Nitrogen release and microbial community characteristics during the decomposition of field-incorporated corn straw in Northeast China

Abstract Straw incorporation increases the amount of nutrients in soil and has a significant impact on soil nitrogen and microbial communities. However, no study has quantified the amount of nitrogen released and taken up by straw during its decomposition after it is incorporated into soil in the field. In this study, a method for estimating the amounts of nitrogen released and taken up by field-incorporated straw was proposed based on 15N-labeled corn straw, and the relationships between nitrogen release and uptake amounts and the related microbes were established. The results showed that the amounts of nitrogen released by the straw at different incorporation depths were not significantly different. Among all the treatments, the straw placed 15 cm above the soil surface and the straw mulched on the soil surface had the highest nitrogen uptake, and the straw placed 15 cm above the soil surface had the lowest net nitrogen release. The relative abundances of Burkholderiales, Flavobacteriales, Pseudomonadales, and Sphingobacteriales were significantly positively correlated with the 15N abundance and the nitrogen release speed of the straw. The relative abundances of Rhizobiales and Sphingomonadales were significantly negatively correlated with the 15N abundance in straw and significantly positively correlated with the amount of straw nitrogen uptake.