Alley cropping kenaf (Hibiscus cannabinus) with leucaena (Leucaena leucocephala) in south-eastern Queensland

Abstract

Kenaf (Hibiscus cannabinus) was intercropped for 3 seasons between hedgerows of leucaena (Leucaena leucocephala) spaced 3 or 5 m apart on an infertile soil at Mt Cotton, south-eastern Queensland. The leucaena was cut at a height of25 or 50 cm, 2 or 4 times per season and the fresh material spread as a mulch between the rows of kenaf. The yield of kenaf from mulched plots was compared with that from plots fertilised with nitrogen as urea at 0, 50 or 100 kg N/ ha.year. In the third season, kenaf yield from the mulched plots was maintained at about 4.7 t DM/ha, whereas that from the control and urea fertilised plots declined by about 30%. However, phosphorus deficiency in the unmulched plots was suspected and this may have contributed to the lower yield. Leucaena row spacing had no significant effect on kenaf yield. Leucaena yield ranged from 2 to 4 t DM/ha per season. Cutting height had no significant effect on leucaena yield, but less frequent pruning gave a higher yield in the second and third seasons. The results confirm the potential of alley cropping to sustain arable crop yield at a moderate level without high inputs of inorganic fertilisers.