Economic Benefits of Using SOI Phase Information for Crop Management Decision in Rice-Base Farming System of West Java, Indonesia

Abstract

Variability of dry season rainfall in Indonesia is strongly influenced by the El-Nino- Southern Oscillation (ENSO) phenomenon. In ENSO ‘warm event’ (El-Niño) years, for most cases the dry season starts earlier and the rainfall amount is often substantially reduced. Under this condition most of second rice crops will suffer from drought. Based on historical rainfall data in the study areas, i.e. Ciparay and Bojongsoang subdistricts, when SOI phase prior to this season was constantly negative (phase 1) or rapidly falling (phase 3), the chance of having rainfall far below normal in this season would increase. Keeping planting rice in this season when rainfall far below normal would result in increasing production risk. Therefore, the use SOI phase information prior to the season would be useful for assisting farmers in making a satisfactory planting decision. The results of this study indicates that farmers who switch their crop to soybean or maize for May planting if April SOI Phase is 1 or 3 will get a higher income compared to farmers that keep planting rice. Cumulatively, over 24 years, the net income difference between farmers that use April SOI Phase information in deciding a crop type for May planting and those that do not is about 2000 USD at Ciparay and 2500 USD at Bojongsoang if they chose soybean as the second crops, and about 1000 and 1500 USD respectively if they chose maize. Farmers who choose not to plant a second crop will accrue a lower income than those that plant the crops. Furthermore, farmers who decide not to plant a second crop in April if March SOI Phase is 1 or 3 will get a much lower income compared to farmers who plant the second crops. This outcome suggests that the decision to planting or not to plant a second crop in May is more crucial than in April. Farmers who make what appears to be a proper decision for May planting based on April SOI Phase will, in the long term get consistently a much higher benefit than farmers who keep planting rice irrespective of the April SOI Phase.