Analyses accounting for Collembola, Acari and microbial biomass at 8 and 14 months
Mass loss . PIA did not directly affect mass loss after 8 and 14 months. PIB increased mass loss after 8 months, but decreased mass loss after 14 months (main effects in Table 2). The observed positive effects of PIB after 8 months were replaceable by shorter vegetation period, delayed budburst and decreasing soil moisture (Supplementary Table S2). Moreover, Acari abundance (which was increased by PIB after 8 months, Fig. 2) directly increased mass loss after 8 and 14 months (main effects in Table 2). There was a negative interaction between PIB and Acari abundance on mass loss after 8 months, in which PIB was replaceable by delayed budburst (Table 2; Supplementary Table S2). There was a negative interaction between PIB and Collembola abundance, in which PIB was replaceable by longer vegetation period. In addition, there was a positive interaction between PIB and microbial biomass on mass loss after 14 months, in which PIB was replaceable by increasing soil moisture (Table 2; Supplementary Table S2).
Carbon loss . PIA directly increased C loss after 8 months, but PIB directly decreased C loss after 8 months (main effects in Table 2). The observed positive effect of PIA on C loss was replaceable by decreasing phytophagy, and the observed negative effects of PIB was replaceable by delayed budburst (Table 2; Supplementary Table S2). Moreover, Collembola abundance (which was decreased by PIB, Fig. 2) directly increased C loss after 14 months. There was a negative interaction between PIA and Collembola abundance after 14 months, in which PIA was replaceable by both increasing phytophagy and decreasing phenolics (Supplementary Table S2). Acari abundance (which was decreased by PIB after 8 months) directly decreased C loss after 8 and 14 months. There was a positive interaction between PIB and Acari abundance, in which PIB was replaceable by increasing budburst or decreasing soil pH (Table 2; Supplementary Table S2).
Nitrogen loss . Only PIB directly decreased N loss after 8 months (main effects in Table 2). This negative effect of PIB on N loss was replaceable by longer vegetation period (Supplementary Table S2). Moreover, microbial biomass (which was decreased by PIB after 8 months; Fig. 2) directly decreased N loss after 8 months. No interaction effects were found between either PIA or PIB and soil biota (Table 2).