Plants occupying different vertical positions in a multicanopy agroforestry system (Issa Aliga)
In multicanopy agroforestry, annual crops that include maize, beans and shrub species such Calliandra and Sesbania are integrated so as to occupy the lower vertical spaces. The next height is occupied by taller crops such as coffee, cocoa and bananas while the highest layer is occupied by tall trees such as Maesopsis eminii, Makhamia lutea and Ficus nantalesis. This arrangement ensures that as much land as possible is utilized.
The upper strata of a multi-layered planting is called the overstory, or canopy. The trees that make up this layer play the key role in creating the understory. The shady environment in the understory (i) Reduces evapotranspiration (evaporation of water through the leaves and branches of the plant), conserving moisture in the plants and reducing water use (ii) Buffers crops from temperature extremes and fluctuations (iii) Protects crops from winds (iv) Suppresses many invasive problem weeds, which tend to prefer open conditions and full sun and (v) Supports a range of beneficial soil microlife that do not thrive in the open. On the other hand, understory crops should (i) tolerate partial shade (ii) exploit, at least partially, different soil horizons than the overstory trees (iii) be less tall than the overstory trees when mature (although some trees may be planned to use the shade as seedlings, but eventually overtake and become part of the upper layer) (iv) be less susceptible than the overstory trees to diseases they may have in common and (v) not involve damage to the overstory trees during cultivation or harvest of understory crops. The most important consideration when implementing this technology is that the various components of the plant system have to be compatible.
Management should be done to reduce competition for vertical and horizontal space. The number of trees per acre is 50% less compared with timber or fruit trees planted alone. Spacing should be planned to provide the most optimal environment for the understory, and minimize competition for space, light, and nutrients. The species growth rate, rooting patterns, and other factors should be taken into account when planning.
Required management activities include weeding, pruning, and thinning. Weeding is usually done twice every season mainly to take care of the annual crops such as maize and beans. Pruning is done whenever the farmer sees that light intensity from the upper canopy is no longer enough to support the understory crops. Usually, once a year is appropriate. Pruning is also done to reduce the risk of old branches falling and damaging crops and other farm structures. Thinning is done to reduce the number of seedlings from the soil ground.
The technology increases biodiversity on-farm, and protects the environment from degradation, soil loss, and wind break. This diversity has the advantage of reducing pest and disease incidence. The mixed fruits and trees provide timber and fuel wood, shade for coffee and banana, and keep the soil moist. It also acts as wind break which protects crops, farm structures and reduce soil loss by wind. It is a source of income to land user, provides food, improves the ecosystem, and leguminous plants fix nitrogen in the soil.
The technology is generally cheap to establish because the main inputs needed include tree seedlings, which were raised by the land user with the exception of the coffee seedlings and banana suckers which were obtained from outside. Labour is usually entirely family-based. The economic benefits are difficult to quantify due to the complex nature of the interaction among system components.
The potential limitations of understory intercropping include (i) Shortage of scientific study and information about tree/understory crop interactions (ii) Risk of unforeseen competition or allelopathic effects (iii) Greater complexity in management of multiple species and multiple products and (iv) Potential damage to overstory from harvest of the understory, or vice-versa.
Implementing multi-canopy agroforestry requires skills that are usually developed over long periods of time by farmers who observe the various interactions among the components and manage (especially the trees) to reduce the competition without compromising the benefits.
Байршил: Omoro District, Northern, Уганда
Дүн шинжилгээнд хамрагдсан технологи нэвтрүүлсэн газрын тоо: нэг байршилд
Технологийн тархалт: газар дээр жигд тархсан (approx. < 0.1 км2 (10 га))
Хэрэгжилтийн огноо: 1998
Нутагшууллын төрөл
Техникийн үзүүлэлтүүд
Зохиогч: Food and Nutrition Bulletin Volume 07, Number 3, 1985
- 20 to 30 meters between trees
- 3 meters between between coffee or banana plants - Beans or soybeans can be planted between coffee/banana plants - Trees are pruned to leave about one half of the crown |
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| Зардлын нэр, төрөл | Хэмжих нэгж | Тоо хэмжээ | Нэгжийн үнэ (Uganda Shillings) | Зардал бүрийн нийт өртөг (Uganda Shillings) | Нийт дүнгээс газар ашиглагчийн төлсөн % |
| Хөдөлмөр эрхлэлт | |||||
| Preparing of the nursery bed | Mandays | 30.0 | 5000.0 | 150000.0 | 100.0 |
| Transplanting | Mandays | 12.0 | 5000.0 | 60000.0 | 100.0 |
| Weeding | Mandays | 12.0 | 5000.0 | 60000.0 | 100.0 |
| Prunning of trees | Mandays | 15.0 | 5000.0 | 75000.0 | 100.0 |
| таримал материал | |||||
| Seedlings | Number | 100.0 | 3000.0 | 300000.0 | 100.0 |
| Технологи бий болгох нийт үнэ өртөг | 645'000.0 | ||||
| Зардлын нэр, төрөл | Хэмжих нэгж | Тоо хэмжээ | Нэгжийн үнэ (Uganda Shillings) | Зардал бүрийн нийт өртөг (Uganda Shillings) | Нийт дүнгээс газар ашиглагчийн төлсөн % |
| Хөдөлмөр эрхлэлт | |||||
| Weeding | Mandays | 30.0 | 5000.0 | 150000.0 | 100.0 |
| Pruning | Mandays | 15.0 | 5000.0 | 75000.0 | 100.0 |
| Технологийн арчилгаа/урсгал үйл ажиллагаанд шаардагдах нийт үнэ өртөг | 225'000.0 | ||||
