Root distribution pattern of New Zealand grapefruit (Citrus paradisi Macf.) budded on trifoliate orange rootstock

摘要

Root distribution pattern of 18 years old bearing trees of grapefruit cultivar New Zealand budded on trifoliate orange rootstock was studied by free monolith method of root excavation during spring season of 1999. The roots excavated from 3 radial distances i.e., 0-60 cm, 60-120 cm, 120-180 cm from the tree trunk and 3 depths i.e., 0-20 cm, 20-40cm, 40-60 cm from the ground level indicate that various categories of roots (fibrous, thin, medium and thick) differ significantly at various radial distances and depths (except thin roots). The maximum volume of active (fibrous and thin) roots was found at 0-60 cm radial distance and at 0-20 cm depth. Therefore, the fertilizers and irrigation water may be applied closer to the tree trunk at surface layerof soil for better absorption of water and mineral nutrients.