3.2 Water stable aggregate stability
Among the treatments, the macro-aggregates that size >0.25
mm accounted for 35.4% to 55.9% of the soil weight in 2018 and 37.4%
to 60.6% in 2019 (Table 1). Bio-fertilizer significantly the quantities
of macro-aggregate, increases in BF30, BF50 and BF70 were 22.9%, 57.9%
and 13.3% compared with BF0 in 2018, but there was no significant
difference between BF30 and BF70; BF100 had no significant effect on the
content of macro-aggregate in 2018. The micro-aggregate (0.25-2 mm
aggregate) were significantly decreased by bio-fertilizer application.
The lowest quantity of micro-aggregate was observed in BF50, which was
84.5% of BF0 in 2018. The contents of <0.053 mm aggregate
showed a similar tendency to micro-aggregate in 2018, namely, the
<0.053 mm aggregate was significantly decreased by
bio-fertilizer except for BF100. The lowest value was recorded in BF50,
and no significant difference was observed between BF30 and BF70. In
2019,the distribution of soil aggregate showed a similar trend with
that in 2018. Significant increase of macro-aggregate and decrease of
<0.053 mm aggregate were recorded, and the change of aggregate
quantity in BF50 was the largest. BF30 significantly increased the
micro-aggregate content and BF50 significantly decreased it, while BF70
had no significant effect on the micro-aggregate compared with BF0.
The values of MWD ranged from 2.16 to 3.16 mm in 2018 and from 2.24 to
3.39 mm in 2019, respectively. Compared with BF0, BF50 significantly
increased MWD by 46.1% in 2018 and by 51.2% in 2019 while BF30 and
BF70 had no effect on MWD compared with BF0 in both years. In addition,
the MWD was not affected by BF100 compared with that of BF0 in both
years.