EFFECTS OF INTERCROPPING MAIZE AND SUNNHEMP ON GROWTH Zea mays L) ON PERFORMANCE.) AND YIELD YIELDS P M Mabuza and O T Edje ABSTRACT Introduction. Maize is the staple crop in Swaziland. Problem Statement. For about two decades, Swaziland has not been able to meet its maize requirements. Shortfalls have been met by imports and donations. Factors contributing to the shortfall include high fertiliser prices which rose by 370% between 2004 and 2008 cropping season. In addition to the high cost, the adverse effects of global warming has challenged the agricultural industry to seek alternatives to synthetic fertilisers, which have also been blamed for global warming. Sunnhemp is an ideal solution to these challenges. Objective The objective of this experiment was to evaluate the performance of two sunnhemp [Crotalaria juncea (L.)] cultivars for maize production. Materials and Methods. A field trial was conducted at the University of Swaziland Crop Production Farm during the 2008/2009 cropping season. The design was randomised complete block. The treatments were: (1) maize, variety SC 403, in monoculture with the addition of synthetic fertilisers; (2) sunnhemp cultivar A (dwarf) in monoculture; (3) Sunnhemp cultivar B (tall) in monoculture; (4) sunnhemp cultivar A in mixed stand with maize and (5) sunnhemp cultivar B in mixed stand with maize. Each treatment was replicated four times and all treatments, including maize, were planted on the 30 October, 2008. Data collected for sunnhemp included plant height and biomass, maize data collected included plant height, number of leaves, leaf area and leaf area index, biomass, seed yield components and seed yield. Data on growth analysis were taken between seven and 15 weeks after planting (WAP). The results showed that sunnhemp fresh biomass for the dwarf and the tall cultivars in monoculture at 15WAP were and 24.2 and 39.3 tonnes/ha, respectively. Maize in monoculture was 7877 kg/ha. Maize yields in mixed stand with the dwarf and the tall cultivars were 7295 and 3891 kg/ha, respectively. The yield differences were significant at P < 0.01. Maize seed yield was positively and significantly (P < 0.01) correlated with 100-seed mass. The coefficient of determination, R2 , was 0.9082, indicating that 90.82% of the differences in seed yield could be attributed to the difference in 100-seed mass. Conclusion. It is concluded that the tall cultivar performed better than the dwarf with respect to biomass production, but was too aggressive and competitive by its size and frame and thus reduced maize seed yield. Recommendation. It is recommended the tall sunnhemp should not be grown in mixed stand with maize if both crops will be allowed to grow to maturity. However, farmers who wish to grow sunnhemp as a monocrop for biomass production are encouraged to grow the tall cultivar. Index words: Intercropping, sunnhemp, crop rotation, conservation agriculture, cropping system, maize, green manure crop.