Plant clippings improved soil microbial community structure and potential functionality in farmland as organic amendments: fresh vs dry

Abstract

Background and aims

Agricultural residues can be used as organic amendments to improve soil properties, but also as a strategy for recycling massive amounts of wastes. The way organic amendments are introduced into the soil ecosystem can impact their potential benefit.

Methods

Here, we examined how the incorporation of fresh maize clippings vs. dry ones impacts soil physicochemical properties and bacterial and fungal communities in a two-year field experiment under semi-arid climatic conditions.

Results

Both amendments improved soil porosity and moisture respect to the unamended treatment, with fresh clippings increased to a higher extent soil moisture content. Moreover, soil amended with fresh clippings increased bacterial diversity, but did not change microbial biomass. Bacterial community composition under amended treatments showed a shift from oligotrophic to copiotrophic. Furthermore, bacterial and fungal co-occurrence networks were more complex under soil amended with fresh plant clippings and dried plant clippings, respectively. Fresh plant clippings pruning enhanced phototrophic, photoheterotrophic and methylation functions, but inhibited denitrification function.

Conclusion

Our results highlight that amended treatments increased soil organic carbon via improving soil microhabitat and regulating bacterial community structure rather than fungal community, emphasizing that soil variables and bacterial communities were more responsive to fresh plant clippings. Consequently, we suggest that future research consider fresh plant clippings as a raw material for cropland soil amendment, which is important for enhancing soil quality and regulating soil carbon and nitrogen cycling functions.