After the official opening of the Workshop the 57 organizers and participants
were divided into two groups. Group I visited agricultural research
stations and farmer managed on-farm trials in the Department of Oueme, southern
Benin. Group II (which included the author) toured on-station research
trials and numerous farmer managed on-farm trials using mucuna in the Atlantic
Department of coastal Benin.
Field Site 1:
This visit consisted of a series of on-station trials conducted by the National
Agricultural Research Station of the Ministry of Rural Development in
collaboration with Sasakawa Global 2000. Research trials are being conducted to
determine the optimal sowing dates for relay cropping mucuna with maize.
Treatments included sowing of mucuna at 0, 14, 23, 42, 56, and 70 days after
maize planting. Results suggest 42 days as optimal in terms of reducing mucuna
competition with maize, and increasing maize yield and mucuna seed production.
A second series of trials was investigating effects of NPK fertilizer and Urea
on maize yield in a maize-mucuna intercropping system. A third set of
experimental trials combined the objectives of trials one and two to look at
optimum sowing dates for mucuna seed following maize planting in a relay system
with varied amounts of NPK and urea fertilizer added. While trials are on-going
it appears that 200kg/ha NPK (14-23-14) applied at time of sowing of maize
followed by mucuna seeding 42 days later produces the greatest grain and seed
yields. Urea seemed to produce the same result when applied at rates of 0 or 50
kg/ha in conjunction with the NPK fertilizer. NPK + urea at the rate of
100kg/ha inhibited crop production. Researchers are therefore questioning the
necessity of adding urea. The objective here is to determine the minimal amount
of fertilizer necessary to produce high maize yields. Results will be applied
in extension programs.
The fourth set of trials being conducted looked at mucuna seed production in
fallows and compared Mucuna `veracruz' and M. cochinensis (black
and white seed, respectively) with and without physical support for the mucuna.
In these trials the M. cochinensis is outperforming `veracruz' in terms
of biomass production in t/ha. Further, the provision of supports (`tutors')
for mucuna is resulting in lower rates of flower abortion and higher seed
production. .
Many participants inquired as to why a non-Nitrogen fixing legume- Senna
siamea -was selected. The reason is that it grows extensively in the
area and all farmers participating in the trials had access to it. It is valued
as a MPT and farmers coppice it at 6-month intervals and sell the wood which is
an important source of cash income. Some branches and the leaves are left in
the field. The S. siamea showed vigorous
resprouting ability. It is uncertain for how long the Senna will support hard
coppicing at twice yearly intervals. Additionally,
Senna siamea is indirectly used as "fish fodder". Throughout the field
trip I noted truckloads of S. siamea (both clean stems and stems with
foliage) passing by. I was told that Senna is harvested from fallows and dumped
into local lakes and ponds because it attracts microbes which fish feed on.
Fish are then harvested from the lakes for human consumption. Further,
young, clean stemmed S. siamea and other unidentified trees, ranging
from 6-10" diameter are harvested and used as telephone poles along road ways
in the Atlantic Department, Benin. This represents another market for the
wood.
Mrs. Jeanne Gbegbe, a farmer, has been using this system
for four years and has found her maize yields have more than doubled. This past
year she sold mucuna seed for 125cfa/kg (.25). The amount of mucuna seed
harvested and sold was uncertain. Thus far the increase in maize yield has been
consistent. Mucuna + P resulted in the highest yields.
From an agroforestry perspective, I was also interested to see that Mr Ainou
had a field intercropped with pineapple and papaya. Papaya was both interspersed in rows throughout the
field and planted more closely along the boundaries around his fields.
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The Workshop on Cover Crops for a Sustainable Agriculture in West Africa : Constraints and Opportunities
in West Africa : Constraints and Opportunities
Field Site 2: The participants were then conducted on a tour of
on-station trials at the Research Station for Staple Food Crops, Agronomic
Research Division of the Ministry for Rural Development in Niaouli, Benin. The
station is investigating plant performance and biomass production of Mucuna
cochinensis (sm. gray seed); M. `rajada' (speckled seed); M.
`veracruz' (black seed); Citrulus vulgaris (flat seed); and
Canavalia ensiformis (lg. white seed).
The effect of these cover crops on maize yield in intercropping and relay
systems is also under investigation. A second set of trials is looking at cover
crop performance and maize yields where sawdust, NPK and urea are applied. The
impetus for incorporating sawdust is to test this practice which is employed by
local farmers. These trials, set up on acidic ultisols appeared to be
suffering, both maize and mucuna plants were yellowish. One of the researchers
offered that perhaps 8 t/ha was too high and they would repeat the trials using
lesser amounts. Sawdust is available in large quantities as a by-product of the
furniture production cottage industry in Benin.
Field Site 3: The third field visit was an on-farm trial organized by the
University of Hohenheim. One-hundred and thirty farmers were voluntarily
participating in trials to compare effects of NPK fertilizer (14-23-14) applied
at a rate of 429kg/ha (empirically determined in pre-trials) compared to the
use of Senna siamea mulch planted in either hedgerows at field
boundaries or in scattered plantings throughout the field, in order to
determine weed suppression and biomass production. Each field is split into
four plots. Plot 1 serves as the control. Plot 2 is NPK fertilizer only. Plot 3
is Senna siamea and plot 4 is S. siamea plus NPK. Results suggest that
the effectiveness of the Senna mulch is strongly influenced by the initial
fertility level of the soil. It seems to perform better on poor soils than on
rich soils. Senna + NPK fertilizer produced the greatest biomass in t/ha.
However, in some fields Senna alone produced greater amounts of dry mulch in
t/ha than Senna + fertilizer. The field analysis is not yet complete and there
seems to be considerable variation in results from one field to the next and
from plateau sites to valley sites.
Field Site 4 was a farmer managed on-farm trial using Mucuna
cochinensis and maize in a relay system. The 3ha farm is divided into 3
plots. Plot 1 is maize only. Plot 2 is maize with M. cochinensis relayed
at 42 days post maize sowing. The third plot is maize with a M.
cochinensis relay at 42 days post-maize sowing plus rock phosphate.
Field Site 5 was another farmer managed on-farm trial set up in the same
arrangement as the Site 4 trials. This farmer, Mr Rene Godonou, was in
his second year of experimentation. Mr Godonou has been able to sell 200kg of
mucuna seed this year for 60cfa/kg (a total of 12,000cfa or $23.76)-a
significant increase in cash income). Results as that for Site 4.
Field site 6: This farmer managed trial is run by Mr Raphael
Ainou. He is a dynamic farmer-experimenter and hosts visits by area farmers
to discuss his experience and his field trials. Mr Ainou has established trials to look at plant
performance and biomass production of M. cochinensis, M. puriens,
Dolichos lablab, and Canavalia. Observations he has made thus far
suggest Mucuna is the superior performer, but if there a periodic
drought it suffers more than the Canavalia. The Dolichos was
suffering from some fungal attacks and he felt this was because Dolichos
preferred drier conditions. We also visited a field on his farm that had been
abandoned to Imperata cylindrica. Mr Ainou had the field under a mucuna fallow; in its second year of planting with vigorous Mucuna cochinensis, the Imperata is no longer visible.
Field Site 7: This religious community is headed by a young couple who
moved to the area seven years previous. The area the couple farmed was ~5ha of
land which was completely invaded by Imperata cylindrica. After a number
of failed crops, failed attempts to eradicate the Imperata, and several meetings
with a team of extension agents from MDR and SG2000, they agreed to try mucuna.
After one year of fallowing with mucuna, they were able to begin relay cropping
maize/mucuna. The wife expressed the difficulty in waiting one
year before being able to crop the land, particularly as they regarded the
mucuna as inedible, but said in the longer term it had been well worth it. In addition to maize production,
they practice intensive vegetable gardening on raised beds, have fruit trees
(papaya, guava) and other species such as Hibiscus rabdaffia and ginger which they bottle
as jams and beverages and sell in regional markets. There were a number of teak
trees scattered in small patches of 2-4 trees throughout the farm.
Unfortunately all the ones I saw were infected with a pathogen which caused
them to ooze a sticky black substance and to produce lateral branches. I also
noted that throughout the fields there seemed to be several species of
leguminous trees, particularly Albizzia sp. Some were overgrown by
mucuna, and from questions I asked, it appeared they were not utilized or
managed in any way-although at least they were left on the fields.
For additional technical notes on the field visits described above, contact Karen McCaffery at the following e-mail address: kam26@cornell.edu
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Last edited: December 6, 1996
Authors:
Christine Stockwell
Lucy Fisher
URL http://ppathw3.cals.cornell.edu/gmcc/Benintprt.html