1. Competition, land rehabilitation
& research communication.
Gert Nyberg, Bekele Lemma, Zacharia Gnakambary, Jules Bayala,
Edmundo Barrios, Henry Neufeldt, Bernard Vanlauwe,
Hugues Bazie, Mats Öqvist, John Nyaga, Aida Bergues Tobella

2. Decrease in communal grazing land
Decrease in
inorganic fertilizer
use. Increasing
fertilizer price & no
subside.
Decrease in cattle number
Decrease in manure
increased removal of crop
residue for fodder and fuel
Decrease in soil fertility
Decrease in forest cover

3. Trees
Crops
-Shade
-Soil fertility
animals
- Shade around homestead
- Fodder (leaves & pods)
humans
-Shade for resting and
lunching
-Farm equipments, fuel
wood, construction
material

4. Trees on farm lands
• households - have trees on their farms
• Common trees – acacia, croton and cordia – kela
-acacia and croton – dorebafana
• Distribution – scattered
• Grown naturally- remnant or regenerated
• Age –old and young trees
• Management – pollarding and pruning (dominant)
– To collect fuel wood, construction material, …
– To reduce shade to acceptable level
– Done once in a year or in two year or in three year
• Benefits- crops cattle and humans

5. • Most households believe that on farm trees improve soil
fertility
– Very few think that trees are competitive with crops
• Almost all recognize soil fertility differences under canopy and
outside canopy
– Evidences
• soil color (darker), soil moisture, appearance of crops
(vigor, taller, color of leaves …)
– When applying fertilizers
• 68 %, 52% (Kela, Dore) of households applied less
fertilizer under canopy
– Reason crops grow faster and collapse when applied on the
same rate
• 32 %, 48% (Kela, Dore) of the households claimed
uniform application, but better crop performance
under canopy

8. 0,000
20,000
40,000
60,000
80,000
100,000
120,000
0 1 2 3 4
resp rate/distance from trees
Eucalytptus
Markhamia
Sesbania
Sesbania in Napier
1
1,2
1,4
1,6
1,8
2
2,2
0 1 2 3 4 5
Eucalyptus
Markhamia
Sesbania
Sesbania in Napier
-21
-20
-19
-18
-17
-16
-15
0 1 2 3 4 5
Eucalyptus
Markhamia
Sesbania
Sesbania in Napier
y = -0,4071x - 14,606
R² = 0,8195
-19,000
-18,000
-17,000
-16,000
-15,000
-14,000
-13,000
-12,000
-11,000
-10,000
0 1 2 3 4 5 6 7 8 9

9. y = 0,3392x - 19,974
R² = 0,9923
y = 0,3079x - 19,823
R² = 0,998
y = 0,3153x - 19,828
R² = 0,9964
y = 0,3067x - 19,221
R² = 0,9929
-19,000
-18,000
-17,000
-16,000
-15,000
-14,000
-13,000
-12,000
5,000 6,000 7,000 8,000 9,000 10,000 11,000 12,000 13,000 14,000 15,000
dist 1 dist 2
dist 3 dist 4
y = 0,3601x - 19,785
R² = 0,9966
y = 0,4047x - 19,848
R² = 0,9741
y = 0,3822x - 19,817
R² = 0,9887
-18,500
-18,000
-17,500
-17,000
-16,500
-16,000
-15,500
-15,000
4,000 5,000 6,000 7,000 8,000 9,000 10,000 11,000 12,000
dist 1
dist 2
dist 3

11. Gully rehab Gully reference

12. Woodlot at farmers field
Control

13. 0
1
2
3
4
5
6
7
8
C C ratio
2011
N N ratio
2011
P 2009 ic 2009 ic 2011
Woodlots/reference ratio

14. 0,0
10,0
20,0
30,0
40,0
50,0
60,0
woodlots 2009 control 2009 woodlots 2011 control 2011
mm/h
b
a
c
b
bars with the same letter
are not statistically
different at p<0.05
Infiltrability four & six years after planting

15. Infiltration rates in land rehab
sites 2009 & 2011
0
5
10
15
20
25
30
35
T C
2009
2011