Optimization Of Land Productivity In Zanzibar Through Intercropping Of Cassava (Manihot Esculenta Crantz) And Sweet Potato (Ipomoea Batatas L.Lam)

ABSTRACT

Two field experiments were conducted during the growing season of 2018/2019 at Zanzibar Agricultural Research Institute (ZARI) Unguja and Pemba. The objective of the experiment was to explore the potentiality of optimizing land productivity through intercropping cassava with sweet potato on limited land available. The experiment was a split-split plot laid out in a randomized complete block design (RCBD) with four replications. Improved cassava variety 'Kizimbani' was intercropped with improved sweet potato variety 'Mayai'. The main plot was intercropping time of sweet potato. Fertilizer application was a sub plot and sweet potato intercrop plant density of 10 000, 20 000 and 30 000 plants ha-1was a sub-sub plot. There were 48 intercropped plots and 32 sole-cropped plots. Data on crop establishment, plant height, canopy dimension, foliage cover, vine vigour, root/tuber yields and number of roots/tubers were collected and subjected to analysis of variance (ANOVA). The results revealed that there were significant differences between treatments in crop yields, vine vigor, plant height, foliage cover, canopy length, thickness and number of marketable roots/tubers. Furthermore, there were significant differences in the two sites in most of the observed characteristics. Matangatuani gave the highest yield of cassava (17.63tha-1) in intercropping compared with Kizimbani (13.15tha-1). However, for sweet potato, Kizimbanirecorded14.67tha-1 and Matangatuani13.75tha-1 .In addition, intercropping of cassava with sweet potato gave the highest land equivalent ratio (LER) of 1.75 in combined site analysis. This indicated that the greatest productivity per unit area was achieved by growing the two crops together.