Study design

Study 1

A split-plot field experiment was designed at each site (Umbumbulu and Ukulinga) to compare the effects of planting date and organic fertiliser level on growth, yield, corm crisping quality and mineral content of the three taro landraces. The landraces were planted on four dates: October 2007, November 2007, December 2007 and January 2008, randomised across main plots. Each experiment had three replicates of main plots. Factorial combinations of landraces (Dumbe-Dumbe, Mgingqeni and Pitshi) and levels of organic fertiliser (Gromor Accelerator) (0, 5330 and 10660 kg ha ^-1) were randomised across sub-plots. Gromor Accelerator nutritional composition is as follows:

Soil samples were collected and analysed before the start of the experiment and the amount of organic fertiliser to be applied in each experiment was calculated based on these results. The soil was sampled from the top 30 cm to represent the zone that contains the roots of the plant and a grid was used to collect a set of representative samples. Some of the results of analyses are shown below.

Rainfall and temperature data were obtained from Weather South Africa for the duration of the experiments.