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Francesco Montemurro - One of the best experts on this subject based on the ideXlab platform.
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Long-term effects of Organic amendments on Soil fertility
Sustainable Agriculture, 2011Co-Authors: Mariangela Diacono, Francesco MontemurroAbstract:Common agricultural practices such as excessive use of agro-chemicals, deep tillage and luxury irrigation have degraded Soils, polluted water resources and contaminated the atmosphere. There is increasing concern about interrelated environmental problems such as Soil degradation, desertification, erosion, and accelerated greenhouse effects and climate change. The decline in Organic matter content of many Soils is becoming a major process of Soil degradation, particularly in European semi-arid Mediterranean regions. Degraded Soils are not fertile and thus cannot maintain sustainable production. At the same time, the production of urban and industrial Organic waste materials is widespread. Therefore, strategies for recycling such Organic waste in agriculture must be developed. Here, we review long-term experiments (3–60 years) on the effects of Organic amendments used both for Organic matter replenishment and to avoid the application of high levels of chemical fertilizers. The major points of our analysis are: (1) many effects, e.g. carbon sequestration in the Soil and possible build-up of toxic elements, evolve slowly, so it is necessary to refer to long-term trials. (2) Repeated application of exogenous Organic matter to cropland led to an improvement in Soil biological functions. For instance, microbial biomass carbon increased by up to 100% using high-rate compost treatments, and enzymatic activity increased by 30% with sludge addition. (3) Long-lasting application of Organic amendments increased Organic carbon by up to 90% versus unfertilized Soil, and up to 100% versus chemical fertilizer treatments. (4) Regular addition of Organic residues, particularly the composted ones, increased Soil physical fertility, mainly by improving aggregate stability and decreasing Soil bulk density. (5) The best agronomic performance of compost is often obtained with the highest rates and frequency of applications. Furthermore, applying these strategies, there were additional beneficial effects such as the slow release of Nitrogen fertilizer. (6) Crop yield increased by up to 250% by long-term applications of high rates of municipal solid waste compost. Stabilized Organic amendments do not reduce the crop yield quality, but improve it. (7) Organic amendments play a positive role in climate change mitigation by Soil carbon sequestration, the size of which is dependent on their type, the rates and the frequency of application. (8) There is no tangible evidence demonstrating negative impacts of heavy metals applied to Soil, particularly when high-quality compost was used for long periods. (9) Repeated application of composted materials enhances Soil Organic Nitrogen content by up to 90%, storing it for mineralization in future cropping seasons, often without inducing nitrate leaching to groundwater.
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long term effects of Organic amendments on Soil fertility a review
Agronomy for Sustainable Development, 2010Co-Authors: Mariangela Diacono, Francesco MontemurroAbstract:Common agricultural practices such as excessive use of agro-chemicals, deep tillage and luxury irrigation have degraded Soils, polluted water resources and contaminated the atmosphere. There is increasing concern about interrelated environmental problems such as Soil degradation, desertification, erosion, and accelerated greenhouse effects and climate change. The decline in Organic matter content of many Soils is becoming a major process of Soil degradation, particularly in European semi-arid Mediterranean regions. Degraded Soils are not fertile and thus cannot maintain sustainable production. At the same time, the production of urban and industrial Organic waste materials is widespread. Therefore, strategies for recycling such Organic waste in agriculture must be developed. Here, we review long-term experiments (3-60 years) on the effects of Organic amendments used both for Organic matter replenishment and to avoid the application of high levels of chemical fertilizers. The major points of our analysis are: (1) many effects, e.g. carbon sequestration in the Soil and possible build-up of toxic elements, evolve slowly, so it is necessary to refer to long-term trials. (2) Repeated application of exogenous Organic matter to cropland led to an improvement in Soil biological functions. For instance, microbial biomass carbon increased by up to 100% using high-rate compost treatments, and enzymatic activity increased by 30% with sludge addition. (3) Long-lasting application of Organic amendments increased Organic carbon by up to 90% versus unfertilized Soil, and up to 100% versus chemical fertilizer treatments. (4) Regular addition of Organic residues, particularly the composted ones, increased Soil physical fertility, mainly by improving aggregate stability and decreasing Soil bulk density. (5) The best agronomic performance of compost is often obtained with the highest rates and frequency of applications. Furthermore, applying these strategies, there were additional beneficial effects such as the slow release of Nitrogen fertilizer. (6) Crop yield increased by up to 250% by long-term applications of high rates of municipal solid waste compost. Stabilized Organic amendments do not reduce the crop yield quality, but improve it. (7) Organic amendments play a positive role in climate change mitigation by Soil carbon sequestration, the size of which is dependent on their type, the rates and the frequency of application. (8) There is no tangible evidence demonstrating negative impacts of heavy metals applied to Soil, particularly when high-quality compost was used for long periods. (9) Repeated application of composted materials enhances Soil Organic Nitrogen content by up to 90%, storing it for mineralization in future cropping seasons, often without inducing nitrate leaching to groundwater.
Wulf Amelung - One of the best experts on this subject based on the ideXlab platform.
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amino acids in grassland Soils climatic effects on concentrations and chirality
Geoderma, 2006Co-Authors: Wulf Amelung, Xudong Zhang, Klaus W FlachAbstract:Abstract The response of Soil Organic Nitrogen (SON) dynamics to climate may partly be deduced from changes in the concentration and origin of the major N constituents in Soil, such as amino acids. In this study, we determined the enantiomers of bound amino acids in 18 native grassland Soils (0–10 cm) that were sampled along a transect from central Saskatchewan, Canada, to Southern Texas, USA. Mean annual temperature (MAT) ranged from 0.9 to 23.4 °C and mean annual precipitation (MAP) from 300 to 1308 mm. d -alanine and d -glutamic acid served as markers for the bacterial origin of SON. The d -content of lysine, phenylalanine, and aspartic acid indicated an ageing of the respective SON forms. Deuterium labeling was applied to account for hydrolysis-induced racemization reactions. We found that the concentration of the bacterial biomarkers was weakly but significantly parabolically related to MAT, as previously reported for microbial-derived amino sugars. The age markers d -lysine, d -phenylalanine, and d -aspartic acid comprised 2–15% of the respective l -form. The presence of these compounds demonstrated that the structures that contained these d -enantiomers had survived microbial attack, i.e., these hydrolyzable SON forms were conserved in Soil despite a living environment. First estimates indicate that the mean residence time of the lysine-containing Organic matter forms extend beyond a century. Within this time-scale we did not find that climate significantly affects the degree of ageing of SON constituents in the studied topSoils.
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Losses and biogeochemical cycling of Soil Organic Nitrogen with prolonged arable cropping in the South African Highveld — evidence from d- and l-amino acids
Biogeochemistry, 2005Co-Authors: Sonja Brodowski, Wulf Amelung, Ingo Lobe, Chris C. PreezAbstract:We know little about the mechanisms that cause rapid losses in the Soil Organic N pool during cropping. As the analysis of amino acid enantiomers can provide insight into both the fate of microbial N and the ageing of cells in the environment, we used this technique as a tool to examine how the pool of protein-bound N in subtropical Plinthosols responds to increasing duration of arable cropping. The samples comprised bulk Soils (0–20 cm) and clay fractions from each of three agro-ecosystems in semiarid South Africa; the sites have been cropped for periods varying from 0 to 98 years. The amino acid enantiomers contributed 34% to the total N content. With increasing number of years a piece of land has been cropped, the amino acid concentrations declined bi-exponentially to about 30% of their initial level in the native grasslands. Changes of the remaining Soil protein-N pool were indicated by alterations in the d -content of individual amino acids. As the years of arable cropping increased, the proportions of d -alanine and d -glutamic acid increased relative to the respective l -enantiomers. This was attributed to an accumulation of N in residues of bacterial cell walls. In contrast, the d / l -ratios of leucine and aspartic acid declined in the long-term cultivated plots, probably reflecting losses of old amino acid-N reserves at the most degraded arable land.
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gas chromatographic determination of muramic acid glucosamine mannosamine and galactosamine in Soils
Soil Biology & Biochemistry, 1996Co-Authors: Xudong Zhang, Wulf AmelungAbstract:Muramic acid, glucosamine, mannosamine and galactosamine in Soils may be useful for elucidating the microbial origin of Soil Organic Nitrogen. Therefore, a method was developed to determine the aldononitrile acetate derivatives of the four amino sugars simultaneously in the 6 m HCl hydrolysates of Soil samples by means of high resolution gas liquid chromatography. This method was sensitive enough to detect less than 10 μg muramic acid ml−1 and less than 20 μg ml−1 of the other three amino sugars. The maximum release of amino sugars was found after 6 to 8 h hydrolysis at 105°C. Impurities in the acidic hydrolysates were removed simply by neutralisation with KOH solution. The recovery of amino sugars after hydrolysis and purification was more than 90% on average. The method was applied to determine amino sugars in eight Soils with different properties. The coefficients of variation averaged 6.1% for glucosamine and galactosamine and 10.9% for muramic acid and mannosamine.
Heike Knicker - One of the best experts on this subject based on the ideXlab platform.
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Soil Organic n an under rated player for c sequestration in Soils
Soil Biology & Biochemistry, 2011Co-Authors: Heike KnickerAbstract:The availability of Soil Organic Nitrogen (SON) determines Soil fertility and biomass production to a great extent. SON also affects the amounts and turnover rates of the Soil Organic carbon (SOC) pools. Although there is increasing awareness of the impact of the Nitrogen (N) cycle on the carbon (C) cycle, the extent of this interaction and the implications for Soil Organic matter (SOM) dynamics are still under debate. Therefore, present knowledge about the inter-relationships of the Soil cycles of C and N as well as current ideas about SON stabilization are summarized in this paper in order to develop an advanced concept of the role of N on C sequestration. Modeling global C-cycling, it was already recognized that SON and SOC are closely coupled via biomass production and degradation. However, the narrow C/N ratio of mature Soil Organic matter (SOM) shows further that the impact of SON on the refractory SOM is beyond that of determining the size of the active cycling entities. It affects the quantity of the slow cycling pool and as a major contributor it also determines its chemical composition. Although the chemical nature of SON is still not very well understood, both improved classical wet chemical analyses and modern spectroscopic techniques provide increasing evidence that almost the entire Organic N in fire-unaffected Soils is bound in peptide-like compounds and to a lesser extent in amino sugars. This clearly points to the conclusion, that such compounds have greater importance for SOM formation than previously assumed. Based on published papers, I suggest that peptides even have a key function in the C-sequestration process. Although the mechanisms involved in their medium and long-term stabilization are far from understood, the immobilization of these biomolecules seems to determine the chemistry and functionality of the slow cycling SOM fraction and even the potential of a Soil to act as a C sink. Pyrogenic Organic N, which derives mostly from incomplete combustion of plant and litter peptides is another under-rated player in Soil Organic matter preservation. In fire-prone regions, its formation represents a major N stabilization mechanism, leading to the accumulation of heterocyclic aromatic N, the stability of which is still not elaborated. The concept of peptide-like compounds as a key in SOM-sequestration implies that for an improved evaluation of the potential of Soils as C-sinks our research focus as to be directed to a better understanding of their chemistry and of the mechanisms which are responsible for their resistance against biochemical degradation in Soils.
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how does fire affect the nature and stability of Soil Organic Nitrogen and carbon a review
Biogeochemistry, 2007Co-Authors: Heike KnickerAbstract:After vegetation fires considerable amounts of severely or partly charred necromass (referred to here as char) are incorporated into the Soil, with long-term consequences for Soil C and N dynamics and thus N availability for primary production and C and N transport within the Soil column. Considering results reported in the pyrolysis literature in combination with those obtained from controlled charring of plant material and Soil Organic matter (SOM), it has become clear that common models claiming char as a graphite-like material composed mainly of highly condensed polyaromatic clusters may be oversimplified. Instead, I suggest a concept in which char is a heterogeneous mixture of heat-altered biopolymers with domains of relatively small polyaromatic clusters, but considerable substitution with N, O and S functional groups. Such a concept allows fast oxidation facilitating both microbial attack and dissolution. Although, char is commonly believed to degrade more slowly than litter, over the long term and under oxic conditions, char may degrade to an extent that it becomes indistinguishable from naturally formed SOM. Oxygen depletion or environments with low microbial activity may be necessary for char to survive without major chemical alteration and in considerable amounts for millennia or longer.
Phani Bhusan Ghosh - One of the best experts on this subject based on the ideXlab platform.
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modelling of the contribution of dissolved inOrganic Nitrogen din from litterfall of adjacent mangrove forest to hooghly matla estuary india
Ecological Modelling, 2009Co-Authors: Sudipto Mandal, Santanu Ray, Phani Bhusan GhoshAbstract:Abstract Hooghly–Matla estuarine ecosystem of India is very rich in natural resources and receives large amount of nutrients through litterfall from adjacent mangrove forest. Nitrogen as an important nutrient occurs in various forms and plays a crucial role in the regulation of productivity in this estuarine system. Modelling of Nitrogen dynamics from mangrove litterfall and particularly the release of dissolved inOrganic Nitrogen in this estuarine system is important because of its role in augmenting growth of phytoplankton and other higher plants and all other biological components of grazing food chain. Considering the importance of Nitrogen, a dynamic model with seven-dimension differential equation is proposed. In this model, Nitrogen of the mangrove litterfall is considered as source and its conversion into different Organic and inOrganic forms (Soil total Nitrogen, Soil Organic Nitrogen, Soil inOrganic Nitrogen, total Organic Nitrogen of water, dissolved Organic Nitrogen of water, particulate Organic Nitrogen of water and dissolved inOrganic Nitrogen of water) are considered as state variables. Some physical and chemical factors and also rate parameters such as Nitrogen fraction of litter biomass, litter biomass, redox potential, Soil temperature, conversion rates of Nitrogen of one form to another form, phytoplankton uptake rate of dissolved inOrganic Nitrogen, dissolved oxygen, water temperature and water pH are considered as graph-time functions in this model. These data are collected over two years from our field works and experiments. Other rate parameters are calibrated following standard procedure. Sensitivity analysis is performed before calibration. Model simulation results are properly validated with observed data. Sensitivity analysis reveals that the leaching rate of Soil Organic Nitrogen to total Organic Nitrogen of water and loss rate of Soil Organic Nitrogen as humic acid and fulvic acids are very sensitive parameters in this system. Redox potential plays an important role in the conversion of Soil total Nitrogen to Soil inOrganic Nitrogen whereas Soil temperature is considered to be key factor regulating the microbial activity for the conversion of Soil Organic Nitrogen to Soil inOrganic Nitrogen. Similarly in water, total Organic Nitrogen of water including dissolved Organic Nitrogen and particulate Organic Nitrogen is dependent on Soil Organic Nitrogen. The dissolved Organic Nitrogen, particulate Organic Nitrogen and Soil inOrganic Nitrogen ultimately get converted into dissolved inOrganic Nitrogen and accumulated in water which is taken by phytoplankton and microflora as minerals.
Xiaoli Cheng - One of the best experts on this subject based on the ideXlab platform.
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Soil Organic carbon and Nitrogen dynamics following spartina alterniflora invasion in a coastal wetland of eastern china
Catena, 2017Co-Authors: Wen Yang, Xin Leng, Xiaoli Cheng, Hui Zhao, Shuqing AnAbstract:Plant invasion has been reported to modify ecosystem carbon (C) and Nitrogen (N) cycling processes and pools. The aims of this work were to identify the consequences of plant invasion on C and N dynamics in Soil Organic matter (SOM) and its fractions following invasion chronosequence. In this study, we investigated the Soil C and N contents and the δ13C and δ15N values of the SOM, free light fraction (LF), intra-aggregate particulate Organic matter (iPOM) and mineral-associated Organic matter (mSOM) in invasive 6-, 10-, 17- and 20-year-old Spartina alterniflora communities and compared with bare flat land in a coastal wetland of eastern China. S. alterniflora invasion significantly increased Soil Organic carbon (SOC) and Soil Organic Nitrogen (SON) contents in SOM fractions compared with the bare flat land. The SOC, iPOM-C and iPOM-N progressively increased, but the SON, mSOM-C and mSOM-N did not significantly change following S. alterniflora invasion chronosequence. The proportion of C in iPOM gradually increased, whereas that in mSOM decreased following S. alterniflora invasion chronosequence except for the 20-year-old S. alterniflora Soil. The highest proportion of S. alterniflora-derived C in SOM and its fractions was found in 17-year-old Soil covered by S. alterniflora. The decay rate of old C decreased and the mean residence time of C increased in SOM and its fractions following S. alterniflora invasion chronosequence. The δ15N values of Soil under S. alterniflora were more enriched than were those in bare flat land, whereas the δ15N values depleted following invasion chronosequence. Our results show that S. alterniflora invasion significantly altered SOC dynamics following invasion chronosequence by changing C physical distribution in SOM, S. alterniflora-derived C input and C decomposition, ultimately having a greater impact on SOC incorporation relative to SON accumulation in a coastal wetland of eastern China.
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greenhouse gas co2 ch4 n2o emissions from Soils following afforestation in central china
Atmospheric Environment, 2016Co-Authors: Xiaolin Dou, Wei Zhou, Quanfa Zhang, Xiaoli ChengAbstract:Abstract The effects of afforestation are of great importance for terrestrial carbon sequestration. However, the consequences of afforestation for greenhouse gas (GHG, CO2, CH4 and N2O) fluxes remain poorly quantified. We investigate the temporal variations in CO2, CH4 and N2O fluxes in afforested Soils (implementing woodland and shrubland) and the adjacent uncultivated area in the Danjiangkou Reservoir area of central China. We examined the effects of Soil factors [e.g. Soil temperature, Soil moisture, Soil pH, Soil Organic carbon (SOC), Soil Organic Nitrogen (SON)], litter exclusion and vegetation types on GHG fluxes. Our results revealed that afforestation lead to a higher average CO2 flux from Soils by 63.96% and a higher N2O flux by 54.53% in the observed year. The peak CO2 and CH4 fluxes from afforested Soils occurred in summer, while the peak N2O flux occurred in winter. Afforestation also enhanced CH4 flux from Soil with the largest increase by 247.94% in woodland and by 188.18% in shrubland in spring compared with the open area. On average, surface litter exclusion reduced Soil CO2 fluxes by 18.84% and N2O fluxes by 27.93% in the woodland. The surface litter exclusion did not significantly affect CH4 flux from the afforested Soils. The CO2, CH4 and N2O fluxes from Soils were strongly influenced by Soil temperature, moisture and SOC content across seasons. The N2O flux was also strongly affected by SON content in our experimental field. Our results suggested that afforestation enhanced GHG fluxes from Soils; however, the magnitude of the GHG fluxes should also be considered from various environmental conditions and vegetation types.
