Long-term application of lime or pig manure rather than plant residues suppressed diazotroph abundance and diversity and altered community structure in an acidic Ultisol

• Published in: Soil biology & biochemistry 2018-08, Vol.123, p.218-228
• Main Authors: Lin, Yongxin, Ye, Guiping, Liu, Deyan, Ledgard, Stewart, Luo, Jiafa, Fan, Jianbo, Yuan, Junji, Chen, Zengming, Ding, Weixin
• Format: Article
• Language: English
• Subjects: Diazotroph; Long-term fertilization; nifH; Nitrogen fixation; Soil pH
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2018.05.018

Biological fixation of atmospheric dinitrogen (N2) is an important process that replenishes biologically available nitrogen (N) in soil and helps minimize the use of inorganic N fertilizer in agricultural ecosystems. Diazotrophs are key fixers of atmospheric N2 in a range of soil types, however, there is uncertainty about how they respond to long-term fertilization. Here, using the nifH gene as a molecular marker, we investigated the long-term effects of inorganic and organic fertilization on diazotroph abundance and community structure in an acidic Ultisol. The field experiment ran for 27 years and comprised seven treatments: no fertilization (control); inorganic NPK fertilizer (N); inorganic NPK fertilizer + lime (CaCO3) (NL); inorganic NPK fertilizer + peanut straw (NPS); inorganic NPK fertilizer + rice straw (NRS); inorganic NPK fertilizer + radish (NR); and inorganic NPK fertilizer + pig manure (NPM). Long-term application of fertilizer reduced the abundance and diversity of nifH gene compared with the control (P