Abstract:
Soil macronutrient and micronutrient availability is particularly critical in semi-arid agro-
ecological zones that are characterized by poor soil fertility and low rainfall regimes. An experiment
was
initiated
in
Siakago,
Embu
County
to
investigate
the
effects
of
tied-ridges,
conventional
tillage
and
input
applications
on
soil
nutrient
fertility
using
a
randomized
complete
block
design
with
a
split-split
plot
arrangement
for
4
seasons
(2018–2021).
The
treatments
comprised
of
two
main
plot
tillage
systems,
three
cropping
systems
allocated
to
the
sub-plots
and
four
soil
input
management
treatments
assigned
to
sub-sub
plots.
ANOVA
was
used
to
test
the
effects
of
different
treatments
including
tillage,
crop
system
and
soil
fertility
management
using
Genstat
software.
The
data
was
also
subjected
to
Principal
Component
Analysis
procedures
using
R
("FactoMineR"
and
"factoextra") to examine the inter-relationship patterns between different soil fertility parameters
and
to
reduce
the
data
into
independent
soil
fertility
components.
There
were
significant
main
effects
due
to
crop
system
(Soil
Mn),
tillage
and
crop
system
interaction
(SOC
and
TSN)
and
soil
fertility management (TOC, TSN, Ca, Zn). Soil inputs significantly influenced soil carbon
concentrations (p =
0.002), with the lowest values observed in the control (0.2 %), followed by
sole fertilizer (0.35 %), manure +
fertilizer (0.41 %) and the fully decomposed manure treatment
(0.61 %). The soil-extracted manganese values recorded significant effects due to crop system,
while soil-extracted Zn values were significant due to soil fertility management. Multivariate
analysis results revealed the structure of soil nutrient distribution. Tied ridging can improve soil
micronutrient availability through reduced soil erosion, conservation of soil organic matter,
which can improve soil micronutrient availability. Soil conservation practices such as tied-ridging
integrated with organic input applications can enhance multiple nutrient availability for
improved crop performance and human nutrition in dryland farming systems where farmers lack
soil moisture, technologies and resources to enhance crop nutrient availability.
