Africa cannot grow enough food to feed itself. It is not feasible to
expect a poor African farmer to spend 400 euro to 500 euro per hectare to grow a
crop if he can live on 1 euro per day as many do. For the money he has to spend
on one hectare - he can live for a year. The NEPAD conference shows that they are looking at chemical fertilizer as the solution.
The reasoning behind this is the success enjoyed by relatively wealthy farmers in Africa
(predominantly of European origin), who have enough money to buy fertilizer. "Tè a fatige"
The poor results obtained with organic farming in South Africa together with
the lack of credible research and information, were crucial in the decision
behind initiating research into organic farming as a discipline.
The conventional method of replacing chemical fertilizer with compost was not
feasible, as 50 to 100 tons of compost per hectare created problems with high
levels of Phosphate and heavy metals in the soil. The yields were poor and
the high cost of making compost together with poor disease control forced us
to look for a different approach.
Land preparation and cultivation
The extreme climate variations that are experienced in Africa, with large
variations between wet and dry seasons, both in temperature and other
climatic conditions, demanded a different approach to that employed
elsewhere in the world. The first factor that was researched was the variations
in soil temperature. On bare soil in summer the soil temperature reaches
between 50° and 70 °C, down to a depth of 10 cm. The rate of evaporation of
water reached on windy days climbed to 25mm per day and up to 80% of
water after rain was lost by evaporation. This observation led to the practice of
heavy mulch and as little disturbance of the soil as possible.
For marking planting lines a spring tine cultivator was used to open a little furrow into
which vermicompost was fed by way of preparation. As the soil improved the
need for a ripper disappeared.
Fertilizing
The only fertilizer used was Vermicompost at 2m³/h and bone-meal at 50kg/h
which as only needed initially, as the soil in South Africa has very low
phosphate content. The 2m³/h at planting was found to be sufficient for
successful cultivation, and no other fertilizer was needed.
Micro-organisms
The small variation in results surprised us and led us to the realization that
there were other factors that influenced the result.
As vermicompost is rich in micro-organisms, we realised that this could be a
major contributing factor. After research and further trails we found that this
was indeed the case. The discovery of the importance of micro-organisms
explained why the baring of soil and removing soil cover had such a great
impact on soil and yields under African conditions.
Cover crops are successful in an African context for mulch production.
The cover crops, mostly legumes, are grown and cut down to form mulch.
Using vermicompost in conjunction with a no-till regime and mulch proved to
be a very cost effective way of farming.
Controlling Pests
The other question that needed answering was why in 11 years of perfecting
this system, no destruction from aphids, red spiders, white flies, thripps,
bollworms or any caterpillars ever resulted.
According to Francis Chaboussou's research, pesticides substances cause an
excessive production of amino acids, which these insects and pests use for
food. The mechanism of how this works is not known at present, but it was
found to be the only logical explanation for the lack of insects attack on the
plants. Nitrate fertilizers, herbicides and insecticides all cause this unbalance.
When the pH of plants is monitored, this extra amino acid production can be
measured.
Hennie C Eksteen
Managing Director of Affmech cc and Director of Research
Bonnet Herb Farm, Graskop, Mpumalanga, Republic of South Africa
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