Effect of Phosphate Liberation Bacteria Added in Biochar on the Phosphorus Absorption and Soil Bacterial Community Composition in Winter Potatoes

PurposeTo clarify the impact of biochar and phosphate liberation bacteria on potato growth and phosphorus absorption and utilization, and further explore the application effect of biochar on the combination of phosphate liberation bacteria.

MethodsUsing winter potato as the test material, (wheat bran + sawdust) + phosphorus tailings as the control (CK), adding biochar (WB), phosphate liberation bacteria (WP), biochar + phosphate liberation bacteria (WBP) respectively for field experiments; the soil samples treated by WP and WBP and phosphate liberation bacteria were analyzed by high-throughput sequencing.

ResultCompared with CK group, WP, WB and WBP treatment increased or significantly increased the dry matter accumulation of potato plants (P<0.05), promoting the growth and development of potato plants. At harvest time, WB, WP and WBP could promote the uptake and utilization of phosphorus by plants, and the phosphorus accumulation of WB, WP and WBP group was increased by 53.58%, 45.91% and 90.65% respectively compared with CK. The addition of biochar and phosphate liberation bacteria increased the content of available phosphorus in the soil, the increased of WBP treatment was higher or significantly higher than that WB and WP treatments (P<0.05), with the increase rates of 11.14%-33.22% and 12.11%-30.96%, respectively. The 16S rRNA sequencing results showed that the three strains were Proteobacteria, Bacteroidetes and Firmicutes. When WP and WBP were applied into the soil, the Proteobacteria and Bacteroidetes were the dominant bacteria group, while Firmicutes was no longer the dominant bacteria group due to its weakened activity. Compared with WP treatment, WBP treatment increased the relative abundance of Proteobacteria and promoted their growth and reproduction, but reduced the relative abundance of Bacteroidetes.

ConclusionThe combined application of biochar and phosphate liberation bacteria has better effects on the absorption and utilization of phosphorus and maintaining the richness and uniformity of soil microbial communities than single application of biochar or phosphate liberation bacteria.