I though that I had understood how land tenure is influence farmer's decision making. On my last trip to Adet (near to Bahir Dar), when I interviewed some farmers I discovered that I got it all wrong...
One farmer rented land, that mean his has only the certainty to use this land for one season. So my theory would say that he would never build a terrace as it is very labor intensive. But this farmer was building it. He explained to me that he was allowed to rent the land only if he would build the terrace. The owner does not have enough labor to build the terrace and gave his land for very low cost to anyone who would invest labor on the land.
I also visited a gully (erosion) that has been stabilized with an area exclosure (area where the livestock cannot access) with improved fodder, such as grass with long roots and multipurpose trees. It looked very good, the farmers are proud of it, and all see the benefit of this techniques. Despite of this 300m further there was an other gully, without stabilization, every year some centimetre from the field is lost, grass productivity is very low. So my first though was : a smart farmer improved his gully where as the non treated gully is communal land. And here wrong again : the treated gully was on communal land where as the non treated one belonged to a group of farmer privately.
What happened? Farmers are willing to give equal labour to rehabilitate communal land, as they understand that they are collectively responsible for this area. But on the privately owned land, farmers do not manage to coordinate, mainly because their field size are unequal, and so the smaller farmer would have to provide more labour to the bigger farmer, than the bigger farmer to the small one. As no one has money, one cannot pay for labour...
I had always believed that land tenure is a very important driver of farmers' decision making, but my field trip to Adet showed me that labour dynamics are the most important driver, at least in the Adet watershed.