Objectives Comparing the differences in the bacterial community structure of yellow paddy soil when applying different fertilizers over a long time, and analyzing the effect and mechanism of long-term combined application of organic and inorganic fertilizers on sustaining soil bacterial diversity.
Methods The study relied on the long-term experiment located in Scientific Observation and Experimental Station of Arable Land Conservation and Agricultural Environment (Guizhou), Ministry of Agriculture and Rural Affairs. Soil samples were collected from five treatments, no fertilizer control (CK), chemical fertilizer (NPK), 1/4 manure N plus 3/4 chemical fertilizer (1/4M+3/4NP), 1/2 manure N +1/2 chemical fertilizer (1/2M+1/2NP), and total manure N (M). High-throughput sequencing technology was used to analyze the microbial composition and diversity of colonies. The influence factors were discussed.
Results Analysis of soil bacterial α diversity index of different fertilization treatments showed that long-term application of organic fertilizers increased the Shannon, Simpson and Pielou, with limited effect on Chao1 index. Compared with CK, long-term fertilization increased the relative abundance of Proteobacteria at varying degrees, and the effect of chemical fertilizers was more significant. Compared with CK and NPK, the application of organic fertilizers reduced the relative abundance of Rokubacteria and Nitrospinae, and increased the relative abundance of Bacteroidetes. The difference in other bacterial phyla was not significant (P<0.05). The results of principal component analysis of soil bacterial community structure showed that the soil environment of the 1/4M+3/4NP and 1/2M+1/2NP treatments was similar, and the bacterial community composition was similar, while the CK and NPK treatments were at par in terms of the bacterial community composition. Redundancy analysis of soil bacterial community structure and soil environmental factors showed that soil physical and chemical properties affected bacterial community structure in the order of total nitrogen>available nitrogen>available potassium>pH>available phosphorus>total phosphorus.Total nitrogen, available nitrogen, and available potassium were the key factors.
Conclusions Long-term application of organic fertilizer improves the fertility of yellow paddy soil, changes the growth environment of bacteria, further alters the structure of bacterial community, increases the diversity of bacterial community, and promotes the stability and health of the soil ecosystem.
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