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Chen Jin - One of the best experts on this subject based on the ideXlab platform.
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Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an Acid Soil
Environmental Microbiology, 2014Co-Authors: Yuji Jiang, Chen Jin, Bo SunAbstract:Summary Nitrification plays a central role in global nitrogen cycle, which is affected by interaction between Soil microfauna and microorganisms. The impact of synchronized changes in nematodes and ammonia oxidizers within aggregate fractions on nitrification was investigated in an Acid Soil under 10-year manure application. Nematodes, ammonia oxidizers and potential nitrification activity (PNA) were examined in three Soil aggregate fractions under four fertilization regimes. Pyrosequencing data revealed that the dominant bacterial amoA operational taxonomic units (OTUs) were related to Nitrosospira species, while archaeal OTUs were affiliated with Nitrososphaera and Nitrosotalea species. PNA was more strongly correlated with ammonia-oxidizing bacteria (AOB) abundance than ammonia-oxidizing archaea (AOA) abundance, although AOA were dominant in the Acid Soil. Plant parasites had a negative effect on AOB abundance; however, bacterivores stimulated AOB abundance and contributed more to PNA than plant parasites. Aggregate fractions exerted significant impacts on AOA abundance and AOB community composition. Total carbon content strongly affected the abundance and composition of AOA community, while Soil pH primarily affected that of AOB community. Soil variables explained 62.7% and 58.1% variations, and nematode variables explained 11.7% and 19.5% variations in the AOA and AOB community composition respectively.
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Soil aggregate stratification of nematodes and microbial communities affects the metabolic quotient in an Acid Soil
Soil Biology & Biochemistry, 2013Co-Authors: Yuji Jiang, Chen Jin, Bo Sun, Feng WangAbstract:Abstract The addition of fresh organic matter is known to modify both Soil aggregation and Soil biotic community composition. We hypothesized that fertilization alters the composition of Soil nematode and microbial communities in Soil aggregates, and the interaction between nematodes and microbes can stimulate or inhibit microbial activity. We used a field experiment with 9 years of manure application to investigate changes in nematodes and microbial communities among aggregate size fractions in an Acid Soil planted with maize in subtropical China. Nematodes, microbial communities, and metabolic quotient ( q CO 2 ) were examined within three aggregate size fractions from Soils under four fertilization regimes. Three aggregate fractions include large macroaggregates (>2000 μm; LA), small macroaggregates (250–2000 μm; SA), and inter-aggregate Soil and space ( 0 ), low-rate manure with 150 kg N ha −1 y −1 (M 1 ), high-rate manure with 600 kg N ha −1 y −1 (M 2 ), and high-rate manure with 600 kg N ha −1 y −1 and lime at 3000 kg Ca(OH) 2 ha −1 3 y −1 (M 3 ). Fertilization influenced the proportion of the aggregate size fractions. The proportion of the LA fraction significantly increased under M 2 and M 3 treatments compared to M 0 and M 1 treatments, while the SA fraction significantly decreased. Aggregate fractions significantly affected the total number of nematodes and the abundance of bacterivorous nematodes (dominant genus Protorhabditis ) and plant parasitic nematodes (dominant genus Pratylenchus ), with values following the trend of LA > SA > IA. A high value for the nematode structure index (SI) in the LA fraction suggested a complex community structure with many linkages in the food web. Aggregate fractions also influenced microbial biomass and diversity. PLFA signature analysis revealed that microbial biomass and diversity (Shannon index) increased with decreasing aggregate size. However, the SA fraction had a significantly higher Soil metabolic quotient ( q CO 2 ) than the IA fraction. Only fertilization had a significant effect on the compositions of nematode groups, while both fertilization and aggregate fractions significantly affected microbial community composition. The variations in the composition of nematode and microbial communities could be explained independently by fertilization treatments (44% and 48%, respectively) and aggregate size (6.0% and 21%, respectively). Aggregated boosted trees (ABT) analysis indicated that total C exerted the strongest influence on microbial biomass, while pH influenced the total number of nematodes. The abundance of bacterivores showed a significant positive association with bacterial biomass across fertilization treatments and aggregate fractions ( r 2 = 0.17, P = 0.026), which could partly explain the significant negative correlation between the total number of nematodes and q CO 2 ( r 2 = 0.25, P = 0.002). The grazing on microbes by microbivores may decrease microbial activity.
Bo Sun - One of the best experts on this subject based on the ideXlab platform.
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Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an Acid Soil
Environmental Microbiology, 2014Co-Authors: Yuji Jiang, Chen Jin, Bo SunAbstract:Summary Nitrification plays a central role in global nitrogen cycle, which is affected by interaction between Soil microfauna and microorganisms. The impact of synchronized changes in nematodes and ammonia oxidizers within aggregate fractions on nitrification was investigated in an Acid Soil under 10-year manure application. Nematodes, ammonia oxidizers and potential nitrification activity (PNA) were examined in three Soil aggregate fractions under four fertilization regimes. Pyrosequencing data revealed that the dominant bacterial amoA operational taxonomic units (OTUs) were related to Nitrosospira species, while archaeal OTUs were affiliated with Nitrososphaera and Nitrosotalea species. PNA was more strongly correlated with ammonia-oxidizing bacteria (AOB) abundance than ammonia-oxidizing archaea (AOA) abundance, although AOA were dominant in the Acid Soil. Plant parasites had a negative effect on AOB abundance; however, bacterivores stimulated AOB abundance and contributed more to PNA than plant parasites. Aggregate fractions exerted significant impacts on AOA abundance and AOB community composition. Total carbon content strongly affected the abundance and composition of AOA community, while Soil pH primarily affected that of AOB community. Soil variables explained 62.7% and 58.1% variations, and nematode variables explained 11.7% and 19.5% variations in the AOA and AOB community composition respectively.
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Soil aggregate stratification of nematodes and microbial communities affects the metabolic quotient in an Acid Soil
Soil Biology & Biochemistry, 2013Co-Authors: Yuji Jiang, Chen Jin, Bo Sun, Feng WangAbstract:Abstract The addition of fresh organic matter is known to modify both Soil aggregation and Soil biotic community composition. We hypothesized that fertilization alters the composition of Soil nematode and microbial communities in Soil aggregates, and the interaction between nematodes and microbes can stimulate or inhibit microbial activity. We used a field experiment with 9 years of manure application to investigate changes in nematodes and microbial communities among aggregate size fractions in an Acid Soil planted with maize in subtropical China. Nematodes, microbial communities, and metabolic quotient ( q CO 2 ) were examined within three aggregate size fractions from Soils under four fertilization regimes. Three aggregate fractions include large macroaggregates (>2000 μm; LA), small macroaggregates (250–2000 μm; SA), and inter-aggregate Soil and space ( 0 ), low-rate manure with 150 kg N ha −1 y −1 (M 1 ), high-rate manure with 600 kg N ha −1 y −1 (M 2 ), and high-rate manure with 600 kg N ha −1 y −1 and lime at 3000 kg Ca(OH) 2 ha −1 3 y −1 (M 3 ). Fertilization influenced the proportion of the aggregate size fractions. The proportion of the LA fraction significantly increased under M 2 and M 3 treatments compared to M 0 and M 1 treatments, while the SA fraction significantly decreased. Aggregate fractions significantly affected the total number of nematodes and the abundance of bacterivorous nematodes (dominant genus Protorhabditis ) and plant parasitic nematodes (dominant genus Pratylenchus ), with values following the trend of LA > SA > IA. A high value for the nematode structure index (SI) in the LA fraction suggested a complex community structure with many linkages in the food web. Aggregate fractions also influenced microbial biomass and diversity. PLFA signature analysis revealed that microbial biomass and diversity (Shannon index) increased with decreasing aggregate size. However, the SA fraction had a significantly higher Soil metabolic quotient ( q CO 2 ) than the IA fraction. Only fertilization had a significant effect on the compositions of nematode groups, while both fertilization and aggregate fractions significantly affected microbial community composition. The variations in the composition of nematode and microbial communities could be explained independently by fertilization treatments (44% and 48%, respectively) and aggregate size (6.0% and 21%, respectively). Aggregated boosted trees (ABT) analysis indicated that total C exerted the strongest influence on microbial biomass, while pH influenced the total number of nematodes. The abundance of bacterivores showed a significant positive association with bacterial biomass across fertilization treatments and aggregate fractions ( r 2 = 0.17, P = 0.026), which could partly explain the significant negative correlation between the total number of nematodes and q CO 2 ( r 2 = 0.25, P = 0.002). The grazing on microbes by microbivores may decrease microbial activity.
Yuji Jiang - One of the best experts on this subject based on the ideXlab platform.
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Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an Acid Soil
Environmental Microbiology, 2014Co-Authors: Yuji Jiang, Chen Jin, Bo SunAbstract:Summary Nitrification plays a central role in global nitrogen cycle, which is affected by interaction between Soil microfauna and microorganisms. The impact of synchronized changes in nematodes and ammonia oxidizers within aggregate fractions on nitrification was investigated in an Acid Soil under 10-year manure application. Nematodes, ammonia oxidizers and potential nitrification activity (PNA) were examined in three Soil aggregate fractions under four fertilization regimes. Pyrosequencing data revealed that the dominant bacterial amoA operational taxonomic units (OTUs) were related to Nitrosospira species, while archaeal OTUs were affiliated with Nitrososphaera and Nitrosotalea species. PNA was more strongly correlated with ammonia-oxidizing bacteria (AOB) abundance than ammonia-oxidizing archaea (AOA) abundance, although AOA were dominant in the Acid Soil. Plant parasites had a negative effect on AOB abundance; however, bacterivores stimulated AOB abundance and contributed more to PNA than plant parasites. Aggregate fractions exerted significant impacts on AOA abundance and AOB community composition. Total carbon content strongly affected the abundance and composition of AOA community, while Soil pH primarily affected that of AOB community. Soil variables explained 62.7% and 58.1% variations, and nematode variables explained 11.7% and 19.5% variations in the AOA and AOB community composition respectively.
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Soil aggregate stratification of nematodes and microbial communities affects the metabolic quotient in an Acid Soil
Soil Biology & Biochemistry, 2013Co-Authors: Yuji Jiang, Chen Jin, Bo Sun, Feng WangAbstract:Abstract The addition of fresh organic matter is known to modify both Soil aggregation and Soil biotic community composition. We hypothesized that fertilization alters the composition of Soil nematode and microbial communities in Soil aggregates, and the interaction between nematodes and microbes can stimulate or inhibit microbial activity. We used a field experiment with 9 years of manure application to investigate changes in nematodes and microbial communities among aggregate size fractions in an Acid Soil planted with maize in subtropical China. Nematodes, microbial communities, and metabolic quotient ( q CO 2 ) were examined within three aggregate size fractions from Soils under four fertilization regimes. Three aggregate fractions include large macroaggregates (>2000 μm; LA), small macroaggregates (250–2000 μm; SA), and inter-aggregate Soil and space ( 0 ), low-rate manure with 150 kg N ha −1 y −1 (M 1 ), high-rate manure with 600 kg N ha −1 y −1 (M 2 ), and high-rate manure with 600 kg N ha −1 y −1 and lime at 3000 kg Ca(OH) 2 ha −1 3 y −1 (M 3 ). Fertilization influenced the proportion of the aggregate size fractions. The proportion of the LA fraction significantly increased under M 2 and M 3 treatments compared to M 0 and M 1 treatments, while the SA fraction significantly decreased. Aggregate fractions significantly affected the total number of nematodes and the abundance of bacterivorous nematodes (dominant genus Protorhabditis ) and plant parasitic nematodes (dominant genus Pratylenchus ), with values following the trend of LA > SA > IA. A high value for the nematode structure index (SI) in the LA fraction suggested a complex community structure with many linkages in the food web. Aggregate fractions also influenced microbial biomass and diversity. PLFA signature analysis revealed that microbial biomass and diversity (Shannon index) increased with decreasing aggregate size. However, the SA fraction had a significantly higher Soil metabolic quotient ( q CO 2 ) than the IA fraction. Only fertilization had a significant effect on the compositions of nematode groups, while both fertilization and aggregate fractions significantly affected microbial community composition. The variations in the composition of nematode and microbial communities could be explained independently by fertilization treatments (44% and 48%, respectively) and aggregate size (6.0% and 21%, respectively). Aggregated boosted trees (ABT) analysis indicated that total C exerted the strongest influence on microbial biomass, while pH influenced the total number of nematodes. The abundance of bacterivores showed a significant positive association with bacterial biomass across fertilization treatments and aggregate fractions ( r 2 = 0.17, P = 0.026), which could partly explain the significant negative correlation between the total number of nematodes and q CO 2 ( r 2 = 0.25, P = 0.002). The grazing on microbes by microbivores may decrease microbial activity.
Alan E. Richardson - One of the best experts on this subject based on the ideXlab platform.
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Effect of Soil Acidity, Soil strength and macropores on root growth and morphology of perennial grass species differing in Acid-Soil resistance.
Plant Cell & Environment, 2010Co-Authors: Rebecca E. Haling, Richard J. Simpson, R. A. Culvenor, Hans Lambers, Alan E. RichardsonAbstract:It is unclear whether roots of Acid-Soil resistant plants have significant advantages, compared with Acid-Soil sensitive genotypes, when growing in high-strength, Acid Soils or in Acid Soils where macropores may allow the effects of Soil Acidity and strength to be avoided. The responses of root growth and morphology to Soil Acidity, Soil strength and macropores by seedlings of five perennial grass genotypes differing in Acid-Soil resistance were determined, and the interaction of Soil Acidity and strength for growth and morphology of roots was investigated. Soil Acidity and strength altered root length and architecture, root hair development, and deformed the root tip, especially in Acid-Soil sensitive genotypes. Root length was restricted to some extent by Soil Acidity in all genotypes, but the adverse impact of Soil Acidity on root growth by Acid-Soil resistant genotypes was greater at high levels of Soil strength. Roots reacted to Soil Acidity when growing in macropores, but elongation through high-strength Soil was improved. Soil strength can confound the effect of Acidity on root growth, with the sensitivity of Acid-resistant genotypes being greater in high-strength Soils. This highlights the need to select for genotypes that resist both Acidity and high Soil strength.
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root morphology root hair development and rhizosheath formation on perennial grass seedlings is influenced by Soil Acidity
Plant and Soil, 2010Co-Authors: Rebecca E. Haling, Richard J. Simpson, R. A. Culvenor, Hans Lambers, Alan E. RichardsonAbstract:Perennial pasture species are important for sustainable pasture systems; yet some species display poor persistence on Acid Soils. This work investigated the effect of Soil Acidity on primary root length and root-hair and rhizosheath development of five perennial grass genotypes varying in Acid-Soil resistance. Plants were grown in three low-P Acid Soils that were limed (CaCO3) to modify Soil pH (0.01 M CaCl2 extractable) from 5.0 and Al3+ concentrations from ≥ 16 to <4 mg kg−1 (0.01 M CaCl2 extractable). Root morphology of tall wheatgrass (Thinopyrum ponticum (Podp.) Z.-W. Liu & R.-C Wang), phalaris (Phalaris aquatica L.), cocksfoot (Dactylis glomerata L.) and weeping grass (Microlaena stipoides Labill. R. Br.) was assessed after 20–25 days growth. The root length of tall wheatgrass and phalaris cv Sirosa was sensitive to Acidity, with lateral root length more sensitive to Acidity than seminal root length. Lime increased the root-hair length and density of both Acid-Soil sensitive and resistant genotypes (cocksfoot and an Acid-resistant line of phalaris) and root-hair length was positively correlated to an increase in rhizosheath size per unit root length. Restricted root length and poor root-Soil contact of Acid-Soil sensitive genotypes may explain their low yield and relatively poor persistence on Acid Soils. The improvement to root-hair and rhizosheath development of genotypes that are Acid-Soil resistant in terms of root length demonstrates the benefit of using resistant genotypes in conjunction with liming to manage Acid Soils. Weeping grass was exceptional in its ability to maintain root length, root-hair and rhizosheath development in Acid Soil.
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transgenic barley hordeum vulgare l expressing the wheat aluminium resistance gene taalmt1 shows enhanced phosphorus nutrition and grain production when grown on an Acid Soil
Plant Biotechnology Journal, 2009Co-Authors: Emmanuel Delhaize, Peter R Ryan, Richard J. Simpson, Phillip Taylor, P J Hocking, Alan E. RichardsonAbstract:Summary Barley (Hordeum vulgare L.), genetically modified with the Al3+ resistance gene of wheat (TaALMT1), was compared with a non-transformed sibling line when grown on an Acidic and highly phosphate-fixing ferrosol supplied with a range of phosphorus concentrations. In short-term pot trials (26 days), transgenic barley expressing TaALMT1 (GP-ALMT1) was more efficient than a non-transformed sibling line (GP) at taking up phosphorus on Acid Soil, but the genotypes did not differ when the Soil was limed. Differences in phosphorus uptake efficiency on Acid Soil could be attributed not only to the differential effects of aluminium toxicity on root growth between the genotypes, but also to differences in phosphorus uptake per unit root length. Although GP-ALMT1 out-performed GP on Acid Soil, it was still not as efficient at taking up phosphorus as plants grown on limed Soil. GP-ALMT1 plants grown in Acid Soil possessed substantially smaller rhizosheaths than those grown in limed Soil, suggesting that root hairs were shorter. This is a probable reason for the lower phosphorus uptake efficiency. When grown to maturity in large pots, GP-ALMT1 plants produced more than twice the grain as GP plants grown on Acid Soil and 80% of the grain produced by limed controls. Expression of TaALMT1 in barley was not associated with a penalty in either total shoot or grain production in the absence of Al3+, with both genotypes showing equivalent yields in limed Soil. These findings demonstrate that an important crop species can be genetically engineered to successfully increase grain production on an Acid Soil.
R B Clark - One of the best experts on this subject based on the ideXlab platform.
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arbuscular mycorrhizal adaptation spore germination root colonization and host plant growth and mineral acquisition at low ph
Plant and Soil, 1997Co-Authors: R B ClarkAbstract:Arbuscular mycorrhizal (AM) fungi colonize plant roots and often enhance host plant growth and mineral acquisition, particularly for plants grown under low nutrient and mineral stress conditions. Information about AM fungi and mycorrhizal ( +AM) host plant responses at low pH ( < 5) is limited. Acaulospora are widely reported in Acid Soil, and Gigaspora sp. appear to be more common in Acid Soils than Glomus sp. Spores of some AM fungi are more tolerant to Acid conditions and high Al than others; t Acaulospora sp., Gigaspora sp., and Glomus manihotis are particularly tolerant. Root colonization is generally less in low than in high pH Soils. Percentage root colonization is generally not related to dry matter (DM) produced. Maximum enhancement of plant growth in Acid Soil varies with AM fungal isolate and Soil pH, indicating adaptation of AM isolates to edaphic conditions. Acquisition of many mineral nutrients other than P and Zn is enhanced by +AM plants in Acid Soil, and the minerals whose concentration is enhanced are those commonly deficient in Acid Soils (Ca, Mg, and K). Some AM fungal isolates are effective in overcoming Soil Acidity factors, especially Al toxicity, that restrict plant growth at low pH.
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Growth traits and mineral concentrations of maize hybrids grown on unlimed and limed Acid Soil
Journal of Plant Nutrition, 1997Co-Authors: R B Clark, S. K. Zeto, Virupax C. Baligar, K. D. RitcheyAbstract:Abstract Growing crop plants tolerant to Acid Soils is an alternative for successful production on Acid Soils with limited inputs, especially lime. Acid Soil‐ or aluminum (Al)‐tolerant plants offer considerable protection against Soil Acidity problems. Thirteen maize (Zea mays L.) hybrids developed for production under various environmental conditions were grown (greenhouse) on two Acid Soils (unlimed and limed) to determine differences among hybrids for growth traits, mineral acquisition, and relative tolerance to Acid Soil. Porters Soil induced greater Acid Soil stress on maize than did Lily Soil, although shoot/root dry matter (DM) ratios were affected more in plants grown on Lily than on Porters Soil. Shoot and root DM and total root length (RL) over all hybrids followed sequences of Limed Lily ≥ Limed Porters > Unlimed Lily > Unlimed Porters, and the trait with the greatest variation among hybrids was total RL. Specific RL (total RL/root DM) over all hybrids followed a sequence of Limed Lily=Limed Po...
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Inheritance of Acid-Soil tolerance in sorghum (Sorghum bicolor) grown on an Ultisol
Plant-Soil Interactions at Low pH, 1991Co-Authors: C. I. Flores, L. M. Gourley, Jeffrey F. Pedersen, R B ClarkAbstract:Inheritance of Acid-Soil tolerance (generally considered Al-toxicity tolerance) in sorghum [Sorghum bicolor (L.) Moench] is not clear. Forty F1 sorghum hybrids and their 14 parents were grown two seasons in the field at relatively high (67 and 71%) and low (43 and 42%) Al saturations on an Acid Ultisol in Colombia, South America to evaluate the effects of Acid Soil on agronomic component traits and to better understand inheritance of Acid-Soil tolerance of sorghum. For plants grown at the high Al saturation levels, hybrids from Acid-Soil tolerant [AS-T] × Acid Soil-sensitive [AS-S] crosses were as tolerant as hybrids from AS-T × AS-T crosses which were as tolerant as their AS-T parents. Hybrids from AS-S × AS-S crosses were all sensitive to the Acid-Soil stress conditions. General combining ability (GCA) and specific combining ability (SCA) effects were significant for Acid-Soil tolerance, and GCA effects were more important than SCA effects. Significant GCA and SCA effects were detected for grain yield and number of roots at the low Al saturation level. Additive genetic effects in these genotypes were important for Acid-Soil tolerance rating, grain yield, and number of roots at the high Al saturation level.
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Genotypic variation of pearl millet for growth and yield on Acid Soil
Field Crops Research, 1991Co-Authors: C. I. Flores, R B Clark, L. M. GourleyAbstract:Abstract Genotypes of plant species need to be assessed for ability to grow with fairly severe Acid Soil constraints. Twenty pearl millet ( Pennisetum glaucum R. Br.) genotypes were grown on an ultisol (Typic Palehumult) with 60% Al saturation and on an oxisol (Tropeptic Haplustox) with 53% Al saturation in Colombia, South America, to determine the effects of Acid Soil factors on growth-and-yield-component traits. Five of the genotypes were also grown on the Acid ultisol at 50% Al saturation. The mean grain-yields of the genotypes grown on both Soils ranged from 2260 to 3820 kg ha −1 . Plants grown on the oxisol had slightly higher yields than plants grown on the ultisol. Grain yield, grain plant −1 , seed plant −1 and head length decreased, and days to flower, number of tillers, plant height, head diameter and seed weight were unaffected when plants were grown on the relatively severe Acid Soils. Pearl millet genotypes grew relatively well on the fairly severe Acid Soils.