Agriculture Reference
In-Depth Information
TABLE 12.5
Soil Chemical Properties of Some Selected Topsoils (0-30 cm) in Maswa
District, Tanzania
Exchangeable Bases
(cmol(+)/kg Soil)
pH
Water
Olsen P
(mg/kg Soil)
CEC (cmol/
kg Soil)
Village
% TN
% OC
Ca
Mg
K
Na
Isulilo
8.75
0.04
0.63
14.46
24.0
13.97
3.89
0.78
7.27
Isulilo
7.73
0.05
0.61
14.46
17.2
10.47
2.52
0.26
3.63
Njapanda
6.68
0.04
0.63
16.52
16.6
8.11
1.73
0.36
7.79
Njiapanda
7.92
0.03
0.46
15.14
16.0
6.09
2.41
0.14
7.36
Njiapanda
8.03
0.05
0.63
17.16
20.6
14.19
2.41
0.23
4.57
Bakangilija
7.55
0.06
0.82
15.69
18.0
12.65
2.94
0.30
3.41
Bakangilija
7.03
0.03
0.38
14.24
7.0
2.26
0.64
0.11
2.09
Bakangilija
8.92
0.04
0.52
16.60
16.0
12.0
1.68
0.18
6.78
±SE
0.27
0.00
0.05
0.40
1.72
1.48
0.34
0.08
0.78
Source:
Kajiru, G.J., J.P. Mrema, F.B. Rwehumbiza, N. Hatibu, and H.F. Mahoo. 2006. Evaluation of the
fertility status of the soils of the Ndala River Catchment, Maswa District, Tanzania for rice pro-
duction under rainwater harvesting systems. In: Msanya, B.M., Kimaro D.N., Kilasara M.,
Mrema J.P., and Kaaya A.K. (Eds.).
Land Resources Management to Enhance Livelihood of
Land Users in East Africa
.
Reviewed Proceedings of the 22nd Conference
, Held at New Safari
Hotel, Arusha, Tanzania, November 29-December 3, 2004.
Note:
Ca, calcium; CEC, cation exchange capacity; K, potassium; Mg, magnesium; Na, sodium; OC,
organic carbon; Olsen P, available phosphorus; TN, total nitrogen.
practices lead to low biomass productivity and, hence, a low contribution to plant
nutrients and organic matter in the soil.
12.2.3 e
FFect
oF
l
and
u
se
on
s
oil
and
n
utrient
l
oss
in
e
ast
a
Frica
Land use changes that have occurred in East Africa have resulted into a decline in
natural vegetation (Kabanza 2013). Land use change coupled with anticipated cli-
mate change has led to accelerated land degradation in terms of soil erosion, declin-
ing soil fertility, loss in biodiversity, and changes in hydrological cycles (Kabanza
et al. 2013b). In the southeastern Tanzania, it was also observed that tied ridges (a
local practice in the Makonde and Rondo plateaus) (Figures 12.1 and 12.2) is the
best localized form of CA, and effective in storing moisture and organic carbon con-
servation in Arenic Ferrasols or Acrisols of the area (Kabanza et al. 2013a). Studies
conducted in East Africa (Uganda and Tanzania) have demonstrated the linkage
between land utilization types, runoff, and soil and nutrient loss (Isabirye et al. 2010;
Semalulu et al. 2012; Msita 2013).
Studies conducted in the Lake Victoria shoreline to determine the rate of sedi-
ment generated by agricultural and settlement land use types show that settlements
