Grain Legumes and Green Manures for Soil Fertility in ... - cimmyt

To Charles Nhemachena, et al.
Q:
1) What target yields (or limits) carrb~
recommended for grain and green manure legumes
lillder the current economic tools of analysis in
order to give a positive feedback to research?
2) Most of the economic evaluation seems to be
based on data sets that do not represent the optimal
practices/experimental designs. Are we sure we
are not dismissing orupgrading technologies
prematurely?
A:
1) Due to great diversity of the biophysical and
socio-economic environments, it is difficult to
recommend specific yields for grain and green
manure legumes. Depending on the available
conditions in an area, yield levels should be high
enough to cover the costs of production incurred
and give positive net returns to farmers. Generally,
from a given grain and green manure legume, yield
levels should be high enough to offer positive net
returns to factors of production used.
2) Economic evaluations of any undertaking or
enterprise make assumptions or goes in the form of
an abstraction from reality to lillderstand
relationships between certain variables, holding
other conditions constant. Like any scientific
experiment, it has controls. In addition, provisions
are given for possible outcomes if other factors
previously held constant come into play, for
example in sensitivity analysis, so I don't think we
are dismissing or upgrading technologies
prematurely.
C: There is need for longer-term rotational trials to
have a quantitative idea about longer effects of
legumes on soil fertility.
To Joseph Rusike, et al.
Q: .Can we learn from what happened in Myanmar
where pigeonpea production has increased
substantially in a few years time?
A: Agricultural sector growth is being actively
promoted by the Myanmar Government.
Q: What is the potential size of the pigeonpea
market in India and the world?
A: Total world pigeon pea production from 1980-82
to 1996-98 is as follows: (in 1000 t).
1980-1982 2,805.4
1990-1992 2,805
1996-1998 2,887
Q: Grain yields for pigeonpea from most
presentations are around 200 kg/ha. Is the yield
potential for pigeonpea any higher than this for
Zimbabwe? How do our potential yields compare
with yield levels achieved elsewhere in the world,
in places such as India?
Q: I too am interested in the pigeon pea yields in
ideal conditions. Seeds are also a constraint. There
are seeds coming through donations, coming
through NGO programs, etc. Maybe the Soil Fert
Net can help with pigeonpea mfuture.
A: Here is the performance of new pigeonpea
varieties in on-station trials at Hombolo and
Makutupora Research Stations, Tanzania, 2001­
2002.
Variety Days to 50% 100-seed Yield
flowering weight (kg/hal
Farmer 183 16.2 476
ICEAPOO053 165 16.4 604
ICEAPOO040 162 20.0 667
ICEAPOO020 163 18.8 752
ICEAPOO068 85 14.0 1530
Q: The market for pigeonpea in India will be
saturated if the whole of SA DC grows pigeonpea.
We need to diversity markets to include domestic
markets.
A: Yes I agree.
Q: How do we promote technologies to farmers?
Are the technologies introduced to the farmers one
after the other or simultaneously.
C: We can ask, should the technologies be
introduced at once or should we choose which
technologies to expose to farmers? One of the
approaches we are using in Zimbabwe is to cluster
technologies in an area. We give each farmer one or
two technologies and give other different
technologies to other farmers in the area to try.
Involve all farmers in the area on implementation,
monitoring, evaluation of all the technologies and
hold field days. Allow farmers later to choose the
technology they want to adopt.
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Grain legumes and Green Manures for Sail Fertility in Southern Africa