Agroforestry Chapter 4 (Part 1): Agrisilvicultural Systems: Alley Cropping, Homegardens and Plantation Crops
Agroforestry Notes · Chapter 4 · Part 1
Chapter 4 (Part 1): Agrisilvicultural Systems
Alley cropping, multispecies tree gardens, MPTs on farmland and parklands, plantation crop combinations, homegardens, hortisilviculture, fuelwood and soil conservation hedges.
1. Alley cropping (hedgerow intercropping)
Developed at IITA, Ibadan (Nigeria) by B.T. Kang and colleagues (Kang et al., 1981). Perennial, preferably leguminous, trees or shrubs are grown as hedgerows in wide rows and the crop is sown in the alleys. The hedges are pruned during cropping; the prunings are used as mulch or green manure to cut evaporation, smother weeds and add nutrients and organic matter. When the prunings also feed livestock it is called alley farming.
Layout
- Hedgerows run east to west so that crops on both sides get full sunlight.
- Spacing: 4–8 m between rows, 25 cm–2 m within rows.
- Closer spacing in humid areas, wider in sub-humid and semi-arid areas.
- On slopes, hedgerows along the contour act as live barriers and build natural terraces.
Ideal hedgerow species
Sparse, small crown; fast re-sprouting after pruning, coppicing, pollarding or lopping.
Deep taproot to draw water and nutrients from depth; shallow laterals that are easily pruned by ploughing.
Fast-decomposing leaf litter.
Ability to fix atmospheric nitrogen.
Non-exacting; grows on poor sites.
Gliricidia sepium, Leucaena leucocephala, Flemingia macrophylla, Calliandra calothyrsus, Erythrina subumbrans, Albizia saman, Paraserianthes falcataria, Cajanus cajan.
- More nutrients and organic matter; less chemical fertiliser
- Better soil physical condition
- Less erosion
- Extra forage, firewood and stakes
- Better weed control
- High labour for pruning
- Tree–crop competition for water in dry areas
- Land taken by hedgerows
- Best only on humid, sub-humid lands
2. Tree gardens, MPTs on farmland and parklands
Multispecies tree gardens are mixtures of many tree species managed for food, fodder and wood for home use and sale. Multilayer tree gardens suit fertile soils, good labour and dense population.
In multipurpose trees on farmlands, trees are scattered at random or in patterns on bunds, terraces and plot boundaries. They give products, while their protective role is fencing and plot demarcation. Typical trees: Leucaena leucocephala, Acacia (Faidherbia) albida, Cassia siamea, Casuarina equisetifolia, Azadirachta indica, Acacia senegal, Cocos nucifera.
Shows reverse phenology: leafless in the rainy (cropping) season and in leaf in the dry season. Crops under it often yield more than in the open.
Key farm tree of the Thar desert; leaves are fodder (loong), pods (sangri) are food; crops grow better under it.
Vitellaria paradoxa (shea butter) and Parkia biglobosa are retained on West African farms.
3. Plantation crop combinations
Perennial plantation crops such as tea, coffee, cacao, coconut, arecanut, rubber and spices are combined with trees and crops in four ways: integrated multistorey mixtures, mixtures in alternate rows, shade trees for plantation crops, and intercropping with agricultural crops.
| Plantation crop | Shade / support trees |
|---|---|
| Tea (Camellia sinensis) | Albizia chinensis, A. odoratissima, A. lebbek, A. procera, Acacia lenticularis, Derris robusta, Grevillea robusta, Erythrina lithosperma, Indigofera teysmannii |
| Coffee (Coffea arabica) | Temporary: Erythrina lithosperma. Permanent: Ficus glomerata, F. nervosa, Albizia spp., Dalbergia latifolia, Artocarpus integrifolius, Bischofia javanica, Grevillea robusta |
| Cacao (Theobroma cacao) | Coconut and arecanut; Dipterocarpus macrocarpa in forest |
| Black pepper (Piper nigrum) | Erythrina indica, Garuga pinnata, Spondias, mango, Gliricidia, Grevillea robusta (live standards) |
| Small cardamom (Elettaria cardamomum) | Forest shade; temporary shade of Maesopsis eminii |
| Large cardamom (Amomum subulatum) | Alnus nepalensis, Schima wallichii, Cinchona, Albizia lebbek, Castanopsis, Terminalia myriocarpa |
Coconut-based systems
- More than 90% of the world’s coconut area is in Asia and Oceania, mostly on smallholdings.
- Light under coconut is high in young stands and again after about 25 years; it is lowest between about the 8th and 25th year, the poorest time for intercropping.
- Multistorey coconut gardens combine coconut with pepper, cacao, banana, pineapple and tubers.
- Cattle grazing under coconut is common in South-East Asia and the South Pacific.
4. Homegardens
The definition comes from Fernandes and Nair (1986). Homegardens are among the oldest agroforestry practices and are found in the high-rainfall areas of South and South-East Asia. They are highly productive, extremely sustainable and practicable. Strictly, a homegarden with livestock is an agrosilvopastoral system.
| Layer | Typical components (Kerala type) |
|---|---|
| Top (above 15 m) | Coconut, arecanut, jackfruit, teak, Ailanthus, other timber trees |
| Middle (5–15 m) | Mango, cashew, guava, banana, papaya, drumstick |
| Lower (1–5 m) | Coffee, cacao, tapioca, shrubs; climbers such as black pepper on trees |
| Ground (below 1 m) | Shade-loving vegetables, ginger, turmeric, colocasia, yam, pineapple, fodder grasses |
- Homestead size is usually 0.2–0.5 ha; most homegardens have 3–5 canopy layers.
- India: Kerala, Tamil Nadu, Tripura, Assam, West Bengal, Andaman and Nicobar Islands.
- Hills: Grewia optiva, Ficus glomerata, Juglans regia, Punica granatum.
- Animals: cattle and poultry; fodder grasses such as Napier, Guinea, Guatemala, Setaria (Kazungula), Stylosanthes.
- Java: Pekarangan (homegarden) and Talun-kebun (mixed garden); homegardens met 15–20% of household fuelwood needs.
- Other names: compound farm (Nigeria), kitchen garden, household garden, homestead agroforestry.
- Chagga homegardens on Mount Kilimanjaro (Tanzania) combine coffee, banana, trees and stall-fed cattle.
5. Hortisilviculture, fuelwood and soil conservation hedges
At UHF Nauni (Solan), the AICRP centre developed hortisilviculture with peach, pear, apricot and pomegranate and Toona ciliata and Grewia optiva on the field boundary. Hortipastoral systems combine fruit trees with grasses only.
Fuelwood trees interplanted on or around farms also act as fences, shelterbelts and boundaries. Species: Acacia nilotica, Albizia lebbek, Cassia siamea, Casuarina equisetifolia, Dalbergia sissoo, Prosopis juliflora, Eucalyptus tereticornis.
Multipurpose and fruit trees with crops, mainly for soil conservation. Species: Grevillea robusta, Acacia catechu, Pinus roxburghii, Acacia modesta, Prosopis juliflora, Alnus nepalensis, Leucaena leucocephala.
6. Alley cropping by the numbers (Nair)
Nair gives the research figures behind alley cropping, which the e-course leaves out. Huxley (1986) calls hedgerow intercropping a zonal arrangement of trees and crops.
| Hedge species (IITA, Ibadan) | Prunings (t dry matter/ha/yr) |
|---|---|
| Leucaena leucocephala | 8.64 |
| Gliricidia sepium | 5.18 |
| Alchornea cordifolia | 3.77 |
| Dactyladenia (Acioa) barteri | 2.07 |
| Species (hedges 4 m × 0.5 m) | N | P | K (kg/ha/yr in prunings) |
|---|---|---|---|
| Leucaena | 247 | 19 | 185 |
| Gliricidia | 169 | 11 | 149 |
| Alchornea | 85 | – | – |
| Dactyladenia (Acioa) | 41 | – | – |
- Duguma (1988): pruning twice a year at 100 cm height gave the most N: Leucaena 245, Gliricidia 206, Sesbania grandiflora 111 kg N/ha/yr.
- Kang (1981): 10 t of fresh Leucaena prunings supply about 100 kg N.
- Yamoah (1986): in 120 days the prunings lost dry matter as follows: Gliricidia 96%, Flemingia 58%, Cassia siamea 46%. Gliricidia supplied 71% of the maize crop’s N; Flemingia only 26%.
- Cassia siamea, although it does not fix N, built up the most soil organic matter because its litter decays slowly.
- Budelman (1989): a 5 t/ha mulch cut soil temperature at 5 cm from 37.1 °C (bare) to 34.2 (Leucaena), 32.5 (Gliricidia) and 30.5 °C (Flemingia).
Worked example: how much N do hedges give?
Only about half of this N reaches the crop. In a similar estimate (Torres, 1983), Leucaena hedges 5 m apart, cut every 8 weeks, gave about 45 g N per metre of hedge a year. There are 2,000 m of hedge per hectare, so this is about 90 kg N/ha/yr.
Yields and erosion
| Study | Finding |
|---|---|
| Kang et al., IITA, 8 years | Maize 2 t/ha with prunings vs 0.66 t/ha without; over 3 t/ha with prunings plus 80 kg N |
| Ghosh (1989), South India, 1,700 mm, 5–9% slope | Soil loss: bare 11.94; Leucaena hedges 5.15; Leucaena + cassava 2.89 t/ha/yr |
| Lal (1989), IITA | Erosion 85% lower with Leucaena and 73% lower with Gliricidia than plough-till; Leucaena at 2 m as good as no-till |
Where alley cropping failed
- Yurimaguas, Peru (acid Ultisol): root competition from about 11 months; crop yields fell.
- ICRISAT, Hyderabad and north-west India (Mittal and Singh, 1989): semi-arid, yields fell because hedges took the water.
- Machakos, Kenya (700 mm, Jama-Adan, 1993): Cassia siamea did better than Leucaena.
- Alley cropping cannot replace fertiliser, but it makes fertiliser more efficient. Yields must be compared per gross area, including the land under hedges.
- In Haiti, farmers value the hedges mainly for fodder and erosion control (Bannister and Nair, 1990).
- AFNETA = Alley Farming Network for Tropical Africa.
7. Homegardens and plantation crops: Nair’s details
One practice, many names
| Name | Used by |
|---|---|
| Mixed-garden horticulture | Terra (1954) |
| Compound farm | Lagemann (1977) |
| Kitchen garden | Brierley (1985) |
| Household garden | Vasey (1985) |
| Homestead agroforestry | Nair and Sreedharan (1986) |
| Homegarden | Place | Feature |
|---|---|---|
| Pekarangan | Java, Indonesia | Five canopy strata |
| Kandy gardens | Sri Lanka | Spice and fruit trees around houses |
| Compound gardens | Kerala, India | Coconut-based, 3–5 layers |
| Compound farms | South-east Nigeria | Food trees around the compound |
| Chagga homegardens | Mt Kilimanjaro, Tanzania (900–1,900 m) | Arabica coffee + banana + trees + stall-fed cattle; five strata |
| Ka/Fuyo | Burkina Faso | Semi-arid; only two strata |
| Huertos familiares | Tabasco, Mexico | Family orchards |
| Kitchen gardens | Grenada (Caribbean) | Small island gardens |
Michon (1983), Citarum basin, West Java, measured how the canopy is shared between layers: below 1 m 14%, 1–2 m 9%, 2–5 m 25%, 5–10 m 36%, above 10 m 16%. The 5–10 m layer of fruit trees is the largest.
- Coffee entered the Chagga gardens around the 1890s.
- Sommers (1978), 40 households in the Philippines: homegardens were an important source of vitamins A and C, iron and calcium.
- Okafor (1981), Nigeria: compound farms keep Irvingia gabonensis, Dacryodes edulis and Tetracarpidium conophorum, whose seeds and fruits are rich in fat and protein.
- An international workshop on tropical homegardens was held at Bandung, Indonesia, in December 1985.
Plantation crops
- Plantation crops cover about 8% of the arable land of developing countries, mostly on smallholdings. Hildebrand: a small farm is “more of a home than a business”.
- Rubber yield has risen about 17-fold since domestication; coconut and cashew have had little research.
- Coconut covers over 6 Mha: Philippines 2.1, Indonesia 1.8, India 1.1 Mha. It needs over 1,000 mm rain; usual spacing 7.5 × 7.5 m; its roots stay close to the bole (Kushwah, 1973), leaving the interspaces free.
| Term (India, Nelliat 1974) | Meaning |
|---|---|
| Intercropping | Annual or seasonal crops in the interspaces of a perennial crop |
| Mixed cropping | Other perennial crops in the interspaces |
| Multistoried cropping | Annuals and perennials grown together in several tiers |
| Mixed farming | Crops combined with livestock |
- 1 ha coconut + fodder grasses (hybrid Napier, Guinea, Guatemala grass Tripsacum laxum: 50–60 t/ha green fodder; stylo and cowpea about 30 t)
- 4 dairy cows and a biogas plant
- Net income about 50% more than coconut alone
- Each cow eats 30–35 kg green fodder a day, grass:legume 3:1
- Coconut + cacao actually raised coconut yield
- Cacao under Erythrina poeppigiana (pruned 2–3 times a year) and Cordia alliodora (timber)
- Prunings and litter return about 270 kg N, 60 P and 150 K/ha/yr
- Litter: Erythrina 22.9 t, Cordia 11.4 t/ha/yr
- Cordia stem growth 9.6 m³/ha/yr
Carrying capacity about 1–2 ha per animal (Plucknett, 1979).
Kebun-talun (Java); Sumatran tree gardens of durian, cinnamon and nutmeg (Michon, 1986); babassu palm (Orbignya phalerata) with crops and pasture in Brazil.
8. Quick revision box
- Alley cropping: IITA Ibadan, Kang (1981); E–W rows; 4–8 m between rows; 25 cm–2 m within.
- Hedge species: Gliricidia, Leucaena, Flemingia, Calliandra; best in humid/sub-humid areas.
- Faidherbia albida: reverse phenology. Khejri: Thar desert.
- Coffee temporary shade: Erythrina lithosperma; tea: Albizia, Grevillea.
- Large cardamom: Amomum subulatum under Alnus nepalensis.
- Coconut: 8th–25th year least light; >90% area in Asia–Oceania.
- Homegarden: Fernandes and Nair (1986); 0.2–0.5 ha; 3–5 layers; Kerala; Pekarangan (Java); Chagga (Kilimanjaro).
- Hortisilviculture: fruit + timber trees; hortipasture: fruit + grass.
- IITA prunings: Leucaena 8.64 > Gliricidia 5.18 > Alchornea 3.77 > Acioa 2.07 t DM/ha/yr.
- Hedges 5 m apart, 6 prunings × 375 g DM/m, 3% N → 135 kg N/ha/yr. Failures: Yurimaguas, ICRISAT, Machakos. AFNETA.
- Ka/Fuyo = Burkina Faso; Chagga 900–1,900 m; Michon: 5–10 m layer 36%.
- Nelliat: mixed cropping = perennials in interspaces; mixed farming = crops + livestock. CPCRI mixed farming +50% income.
9. Interactive MCQ Quiz
26 questions. Tap an option to see the answer and explanation, then go to the next question.
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