Fig 1.
Accumulative C mineralizations after the incubation in the acidic (a) and alkaline soils (b); soil organic carbon content before and after the incubation in acidic (c) and alkaline soils (d) (Values are the mean (n = 3). Different lowercase letters within a column indicate significant differences at the 5% level. Significant difference was performed between that in different types of soils before and after the incubation; JX: Jiangxi; JL: Jilin; YN: Yunnan; CQ: Chongqing; GS: Gansu; IM: Inner Mongolia; TJ: Tianjin; HN: Henan).
Fig 2.
Relationship between initial soil organic carbon and soil organic carbon after the incubation (a) and initial soil nitrogen and accumulative C mineralization after the incubation (c) in the acidic soils, as well as the association between initial CEC content and soil organic carbon after the incubation (b), initial soil clay content and accumulative C mineralization after the incubation (d) in the alkaline soils (Data involved 3 replicates for each indicator; CEC: cation exchange capacity).
Fig 3.
Dominant carbon-relating bacterial phylum after wheat straw addition in the acidic (a) and alkaline soils (b) and their explains for soil organic carbon (c) /accumulative C mineralization (e) in the acidic soils and for soil organic carbon (d) and accumulative C mineralization (f) in the alkaline soils based on the RDA analysis (Values are the mean (n = 3). Different lowercase letters within a column indicate significant differences at the 5% level. Significant difference was performed between that in different types of soils; JX: Jiangxi; JL: Jilin; YN: Yunnan; CQ: Chongqing; GS: Gansu; IM: Inner Mongolia; TJ: Tianjin; HN: Henan).
Fig 4.
Soil total nitrogen (a) and mineralized nitrogen content (c) in acidic soils and soil total nitrogen (b) and mineralized nitrogen content (d) in the alkaline soils after wheat straw addition (Values are the mean (n = 3). Different lowercase letters within a column indicate significant differences at the 5% level. Significant difference was performed between that in different types of soils; JX: Jiangxi; JL: Jilin; YN: Yunnan; CQ: Chongqing; GS: Gansu; IM: Inner Mongolia; TJ: Tianjin; HN: Henan).
Fig 5.
Relationships between initial soil organic carbon and soil total nitrogen after the incubation (a), initial AK content and mineralized nitrogen after the incubation (c) in the acidic soil, as well as the associations between initial clay content and soil total nitrogen after the incubation (b), initial CEC content and mineralized nitrogen after the incubation (d) in the alkaline soil (Data involved 3 replicates for each indicator; AK: available potassium; CEC: cation exchange capacity).
Fig 6.
Dominant nitrogen-relating bacterial genera after wheat straw addition in the acidic (a) and alkaline soils (b) and their explains for soil total nitrogen (c) and mineralized nitrogen (e) in the acidic soils and for soil total nitrogen (d) and mineralized nitrogen (f) in the alkaline soils based on the RDA analysis (Values are the mean (n = 3). Different lowercase letters within a column indicate significant differences at the 5% level. Significant difference was performed between that in different types of soils; JX: Jiangxi; JL: Jilin; YN: Yunnan; CQ: Chongqing; GS: Gansu; IM: Inner Mongolia; TJ: Tianjin; HN: Henan).