The
rhizosphere
dynamics
of
nutrients
is
very
complex
and
depends
on
many
factors,
such
as
soil
temperature,
pH,
water
con-
tent, and soil and plant characteristics. Also, the temporal and
spatial variations of these factors are highly dynamic. Many fac-
tors cannot easily be accurately quantified. The objective of this
work
thus
was
to
evaluate
the
nutrient
dynamics
and
root
uptake
of nutrients by the sugarcane crop grown under drip irrigation with
the state-of-the-art modelling tools and to examine whether ferti-
gation scheduling could be optimized. An attempt has been made
to
better
understand
the
reactive
transport
of
urea
in
the
root
zone
of the sugarcane crop and to quantify the flux of urea, ammonium,
and nitrate into crop roots, ammonia volatilization flux, and deep
drainage.
This
quantification
helped
in
designing
a
satisfactory
fer-
tigation schedule that produced a reduction in the use of urea by
30%, while at the same time providing enough N for its assimilation
at all stages of crop growth. Various parameters used in the model
were
taken
from
the
literature
and
a
few
of
them
were
taken
from
the accompanying field study.
Our results indicate that HYDRUS can be very helpful in improv-
ing
the
fertigation
schedules
using
the
growth
curve
nutrition
approach.
However,
a
field-scale
validation
will
be
required
before
this approach can be recommended to farmers. We are planning to
carry out such field-scale study and will report our results in this
journal
once
the
study
is
concluded.