Volume 39, 88-98

Tropical Grasslands (2005) Volume 39, 88–98

Emergence and seedling survival of leucaena on poorly drained soil and management practices to mitigate negative effects

I.V. EZENWA AND R.S. KALMBACHER

University of Florida, Range Cattle Research and Education Center, Ona, Florida, USA

Abstract

Leucaena (Leucaena leucocephala) has potential in Florida as a pasture legume, but soils are often imperfectly drained making establishment difficult. We conducted 2 glasshouse studies to determine responses of 8 leucaena and 1 Calliandra calothyrsus selection to different soil moisture conditions. In the first, freely drained and waterlogged soils were compared. In freely drained soil, seedling emergence was greater for leucaena (78–93%) than for calliandra (53%), but in waterlogged soil emergence of all entries was depressed (3–20%). In the second, 4 water regimens were compared: maintaining water level at 3 cm above the soil surface; at the soil surface; and 15 cm below the soil surface; and as freely draining soil. Water level at 15 cm below the soil surface gave best seedling growth. Water at or above the surface induced aerenchyma on stem bases, which enabled persistence under waterlogging.
A field study examined the effects of bedding (raised and flat), propagule (seed and seedlings) and time of planting [July (during) and October (after rainy season)] on seedling survival of 5 leucaena selections. Leucaena K636 and K340, with >80% survival, established well in July or October with seed or seedlings, but K749, K784 and LxL, with 63–70% survival, established best in October with seedlings. Results demonstrate that bedding may not improve survival of leucaena seedlings during high rainfall periods, with propagule, selection and time of planting being more important.