| dc.description.abstract | The Arid and semi-arid regions (ASALs) are characterized by declining soil fertility, high
temperatures, low and erratic rainfall resulting in low crop production and food insecurity; a
scenario worsened by abandonment of traditional crops. Considering that these regions are most
vulnerable to climate change, there is need for re-introduction of traditional crops like finger
millet, which are drought resistant and capable of high yield production with low inputs. It is
against this scenario that the current study, involving a survey and field experiments, was
conducted in Lower Eastern Kenya. The survey was carried out in Machakos and Kitui counties
to assess status, constraints and opportunities in finger millet production, farmer’s perception of
climate change, coping and adaptation mechanisms. Field experiments were conducted to
evaluate effects of four finger millet varieties (Gulu e, P224, Nanjala brown, KNE-479), two
tillage practices (oxen plough-OP, ridges and furrows-RF) and fertilizers (Manure, Triple Super
Phosphate (TSP) + Calcium ammonium nitrate (CAN) and control) on soil moisture, nutrients;
Nitrogen (N), Phosphorous (P), Potassium (K), Organic Carbon (OC) and yields. A split-split
plot design with tillage as the main plot, finger millet varieties as split plot and fertilizers as splitsplit plots was employed. The Agricultural Production Systems Simulator Model (APSIM) was
used to determine effect of different climate change scenarios; current temperature (T0), current
rainfall (R0), R1 (R0 -10% rainfall), R2 (R0 +10% rainfall), T1 (T0 +2OC), T2 (T0+3OC) and
combinations of T1+ R0 and T2+ R0 on finger millet yields. Finger millet production was reported
by 93% of respondents in Machakos and 92% in Kitui to be on the decline due to; lack of seeds
(47%, 50%), pests and diseases (33%, 20.8%), overdependence on maize (97.8%, 95.9%) and
climate change (20%, 29.2%) in Machakos and Kitui, respectively. Constraints in production
were blast disease (43.8%, 37.2%), bird predation (39.9%, 39.6%), weed infestation (57.1%,
55.8%), climate change (30%, 39.2%) and lack of seeds (63%, 77.4%) in Machakos and Kitui,
correspondingly. Opportunities for finger millet production lay in its capacity to withstand
climate change (76%, 76%), high nutrient content (74%, 85%), market availability (63%, 74%)
and availability of extension services (87%, 88%) in Machakos and Kitui. Aspects of climate
change experienced were; temperatures rise (88%, 100%), prolonged drought (70%, 62%) and
irregular rainfall (68.3%, 81%) for Machakos and Kitui, respectively. Farmers had taken up early
planting (88.6%, 93.7%), introduced new tillage practices (45%, 54%), irrigation (13%, 9%) and
organic inputs (89%, 92%) as adaptation strategies in Machakos and Kitui, in that order. In Kitui,
plots under ridges and furrows had higher (10.41%) soil moisture than oxen plough (9.64%)
while in Machakos oxen plough (9.3%) had higher soil moisture than ridges and furrows (9.07%)
plots in manure treatments followed by TSP+CAN and control. The effect of fertilizers on soil
nutrients was similar across all tillage practices with highest mineral nitrogen and phosphorous
recorded in TSP+CAN and highest organic carbon and potassium recorded in manure treated
plots. In Kitui ridges and furrows plots had higher (1.66 t/ha) yields than oxen plough (1.58t/ha)
while in Machakos oxen plough (1.65t/ha) had higher yields than ridges and furrows (0.77t/ha)
in TSP+CAN treatments, followed by manure and control. Plots with Gulu e had the highest
yields followed by P224, Nanjala brown and KNE-479 across all tillage practices and fertilizer
inputs. Kitui had higher yields (1.85 t/ha, 2.14 t/ha) than Machakos (1.21 t/ha, 1.80 t/ha) for
observed and simulated values, respectively. Effect of fertilizer was similar across all treatments
with TSP+CAN having highest yields (1.64 t/ha, 2.3 t/ha) followed by manure (1.52 t/ha, 1.85
t/ha) and control (1.41 t/ha, 1.75 t/ha) for observed and simulated yields, in that order. Based on
simulations ridges and furrows performed better (1.84 t/ha, 2.22 t/ha) than oxen plough (1.76
t/ha, 2.07 t/ha) in Machakos and Kitui, respectively. However there was a difference in field
experiments for Machakos with oxen plough (1.65 t/ha) having higher yields than ridges and
furrows (0.77 t/ha). Finger millet yields were well simulated by the model in Machakos oxen
plough as evidenced by high coefficient of determination (0.5) and correlation coefficient (0.7)
showing a close relationship between observed and simulated yields. Plots under ridge and
furrows in Machakos were poorly simulated resulting in low correlation coefficient (0.29) as
well as large range ratio (74%). Finger millet yields in Kitui were well simulated with low root
mean square errors (1.04, 0.94) in ridges and furrows and oxen plough, respectively. Apart from
R2 (R0 +10% rainfall), all climate change scenarios i.e. reduced rainfall, increased temperatures
and their combinations (reduced rainfall + increased temperatures) reduced finger millet yields,
with increase in temperature having a higher negative effect than decrease in rainfall.
The survey corroborated that production of finger millet was declining in lower Eastern Kenya, a
situation exacerbated by increasing effects of climate change (low rainfall and declining soil
fertility). However, combined use of reduced tillage (oxen plough in Machakos and ridges and
furrows in Kitui), Gulu e variety and fertilizer (TSP+CAN) would lead to improved finger millet
yields in the region. APSIM results confirmed that despite finger millet being well adapted to the
ASALs, climate change was expected to have a negative effect on yields. It is therefore
imperative that scientists bring special attention to development of coping, adaptation and
mitigation mechanisms that do not rely solely on the crop but also focus on enhancing soil
fertility and soil water conservation | en_US |
