Agroforestry Chapter 8 (Part 2): Fodder Trees: Mulberry, Grewia, Robinia and Subabul
Agroforestry Notes · Chapter 8 · Part 2
Chapter 8 (Part 2): Fodder Trees: Mulberry, Grewia, Robinia and Subabul
Morus alba, Grewia optiva, Robinia pseudoacacia and Leucaena leucocephala: identity, site, silvics, seed and nursery facts, propagation, spacing and uses.
1. The four fodder trees at a glance
| Point | Mulberry | Grewia | Robinia | Subabul |
|---|---|---|---|---|
| Botanical name | Morus alba | Grewia optiva | Robinia pseudoacacia | Leucaena leucocephala |
| Family | Moraceae | Tiliaceae (now Malvaceae) | Leguminosae: Papilionoideae | Leguminosae: Mimosoideae |
| Origin | Indigenous | Indigenous (sub-Himalaya) | North America | Mexico, Central America |
| Light | Shade bearer | Strong light demander | Strong light demander | Light demander |
| Seed count | 430–460 per g | 12,000–15,000 per kg | 60,000–80,000 per kg | 20,000–26,000 per kg |
| Main propagation | Stumps; branch cuttings for clones | Seed (pre-treated); stumps | Seed after hot water; root suckers | Direct seed after hot water/scarification |
| Key use | Sports goods; silkworm leaves | Fodder, fibre; elastic wood | Fodder, bee flora | Fodder, fuel, pulp |
2. Mulberry (Morus alba L.)
- Names: Shahtut, tut, tutri, chinni; moderate-sized, short-lived tree whose trunk becomes hollow with age.
- From Jammu and Kashmir to Assam, up to about 1200 m; rainfall 400–4500 mm, needs irrigation below about 1200 mm.
- Cannot tolerate alkalinity; best at pH 6.0–7.5.
- Shade bearer (good understorey), surface feeder with high water need; coppices and pollards very well, but trees above 30 cm diameter coppice poorly.
- Seed dispersed by water and birds; collect fruits from the tree, not the ground.
- Seed in gunny bags loses vitality in a year; in dry sand or ash it keeps over two years. Stratify in moist sand at about 5 °C for 30–90 days; kerosene treatment against ants.
- Sow in May–June. Stump planting beats entire plants: stumps of 1.5–2 cm collar, 22 cm root and 8 cm shoot.
- Spacing 4 × 4 m or 5 × 5 m when timber and leaf are both wanted.
- Wood for hockey sticks, rackets, cricket bats; CV sapwood 4658, heartwood 5003 kcal/kg; leaves feed cattle and silkworms.
3. Beul (Grewia optiva Drumm.)
- Names: Beul, Bhimal, Dhaman. The most popular farm fodder tree of the sub-Himalayan tract: fodder, fibre and fuel.
- On field boundaries and terraces from J&K to Nepal up to 2000 m; max temperature seldom above 38 °C, min rarely below −2 °C.
- Leaf fall Mar–Apr; flowers Apr–May; fruit ripe Oct–Nov. Strong light demander, frost hardy, coppices very well.
- Fruit is a 2–4 lobed drupe, black and edible; fruits are not borne on the current year’s shoot, so completely lopped trees do not fruit.
- 12,000–15,000 seeds/kg; hard testa; soak more than 12 hours; sow Mar–Apr, 2 cm deep, lines 15 cm apart; plantable by July.
- Planting at monsoon onset at 4 × 4 m, or 4–5 m apart on bunds; stumps from 15-month seedlings.
- Cuttings soaked 20 h in IAA 100 mg/l gave 77.5% rooting in June under mist; air layering also works.
- Wood is white, hard and elastic (oars, axe handles, bows); bark gives cordage fibre; fuel smells bad.
Exam point: Grewia is lopped heavily in winter, the lean fodder season in the hills, and is the classic protein bank tree of Himachal and Uttarakhand.
4. Black locust (Robinia pseudoacacia L.)
- Medium-sized, thorny, deciduous tree with paired triangular spines; native to North America.
- Introduced to Himachal Pradesh in 1890 and to J&K in 1919; does well at 1800–3000 m, rainfall 700–1750 mm.
- Favours lime-derived soils (pH 4.6–8.2); versatile colonizer of eroded slopes.
- Strong light demander, frost hardy, drought hardy when mature, coppices freely, and sends up root suckers from roots running 12–15 m.
- Seeds from age 2–3; 60,000–80,000 seeds/kg; hot-water treatment (or 24 h cold soak); sow in March; germination 70–85%.
- Spacing 2.5 × 2.5 m in blocks, about 4 m in lines round fields, 2 × 2 m on poor sites.
- Protein-rich leaf fodder (Ca, P); leaves lopped in Sept–Oct have higher TDN than in June–July. Also timber and bee flora.
5. Subabul (Leucaena leucocephala (Lam.) de Wit)
- Names: Subabul, Ipil-ipil; evergreen shrub or small tree with feathery bipinnate leaves; native to Mexico, Guatemala, Honduras, El Salvador.
- Four types: Hawaiian (bushy), Salvador (tall tree, “giant”), Peru (branching, fodder) and Cunningham (Salvador × Peru).
- Needs neutral to alkaline soils: yield falls 50% at pH 6.8 and 80% at pH 6.3; thrives on coral and limestone.
- Long taproot, fire tolerant, drought resistant, frost tender, good coppicer, aggressive colonizer; needs Rhizobium and VAM.
- 20,000–26,000 seeds/kg; refrigerated seed keeps 20 years. Hard waxy coat: hot water 3–4 min (~80% germination), acid or scarification.
- Direct seeding 10–20 kg/ha, 1–2 cm deep; germination in 6–8 days. Cuttings root best (80%) with IAA 100 ppm in January.
- Spacing: timber 10 × 2 m (thinned to 10 × 4, 10 × 6 m); firewood 1 × 2 m; forage in furrows 75 cm apart.
- Uses: fodder, fuelwood, charcoal, pulp, poles, alley cropping; fixes 100–500 kg N/ha/yr (Nair).
Exam point: Leucaena leaves contain the toxic amino acid mimosine; feed no more than about a third of the ration and mix with other fodder. The psyllid Heteropsylla cubana devastated Leucaena in Asia in the late 1980s (Nair).
6. Quick revision box
- Mulberry: Moraceae, shade bearer, 430–460 seeds/g, stump 22 cm root + 8 cm shoot, sports goods.
- Grewia: Tiliaceae (now Malvaceae), up to 2000 m, lopped trees do not fruit, IAA 100 mg/l → 77.5% rooting.
- Robinia: North America; HP 1890, J&K 1919; root suckers; 60–80 thousand seeds/kg; bee flora.
- Leucaena: 4 types (Hawaiian, Salvador, Peru, Cunningham); −50% at pH 6.8, −80% at pH 6.3; mimosine.
7. Interactive MCQ Quiz
15 questions. Tap an option to see the answer and explanation, then go to the next question.
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