Effects of straw amendment and moisture on microbial communities in Chinese fluvo-aquic soil

Abstract

Purpose Returning crop straw into fields is a typical agricultural practice to resolve an oversupply of straw and improve soil fertility. Soil microorganisms, especially eukaryotic microorganisms, play a critical role in straw decomposition. To date, microbial communities in response to straw amendment at different moisture levels in Chinese fluvo-aquic soil are poorly understood. The aim of this study was to explore the effects of straw amendment and moisture on microbial communities in Chinese fluvo-aquic soil. Materials and methods Two soils (one was applied with organic manure, and the other was not applied with any fertilizer) from a long-term field experiment in the North China Plain were collected. Soils with and without straw amendment at 25 and 55 % of the average water-holding capacities of the two soils were incubated at 25°C for 80 days. All treatments were sampled 20 and 80 days after the start of incubation. Microbial biomass and community structure were analyzed by phospholipid fatty acids (PLFA) assay, and the eukaryotic diversity and community composition were assessed via barcoded pyrosequencing of the 18S ribosomal RNA (rRNA) gene amplicons.Results and discussion PLFA analysis showed that straw amendment increased the biomass of Gram-positive bacteria, Gram-negative bacteria, actinobacteria, and fungi and shifted microbial community structure. The varied straw availability resulted in a large variation in microbial community structure. In the presence of straw, actinobacterial and fungal biomass both decreased under high moisture content. 18S rRNA gene pyrosequencing indicated that straw amendment decreased eukaryotic diversity and richness and probably restructured the eukaryotic community. Under identical moisture content, long-term organic manure-fertilized soil had higher eukaryotic diversity and richness than the unfertilized soil. In the amended soils under high moisture content, the relative abundance of dominant fungal taxa (Dikarya subkingdom, Ascomycota phylum, and Pezizomycotina subphylum) decreased. Conclusions Straw amendment increases microbial biomass, shifts microbial community structure, and decreases eukaryotic diversity and richness. High moisture content probably has a negative effect on fungal growth in the amended soils. In conclusion, microbial communities in Chinese fluvo-aquic soil are significantly affected by straw amendment at different moisture levels.

Integrative effects of no-tillage and straw returning on soil organic carbón and water stable aggregation under rice-rape rotation

“…These results are same with another study that MWD was significantly affected by straw returning and no-tillage systems in the top 0-30 cm (Gwenzi et al, 2009). In agreement to our results, Kahlon et al (2013) and Chen et al (2014) In present study, tillage and straw returning plots NTS and CTS treatments significantly increased MWD and GMD values of soil aggregates in both soil depths, but was more obvious at 0-20 cm depth. Soil aggregate stability always determined in relation to MWD and GMD, indicate the soil capability to resist degradation (Kemper and Rosenau, 1986).…”

“…The soil organic C (SOC) plays an imperative role in regulating soil ecological and C cycling processes in the global scale (Chen et al, 2014). The soil management practices are considered essential to conserve soil quality (Kahlon et al, 2013), and can greatly affect the composition and stability of SOC through plough layer (Stone and Schlegel, 2010;Bhattacharyya et al, 2012;Ghosh et al, 2016).…”

Effects of Insect-Proof Net Cultivation, Rice-Duck Farming, and Organic Matter Return on Rice Dry Matter Accumulation and Nitrogen Utilization

“…In the present study, WS and BR decreased the dry matter accumulation from the TP to EG but increased the dry matter accumulation from the EG to MT ( Table 5 ). This was primarily because the microorganisms increased rapidly and consumed a portion of the mineral N after returning wheat straw into the soil (Chen et al, 2014). On the other hand, wheat straw decomposition produced reducing harmful substances at an earlier stage, which influenced rice root growth (Bradford and Peterson, 2000).…”

Bacterial community structure in maize stubble-amended soils with different moisture levels estimated by bar-coded pyrosequencing

“…After visible plant residues and stones were removed, soil samples from four replicated plots were mixed, homogenized, and air-dried. To lessen the influence of different aggregate distribution between soils from the two treatments, soils were passed through a 0.25 mm mesh sieve and all macroaggregates with size >0.25 mm were broken down (Chen et al, 2014a).…”