Response of soil characteristics and bacterial communities to nitrogen fertilization gradients in a coastal salt‐affected agroecosystem

Abstract

Understanding the relationship between fertilization and soil bacterial communities in a salt-affected environment is essential for alleviating the adverse impact of excessive salinity on soil biochemical functioning. However, how soil bacterial communities respond to consecutive fertilization across nitrogen gradients in coastal agroecosystemhas not yet been clarified. We conducted a field plot experiment with four nitrogen fertilization rates (0, 150, 300, and 450 kg N hm −2 yr −1 ) on coastal salt-affected soil for three consecutive years. Temporal dynamics of soil chemical and microbial properties was characterized, and soil bacterial community composition against N fertilization rates was investigated using 16S rRNA gene sequencing. Results indicated that consecutive N fertilization significantly increased soil organic carbon, total nitrogen (TN), available nitrogen (AN), available phosphorous, microbial biomass carbon (MBC), microbial biomass nitrogen and net nitrogen mineralization rate (NMR). N fertilization rates and cultivation years exhibited interactive effect on TN, AN, MBC and NMR. Soil bacterial community richness and diversity increased with the nitrogen rates. Predominant bacterial classes were Deltaproteobacteria, Anaerolineae, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria and Planctomycetia. Increasing nitrogen fertilization resulted in an elevation in the relative abundance of classes Alphaproteobacteria, Gammaproteobacteria, Planctomycetia and Nitrospira, and a decline in Anaerolineae, Acidobacteria_Gp6, Cytophagia, Bacilli and Acidobacteria_Gp10. Community composition of Alphaproteobacteria, Planctomycetia and Nitrospira was significantly associated with potential nitrification rate (PNR), whereas that of Actinobacteria was relevant to carbon mineralization rate. Results underlined that nitrogen fertilization improved nutrients, biochemical characteristics and metabolic activities to create more suitable bacterial microhabitats in the coastal agroecosystem.

Assessing the Impact of Rice Cultivation and Off-Season Period on Dynamics of Soil Enzyme Activities and Bacterial Communities in Two Agro-Ecological Regions of Mozambique

“…Proteobacteria was the most abundant phyla across most RCST, while others with a relatively high abundance were Bacteroidetes, Acidobacteria and Actinobacteria. This finding is consistent with previous studies that profiled the abundant bacterial phyla in rice-cultivated mudflats [118,119]. An important observation in the distribution of bacteria across all RCST was the dominance of Proteobacteria and Acidobacteria in the rice cultivated PH soil in Chokwe and also the dominance of Bacteroidetes in the rice cultivated soil in Umbeluzi.…”

“…Investigation of bacterial species-environment relationship revealed that ammonium (NH 4 + ), nitrate (NO 3 − ), total nitrogen, P-Olsen, moisture, SOC, pH and electrical conductivity (EC) significantly (p < 0.05) influenced the bacterial communities (Table S4). Changes in physicochemical parameters have been severally reported to have a strong influence on bacterial community structure in diverse environments [17,84,115,118]. The impact of some of these physicochemical terms and the microbial community changes they drive in rice-cultivated soils have been extensively reviewed [94].…”

Could Land Abandonment with Human Intervention Benefit Cropland Restoration? From the Perspective of Soil Microbiota

“…However, HIS increased nitrogen consumption, which was the same as in HIM and HII. Although the nutrient consumption of HIS did not cause significant between-group differences in our study, the relationship between soil nitrogen content and bacterial communities involved in nitrogen cycling indicated that HIS exhibited oligotrophic status and increased nitrogen consumption [14,[48][49][50][51][52]. The reason may be that forage grass enhances nitrogen cycling and causes nitrogen loss via nitrite reduction [69].…”

“…In 2016 and 2017, HIS had significant effects on some oligotrophic bacteria, including Acidobacteria Gp3, Gemm-4, NB1-I, Polaromonas, and Novosphingobium (LDA score > 2, K-W test P < 0.05) [14,[48][49][50]. In 2018, some bacteria involved in nitrogen cycling and plantgrowth promotion increased in the HIS, including Solibacteres, Planctomycetia, Sva0725, Rubrivivax, and Nitrospira (LDA score > 2, K-W test P < 0.05) [51][52][53]. In terms of fungi, some fungi associated with AMF and endomycorrhizae formation were promoted in HIS in 2017 and 2018, including Diversisporales, Tuberaceae, and Acaulospora (LDA score > 2, K-W test P < 0.05) [46,47,54].…”

Soil microbial community composition in a paddy field with different fertilization managements

“…However, the effects of N and/or P fertilizer application on microbial diversity and composition were currently inconsistent among various studies. Yao et al (2021) reported that soil bacterial community richness increased with N application rate in a coastal salt-affected agroecosystem.…”