Abstract
An experiment was conducted to determine the behaviour of taro [Colocasia esculenta (L.) Schott] in response to increasing rates of N from 0 kg N to 600 kg N ha-1 as CO(NH2)2 under an intercrop with pigeonpea [Cajanus cajan (L.) Millsp.] and two monocrop upland production systems in a Fluventic Eutropepts soil. Application of N improved vegetative growth which was characterized by an increase in plant height and a shorter leaf emergence interval (LEI) resulting in a more than doubling of the leaf area index (LAI) compared to the control. Cut-leaf yield of plants treated with N increased by 160% relative to the control, while the corm yield had declined by 40% in the same plants. A compensatory effect of a significantly more rapid leaf emergence rate and longer leaf duration was observed in these plants that had been defoliated and is identified as a response mechanism that allows this crop to support multiple organ harvest. In the intercrop, however, the LAI was reduced due to a longer LEI and shorter leaf duration but main corm yield was reduced by only 8.2%. The results showed a clear potential for taro to be cultivated in a range of production systems on upland soils which could be useful in providing farmers with alternatives for the same crop. Nitrogen fertilization was also influential in the production levels generated both from leaf and corm harvesting, however, the need to improve on the uptake efficiency of added N by the crop is recognized.
