Influences of surface runoff detachment and sediment transport on
insoluble nitrogen and phosphorus loss under two planting methods with
Prunella vulgaris
Abstract
A lack of research on sediment displacement has led to a corresponding
lack of understanding regarding the movement of insoluble N and P. In
this study, we used field simulated rainfall experiments and discovered
the following: first, the regulatory effects of the two planting methods
on the runoff detachment rate was greater than that on the runoff
sediment transport rate, and the influence of rainfall intensity was
greater than that of slope. Outside the threshold, the regulatory
effects of the two planting methods on runoff detachment and sediment
transport on different slope gradients were diametrically opposed.
Second, N loss was 10 times higher than P loss during rainfall events. N
and P losses were highest on bare slopes, and lowest on slopes on which
the Prunella vulgaris combined with earthworms planting method
was used. N and P loss during rainfall events increased as rainfall
intensity increased, and decreased as slope increased. The rate of
change increased under high rainfall intensity or slope gradient. Third,
regulation of insoluble N loss under the P. vulgaris-only
planting method was achieved through regulation of runoff detachment and
sediment transport, with contribution rates of 23.89% and 31.98%,
respectively. Regulation of insoluble N loss under the P.vulgaris
combined with earthworms planting method was achieved by regulating
runoff detachment, with a contribution rate of 66.92%. Regulation of
insoluble P loss under the two planting methods was achieved by
regulating both the runoff detachment and sediment transport rates.