<p>This study captures the structural transformation in crop composition in Chumphon Province in southern Thailand at the macro (province) and micro (farm household/plot) levels. Based on the decomposition of crop production value growth into the effects of price, productivity, area reallocation between crops, and enlargement of the total area, production at the province level has been found to be driven by price and productivity effects for the past two decades. This raises the question of how farmers obtain crop price or technical information for crop choice decisions. In our original survey, farm or plot-level crop diversification was studied in villages where coffee production was historically active. We found that the capacity for diversification differs according to farm scale, and information use regarding crop price or farming practices is highly dependent on informal social networks. Furthermore, the role of social relationships in information sharing on price and farming practices of a specific crop is important even for farmers who do not produce that crop, suggesting that social relationships are the effective channel for the promotion of crop diversification and sustainable farming practices</p>