ROOT DISTRIBUTION PATTERN OF THE WILD JACK TREE (ARTOCARPUS HIRSUTUS LAMK) AS STUDIED BY P-32 SOIL INJECTION METHOD

Root distribution of the wild jack tree (Artocarpus hirsutus) was dete rmined by selective placement of P-32 at various depths and lateral di stances from the tree, in Kerala, India. In eight-and-a-half-year-old trees growing on a lateritic site, absorption of P-32 from a lateral d istance of 75 cm and 30 cm depth was much greater than from 150 and 22 5 cm lateral distance and 60 and 90 cm depth. Root activity declined w ith increasing depth and lateral distance. Most of the physiologically active roots were concentrated within a radius of 75 cm and 30 cm dep th, although the tap root might reach even deeper. Possibly, surface a ccumulation of feeder roots may cause considerable overlap of the tree and crop root zones in intercropping situations. However, as the tree roots seldom extend beyond 2.25 m laterally from the hunk, the effect of overlapping root zones and the associated competitive effects may not be a serious problem for intercropping during the first few years (<10 years after planting) of tree growth.