We have also been experimenting...
At some point in the past ( I am not sure how far back it was), I visited a water conservation project in Machinga.
The communities there have built stone bunds along the contours of the hillside to slow the water down. They have also dug trenches of different sizes along the contour lines in their fields to both slow water down and allow the water to be absorbed more slowly permitting the villagers to cultivate their land for longer.
So we wanted to see if we could demonstrate how it was done here.
We chose this field as it runs along a road which many people use. The farmer asked us for seed and in exchange, I asked him if he would be interested in having a demonstration plot, and he agreed :)
Half his plot has been cultivated normally and half has trenches running along it at 10m intervals.
In plots with slopes less steep the trenches can be made at 20m intervals.
The idea is that people will notice the difference in the productivitiy of his plot and want to emulate it :)