Successul Organic Technologies and Practices in Africa
According to the World Agroforestry Centre,
Agro-forestry is a collective name for land use systems and practices in
which woody perennials are deliberately integrated with crops and/or
animals on the same land management unit. The integration can be either
in a spatial mixture or in a temporal sequence. There are normally both
ecological and economic interactions between woody and non-woody
components in agro forestry.
In agroforestry systems, trees or
shrubs are intentionally used within agricultural systems, or non-timber
products are cultured in forest settings. Knowledge, careful selection
of species and good management of trees and crops are needed to optimize
the production and positive effects within the system and to minimize
negative competitive effects.
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tree species of research interest in the tropics, particularly in
relation to improving maize yields in sub-Saharan Africa, include the
nitrogen fixing species Sesbania sesban, Tephrosia vogelii, Gliricidia
sepium and Faidherbia albida. For example, a ten year experiment in
Malawi showed that by using fertilizer trees such as Tephrosia vogelii
and Gliricidia sepium, maize yields averaged 3.7 tonnes per hectare,
compared to 1 tonne per hectare in plots without fertilizer trees or
mineral fertilizer. Research with Faidherbia albida in Zambia over
several years showed that mature trees can sustain maize yields of 4.1
tonnes per hectare compared to 1.3 tonnes per hectare beyond the canopy
of the tree. Unlike other trees, Faidherbia sheds its nitrogen-rich
leaves onset of the rains and retains them in the dry season. This makes
it compatible with the maize crops, as it does not compete with them
for water, nutrients or light.
- Biodiversity in agroforestry systems is typically higher.
- Agroforestry incorporates at least several plant species into a given
land area and creates a more complex habitat that can support a wider
variety of birds, insects, and other animals.
- Agroforestry also
has the potential to help reduce climate change since trees take up and
store carbon at a faster rate than crops.
- Poverty alleviation through increased production of agroforestry products for home consumption and sale.
- Contributing to food security by restoring farm soil fertility for food
crops and production of fruits, nuts and edible oils.
- Reducing deforestation and pressure on woodlands by providing fuel wood grown on farms.
- Increasing diversity of on-farm tree crops and tree cover to buffer farmers against the effects of global climate change.
- Improving nutrition to lessen the impacts of hunger and chronic illness associated with HIV/AIDS.
- Augmenting accessibility to medicinal trees, the main source of medication for 80% of Africa's population.
A case study - Agroforestry in the dry land of Eastern Africa
case study shows how agroforestry practices can contribute to
sustainable land in dry lands by drawing examples from Uganda, Ethiopia,
Tanzania, Kenya and the Sahel.
For the full information on the case study, click here.
The push-pull method developed by the International Research Institute ICIPE in Kenya, together with local farmers is an effective and low-tech solution to control maize stem borer in Africa. The Push-pull strategy is scientifically well evidenced. It reduces stem borer attack and improves soil fertility, resulting to yield increases of up to 200 percent, while reducing dependency on chemical pesticides and Genetically Modified Organisms (GMOs).
The technique involves planting the legume desmodium (Desmodium uncinatum or silver leaf) between rows of maize. Desmodium produces an odor that “pushes” away the stem borer moths from the maize crop. Desmodium also suppresses striga weed and being a legume, fixes nitrogen in the soil and thus improve soil fertility. Napier grass (Pennisetum purpureum) is planted as a trap in the border around the maize fields. Napier grass has an odor that makes it more attractive to stem borer moths than maize and it “pulls” the egg laying adult moths away from the food crop to the trap crop. Most of the eggs are killed in the sticky sap of the Napier grass. Therefore very few stem borer larvae survive and the maize is saved because of the “push-pull” strategy.
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All these benefits result to improved standards of living through the increased level of education and health status.
- Increase maize yield,
- Continues supply of cattle feed from the Napier grass,
- Nitrogen fixed to the farm by the desmodium legume, so one saves money,
- Soil protected from erosion as demodium acts as soil cover,
- Soil retains more water as desmodium acts as mulch,
- Money from selling of desmodium seed,
- Money from selling of milk from the cows.
- Saving on farm labor as no need to weed the string weed,
- Maize protected from strong winds by the Napier grass.
A case study - A novel farming system for ending hunger and poverty in sub-Saharan Africa
This Case study was done to evaluate on the impact of the push - pull technology developed and promoted by icipe and its partners in Eastern Africa.
For the full information on the case study, click here.
The System of Rice Intensification (SRI)
The System of Rice Intensification (SRI) is a “set of insights and practices that change the management of plants, soil, water and nutrients used in growing irrigated rice.” Unlike the continuous flooding of paddy fields, SRI involves intermittent wetting and drying of paddies as well as specific soil and agronomic management practices.
SRI involves some combination of the following changes in rice agronomic practices:
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- Transplanting seedlings at a very young age – 8 to 12 days old, at most 15 days old, instead of the usual age for seedlings of 3-4 weeks or more.
- Raising seedlings in un-flooded nurseries, not planted densely and well-supplied with organic matter. There is an option of direct-seeding, but transplanting is most common.
- Transplanting seedlings quickly, carefully and shallow – taking care to have minimum trauma to roots, not inverting plant root tips upward which delays resumption of growth.
- Transplanting seedlings at wider distance and singly (one seedling only) – instead of clumps of 3-4 seedlings per hole -- and in a square pattern, usually 25x25 cm, giving roots and leaves more space to grow.
- No continuous flooding of the soil – soil saturation cause plant roots to degenerate and suppresses soil organisms that require oxygen; either apply small amounts of water daily, to keep soil moist but not saturated, or alternately flood and dry the soil.
- Weed controlling preferably done with a simple mechanical hand weeding. This aerates the soil as it eliminates weeds, giving better results than either hand weeding or herbicides.
- Providing as much organic matter as possible to the soil – while chemical fertilizer gives positive results with SRI practices, the best yields will come with organic fertilizers or manures. This does more than feed the plant: it feeds the soil, so that the soil can feed the plant.
Case studies - SRI practices in the Senegal River Valley and in the Podor region
- SRI gives higher yields -- more tons of rice per hectare, sometimes up to 200% increase over flooded paddies.
- It requires less seed and water compared to traditional methods or improved methods using synthetic fertilizers. The water savings, for example, can be by up to 50% water - because plant populations are reduced, and paddy fields are not kept continuously flooded.
- SRI makes use of what the farmer has. It may not be necessary to purchase any extra external inputs. SRI does not require the purchase of new seed varieties – since practically all rice varieties give higher yield with SRI.
During 2007-2009, Tim Krupnik and colleagues at FAO and the Africa Rice Center did a series of evaluations that included adapted SRI practices in the Senegal River Valley and in the Podor region. Their research during 2008-2009 showed that adapted SRI practices resulted in significantly higher yields than farmer practices and were as good as or better than recommended management practices.
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The Vetiver System technology
The Vetiver System (VS), which is based on the application of vetiver grass (Vetiveria zizanioides L Nash, now reclassified as Chrysopogon zizanioides L Roberty), was first introduced by the World Bank for soil and water conservation in India in the mid 1980s.
The Vetiver System (VS) is a very simple, practical, inexpensive, low maintenance and very effective means of soil and water conservation, sediment control, land stabilizations and rehabilitation, and phyto-remediation. It is based on the application of vetiver grass (Vetiveria zizanioides L Nash, now reclassified as Chrysopogon zizanioides L Roberty). Being vegetative it is also environmental friendly. When planted in single rows vetiver plants will form a hedge which is very effective in slowing and spreading run off water, reducing soil erosion, conserving soil moisture and trapping sediment and farm chemicals on site.
For full information about the vertiver system and its establishment, click here.
The Vetiver System has many agricultural uses. For example:
• Soil and water conservation, soil moisture improvement, groundwater recharge, recycling soil nutrients, pest control, mulch, forage, clean up of agricultural contaminated waste water, protection of farm infrastructure (canals, drains, roads, and building sites).
• The Vetiver System will reduce soil loss from farm land by as much as 90% and will reduce rainfall runoff by as much as 70%, thus significantly increasing the effective rainfall available to crops. The impact goes further - groundwater is recharged to the extent that ephemeral streams flow longer and stronger, wetlands are rejuvenated, wild life habitat is improved and soil fertility improves - resulting in increased crop yields that have been measured as much as 40%.
• The leaves of the Vetiver has been used for thatching and as mattress stuffing(lice repellant), for religious and ceremonial purposes and for weaving purposes such as making of baskets and mats.
A Case study in South Africa - KwaZulu/Natal, South Africa a single large-scale commercial farm
Zaï Permanent planting holes
Zaï is a hole, a planting pit with a
diameter of 20-40 cm and a depth of 10-20 cm depending on the type of
soil. Pits are dug during the dry season and the number of Zai pits per
hectare varies from 12,000 to 25,000. The number of zai pits per hectare
and their dimensions determine how much water they harvest. The bigger
the number and the smaller their size, the less water they each harvest.
The excavated earth is ridged around the demi-circle to improve the
water retention capacity of the pit.
After digging the pits,
composted organic matter is added at an average, recommended rate of 0.6
kg/pit. After the first rainfall, the matter is covered with a thin
layer of soil and the seeds placed in the middle of the pit.
Zaï fulfills three functions: soil and water conservation and erosion control for encrusted soils.
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On degraded and encrusted soils, the Zaï
• Captures rain and surface/ run-off water;
• Protects seeds and organic matter against being washed away;
• Concentrate nutrient and water availability at the beginning of the rainy season;
• Gives much better crop yields than normal cultivation without planting holes; and
Reactivates biological activities in the soil and leads to an
improvement in soil structure, water infiltration and water holding
The manure applied to the pits contains seeds of trees
or bushes. This helps the regeneration of the vegetation on fields
treated with pits.
The application of the Zai technique can reportedly increase production by up to 500% if properly executed.
A case study - The emergence and spreading of an improved traditional soil and water conservation practice in Burkina Faso
zaï emerged in a context of recurrent droughts and frequent harvest
failures, which triggered farmers to start improving this local
For information about the case study, click here.