The aim of the project is to set up a ten hectare field trial at each of the planting sites. These field trials are in three main parts.
The first is a straight forward randomised plot provenence trial. Provenances or accessions have been collected or bought from reliable sources, mostly in Kenya and also in Tanzanian and Uganda. DEGJSP was also able to import three provenances from Madagascar, one from India and will explore in Mexico in the harvesting season in May/June. In total, around 25 - 30 accessions are expected to be tried out in the provenance trials.
Using a vigorous and suitable provenance for tha area, the 'agronomy' trials will use randomised plots to measure the effect of different spacings, prunings and the application of key micronutrients before flowering.
Each company will then plant the remaining area with chosen provanances in an 'economic' trial to see how they can mazimise yeild, keeping a record of what they do.
Lessons are already being learnt, such that in some instances, presoaking does not always yield better germination results. The same seed can germinate 100% in the lab and do very poorly in the field. Jatropha seems to like high temperatures and a moist environment above 30 degrees c to germinate well. Putting the seed in at 3cm depths seems about optiumum. Where soils test have been done under wild plants in Kenya, the pH has often been above 7.5.
It is crucial to avoid ' J' root in nursery seedlings and in the planting out technqiues. Jatropha has to thrive in the first season (enough rain (<300mm) and warmth and nourishment) to do well from then onwards. If it has insufficient water initiall,y, it does not thrive.
Planting out is being slowed this year by the lack of rains.
One of the main features of the different sites is the variation in altitude from sea level up to 1900meters. It is clear that Jatropha can grow at 2000m on the equator, needing full attention and care to yield any fruit. Altitude probably most affects the maximum, minimum and mean temperatues as well as surrounding humidity. Some pretrials suggest that at very high altitudes, it can thrive by initially being intercropped wiith a taller plant such as maize or grown very close together. Amongst many other variables which will be measured, this study will probably contribute some insight into how much the effects of altitude are a factor to be considered in where Jatropha can be commercially viable in Eastern Africa.
