The response of the abandoned fallow soil microbiome to wheat cultivation and the use of biofertilizer

Introduction The re-involvement of fallow soils in agriculture is a pressing issue in ensuring food safety. We used the soil microbiome as an indicator of the state of fallow land in the taiga climatic zone compared to arable land and native soil, and its response to crop cultivation and the use of biofertilizer. For this purpose, a laboratory vegetation experiment was conducted on growing wheat using the biofertilizer “Extrasol” on fallow, arable (Plaggic Retisols), and native forest (Retisol) soils. Methods The soil performance was evaluated through the measurement of chemical parameters and crop yield. The changes in the microbiome were assessed using amplicon sequencing of 16S rRNA gene libraries. Results In terms of the main chemical parameters and taxonomic profile of the microbiome, the fallow soil resembled arable land. Both agrogenic soils maintained a crop yield higher than the benchmark forest soil. The introduction of the biofertilizer led to more pronounced changes in the soil microbiomes of the fallow and field soils compared to the forest. However, the composition of the fallow soil microbiome was resilient to wheat cultivation, similar to the undisturbed Retisol. Namely, wheat cultivation produced less significant changes to the microbiome of forest and fallow soils than to the microbiome of arable land. Moreover, the application of biofertilizer did not have a substantial impact on the yield of wheat on fallow and forest soils, unlike on field soil. Conclusions The results showed that the fallow soil exhibited properties typical of both arable land and undisturbed Retisol in different aspects. Over time, the fallow microbiome retains the signature profile and the response to biofertilizer of anthropogenic plaggic soil, but becomes more resilient to wheat cultivation, as does native soil. This suggests that the 30-year fallow soil of the taiga has economic potential for re-involvement in agricultural practice.