4. Research Development Division

4.3 Methodological and Conceptual Work

Tree/crop interface research methodology

A key issue in selecting, arranging and managing multipurpose tree/crop (or grass) mixtures of different kinds is to understand the ways to optimize environmental resource sharing for any selected set of outputs. At its simplest, this means the study and understanding of the tree/ crop interaction at their "interface". A project to derive appropriate field methods for carrying out experiments and sample trials with tree/crop interfaces is now in its third year.

The four small plots on the Field Station which had previously been used were supplemented in 1986 by additional plantings on a newly cleared, more suitable area — a 45° angle, replicated-plot geometric layout (using Grevillia robusta) and, a replant of the Cassia siamea/castor bean "Y" geometric design, with a duplicate layout using an inert fence, are the main ones.

The existing Cassia siamea/maize "Y" design was subjected to a detailed study, across one arm, of the rainfall inputs and, later in the year, soil water status. More equipment has been purchased for the environmental studies, as well as an additional microcomputer for data analysis (Wang APC). In addition "Lotus 1-2-3" and "Genstat" are among two of the software packages now being used to assist in this.

New data transfer programmes to assist with loading environmental information from the datalogger to the microcomputer have been prepared. A start was made on the analysis of data from previous seasons in preparation for presentation at the ICRAF/WMO/UNEP Workshop to be held in February 1987. The list of the factors to consider, and an appreciation of the potential and limitations of this experimental approach, are now becoming clear.

A documentalist and an analyst /programmer at work computer modelling.