Fine roots in mixed plantations of Hevea (Hevea brasiliensis H.B.K. Müll. Arg.) and cacao (Theobroma Cacao L.). In: Theobroma v. 12 p. 101-105, 1982.

Abstract

Rootlet distribution in mixed plantations of Hevea (Hevea brasiliensis H.B.K. Müll. Arg.) and cacao (Theobroma cacao L.) was analyzed. Fine roots of both species occupy preferentially the upper 15 cm of the soil. Two to nine times more Hevea than cacao rootlets were found in all soil samples. Hevea rootlets are three times thicker (0.73 mm) than cacao rootlets (0.22 mm). Thus, 1 g dry weight of cacao rootlets extends over 36 m vs. 6.7 m of Hevea rootlets. Nevertheless, the rootlet surface area (2 r X length of rootlels) of Hevea reached 1 m2.m-2 vs. 0.5 m2 .m-2 in cacao. These observations suggest thal fertilizing in mixed Hevea cacao plantations of the conventional 7 x 3 m spacing would benefit preferentially the Hevea trees. This would result in higher leaf area indexes of Hevea and consequently produce light Iimitations for the shaded cacao trees.