Legacy effects of 8-year nitrogen inputs on bacterial assemblage in wheat rhizosphere

• Published in: Biology and fertility of soils Vol. 56; no. 5; pp. 583 - 596
• Main Authors: Liu, Wenbo, Ling, Ning, Guo, Junjie, Ruan, Yang, Zhu, Chen, Shen, Qirong, Guo, Shiwei
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-07-2020; Springer Nature B.V
• Subjects: Agriculture; Bacteria; Biomass; Biomedical and Life Sciences; Clustering; Community composition; Crop growth; Experiments; Fertilizers; Life Sciences; Microorganisms; Nitrogen; Original Paper; Phylogenetics; Phylogeny; Rhizosphere; Salinity; Soil; Soil Science & Conservation; Soil stresses; Species diversity; Wheat; Rhizosphere bacteria; Net relatedness index; Legacy effects; Nearest taxon index; N fertilization; Co-occurrence network
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s00374-020-01435-2

This study focused on the legacy effects of 8-year application of N (in gradient of 0, 140, 280, 470, and 660 kg N ha
−1
 year
−1
) on the bacterial community diversity, interactions, and assembly processes in the wheat rhizosphere. The rhizosphere bacterial α-diversity increased with the rate of historical N input, while it did not change at N addition rates of over 280 kg N ha
−1
 year
−1
. Historical N input clearly shifted the rhizosphere bacterial community composition, and soils with more N input were more dissimilar to those without N input. The net relatedness index (NRI) and nearest taxon index (NTI) analysis revealed that the rhizosphere bacterial communities in most samples were phylogenetically clustered, and the treatments with high N (> 470 kg N ha
−1
 year
−1
) showed higher levels of clustering than those with low N (< 140 kg N ha
−1
 year
−1
), indicating more environmental selection stress in soil with higher historical N input. Increased co-occurrence network size and connectivity were accompanied by increased aboveground biomass of wheat. Overall, with the increase in historical N input, the resulting legacy effects forced the bacterial community in the rhizosphere to undergo higher environmental selection pressure, and indirectly affected the complexity of wheat rhizosphere assemblages during subsequent crop growth.