TO CONTROL OR NOT TO CONTROL: HOW DO WE LEARN MORE ABOUT HOW AGRONOMIC INNOVATIONS PERFORM ON FARMS?

Abstract

Our paper 'Loading the dice in favour of the farmer: reducing the risk of adopting agronomic innovations'revealed mean increases but also large variation in the impact of four agroforestry practises on maize yield,as experienced by farmers in Malawi. This prompted a response from Sileshi and Akinnifesi that wascritical of the data and methods used. Their main concern was that farmers did not necessarily managecrops identically in plots with and those without trees, so the yield differences that we measured may bepartly caused by these differences in crop management. We argue here that it is valid and useful to lookat the actual effect on crop yield of farmers having trees intercropped with maize, rather than controllingfor how the crop is managed, because this is what happens in the real world. Farmers respond to havingtrees in their field by treating their crop differently, so this is part of the system response to having trees infields. Attempts to eliminate this will result in measuring an artefact rather than the real impact of treeson crop yield. By doing this, we revealed important variation in the impact of trees on crop yield amongstfarmers, and we argue that it is important to explore, assess and communicate to farmers and developmentactors the extent and implications of this variation. Understanding the contextual factors that determinewho is likely to benefit most from an innovation and for whom it is less suitable can then be incorporatedin scaling up, so that targeting of innovations and the appropriateness of messages given to farmers arecontinuously refined