Pregermination treatments
Suggested pregermination treatments for key nitrogen fixing tree and shrub species that tolerate acid soils.
| Species | Treatment | Seeds/kg |
| Acacia aneura | B 1 min, S | 75,000–80,000 |
| Acacia angustissima | B, S | 90,000–100,000 |
| Acacia auriculiformis | B 30 sec, S | 30,000–90,000 |
| Acacia holosericea | B 1 min, S | 70,000–80,000 |
| Acacia koa | B 2 min, S | 8,500–20,000 |
| Acacia mangium | B 30 sec, S | 80,000–100,000 |
| Acacia mearnsii | B 5 mins | 48,000–85,000 |
| Acacia melanoxylon | B, S | 60,000–100,000 |
| Albizia lebbeck | B 3 sec | 6,000–16,000 |
| Albizia saman | B 2 min, C, S | 6,000–8,000 |
| Alnus acuminata | R | 200,000–2,000,000 |
| Alnus glutinosa | R | |
| Calliandra calothrysus | B | 14,000–19,000 |
| Casuarina cunninghamiana | R | 1,800,000 |
| Casuarina junghuhniana | R | 1,000,000–1,600,000 |
| Casuarina sumatrana | R | |
| Chamaecytisus palmensis | B 1 min | |
| Cedrelinga catenaeformis | B | |
| i>Dalbergia nigra | C | 10,000–30,000 |
| Desmodium gyroides | R | 500,000 |
| Desmodium nicaraguense | R | 500,000 |
| Desmodium velutinum | R | 500,000 |
| Enterolobium cyclocarpum | C, S | 800–2,000 |
| Enterolobium contortisiliquum | C, B | |
| Erythrina abyssinica | C | |
| Erythrina berteroana | C | |
| Erythrina poeppigiana | C | 3,000–5,000 |
| Erythrina fusca | C | |
| Erythrina variegata | B 10 min | |
| Flemingia macrophylla | R | 50,000–80,000 |
| Gliricidia sepium | C, B, or S | 7,000–12,000 |
| Inga acrocephala | R | |
| Inga codonantha | R | |
| Inga edulis | R | |
| Inga marginata | R | |
| Inga punctata | R | |
| Inga spectibilis | R | |
| Mimosa scabrella | B 3 mins | 60,000–90,000 |
| Mimosa caesalpinaefolia | B | |
| Paraserianthes falcataria | B 10 mins | 40,000–50,000 |
| Pithecellobium dulce | R | |
| Prosopis juliflora | B, S | |
| Pterocarpus indicus | R | 1,500–2,000 |
| Robinia pseudoacacia | B 2 min, S | 35,000–50,000 |
| Stryphnodendron adstringens | B | |
| Stryphnodendron excelsum | B |
B: Pour boiling water over seeds (about five times as much water as the volume of the seeds), stir gently for 1 to 2 minutes (or as specified), and then soak in cold water for 12 to 24 hours.
C: Soak seeds in cold water for 12 to 24 hours.
S: Nick the round end of each seed with a file, knife, or nail clipper or rub the round end on a rough surface such as cement until the white interior is barely visible. Soak the treated seeds in cold water for 12 hours.
R: Recalcitrant seed; no treatment needed.
Source:
Briscoe, C.B., S.M. de Faria, V. Lambert, G. Minnick, and R. Russo. 1996. Growing Nitrogen Fixing Trees in Acid Soils. In: M.H. Powell (ed) Nitrogen Fixing Trees for Acid Soils – A Field Manual. Winrock International, Morrilton (AR), USA. p. 22.