The objectives of this study were to analyze factor affecting on adoption related to Good Agricultural Practices (GAP) standard of farmers who produced GAP vegetables in the upper north by means of ordered probit model and to analyze Composite Indicators of Agricultural Sustainability (CIAS) from economic, social, and environmental indexes. The samples of this study were randomized by means of stratified random sampling from districts, sub-districts, communities to GAP farmer households according to database of the Office of Agricultural Research and Development Region 1 (OARD 1). Data were collected in the form of interviews with questionnaires from farmers who produced basil and sweet basil group, bell-pepper group, purple eggplant group, and other GAP vegetable group (long and small eggplants, bitter gourd, parsley, cowpea, cabbage, and cauliflower) divided into 138 households in Chiang Mai, 50 households in Chiang Rai, 95 households in Lamphun, and 100 households in Lampang provinces.
It could be concluded that the proportion between own and loan to produce GAP vegetables, variety of GAP vegetables, suitable prices on quantities, safety knowledge of GAP vegetable consumption by private agencies, attitude on GAP vegetable production, members of Bank for Agriculture and Agricultural Cooperatives, members of farmer groups, members of community enterprises, and members of other groups had influence on adoption in a very suitable level with the high probability of occurrence while age, education of the farmers, freshness of GAP vegetables, safety knowledge of GAP vegetable consumption by government agencies, members of village funds, and adoption level of practices according to GAP requirements had influence on decreased adoption in a very suitable level with the probability of occurrence from marginal effect values. Furthermore, the practices related to GAP vegetable production of farmers was consistent at a very suitable level of the average of 1.70 according to likert scales in 5 practices which were hygienic practice management in the fields, agricultural tool management, input management, practice and control, and recording and controlling documents.
According to the creation of CIAS, CIAS consisted of economic, social, and environmental indexes. Each index was analyzed by the component factors. It was found that the component factors were divided into 2, 2, and 1, respectively. It indicated that the component factors of economic index were sales of GAP vegetables and variety of income sources of the farmers and that of social index were agricultural career security and working hours of labors to produce GAP vegetables. Moreover, the component factor of environmental index was environmental conservation index. These indexes led to the CIAS index that was less value. It indicated that although the farmers remained GAP vegetable production, the production was not widespread and was not strict according to GAP standard. After, the farmers have already produced the based cropping system, the GAP vegetable production was produced as the minor cropping system. However, the GAP vegetable production should be improved to develop expansion path of GAP vegetable production broadly, resulting in demand correspondence