Nitrogen and phosphorus fertilization promotes rapid initial growth of leucaena on Alfisol

Abstract Early growth of leucaena (Leucaena leucoceohala (Lam) de Wit) is often slow, especially on soils low in organic matter and total N. This study was conducted to determine whether small quantity of N fertilizer in combination with P will enhance early growth. Nitrogen as urea was applied at 0, 25, and 100 mg/kg soil with 50 mg P/kg soil as monocalcium phosphate or without P to leucaena seedlings in pots. All plants were inoculated with leucaena Rhizobium (LX 382). Growth rates declined from 0.3 cm/day at 14 to 0.22 cm/day at 42 days after planting (DAP) in no‐P plants. Fertilizer N and P application increased growth rates sharply thus hastening shoot and root dry matter accumulation. P uptake was enhanced with 25 mg N/kg soil at 42 and 84 DAP, but not at 126 DAP. It appears small amount of N applied with adequate P enhanced P uptake and hence early growth of leucaena.