Desire for Greener Land

No. of case studies
Reduced surface runoff
9
8
7
6
5
4
3
2
1
0
Cropping
management
Water
management
Cross-slope
barriers
Grazing land
management
SLM technology groups
no
little
medium
high
and stored it will not be available for later use during the
dry seasons. Reducing surface runoff is thus a major concern
in drylands. As indicated by the authors of the case studies,
the most effective technologies are improved cropping management
and cross-slope barriers. For both, they indicated
that runoff and erosion is a major problem to be addressed
on cropland. For the two grazing land experiences they did
not indicate an impact on runoff, which, as noted earlier,
does not seem to be an issue for these cases. Experiences
from other WOCAT cases show that especially overused grazing
areas have the highest runoff and that improved grazing
land management leads to significant reductions of runoff
and erosion.
Improving soil moisture through in-situ conservation of
rainwater or irrigation water is effective water conservation.
This is another key function that is most important to
drylands. Cropping management and cross-slope barriers
show the greatest potential to increase the water availability
to crops in that way. Under dryland conditions, this often
results in increased yields.
Reduced evaporation was only reported in three case studies
(Afforestation Cape Verde, Roof Rainwater Harvesting
Botswana and Drip Irrigation Turkey). Drylands usually suffer
from extreme evaporation losses on the bare soil surface,
which accounts for 40-70% of the already scarce rainfall 8 .
Forest
management
DESIRE - WOCAT 2012
Figure 19: Reduced surface runoff across the SLM technology
groups.
Morocco, Erik van den Elsen
No. of case studies
Increased soil moisture
9
8
7
6
5
4
3
2
1
0
Cropping
management
Water
management
Cross-slope
barriers
Grazing land
management
SLM technology groups
no
little
medium
high
Yet, evaporation loss is often not perceived and therefore
not seen as a problem. The role and importance of these
technologies to reduce water losses through unproductive
evaporation of the soil surface needs to be recognized.
Improved soil cover management (see impact on reduced
surface runoff, Figure 19) can heavily reduce such losses.
The potential of improved soil water availability has been
highlighted in previous WOCAT analyses, especially in the
guidelines for Sub-Saharan Africa, where water scarcity is
the main challenge 9 . Increase of soil moisture can also be
combined with improved water harvesting techniques.
Improved harvesting and collection of water (Figure 21) is
achieved by improved water management, e.g. collecting
excess water from the fields or from episodic streams, storing
it in intermediate storage facilities such as dams, ponds
and tanks and guiding it to areas where the water is most
productive. It is mainly the technologies aiming at improving
available water, such as the water management technologies
and the cross-slope barriers, which do show highly positive
results, especially where availability of surface water was
poor before the technology implementation. No impact was
mentioned for all grazing and forest management technologies
and for most of the cropping management technologies.
Looking at the impact of those technologies for which water
decrease was indicated as a degradation problem before
Forest
management
DESIRE - WOCAT 2012
Figure 20: Increased soil moisture across the SLM technology
groups.
8 Liniger et al., 2011
9 WOCAT, 2007, Liniger et al., 2011
Analysis of assessed SLM technologies and approaches across DESIRE sites DESIRE – WOCAT 2012
51