Poster prepared by T. Amede, K. Descheemaeker, E. Mapedza, P. Masikati, M. Munyaradzi, A.Sibanda, D.Nkomboni, S.Homann and A.van Rooyen for the ILRI Annual Program Meeting (APM) 2010, held at ILRI campus, Addis Ababa, Ethiopia, April 14-17, 2010.

1. Three Ways to Improve Water Productivity
in Zimbabwe
T. Amede, K. Descheemaeker, E. Mapedza, P. Masikati, M. Munyaradzi, A.Sibanda, D.Nkomboni, S.Homann, A.van Rooyen
Water Productivity in Farmers’ words
1) Drought has been with us for decades; what has changed is its frequency and impact on
our livelihoods;
2) Most degraded are croplands (50%), followed by communal trees, forests, rivers and
wetlands;
3) When drought occurred in the past, our neighbors would grow enough food and feed;
now every village is drought-prone, even livestock mobility doesn’t help;
4) Local varieties were more tolerant to drought; modern varieties need more water, more
fertilizer and more labour. We like them only when the season is good;
5) Changing rangelands to crop fields is happening to produce food; but we are not getting
as much feed from crop lands compared to rangelands;
6) We keep our goats: to sell and buy food, send our kids to school and feed our family.
However, Goats die before they reach markets; leaving us in duress;
7) If research has solutions, help us growing more food with our shrinking land, decreasing
livestock numbers and frequent droughts;
Fig 1. Livestock production systems in
Nykai, Zimbabawe
I. Dual purpose cultivars enhance water productivity
Lessons from Bulawayo, Zimbabwe with 20 sweet sorghum varieties: Table 1. Differences in grain yield, feed quality and water use efficiency of
sorghum cultivars in Zimbabwe.
1) Significant variation exists between cultivars in grain & stover yield, stover digestible, Cultivars Grain Stover Harvest Digestible ME
yield yield Index stover Rain water use
metabolizable energy and rain water use efficiency (Table 1); efficiency; kg m-3
2) Trade-off between grain yield and feed quality across sorghum cultivars (R2 - 0.85); while (tha-1) (tha-1) (%) Stover Grain
few cultivars offer dual purpose benefits;
3) Livestock Water productivity increases with increasing feed quality (metabolizable energy JJ1041 4.53 2.55 0.62 42.9 5.58 1.5 2.40
(ME)) and declining harvest index;
ICSR 93034 3.83 4.20 0.45 45.8 6.64 2.55 2.03
4) Dual purpose, taller varieties produce more biomass, quality feed but are also less
drought resistant; higher water productivity (WP) in good years and low WP in dry years; ICSV 93046 2.08 5.70 0.24 50.6 7.74 3.64 1.10
Mateebe 1.12 2.31 0.31 55.1 8.66 1.40 0.60
Sweet
Table2. Reduced mortality rate increases offtake and improves water
II. Reducing livestock mortality enhances water productivity and returns productivity (Van Rooyen etal)
In SSA, animal mortality is so high; seriously undermines all other efforts. 900000
800000 Increased prolificacy to 1.2
1) High livestock mortality is caused by interrelated factors such as diseases, drought and 700000
Increased fertility to 0.85
high stocking rates; 600000
2) In Zimbabwe, annual mortality ranges between 10-22% for cattle; with mortality being the
Off take
500000
major cause of outflow. Highest is with juveniles (17-22%) followed by sub-adults (10-
400000
15%);
300000
3) Above 80% of mortality is caused by diseases;
4) Poor veterinary services is partly responsible; investing on it pays off. 200000
5) With high mortality rates it takes14 Years to recover from a severe drought; 100000
6) With mortality rates reduced to less 10% it still takes 8 Years to recover from a severe 0
1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.70 0.70
drought; Reduction in mortality
7) A 10% decrease in mortality could improve WP by at least 20%.
Fig 2. Trends in contribution of maize stover to dry season feed at 20, 40 and 60% of daily
III. Soil fertility effects degree of water productivity of systems DM requirements under different treatments. Horizontal lines show stover different % of total
feed required. FP = farmer practice, MD = micro-dose, RC = recommended rates
System productivity in SSA (particularly in Zimbabwe), is constrained by nutrient mining
6
1) Nutrient removal through harvest was consistently higher than application of external 5
maize stover t/ha
4 FP
inputs; MD
3
2) These systems are responsive to application of chemical fertilizers; WP trends positively 2
RC
20%
correlate with levels of chemical fertilizers (Fig 2); 1
40%
60%
3) Crop residue production under traditional, low-input systems cover only about 20% of the 0
daily dry matter feed requirement, low quality;
4) Maize stover produced under microdose, recommended application (100 kg ammonium
nitrate) contributed up to 40% and 60% of the feed requirement, respectively, while
combination of stover and mucuna commonly satisfy daily protein requirements;
5) Livestock Water productivity has doubled due to the application of optimum chemical
fertilizers; significant gain in crop residue for livestock feed.
The good news is … And the not so good news is …
Reducing livestock mortality associated with improving Conversion of Rangelands to crop fields increases human and
soil fertility and dual purpose cultivars will not only livestock pressure on crop lands thereby facilitate land
improve water productivity but also increase incomes and degradation and water depletion
April 2010
livelihoods
We would like to acknowledge BMZ-Germany for supporting the project on Improving productivity
of mixed crop-livestock systems in sub-Saharan Africa, ICRISAT-India and Dr. Michael Blummel of
ILRI-India for their technical support in the dual purpose varieties research.