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al. 2000; Nyssen 2001). Although tillage erosion became better documented recently
(Govers et al. 1994, 1996; Guiresse and Revel 1995), there is still inadequate infor-
mation on this process particularly in tropical mountainous areas (Nyssen 2001).
In view of these observations, a study was conducted in the Uluguru Mountains,
Tanzania, on tillage erosion to investigate the effects of slope gradient, tillage depth,
and surface ground conditions on tillage erosion due to manual hoeing (Kimaro et
al. 2010). In this study, soil flux by manual tillage was measured by means of an on-
farm experiment in the farmers' fields during the dry season of the years 2000 and
2001. Twenty-four plots (1.2 m wide and 8 m long) at different slopes (31%, 47%,
51%, 54%, 58%, 61%, 65%, and 67%) were demarcated before seasonal land prepa-
ration. Two sets of treatment at each slope site were done: deep tillage and shallow
tillage under conditions of bare soil surface and soil surface with residues to both
treatments. In the field, local farmers were requested to till the plots in a traditional
way. The plots were tilled starting from the bottom of the field and moving up the
slope. Farmers used a hoe with a steel blade of about 18.5 cm long and 16.5 cm wide
and a wooden handle about 100 cm long. To measure soil translocation, the Gerlach
trough method (Gerlach 1967) was used. This method provided quick assessment of
soil movement in the field by manual tillage (Poesen et al. 2000).
The results from this study (Tables 12.2 and 12.3) showed that rates of soil flux
due to tillage erosion generally increased with increasing slope gradient (Kimaro
TABLE 12.2
Effect of Slope Gradient on Soil Flux Due to Tillage by Manual
Cultivation in Uluguru Mountains, Tanzania
Mean
Soil Flux
Standard
Deviation
Minimum
Maximum
Slope (%)
(kg/m/tillage pass)
N
31
16 a
6
7
23
12
47
31 b
16
8
67
12
51
53 c
27
21
81
12
54
59 dc
30
21
92
12
58
59 c
21
35
95
12
61
67 de
24
34
101
12
65
75 e
23
40
100
12
67
70 e
27
44
111
12
Source: Kimaro, D.N., J. Poesen, J.A. Deckers, and H.B. Msita. 2010. Effects of agroeco-
logical conditions and slope gradient on tillage erosion in the northern slopes of
the Uluguru Mountains, Tanzania. Chapter 9 in Earl T. Nardali (Ed.). No-Till
Farming: Effects on Soil, Pros and Cons and Potential . Agriculture Issues and
Policies Series. ISBN: 978-1-60741-402-5. Nova Science Publishers Inc., New
York. pp. 159-172. With permission.
Note: Means with the same superscript letters are not significantly different ( P < .05).
N , number of observations.
 
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