摘要："Clean and safe" agricultural products are an important issue among consumers, farmers and governments. Many developing countries develop their produce at various points along the ‘clean’ continuum based on production practices related to use of synthetic chemicals. Organic farming is applied to technologies with no chemicals or synthetic fertilisers used during production or processing. It was initially developed by farmers and non-government organisations in Thailand, and subsequently implemented by the Thai government through a series of policies on clean produce to meet international standards. Safe-use and pesticide-free practices lie between organic and conventional practices, and are possible steps when converting conventional farms to organic farms. We compare the technical efficiencies and technology gaps of the four farming systems in northern Thailand of which three - organic, pesticide-free and safe-use - are designated ‘clean and safe’. Farm-level data on vegetable production were collected from random samples of farms using these technologies. A metafrontier model was estimated, enabling the estimation of technical efficiencies and technology gap ratios (TGRs) for vegetable farms operating under the different production systems. Conventional farms were expected to have the highest mean TGR (smallest distance from the metafrontier) as they are least constrained in the way they farm, and results bear out this expectation. The mean TGR for conventional farms is 0.80, significantly higher than that for organic farms at 0.45. But all production systems have farms lying on the metafrontier. In contrast to the TGR results, conventional farms have the lowest mean technical efficiency relative to their group frontier (0.33) and pesticide-free vegetable farms the highest (0.47), most likely reflecting the different degrees of technical assistance provided to farmers in these groups. Organic farming is that farmers in this group did not perform markedly worse than farmers in other groups in terms of productivity. There are numerous organisations and projects providing assistance for ‘clean and safe’ vegetable farming in northern Thailand. Scope exists to improve the performance of farmers in all groups as technical efficiencies and TGRs of farms vary widely in all groups. Improvements are needed for agronomic technology, supply chains, farmer capacity in production and marketing, and effectiveness of technology transfer strategies.
