This paper designed and developed a multi-objective programming (MOP) model to illustrate the dynamic relationship among technologies, productive activities, constraints and farmers' objectives in the peri-urban vegetable production system and use the model as an economic tool in analysing probable consequences of a given action or innovation on the farm. The best compromise solution was generated using four analytical steps, as follows: single-objective optimization (to determine the ideal and anti-ideal values of the objective functions); constrained optimization (to generate the set of Pareto non-dominated solutions); cluster analysis (to trim down efficient set into smaller homogeneous groups); and compromise programming (to determine where the best compromise solution lies). The study then evaluated the income and risk impacts of technological innovation, specifically that of the technologies espoused by the AVRDC-Manila Peri-urban project for tomato and pak choi production during the hot-wet season. It was found that relative to the current production system, the entry of grafted tomato under rainshelter in the best compromise solution could increase farmer's income, however, the price-induced risk also increased. This effect was brought about by the increased yield of tomato that caused variance of income to increase. This result indicates that under existing conditions, the higher income offered by the costly technology will only be acceptable if farmers are willing to take on the higher risk. The MOP model also assessed how making capital more accessible to the farmers will affect the extent of adoption (proxied by area planted to the crop) of the technology. Results showed that income would increase when capital constraint was relaxed. This increase in income, however, was made possible largely by the change in crop mix, with a relatively small increase in area planted to tomato. With regard the level of risk, the change in production resulted in an increase in price-induced risk. The results seem to indicate that for a risk-averse farmer, the availability of capital will not guarantee a significant increase in adoption of capital-intensive technologies. Rather, the results will be a non-linear, non-additive expansion of the original cropping mix or a significant modification of the crop mix at the farm level. (c) 2005 Elsevier Ltd. All rights reserved.
