Impact of a Low External Input Approach on Yields of Brackish Water Shrimp Ponds in Indonesia

In Indonesia, destruction of mangrove forest for ponds, ground-water extraction and climate change resulted in loss of land and yield' reductions. Farmers in Demak harvested 200 and 43 kg/ha/year of milkfish and shrimp, respectively. Demak's Building with Nature project uses Aquaculture Field Schools to train farmers in Low External Input and Sustainable Aquaculture (LEISA) that applies compost and a home-made organic fertiliser called MOL. Our team monitored the yield and others factors in three of the ten villages. Average yields of farmers applying MOL and cultivating both milkfish and shrimp increased to about 700 kg/ha and 260 kg/ha, respectively. Farmers having small multi-species ponds made 3 times higher operational cost and reached slightly lower gross margins than those with larger. LEISA increased cost and lead to slightly higher yields, but because most farmers applying MOL successfully stocked shrimp their income was almost double: 11.3 compared to 22 million IDR/ha/yr.