Promoted soil C and aggregate stability in soil applied with
bio-fertilizer in North China Plain
Abstract
Application of bio-fertilizer can improve soil fertility and retard the
soil degradation. Based on a field experiment, the changes of soil
organic C, aggregate stability and organic C in aggregate fractions were
analyzed to investigate the effects of bio-fertilizer (BF) combined with
a reduced chemical fertilizer. Bio-fertilizer was applied at rates of 0
(BF0), 30 (BF30), 50 (BF50) and 70 (BF70) t ha-1 and soil samples were
collected from 0-20 cm layer in 2018 and 2019. Soil cores were separated
into three aggregate sizes (>0.25 mm, 0.053-0.25 mm and
<0.053 mm) using the wet sieving method. The highest soil
organic C and water soluble organic C were measured in BF70, while BF50
had the highest concentrations of microbial biomass carbon, extractable
organic C and KMnO4-C. Significant increases of mean weight diameter
(3.16 mm in 2018 and 3.39 mm in 2019) in BF50 compared with BF0 showing
the improved soil structural stability after bio-fertilizer application.
Increased with increasing bio-fertilizer application rates then remained
relative stable, organic C in aggregate fractions was highest in BF50.
More organic C was accumulated in aggregates of 0.053-0.25 mm in
bio-fertilizer amended soils, suggested that C was mainly occluded in
micro-aggregate and benefit for protection of C from microbial
decomposition. Our results indicated that bio-fertilizer combined with
chemical fertilizer was effective in increasing organic C and its labile
fractions, which promoted soil structural stability in turn, thereby
improving soil quality.