2017 年 6 巻 2 号 p. 325-338
Cropping intensification in rainfed rice-based farming systems through multiple cropping after the rice harvest by using residual soil moisture and supplemental irrigation offers a way to increase agricultural productivity and boost rural incomes in Northeast Thailand. This study identifies localities, planted areas, types of crops, and number of households growing crops after rainfed rice in Khon Kaen Province; it also analyzes some of the physical and social factors associated with the occurrence of this system. A questionnaire survey was conducted in 2013 of 198 agricultural extension officers in each subdistrict (tambol) in the province to collect data on multiple cropping. An area of 10,384 ha (2.9% of the total rainfed rice area) was used for multiple cropping by 16,184 households (10.9% of all rainfed rice farming households). Both field crops (e.g., cassava, crotalaria, field corn) and vegetables (e.g., sweet corn, watermelon, Chinese radish) were grown. These crops generated USD414–49,072 per hectare per crop for a total revenue of USD32 million, which is three times higher than the value of rice grown in the same field area. However, the area that can be utilized for multiple cropping in different subdistricts may be limited by physical conditions, including availability of irrigation sources and soil texture, as well as social and economic factors such as availability of markets, institutional support, and farmer skills.
