Fig. 1

Flow diagram of the key experimental settings in the current study. Field sampling: peanut plants were grown in soils collected from fields representing different years of continuous monoculture cropping. Specifically, P1, P5, and P10 represent soils under continuous monoculture cropping of peanut for 1, 5, and 10 years, respectively. Soils were collected in April 2019 for greenhouse pot experiment. Greenhouse experiment: on 10 May 2019, each experimental pot was filled with 3 kg of the soil, and three surface-disinfect peanut seeds were sown in it. On 2 June 2019, four biological replicate pots of each treatment were randomly selected and were then uniformly labeled with ¹³CO2 in a temperature-controlled glass chamber. Four other biological replicate pots were cultivated in open air as control. On 2 July 2019, another four biological replicate pots of each treatment were randomly selected and were then uniformly labeled with ¹³CO2. Similarly, four other biological replicate pots were also cultivated in open air as control. Sampling: on 23 June 2019 (W6: about 6 weeks after seeds were sown)/23 July 2019 (W10: about 10 weeks after seeds were sown), we stopped the labeling. Then, the plant organs, soils, rhizodeposits, and rhizosphere soils were collected. Samples were then processed for subsequent analyses