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Baseline Report Yala and Nzoia River Basins


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Middle Yala


The Middle Yala block is located in Vihiga and Kakamega Districts. The block contains twenty-eight sub-locations as well as the Kaimosi forest (Figure 4.1). The landscape consists of mountainous highlands in the northern part of the block, with numerous small streams and clusters of wetlands. In the south-eastern part of the block, the Kaimosi forest is located where logging is taking place and the forest reserve is being used for cultivation. Throughout the block there are remnant forests which are used for cultural ceremonies. These forests are preserved and not accessible for the communities for wood and firewood supply. The conversion to agriculture took place in the 1930s. Today the majority of the farms are over utilized and few farms are practicing the traditional rotations with periodic fallows.





Figure 4.1. Administrative map of the middle Yala Block.
The Gold River divides the block into the southern and northern parts. The southern part of the block is characterized by better farming practices and a greater presence of trees in the landscape. The major cash crop is tea. In this area all farms have hedges along the farm boundaries and few animals are seen to graze freely. The northern part of the block is characterized by poor farming practices with cultivation of steep slopes without conservation measures. In this area, few trees are seen in the landscape and few land owners have demarcated their farms. The area around cluster 16 is part of the Kakamega forest reserve, however, all trees have been cut and the area is bare, with scattered patches of grasses present. The tea farms in this area are not well managed, contrary to the southern part of the block where the tea is well established and managed.
The map above shows the sampling scheme in Middle block of Yala. The blue dots are the sampling points for the biophysical survey – e.g. the points fall in 16 clusters. The socio economic team uses the 16 clusters as their entry point and identifies 10 households per cluster.
    1. Bio physical baseline data summary

      1. Topography


The area of Middle Yala is made up of mountainous highlands with numerous small streams and clusters of wetlands. Average slope ranges from 1 to 11%; however, slopes of more than 15% are not uncommon and steep slopes are found throughout the block (Table 4.1). The table below lists average slope, slope range in point with slopes larger than 10%.
Table 4.1. Average slope, slope range and incidence of steep slopes

Cluster

Average slope

(%)

Slope range

(%)

No. values > 10%

1

11.2

2.62 – 44.62

3

2

12.3

5.67 – 31.73

5

3

13.9

5.23 – 36.24

6

4

15.9

6.1 – 32.14

7

5

7.4

2.18 – 19.51

2

6

12.0

3.05 – 39.07

3

7

17.3

5.67 – 37.46

8

8

12.6

4.36 – 31.73

6

9

6.1

1.75 – 19.08

1

10

9.8

3.49 – 19.51

3

11

8.3

2.18 – 21.64

2

12

13.0

5.67 – 27.56

6

13

22.0

3.93 – 40.27

6

14

12.7

4.8 – 25.88

6

15

16.6

8.28 – 39.87

7

16

14.3

5.67 – 30.07

8




Figure 4.2. Topographic map of the Middle Yala block showing strems and rivers

      1. Soil texture and soil depth restriction


The soils found in this block are predominantly loamy to clayey in texture. The most common soil type is clay (46%) and silty clay soils (32%) as listed in Table 4.2.
Table 4.2. Soil texture.

Silty clay

Clay

Clay loam

Silty clay loam

Silty loam

Loam

32%

46%

15%

1%

6%

<1%

Soils in the block are moderately deep to deep. Soil depth restriction was not important in this block. Restrictions were apparent in less than 10% of the sites sampled and found to be present mainly around clusters 4, 8, 9 and 13.




      1. Vegetation and land use

Farming is the major land-use and drives land cover in the block (Table 4.3; Figure 4.3). Agriculture is dominated by maize, beans, banana, and sweet potatoes. The southern part of the block has a significant areas under tea, which is sold to the local factory in the area.

Table 4.3. Land cover classification (N=158) not N=160?

Vegetation strata

No. points

Percentage

Farm land

121

77%

Forage land

4

3%

Perennial grassland

15

9%

Shrub land

3

2%

Plantation / forest

7

4%

Other

8

5%

The second most common vegetation type was grasslands. Some remnant forests are also seen around cluster 7, 10, and 11 which are all located in the centre of the block. The woody vegetation found in these forests has not been assessed since outsiders are not allowed inside these areas, for cultural reasons. The Kaimosi forest, which is located in the proximity of cluster 16 is the only forest left in the area. A classification of the primary current land use showed the following:




Food / beverage: 69%

Forage: 28%

Timber / fuel wood: 19%

Other: 8%



Figure 4.3. Land-use map of the Middle Yala Block (why a map if there is not variation within the block area???
Generally the woody vegetation is broadleaf and evergreen (Table 4.4). An assessment of the trees in the landscape shows that of the 160 sampled plots only 53 (33%) had trees in the vicinity. Clusters for which more than half of the sampled plots had trees in the vicinity were 5, 7, 9, 11, 13 and 14.
Table 4.4. Woody vegetation type (% of plots with vegetation types present)

Broadleaf

Needle leaf

Allophytic

Evergreen

Deciduous

68.1

0.0

3.1

53.1

3.1

The following species were seen in the landscape: Eucalyptus spp., Pinus patula, Bischovia spp., Croton macrostachyus, Cupressus lusitanica and Bridelia micranthus. Eucalyptus is mainly planted for timber and construction whereas the other species are planted for shade, boundary demarcation and fuel wood. Fruit trees in the area are mainly Mango (Mangifera indica), Avocado (Persia Americana) and Paw paw (Carica papaya). There appears to be a culture of planting trees in the southern part of the block, which the project should build upon. However, the majority of the farmers are planting Eucalyptus seedlings and there is therefore a need for diversification of the woody vegetation. This can be achieved through training and nursery establishment in the targeted microcatchments.


The shrubby vegetation is generally less than 1m in height. Of the sampled plots, 67% have vegetation in the range of 0.03 to 0.8m, whereas 11% of the plots do not have any shrubby vegetation present. Hence, 23% of the plots have shrubby vegetation larger than 0.8m.
In this area the majority of the farms are privately owned (94%). No farms are located on communal land, whereas nine farms are situated on government land. Land-use appears stable as owners of 46 % of the surveyed plots report that has not changed since 1990; 40% of the farms did not know whether land use has changed or not. Only 14% of the farmers reported that land use on their farms has changed since 1990.

      1. Soil erosion and conservation measures


Soil erosion is visible overfor about half of the survey area: 41% of the sampled plots showed visible signs of sheet erosion and 5% showed active rill erosion (Table 4.5). One farm experienced gully erosion.
Sheet erosion is widely observed in clusters 1, 2, 7, 10 and 13; however, only 20 farms have established soil and water conservation measures: 11 vegetative and 9 structural. Of the 63 plots experiencing sheet erosion, only 19 have soil and water conservation structures in place: 9 vegetative and 9 structural. Of the plots experiencing rill erosion (7) only one farmer has established measures to control erosion and runoff. The high presence of soil erosion and the low numbers of soil and water conservation measures should be one of the key-entry points in this block.
Table 4.5. Percent of plots showing different types of

erosion in each cluster.

Cluster

None

Sheet

Rill

Gulley

1

40

60

0

0

2

30

70

0

0

3

80

10

10

0

4

60

40

0

0

5

40

10

50

0

6

60

40

0

0

7

20

60

0

0

8

80

20

0

0

9

90

10

0

0

10

10

80

10

0

11

70

20

0

0

12

60

20

0

0

13

30

70

0

0

14

60

40

0

0

15

60

40

0

0

16

50

40

0

10


Table 4.6. Summary of baseline parameters

Cluster

Texture

Slope (%)

Woody vegetation cover*

Soil depth restriction

(%)

Soil erosion (%)

Household size

1

Silty clay

6.5

Low

0

60

6.9

2

Clay

7.1

Low

0

70

6.2

3

Silty clay

8.1

Low

0

10

8

4

Silty clay

9.2

Low

0

40

5.2

5

Clay

4.3

Low

0

10

5.3

6

Clay to Clay Loam

7.0

Low

0

40

6.9

7

Clay

10.0

Low

0

60

7.1

8

Silty clay

7.3

Low

0

20

6.7

9

Clay

3.5

Low

0

10

8

10

Clay

5.6

Low

0

80

6.1

11

Silty clay

4.8

Low

0

20

6.8

12

Silty clay

7.5

Low

0

20

6.6

13

Silty clay

12.9

Moderate

0

70

6

14

Clay

7.3

Low

0

40

7.4

15

Clay loam

9.6

Low

0

40

5.8

16

Silty clay

8.2

Low

0

40

5.3

    • * Low: <15%; Moderate: 15 to 65%, High: > 65%

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