AUTHOR=Zou Xiangbo , Jiang Xinyu , Guan Jinshun , Huang Shaoqiang , Chen Chuangting , Zhou Tiancheng , Kuang Cao , Ye Ji , Liu Tong , Cheng Jiong , Chen Sanxiong , Yu Shiqin 

TITLE=Both organic fertilizer and biochar applications enhanced soil nutrition but inhibited cyanobacterial community in paddy soils

JOURNAL=Frontiers in Environmental Science

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2024.1376147

DOI=10.3389/fenvs.2024.1376147

ISSN=2296-665X

ABSTRACT=Cyanobacteria plays an important role in other ecological processes in paddy soils, especially in nitrogen input to the ecosystem. Organic fertilizer and biochar are common soil amendment materials to preserve soil health in agricultural intensification background. However, the consequent increased soil nutrition may inhibit soil cyanobacteria, which therefore decreases nitrogen fixation and changes other soil processe. To test this hypothesis, in a paddy field in South China, we established a 2×2 full factorial experiment including four treatments: Ctr (control, receiving no organic fertilization or biochar addition), +OF (organic fertilizer application only), +BC (biochar application only), and +Mix (organic fertilizer and biochar applications). The soil cyanobacterial community was analyzed using metagenomics technology, and 14 soil property variables were measured.The results suggested that organic fertilizer was effective in enhancing nutrient levels, contributing to a significant increase in extractable and soluble nitrogen, phosphorus, and potassium, while biochar application had stronger effects on total soil carbon and potassium and soil pH. In contrast, both organic fertilizer and biochar applications induced significant decreases in overall cyanobacterial abundance and species number. Dominant cyanobacterial organisms, especially the two most abundant genera, Leptolyngbya and Phormidium, decreased more than others. Canonical correlation analyses and structural equation models indicated that organic fertilizer and biochar applications affected soil cyanobacterial community mainly through soil available nitrogen and pH. In total, the present study highlighted that both organic fertilizer and biochar applications in paddy soils notably change soil physicochemical traits, inhibiting rather than benefiting cyanobacterial microorganisms, especially those dominant ones, and therefore potentially depressed nitrogen input. Our study revealed the impacts of oragnic fertilizer and biochar applications in paddies on soil cyanobacteria and how the consequent soil property changemediated the impact, enhancing our knowledge of different soil microbial groups' responses to soil improvement..