Assessment of the aquaculture subsystem in integrated agriculture-aquaculture systems in Northeast Thailand

A survey of integrated agriculture-aquaculture systems (IAAS) was carried out in four different agroecologies. an irrigated and three rainfed agroecologies (drought-prone. rainfed lowland and rolling land), in Northeast region of Thailand, of tropical wet:dry climate. Fish culture system of IAAS varied with agroecology but not with the length of farmers' experience in IAAS farming. The size of pond holdings in the rainfed lowland agroecology was estimated to be significantly smaller (P less than or equal to 0.05) than in the three other agroecologies. The highest average extrapolated gross fish yield of 2.3 tonnes ha(-1) was recorded in the irrigated agroecology and this was significantly higher (P less than or equal to 0.01) than in the three rainfed agroecologies: drought-prone (1.1 tonnes ha(-1)). rainfed lowland (0.5 tonnes ha(-1)) and rolling land (0.4 tonnes ha(-1)). Higher fish yield in the irrigated agroecology was associated with longer stocking period and higher amount of pond inputs. Average income of IAAS households from fish also varied across agroecology in a fashion that was noted for yields. However, the farm pond played a pivotal role in the diversification of the farming system in rainfed agroecologies, as it was essentially the only source of water supply for fruit and vegetables production. While fish culture in all agroecologies was a low-input system, intensification through fertilization of ponds with chemical fertilizers can be envisaged to increase fish production in IAAS in Northeast Thailand.