Page 114 - EER-2-2

Explora: Environment
and Resource Climate suitability of AWD practice

Table 3. Predicted soil percolation rates
Soil type Variation of soil percolation with texture
(mm/day)
LB UB BS
Clay 0.406556 2.032782 1.219669
Sandy clay 0.150027 0.450082 0.300055
Loam sandy 0.31963 1.917782 1.278522
Sandy clay loam 0.79697 3.984849 2.390909
Loam 0.002357 0.007072 0.004715
Sandy loam 0.039779 0.198895 0.119337
Total percolation 1.71532 8.591462 5.313206
Note: LB, UB, and BS represent lower bounds, upper bounds, and basic
settings, respectively.

textural classes and then summating ratios area for each
depth and texture class to the total area.

3.6. Climatic suitability of AWD irrigation practice
Generally, all the dekads during the drought period were
appropriate for AWD irrigation practice owing to a water
deficit from limited rainfall (0 – 6 mm/day) and substantial
evapotranspiration (3.5 – 8.6 mm/day) within the region.
AWD suitability for the rainy season (July – October)
with fixed potential percolation rates; Pot is shown in
pc
Figures 7 and 8. The AWD climatic suitability, where
Pot is based on the soil texture classes (Table S4), can be
pc
observed in Figure 9.
Our findings indicate that all fixed Pot values during
pc
December, January, and February (dekads 1 – 6) are suitable
for AWD practice where precipitation values <10 mm/day. Figure 7. Climatic suitability of AWD with Pot (1 mm/day) between
The temporal variation of water balance components in April and June (rainy season) pc
the paddy fields – excess and deficit – is due to the slow Abbreviation: AWD: Alternate wetting and drying.
onset precipitation pattern in March and maximum
precipitation in April, May, and June, which decreases in
July (dekads 18 – 21). Similarly, precipitation increases are which resulted in excess water balance. The different
evident in September, October, and early November, with climatic conditions are summarized in Table S5. There was
variation in AWD suitability with months across the dry
a gradual reduction until early December. AWD climate season, with high suitability observed from late November
suitability aligns with the precipitation pattern of high
Pot fixed values between 4 and 5 mm/day. However, the to January and suitability in November, February, and
pc
Pot (≥10 mm/day) makes the whole region suitable for July. The high suitability is attributed to low precipitation
pc
irrigatable paddy farming with AWD practice. (<6 mm/day), and suitability in February and July was
attributed to moderate rainfall (6 – 10 mm/day) with all
In addition, 70% of the area was suitable, lying percolation rates.
in several districts, including Butaleja, Busia, Mbale,
Bugiri, Tororo Bukedia, Mayuge, Namayingo, Manafwa, 4. Discussion
Namutumba, Bugweri, Kaliro, and Palisa. Dekads (23
– 31) are from the rainy season, corresponding between 4.1. AWD irrigation suitability: Rice expansion,
March and early November, although the rainfall intensity water management, food security and national
irrigation policies in Uganda
may differ. Furthermore, most of the dekads between April
and June are under 1 mm/day percolation and were found The region and entire country have the potential to increase
unsuitable for AWD due to low Pot and high rainfall, paddy rice cultivation through the implementation of
pc

Volume 2 Issue 2 (2025) 10 doi: 10.36922/EER025040005