Abstract:

Seasonal water fluctuations both in quality and quantity negatively affect livestock production
and subsequently reduce livestock-water productivity (LWP) in rainfed pastoral production
systems. The major contributing factors to this phenomenon are poor upper catchment and water
resource management which result in contamination, sedimentation/silting, eutrophication due to
nutrient enrichment, and excessive discharge of runoff into water reserviors. This study
investigated the effect of upper catchment management (un-vegetated and vegetated catchment,
surface water reservoirs, and their impacts on livestock water productivity (LWP) in rainfed
pastoral production systems of Uganda. Water quality and quantity in sixteen reserviors were
monitored on a monthly basis in Nakasongola and Kiruhura districts for a period of one year
covering two dry and two rain seasons.
Sedimentation studies showed that about 250 m3 of silt from un-vegetated catchment entered a
reservoir, reducing the storage capacity by 18 % in a period of one year. The silt that entered the
3 of water. Un-vegetated upper
catchments therefore had detrimental impacts on water reservoirs.
Total coliform (TC), feacal coliform (FC), ammonium-nitrogen (NH4-N) and total phosphorus
significantly higher (p 0.001) in reservoirs receiving water from open gullies
while reservoirs with un-vegetated catchments had significantly higher concentrations (p
0.001) of nitrite-nitrogen (NO2-N), nitrate-nitrogen (NO3-N), total nitrogen (TN), total dissolved
solids (TDS), total suspended solids (TSS) and turbidity.
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un-vegetated and vegetated gullies); and water cover plants on water quality and quantity in
(TP) levels were
reservoir was responsible for degradedation of about 47 m
TC and FC concentrations were significantly high (p 0.001 and p 0.05, respectively) in the
dry season, with highest concentrations recorded in reservoirs receiving water from open gullies.
NO2-N and NO3-N were significantly high (p 0.001) in the rain season. There were significant
interactions between season and treatment effects on the concentration of NO2-N, NO3-N, TSS
and turbidity (p 0.001). Reservoirs receiving water from un-vegetated catchments had high
NO2-N, TSS and turbidity in the rain season while those with vegetated gullies had high NO3-N
in the rain season.
plant species covering water reserviors in the study area. The results showed that reservoirs
covered by Lenina sp had significantly lower (p 0.001) TC, FC, NO2-N, NO3-N, TN, TSS, and
turbidity than reservoirs covered by other cover plants in the study, indicating its potential
application in water quality improvement for livestock production systems. Nymphaea spp had
significantly higher (p 0.001) concentrations of nitrite, total nitrogen, TDS, TSS and turbidity
while Azolla spp had significantly high (p 0.001) TC concentrations compared to other water
cover plants. This indicated that Nymphaea spp is an undesirable water cover plants species and
hence should be eliminated.
Improvement of upper catchment and water resource management greatly increased livestock
water productivity (LWP) by 353%, 518% and 280% in the settled, semi-settled and non-settled
pastoral communities. In addition, un-vegetated catchments and gullies were shown to have
detrimental impacts on the reservoir water quality. Therefore, a great potential exists for
improving livestock water productivity in the pastoral communities of Uganda through use of
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Four plant species (JPistia, Azolla, Lenina and Nymphaea spp.) were identified as the common
vegetated catchments and gullies. Although the amount of rainfall in the pastoral communities of
Uganda greatly contributes to the quantity of water available in reservoirs to sustain livestock
and human needs through dry seasons, other factors such as evaporation, sedimentation and
degradation of water quality may critically reduce the availability of water in pastoral
temporal solution to problems of livestock water scarcity in dry seasons within the rangeland
pastoral communities of Uganda due to high evaporation and reservoir sedimentation rates
experienced in these communities.
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resources without proper upper catchment and water management practices would only provide a
communities. Therefore, increasing water supply through creation of more surface water