Global attention on biofuels and the potential for Jatropha curcas to produce biodiesel from marginal land with low inputs has recently created world-wide interest in this species. This paper reports on the water dynamics and productivity of]. curcas in a silvopastoral experiment with Penniseturn clandestinum at the Ukulinga research farm of the University of KwaZulu-Natal near Pietermaritzburg, South Africa. Measurements of daily total evaporation rates during December February (summer) on clear hot days ranged between 3 and 4 mm d(-1). However, due to the deciduous nature of the species, water use was negligible (<1 mm d(-1)) during winter (May August). The results have shown that two- to four-year-old J. curcas trees were conservative water users. High oil yields are unlikely due to the low seed production. The best seed yield was in 2009 (348.8 kg ha(-1)) in the J. curcas only plots. The other treatments (where pasture competition was a factor) ranged between 77.8 and 166 kg ha(-1) Data collected on the time taken by labourers to harvest and dehusk the seeds, showed that 1 kg of seed took approximately 3 h to process, suggesting that mechanical harvesting would be necessary to make seed production economically viable. J. curcas showed a low tolerance to pests and was prone to diseases. This significantly increased the input costs for insecticides and fungicides. The South African results are so unequivocal that]. curcas under the experimental conditions does not fulfil the claims that it is a wonder biodiesel plant. (C) 2012 Elsevier Ltd. All rights reserved.