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Christoph Müller - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms for the retention of inorganic N in acidic Forest Soils of southern China
Scientific Reports, 2013Co-Authors: Jinbo Zhang, Wenyan Yang, Christoph MüllerAbstract:The mechanisms underlying the retention of inorganic N in acidic Forest Soils in southern China are not well understood. Here, we simultaneously quantified the gross N transformation rates of various subtropical acidic Forest Soils located in southern China (southern soil) and those of temperate Forest Soils located in northern China (northern soil). We found that acidic southern Soils had significantly higher gross rates of N mineralization and significantly higher turnover rates but a much greater capacity for retaining inorganic N than northern Soils. The rates of autotrophic nitrification and NH3 volatilization in acidic southern Soils were significantly lower due to low soil pH. Meanwhile, the relatively higher rates of NO3− immobilization into organic N in southern Soils can counteract the effects of leaching, runoff, and denitrification. Taken together, these processes are responsible for the N enrichment of the humid subtropical Forest Soils in southern China.
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nitrogen cycling in Forest Soils across climate gradients in eastern china
Plant and Soil, 2011Co-Authors: Jinbo Zhang, Christoph Müller, Tongbin Zhu, Zucong CaiAbstract:A 15N tracing study was carried out to investigate the potential gross nitrogen (N) dynamics in thirteen Forest Soils in Eastern China ranging from temperate to tropical zones (five coniferous Forests, six deciduous broad-leaf Forests, one temperate mixed Forest, one evergreen broad-leaf Forests ecosystems), and to identify the major controlling factors on N cycling in these Forest ecosystems. The soil pH ranged from 4.3 to 7.9 and soil organic carbon (SOC) ranged from 6.6 g kg−1 to 83.0 g kg−1. The potential gross N transformation rates were quantified by 15N tracing studies where either the ammonium or nitrate pools were 15N labeled in parallel treatments. Gross mineralization rates ranged from 0.915 μg N g−1 soil day−1 to 2.718 μg N g−1 soil day−1 in the studied Forest Soils. The average contribution of labile organic-N (M Nlab ) to total gross mineralization (M Nrec +M Nlab ) was 86% (58% to 99%), indicating that turnover of labile organic N plays a dominant role in the studied Forest ecosystems. The gross mineralization rates in coniferous Forest Soils were significantly lower (ranging between 0.915 and 1.228 μg N g−1 soil day−1) compared to broad-leaf Forest Soils (ranging from 1.621 to 2.718 μg N g−1 soil day−1) (p < 0.01). Thus, the dominant vegetation may play an important role in regulating soil N mineralization. Nitrate production (nitrification) occurred via two pathways, oxidation of NH 4 + and organic N the Forest Soils. Correlations with soil pH indicated that this is a key factor controlling the oxidation of NH 4 + and organic N in theses Forest ecosystems. NH 4 + oxidation decreased with a decline in pH while organic N oxidation increased. The climatic conditions (e.g. moisture status) at the various sites governed the NO 3 − -N consumption processes (dissimilatory NO 3 − reduction to NH 4 + (DNRA) or immobilization of NO 3 − ). Total NO 3 − consumption and the proportion of total NO 3 − consumption to total NO 3 − production decreased with an increase in the drought index of ecosystems, showing that strong interactions appear to exist between climatic condition (e.g. the drought index), N mineralization and the rate of DNRA. Interactions between vegetation, climatic conditions govern internal N cycling in these Forests Soils.
Shinya Funakawa - One of the best experts on this subject based on the ideXlab platform.
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decoupling of protein depolymerization and ammonification in nitrogen mineralization of acidic Forest Soils
Applied Soil Ecology, 2020Co-Authors: Kazumichi Fujii, Chie Hayakawa, Asami Nakanishi, Takahiro Yamada, Shinya FunakawaAbstract:Abstract Soil nitrogen (N) mineralization is generally limited by amino acid production by proteases (depolymerization). Protease activities can be stimulated under N limitation, but it cannot directly increase microbial N release (ammonification) in temperate Forest Soils. To analyze factors determining rate-limiting steps of soil N mineralization, we compared microbial potentials of depolymerization and ammonification by measuring casein degradation and arginine ammonification rates in casein- or arginine-amended and control Soils, respectively. The microbial potentials of casein depolymerization were positively correlated with soil carbon (C)/N ratios, whereas arginine ammonification exhibited the opposite pattern. The soil N mineralization was limited by depolymerization in N-rich broad-leaved Forest and cropland Soils, while N mineralization could be limited by the low microbial potentials of ammonification for microbial N conservation in coniferous Forest Soils with C/N ratios > 20. Due to the increased depolymerization and microbial N conservation under N limitation, ammonification as well as depolymerization can be a rate-limiting step of N mineralization in fungi-dominated acidic Forest Soils. Contrasting responses of depolymerization and ammonification to N limitation and low pH can induce a shift in rate-limiting steps in soil N mineralization.
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Charge characteristics of Forest Soils derived from sedimentary rocks in Kinki District, Japan, in relation to pedogenetic acidification process
Soil Science and Plant Nutrition, 2003Co-Authors: Shinya Funakawa, Mioko Azuma-ashida, Koyo YonebayashiAbstract:Abstract Charge characteristics of Forest Soils derived from sedimentary rocks in the Kinki District, western Japan, were investigated with special reference to the process of pedogenetic acidification. Charge characteristics of the Soils were analyzed based on the coefficients a, b, and c in the regression equation log CEC = a pH + b log C + c, after CEC determination at different ionic concentrations (C) and pH values. The values of (a + b) /2 and c of the B horizons of Forest Soils with a thermic soil temperature regime (TSTR) were similar to those of Ultisols or Oxisols, whereas the values for the B horizons of Forest Soils with a mesic soil temperature regime (MSTR) were comparable to those of the B horizons of Andisols. Unlike in some Oxisols or Andisols, the variable positive charge, or AEC, of the Soils studied here was very low even in the low pH range, presumably because it was neutralized by the permanent negative charge of 2 : 1 minerals in the Soils. Multiple regression followed by principal ...
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Pedogenetic acidification process of Forest Soils in Northern Kyoto
Soil Science and Plant Nutrition, 1993Co-Authors: Shinya Funakawa, Kei Mambu, Hideaki Hirai, Kazutake KyumaAbstract:Abstract A natural process of soil acidification in the pedogenesis of the Forest Soils (i.e. brown Forest soil and podzolic soil) in the northern Kyoto area was studied with special reference to the dynamics of amorphous and exchangeable Al in the profiles. The very low base saturation with low pH of the sampled Soils showed that all the profiles were highly acidified. The amount of exchangeable Al was largest at the surface in the brown Forest soil profiles, whereas it was largest in the E to B horizons in the podzolic profiles. These findings suggested that soil acidification affected the deeper horizons in the podzolic profiles. To analyze the mechanism involved in the pedogenetic acidification process, acid and alkali titrations of the sampled Soils were performed. The titratable alkalinity was highly correlated with the amorphous Al content (Alo) among various soil properties, suggesting its importance in the in situ acid buffering by the solid phase of the Forest Soils. On the other hand, the titra...
Bufeng Chen - One of the best experts on this subject based on the ideXlab platform.
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distribution and source apportionment of polycyclic aromatic hydrocarbons pahs in Forest Soils from urban to rural areas in the pearl river delta of southern china
International Journal of Environmental Research and Public Health, 2014Co-Authors: Yihua Xiao, Fuchun Tong, Yuanwen Kuang, Bufeng ChenAbstract:The upper layer of Forest Soils (0–20 cm depth) were collected from urban, suburban, and rural areas in the Pearl River Delta of Southern China to estimate the distribution and the possible sources of polycyclic aromatic hydrocarbons (PAHs). Total concentrations of PAHs in the Forest Soils decreased significantly along the urban–suburban–rural gradient, indicating the influence of anthropogenic emissions on the PAH distribution in Forest Soils. High and low molecular weight PAHs dominated in the urban and rural Forest Soils, respectively, implying the difference in emission sources between the areas. The values of PAH isomeric diagnostic ratios indicated that Forest soil PAHs were mainly originated from traffic emissions, mixed sources and coal/wood combustion in the urban, suburban and rural areas, respectively. Principal component analysis revealed that traffic emissions, coal burning and residential biomass combustion were the three primary contributors to Forest soil PAHs in the Pearl River Delta. Long range transportation of PAHs via atmosphere from urban area might also impact the PAHs distribution in the Forest Soils of rural area.
Jinbo Zhang - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms for the retention of inorganic N in acidic Forest Soils of southern China
Scientific Reports, 2013Co-Authors: Jinbo Zhang, Wenyan Yang, Christoph MüllerAbstract:The mechanisms underlying the retention of inorganic N in acidic Forest Soils in southern China are not well understood. Here, we simultaneously quantified the gross N transformation rates of various subtropical acidic Forest Soils located in southern China (southern soil) and those of temperate Forest Soils located in northern China (northern soil). We found that acidic southern Soils had significantly higher gross rates of N mineralization and significantly higher turnover rates but a much greater capacity for retaining inorganic N than northern Soils. The rates of autotrophic nitrification and NH3 volatilization in acidic southern Soils were significantly lower due to low soil pH. Meanwhile, the relatively higher rates of NO3− immobilization into organic N in southern Soils can counteract the effects of leaching, runoff, and denitrification. Taken together, these processes are responsible for the N enrichment of the humid subtropical Forest Soils in southern China.
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N2O production pathways in the subtropical acid Forest Soils in China.
Environmental Research, 2011Co-Authors: Jinbo ZhangAbstract:To date, N2O production pathways are poorly understood in the humid subtropical and tropical Forest Soils. A 15N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N2O production in four subtropical acid Forest Soils (pH
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nitrogen cycling in Forest Soils across climate gradients in eastern china
Plant and Soil, 2011Co-Authors: Jinbo Zhang, Christoph Müller, Tongbin Zhu, Zucong CaiAbstract:A 15N tracing study was carried out to investigate the potential gross nitrogen (N) dynamics in thirteen Forest Soils in Eastern China ranging from temperate to tropical zones (five coniferous Forests, six deciduous broad-leaf Forests, one temperate mixed Forest, one evergreen broad-leaf Forests ecosystems), and to identify the major controlling factors on N cycling in these Forest ecosystems. The soil pH ranged from 4.3 to 7.9 and soil organic carbon (SOC) ranged from 6.6 g kg−1 to 83.0 g kg−1. The potential gross N transformation rates were quantified by 15N tracing studies where either the ammonium or nitrate pools were 15N labeled in parallel treatments. Gross mineralization rates ranged from 0.915 μg N g−1 soil day−1 to 2.718 μg N g−1 soil day−1 in the studied Forest Soils. The average contribution of labile organic-N (M Nlab ) to total gross mineralization (M Nrec +M Nlab ) was 86% (58% to 99%), indicating that turnover of labile organic N plays a dominant role in the studied Forest ecosystems. The gross mineralization rates in coniferous Forest Soils were significantly lower (ranging between 0.915 and 1.228 μg N g−1 soil day−1) compared to broad-leaf Forest Soils (ranging from 1.621 to 2.718 μg N g−1 soil day−1) (p < 0.01). Thus, the dominant vegetation may play an important role in regulating soil N mineralization. Nitrate production (nitrification) occurred via two pathways, oxidation of NH 4 + and organic N the Forest Soils. Correlations with soil pH indicated that this is a key factor controlling the oxidation of NH 4 + and organic N in theses Forest ecosystems. NH 4 + oxidation decreased with a decline in pH while organic N oxidation increased. The climatic conditions (e.g. moisture status) at the various sites governed the NO 3 − -N consumption processes (dissimilatory NO 3 − reduction to NH 4 + (DNRA) or immobilization of NO 3 − ). Total NO 3 − consumption and the proportion of total NO 3 − consumption to total NO 3 − production decreased with an increase in the drought index of ecosystems, showing that strong interactions appear to exist between climatic condition (e.g. the drought index), N mineralization and the rate of DNRA. Interactions between vegetation, climatic conditions govern internal N cycling in these Forests Soils.
Mary K Firestone - One of the best experts on this subject based on the ideXlab platform.
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dissimilatory nitrate reduction to ammonium in upland tropical Forest Soils
Ecology, 2001Co-Authors: Whendee L Silver, Donald J Herman, Mary K FirestoneAbstract:The internal transformations of nitrogen in terrestrial ecosystems exert strong controls over nitrogen availability to net primary productivity, nitrate leaching into ground- water, and emissions of nitrogen-based greenhouse gas. Here we report a reductive pathway for nitrogen cycling in upland tropical Forest Soils that decreases the amount of nitrate susceptible to leaching and denitrification, thus conserving nitrogen in the ecosystem. Using '5N tracers we measured rates of dissimilatory nitrate reduction to ammonium (DNRA) in upland humid tropical Forest Soils averaging -0.6 p1g-g-'d-'. Rates of DNRA were three times greater than the combined N20 and N2 fluxes from nitrification and denitrification and accounted for 75% of the turnover of the nitrate pool. To determine the relative im- portance of ambient C, 02, and NO3 concentrations on rates of DNRA, we estimated rates of DNRA in laboratory assays using Soils from three tropical Forests (cloud Forest, palm Forest, and wet tropical Forest) that differed in ambient C and 02 concentrations. Rates of DNRA measured in laboratory assays ranged from 0.5 to 9 (Lgg-'gd-' in Soils from the three different Forests and appeared to be primarily limited by the availability of NO3, as opposed to C Or 02. Tests of sterile Soils indicated that the dominant reductive pathway for both NO2 and NO3 was biotic and not abiotic. Because NH4 is the form of N generally favored for assimilation by plants and microbes, and NO3 is easily lost from the ecosystem, the rapid and direct transformation of NO3 to NH4 via DNRA has the potential to play an important role in ecosystem N conservation.