Acid Soil - Explore the Science & Experts | ideXlab

Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an Acid Soil

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.

Soil aggregate stratification of nematodes and microbial communities affects the metabolic quotient in an Acid Soil

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.

Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an Acid Soil

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.

Soil aggregate stratification of nematodes and microbial communities affects the metabolic quotient in an Acid Soil

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.

Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an Acid Soil

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.

Soil aggregate stratification of nematodes and microbial communities affects the metabolic quotient in an Acid Soil

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.