stabilization. Most notably, tree diversity effects on soil microbial respiration were mainly mediated by soil microbial biomass rather than soil microbial community taxonomic or functional diversity. The effects of tree diversity on microbial biomass were mediated by biotic and abiotic conditions. Taken together, we revealed the importance of considering space to understand biodiversity-ecosystem functioning relationships. Finally, we argued that tree diversity is a promising avenue to maximize the potential of re-/afforestation projects to mitigate increasing atmospheric carbon. Moreover, we highlighted that diversifying forests in re-/afforestation initiatives can help to reduce climate change effects on ecosystems: first, by increasing resistance and resilience to extreme climatic events, and second, by buffering microclimatic conditions in natural and urban areas. My investigation highlighted that tree diversity effects on ecosystem functioning could be explained by both mass and diversity effects on higher trophic levels and their functions. In addition, I showed the key role of tree diversity-induced spatial heterogeneity and the need to consider space and time in further research. Moreover, these results need to be combined with practitioner constraints to enable feasible restoration projects.:Summary table Bibliographic information .................................................................................... I ~ XV Main body ......................................................................................................... 1 ~ 212 Supplementary materials ..................................................................................... i ~ xv Scientific supplementary materials ............................................................. -1- ~ - 154- Table of Contents Table of figures .......................................................................................................... XI Table of scientific supplementary materials ............................................................. XIII Glossary ................................................................................................................... XV Introduction ................................................................................................................. 3 Chapter I - Tree diversity effects on litter decomposition are mediated by litterfall and microbial processes .................................................................................................. 35 Transition I - II ........................................................................................................... 67 Chapter II - Tree diversity and soil chemical properties drive the linkages between soil microbial community and ecosystem functioning................................................ 71 Transition II - III ....................................................................................................... 107 Chapter III - Abiotic and biotic drivers of scale-dependent tree trait effects on soil microbial biomass and soil carbon concentration ................................................... 111 Transition III - IV ..................................................................................................... 155 Chapter IV – Diverse forests are cool: promoting diverse forests to mitigate carbon emissions and climate change ............................................................................... 159 General discussion ................................................................................................. 173 Abstract .................................................................................................................. 195 General acknowledgments ..................................................................................... 209 Supplementary materials ..............................................................................................i
16

Biomass and carbon stocks of the natural forests at Me Linh biodiversity station, Vinh Phuc province, Vietnam / Sinh khối và trữ lượng các bon của thảm thực vật rừng tự nhiên tại trạm đa dạng sinh học Mê Linh, tỉnh Vĩnh Phúc, Việt Nam

Dang, Thi Thu Huong, Do, Huu Thu 09 December 2015 (has links) (PDF)
Biomass and carbon stock of the natural forests in Vietnam are still not clear due to limitation of knowledge and financial. In this paper, the results of estimating biomass and carbon stocks of the natural forests at Me Linh Biodiversity Station are shown. There are two forest types in this study: the forest vegetation restored after shifting cultivation (vegetation type I) and the forest vegetation restored after clear cutting exploitation (vegetation type II). As the results, the estimated biomass of the forest vegetation restored after shifting cultivation is 86.80 ton.ha-1 and the estimated biomass of the forest vegetation restored after clear cutting exploitation is higher, about 131.59 ton.ha-1. The carbon stock in plants was about 43.40 ton.ha-1 of vegetation type I and 65.79 ton.ha-1 of vegetation type II. The carbon storage in soil of vegetation type I is 79.01 ton.ha-1 and vegetation type II is 99.65 ton.ha-1. Hence, the total of carbon stock in forest vegetation I and II are accounted by 122.41ton.ha-1 and 165.44 ton.ha-1, respectively. In general, it can be pointed out that the naturally recovering secondary forest at Me Linh Station is the secondary young forest with the low economic value due to shortly restored process (about 10-20 years), the flora is not rich and abundant, and there are only commonly pioneer and light demanding tree species. / Sinh khối và trữ lượng các bon của rừng tự nhiên ở Việt Nam vẫn ít được quan tâm của do hạn chế về kiến thức và tài chính. Trong bài báo này, chúng tôi đưa ra kết quả của việc ước lượng sinh khối và tổng hợp các bon của các thảm thực vật rừng thứ sinh phục hồi tự nhiên tại Trạm Đa dạng Sinh học Mê Linh, tỉnh Vĩnh Phúc- Việt Nam, nơi có loại hình thảm thực vật chính, đó là thảm thực vật phục hồi sau nương rẫy (kiểu thảm thục vật I) và thảm thực vật phục hồi sau khai thác kiệt (kiểu thảm thực vật II) nhằm mục đích đánh giá tiềm năng của rừng thứ sinh tại khu vực nghiên cứu. Sinh khối của thảm thực vật phục hồi sau nương rẫy là 86,80 tấn/ha. Sinh khối của thảm thực vật phục hồi sau khai thác cao hơn, đạt 131.59 tấn/ha. Lượng các bon hấp thu trong đất của thảm thực vật I là 79,01 tấn/ha và thảm thực vật II là 99,65 tấn/ha. Như vậy, tổng lượng các bon được hấp thu trong mỗi loại hình thảm thực vật trên là: 122,41 tấn/ha (thảm thực vật I) và 165,14 tấn/ha. Nhìn chung, rừng thứ sinh phục hồi tự nhiên tại Trạm Đa dạng Mê Linh chủ yếu là rừng non thứ sinh, ít có giá trị kinh tế do quá trình phục hồi diễn ra ngắn (khoảng 10-20 năm) nên thành phần thực vật nghèo nàn, không phong phú, thành phần chính chủ yếu là các cây gỗ tiên phong, ưa sáng.
17

The long-term dynamics of soil organic carbon in the anthropogenic soils of Scotland's medieval urban landscape

Esiana, Benneth O. I. January 2015 (has links)
In an interdisciplinary study requiring the synergistic association of historical evidence and chemical and biochemical analyses, this thesis investigates the properties and characteristics of historically modified soils known as anthrosols. These soils, developed through the anthropogenic addition of high volumes of organic-rich municipal waste materials to land, including human and animal waste, as part of the waste management practices in medieval urban communities in Scotland at St Andrews, Roxburgh and Elgin, offer an insight to the state and dynamics of these organic material. Soil is one of the most sensitive environmental domains to transformation. These transformations are visible from the alterations to the physical and chemical properties of soil. Anthropogenic activities may leave behind signatures in the soil in the form of artefacts, ecofacts, elemental enrichment or depletion, enhancement in soil magnetic properties and organic matter content. In the historical dimension of this study, the observable features and measurable properties of soil profiles are exploited to reveal past organisation and functions of cultural landscapes by carefully studying the stratigraphic units of soil profile, and examining the association of each unit with settlement artefacts and soil properties. Through comparison with historical records of past events on the respective study sites, the relationship between the soils record of past human activities is observed through physical, chemical and biochemical properties. The historical record is used to assess if such evidence can be used reliably to develop the account of site use for the medieval burghs of Scotland. In the environmental aspect, investigation focuses on the physical and chemical conditions of these soils in terms of their carbon content, composition, residence time estimates and their role in global C cycle and terrestrial carbon budgeting. Past investigations of anthopogenically-deepened soils have been interpreted with respect to historical site use, however, the environmental implications of the resultant accumulated organic material or residue have not previously been considered in much detail. A particular novelty of this aspect of the project is that it is an in-depth examination of anthropogenic soils with known histories extending into the medieval period. This time-depth allows a new understanding of the processes and products of decomposition of known organic materials that were added to soil. The biophysicochemical data obtained from these soils such as their extant organic carbon content and variability with depth, the composition of the various carbon species that together constitute soil organic matter, and biological community and activity (microorganisms and enzymes) provides critical information on the relative recalcitrance, state of decomposition, and the mechanism of stabilisation of these materials in the soil.
18

Humus Dynamics along Forest Conversion Sequences in the Lowland and Ore Mountain Region of Saxony, Germany

Koch, Juliane 24 August 2007 (has links) (PDF)
Vor dem Hintergrund der steigenden CO2-Konzentration in der Atmosphäre gewinnt die Rolle des Waldes als C-Speicher zunehmend an Bedeutung. Eine besonders wichtige Funktion kommt hierbei dem Boden zu, denn Böden speichern weltweit mehr C als Vegetation und boden zusammen (Brady and Weil, 2002). Im Sinne einer nachhaltigen Waldbewirtschaftung werden in Sachsen derzeit großflächig die bestehenden Nadelforsten in naturnahe, strukturierte Laub- und Laubmischwälder umgewandelt. Ziel dieser Arbeit war es daher, baumarten- und bewirtschaftungsspezifische Effekte auf den Humus und die C-Speicherung im Waldboden aufzuzeigen. Die Untersuchungsflächen wurden entlang von Waldumbausequenzen gruppiert, welche die Entwicklung von konventionell bewirtschafteten Kiefern- und Fichten-Reinbeständen zu mehr oder weniger strukturierten Rotbuchen- und Rotbuchen-Traubeneichenbeständen über die Stufe der Voranbauten widerspiegeln. Die Untersuchungen wurden im Mittleren Erzgebirge und im Nordsächsischen Tiefland durchgeführt. Zusammenfassend zeigte die Untersuchung (i) einen um 24 % höheren C-Input über den Streufall unter Laubholz, (ii) eine höhere C-Freisetzung durch die C-Mineralisierung, welche im Laufe des Jahres im Of-Horizont unter Laubholz (BuEi) um 68 % höher war als unter Ki und (iii) eine höhere Akkumulation von C unter laubholzbestockten Beständen. Die Oh-Lagen unter den untersuchten Voranbauten und Laubholzbeständen enthielten entsprechend hohe Anteile von 61 % (Bu) und 40 % (BuEi) des in der organischen Auflage gespeicherten C und auch die oberen Mineralböden enthielten deutlich höhere C-Mengen unter LH als unter NH. Die Mechanismen, welche zur C-Sequestrierung in der Oh-Lage unter BuEi führen, konnten in der vorliegenden Arbeit detailliert durch die Humusdynamik in der organischen Auflage im verlauf eines Jahres erklärt werden. Im Gegensatz indizieren die Ergebnisse unter Ki einen verzögerten, aber vergleichbar intensiven Streuabbau im L-Horizont, gefolgt von einer Phase relativer Stagnation in der Of-Lage und einer wiederum aktiven Umsatzphase im vergleichsweise geringmächtigen Oh-Horizont. Die Menge bzw. der Anteil der langfristig gespeicherten organischen Substanz wird wesentlich durch die Streuqualität bestimmt, d.h. die Qualität der Streu steuert die bestandesspezifische Humusdynamik. Neben den standörtlichen und klimatischen Faktoren ist der Einfluss der Bewirtschaftung hingegen ein Faktor, welcher sich primär auf die Abbauaktivität und somit auf die Menge des akkumulierten C auswirken. Die für das Tiefland dokumentierten Effekte werden vermutlich auch im Erzgebirge wieder relevant sein, wenn die Kalkung an Wirkung verliert. Aus der vorliegenden Arbeit kann die Schlussfolgerung gezogen werden, dass im Vergleich zur Ki in der organischen Auflage unter LH (BuEi) größere Mengen C aktiv umgesetzt werden und in Folge dieser spezifischen Humusdynamik größere Mengen C in der Oh-Lage und im Mineralboden gespeichert werden können. / Against the background of the increased CO2 concentration of the atmosphere the role of the forest as C store gains interest. An especially important function comes up to soil as soils sequester more C than vegetation and atmosphere together on a global scale (Brady and Weil, 2002). In the sense of a sustainable forest management of Saxony the vast areas covering coniferous stands are currently converted to semi-natural and structured deciduous and mixed forests. It was thus, the aim of this study to show species- and management-specific effects on humus dynamics and to evaluate top soils as possible C sink. All study sites involved were arranged along sequences representing the development from pure and conventionally managed Scots pine or Norway spruce stands to more or less structured European beech or European beech/Common oak stands via advanced plantings. The study was performed in the Ore mountain region and lowland of Saxony. In sum, the study revealed (i) a by 24 % higher litter-derived C input in the deciduous stand, (ii) a higher release of C by potential C mineralisation, that was in mean of one year by 68 % significantly higher in the F layer under beech/oak than under pine, and (iii) a higher accumulation of C under deciduous stands. The H layer under the studied advanced plantings and deciduous stands contained higher portions of 61 % (beech) and 40 % (beech/oak) of the total C accumulated in the organic layer and also upper mineral soil held evidently higher C under deciduous than under the pine stand. The specific mechanisms of C storage in the H layer under the beech/oak stand were explained in detail by explaining humus dynamics in the different horizons throughout the year. In contrast, the results under pine indicate a retarded, but as intensive decomposition in the L layer, followed by a phase of relative stagnancy (F layer) and in turn again active turnover phase in the comparatively thin H layer. The amount and portion of the long-term sequestered organic matter is substantially affected by the quality of the litter, that is that litter quality rules the stand-specific humus dynamics. Besides the site- and climate-specific factors, forest management in contrast is a factor, that affects turnover activity and thus, the amount of C accumulated. The effects documented for the lowland will presumably be relevant in the Ore Mountain region once the lime looses its effect. It can be concluded that in comparison to pine in the organic layer under deciduous trees (i.e., beech/oak) a higher amount of C is actively turned over and subsequently of this specific humus dynamics a higher amount of C is sequestered in the H layer and in mineral soil.
19

Influence of liming substances and temperature on microbial activity and leaching of soil organic matter in coniferous forest ecosystems /

Andersson, Stefan, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
20

Matéria orgânica e atributos químicos em solo de tabuleiros costeiros sob diferentes coberturas vegetais / Organic matter and chemical attributes of an Coastal Tableland soil under different vegetation covers

Ribeiro, Paulo Henrique 19 December 2011 (has links)
Made available in DSpace on 2016-12-23T13:51:53Z (GMT). No. of bitstreams: 1 Paulo Henrique Ribeiro.pdf: 759583 bytes, checksum: c4d8c6d713b57420b683cda1ffa23bed (MD5) Previous issue date: 2011-12-19 / A substituição da vegetação nativa por cultivos agrícolas e florestais resulta em modificações nos atributos do solo. Neste trabalho objetivou-se avaliar a dinâmica dos atributos de um Latossolo Amarelo em diferentes coberturas vegetais nos Tabuleiros Costeiros. As amostras de solo foram coletadas nas profundidades de 0-10, 10-20 e 20-40 cm em junho de 2011, em Sooretama, ES, considerando quatro coberturas vegetais: mata nativa, café conilon em monocultivo, café conilon em consórcio com cedro e cacau em consórcio com cedro. O delineamento experimental utilizado foi o inteiramente casualizado em parcelas subdivididas com três repetições. Foram avaliados os seguintes atributos do solo: pH em água; fósforo disponível; potássio, cálcio e magnésio trocáveis; alumínio trocável; acidez potencial; soma de bases; capacidade de troca de cátions efetiva e potencial; saturação por bases e por alumínio; carbono orgânico total (COT); nitrogênio total (NT); carbono orgânico solúvel em água (CSA); relações COT/NT e COT/CSA; matéria orgânica leve; e estoques de COT e NT. Avaliou-se também a serapilheira, e com base na produção de matéria seca e nos teores de nutrientes da mesma, calcularam-se os acúmulos de cada nutriente. Os resultados obtidos foram submetidos à análise da variância e os contrastes comparadas pelo teste F a 1, 5 e a 20 % de probabilidade. Os resultados experimentais mostraram que os sistemas de uso e manejo comportaram-se de forma diferenciada para determinados atributos do solo. A mata foi a cobertura que mais favoreceu o estoque de carbono e nitrogênio no sistema, demonstrado pelos maiores teores de COT e NT, carbono solúvel em água, matéria orgânica leve e acúmulo de serapilheira. Os cultivos agrícolas demonstraram potencial de estocar carbono e nitrogênio no solo. As condições químicas do solo mais adequadas para o desenvolvimento de plantas foram encontradas no solo sob cafeeiro em monocultivo. A elevada acidez, altos níveis de alumínio e baixa disponibilidade de nutrientes no solo sob mata refletiram sua condição natural. Os consórcios agroflorestais apresentaram condição similar para a fertilidade do solo. No entanto, diferenciaram quanto ao acúmulo de serapilheira e nutrientes na serapilheira. / The conversion of native vegetation in agricultural and forest crops results in changes in soil properties. The aimed was to assess the dynamic attributes of a Yellow Oxisol under differents vegetation covers in the Coastal Tableland. Soil samples were collected at depths of 0-10, 10-20 and 20-40 cm in June 2011 in Sooretama, ES, considering four soil vegetation covers: native forest, coffee monoculture, coffee-cedar intercropping, cocoa-cedar intercropping. The experimental design was completely randomized with three replications in split-plot. The following soil atributes were evaluated: water pH; available phosphorus; exchangeable potassium, calcium and magnesium; aluminum; potential acidity; bases content; effective and potential cation exchange capacity; base and aluminum saturation; total organic carbon (TOC); total nitrogen (TN); water-soluble carbon (WSC); C/N and TOC/WSC ratio; light organic matter; TOC and TN stocks. The litter pool was also measured, and based on dry matter yield and nutrient content the same, was calculated the accumulation of each nutrient. The results were submitted to analysis of variance and differences between medium contrasts compared by F-test, verifying a statistical significance (1 and 5%) and trend (20%). The experimental results showed that vegetation covers behaved differently to certain soil attributes. The forest was the cover that most favored the carbon and nitrogen stocks in the soil, demonstrated by higher total organic carbon and total nitrogen, litter pool, water-soluble carbon and light organic matter. Crops demonstrated the potential for carbon and nitrogen stocks in soil. Soil chemical conditions of coffee monoculture were the best for the plant development. The high acidity, high levels of aluminum and low availability of nutrients in the soil under forest reflected its natural condition. The agroforestry consortia had similar condition to soil fertility. However, differed as to litter pool and nutrients in litter

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