A pilot project on the use of Farmer Participatory Research (FPR) methodologies with the objective of enhancing farmer adoption of practices that minimize soil erosion in cassava-based cropping systems, was conducted jointly by DOA and DOAE with technical and financial support from CIAT in two sites in Nakhon Ratchasima and Sra Kaew provinces. The activities involved a preliminary survey using RRA methodologies, the setting out of demonstration plots, as well as farmers meetings and farmers field trips to observe the demonstration plots.

A guideline for carrying out regional trials in cassava is given, including necessary steps (identification of collaborators, selection of sites, identification of person in charge, planting and harvesting season, exptl. design, plot size, and border rows); the technology used (selection and treatment of cuttings, plant density, land preparation, planting position, application of herbicides and fertilizers, pest and disease control); necessary visits (a min. of 7); and final agronomic trials to determine optimum density and age of var. at harvest.

In May 1980 the soil section of CIAT's cassava program established a fertilization trial with 3 cassava var. [Barranquena (regional), M Col 113, and CMC 921 to measure its effect on yield and establish optimum levels from an economical point of view. The trial took place in Mondomito and Agua Blanca, municipality of Santander de Quilichao, Cauca (Colombia). Twelve levels of NPK (0-0- 0; 0-100-100; 50-100-100; 100-100-100; 200-100-100; 100-0-100; 100- 50-100; 100-200-100; 100-100-0; 100-100-50; 100-100-200; 200-200- 200) were applied. Partial budgeting was used for the economic analysis.